tag:theconversation.com,2011:/uk/topics/light-pollution-8609/articlesLight pollution – The Conversation2024-02-08T19:17:30Ztag:theconversation.com,2011:article/2223902024-02-08T19:17:30Z2024-02-08T19:17:30ZHarry Potter and the Disenchanted Wildlife: how light and sound shows can harm nocturnal animals<p>Light and sound shows in parks can enthral crowds with their colour, music and storytelling. Lasting for weeks to months, the shows provide entertainment and can boost local economies. But unless they are well-located, the shows can also harm wildlife.</p>
<p>A planned production at a wildlife sanctuary in outer Melbourne has brought these concerns to the fore. In April and May this year, a wildlife reserve on the Mornington Peninsula will host <a href="https://hpforbiddenforestexperience.com/melbourne/#location">Harry Potter: A Forbidden Forest Experience</a>. The event involves a two-kilometre night walk where, according to organisers, characters from the film are “brought to life”.</p>
<p>The event has prompted an <a href="https://www.savebriarssanctuary.com/">outcry</a> from people worried about the effect on the reserve’s vulnerable wildlife. The sanctuary, known as The Briars, is <a href="https://biocache.ala.org.au/explore/your-area#-38.2695%7C145.0465%7C14%7CAnimals">home to</a> native animals <a href="https://ebird.org/hotspot/L2294907">including</a> powerful and boobook owls, owlet-nightjars, koalas, wallabies, Krefft’s gliders, <a href="https://biocache.ala.org.au/explore/your-area#-38.2695%7C145.0465%7C14%7CReptiles">lizards</a>, <a href="https://biocache.ala.org.au/explore/your-area#-38.2695%7C145.0465%7C14%7CAmphibians">frogs</a>, moths and spiders. A <a href="https://www.change.org/p/urge-mornington-peninsula-shire-to-relocate-the-harry-potter-forbidden-forest-experience">petition</a> calling for the event to be relocated has attracted more than 21,000 signatures.</p>
<p>Research shows artificial light, sound and the presence of lots of people at night can harm wildlife. It’s not hard to see why. Imagine if a music and light show, and thousands of people, turned up at your house every night for weeks on end. How would you feel?</p>
<h2>A history of community opposition</h2>
<p>In addition to the lights and sounds, these shows can involve artificial smoke and animated sculptures. While they often take place along existing walking trails, they attract huge crowds at a time when animals usually have the place to themselves.</p>
<p>Most of Australia’s mammals and frogs and many bird and reptile species are nocturnal, or active at night. They have adapted to the natural darkness, sounds and smells of the night.</p>
<p>The Harry Potter experience planned for The Briars has taken place elsewhere around the world, including at a nature area near the Belgian capital of Brussels. That event, in February last year, was also <a href="https://www.brusselstimes.com/325125/belgian-harry-potter-theme-park-draws-backlash-from-local-residents">opposed by locals</a> on ecological grounds. Belgian Minister for Nature Zuhal Demir has <a href="https://www.brusselstimes.com/363616/no-repeat-flanders-says-evanesco-to-harry-potter-event">reportedly</a> said the show would not return this year due to concern for wildlife.</p>
<p>Light shows proposed for other wildlife conservation areas have also faced community opposition. In Australia, there were calls to halt the <a href="https://www.theguardian.com/environment/2016/sep/16/calls-to-halt-nt-light-festival-over-fears-for-vulnerable-rock-wallaby">Parrtjima</a> light festival in the Alice Springs Desert Park over potential harm to the threatened black-footed rock wallabies. The <a href="https://www.abc.net.au/news/2023-09-03/lumina-light-show-mount-coot-tha-wildlife-concerns/102804780">Lumina</a> light show proposed for Mount Coot-tha in Brisbane has also attracted concern for wildlife.</p>
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Read more:
<a href="https://theconversation.com/predators-prey-and-moonlight-singing-how-phases-of-the-moon-affect-native-wildlife-140556">Predators, prey and moonlight singing: how phases of the Moon affect native wildlife</a>
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<h2>Light, sounds, action!</h2>
<p>Research shows <a href="https://www.nature.com/articles/S41559-020-01322-x">artificial light</a> affects wildlife in many ways. For example, it can <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife_gVmenJh.pdf">change</a> their hormone levels, and the numbers and health of their offspring.</p>
<p>Light also interferes with the ability of many species to navigate. This can cause birds to become <a href="https://doi.org/10.1073/pnas.1708574114">disorientated</a> and <a href="https://www.jstor.org/stable/44973632">crash</a>. It can also prevent <a href="https://www.ecolsoc.org.au/?hottopic-entry=the-impacts-of-artificial-light-on-marine-turtles">baby turtles</a> from finding the sea. </p>
<p>Some animals will forgo <a href="https://doi.org/10.1111/1365-2664.12206">feeding</a> or <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/acv.12340">drinking</a> and <a href="https://doi.org/10.1139/z06-142">attracting mates</a>. Other animals will try to move to a darker location. In the Belgian case, locals claimed owls left the park to avoid the lights.</p>
<p>Studies of small mammals such as <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/acv.12635?campaign=wolearlyview">bats</a>, <a href="https://doi.org/10.1111/aec.12034">micro-bats</a>, <a href="https://www.nature.com/articles/s41598-023-37166-1">possums and bandicoots</a> have shown many will avoid using habitat that is artificially lit. When there is no alternative dark habitat, species forced to deal with bright conditions – whether natural or artificial – have been found to reduce their activity. </p>
<p>Conversely, some animals are attracted to light. Insects such as moths will cluster around the artificial light source, unable to leave. Some will become so exhausted they will <a href="https://doi.org/10.1111/1365-2664.12381">become easy prey</a>. </p>
<p>What’s more, human-caused <a href="https://www.frontiersin.org/articles/10.3389/fevo.2023.1130075/full">noise</a> also stresses animals and changes animal behaviour. It <a href="https://www.nature.com/articles/s41559-020-1135-4">masks the natural soundscape</a>, making it harder for animals to find mates or hear the calls of their young. It can also mean animals can’t hear predators or their prey.</p>
<p>When thousands of humans travel through an area they leave strong <a href="https://www.sciencedirect.com/science/article/pii/S0006320717314453">predator-like smells</a>. This can be <a href="https://peerj.com/articles/9104/">stressful</a> for wildlife. It can also <a href="https://www.nature.com/articles/s41559-020-1135-4">mask smells</a> vital for an animal’s <a href="https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2015.1053">survival</a>, such as that of food and predators.</p>
<h2>Long-term harm</h2>
<p>When faced with all this disruption, many nocturnal animals will hide until a site returns to normal, which in the case of light shows is often close to midnight. This cuts in half the time animals have to go about their life-sustaining activities and <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2206339119">exposes them to greater risks</a> when they do go out.</p>
<p>Light and sound shows are usually temporary – but can have major long-term impacts.</p>
<p>In species with low birth rates and short lifespans, a disturbance to breeding can be catastrophic. For example, males of the genus <a href="https://academic.oup.com/zoolinnean/article/186/2/553/5480676?login=true">Antechinus</a> (small marsupials) live long enough for just one <a href="https://link.springer.com/article/10.1007/s00360-007-0250-8">short breeding season</a>. If they are <a href="https://www.publish.csiro.au/zo/zo17041">disrupted</a>, there are no second chances.</p>
<p>The stress of human lights, sounds, smells and disturbance can shorten an animal’s <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2011.1291">life</a>. Stress can make them more prone to <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2011.1291">illness</a> and create <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife_gVmenJh.pdf">problems</a> with <a href="https://journals.biologists.com/jeb/article/221/6/jeb156893/20849/Hormonally-mediated-effects-of-artificial-light-at">sleeping</a>, <a href="https://doi.org/10.1016/j.envpol.2019.113883">reproduction</a>, development and growth that can last for <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159114000574">multiple generations</a>. </p>
<h2>Find a better location</h2>
<p>The Mornington Peninsula Shire Council has <a href="https://www.abc.net.au/news/2023-12-31/briars-wildlife-reserve-harry-potter-experience-petition/103275544">defended</a> the Harry Potter event, saying the placement of props, lights and sounds has been carefully considered.</p>
<p>Organisers may have minimised impacts where they can, but evidence suggests the impact on wildlife will still be extensive. </p>
<p>The sanctuary where the event will be held is <a href="https://www.mornpen.vic.gov.au/files/content/public/environment/the-briars/whats-on-at-the-briars/briars-dl-brochure-wildlife-sanctuary_v02_2020-1.pdf">billed as</a> “an ark – a place which nurtures, protects and celebrates the unique flora and fauna of the peninsula, now rare but not lost”. Deliberately locating a light and sound show at the reserve seems at odds with this mission.</p>
<p>Events such as this clearly affect wildlife. Finding genuinely suitable locations should be done with care – and should avoid wildlife conservation areas altogether.</p><img src="https://counter.theconversation.com/content/222390/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaana Dielenberg works for the Biodiversity Council. The Biodiversity Council was founded by 11 universities and receives support from The Ian Potter Foundation, The Ross Trust, Trawalla Foundation, The Rendere Trust, Isaacson Davis Foundation, Coniston Charitable Trust and Angela Whitbread. Jaana is employed by the University of Melbourne and is a Charles Darwin University Fellow.</span></em></p><p class="fine-print"><em><span>Euan Ritchie receives funding from the Australian Research Council and the Department of Energy, Environment, and Climate Action. Euan is a Councillor within the Biodiversity Council, and a member of the Ecological Society of Australia and the Australian Mammal Society.</span></em></p><p class="fine-print"><em><span>Therésa Jones receives funding from the Australian Research Council and is affiliated with NERAL (Network for Ecological Research on Artificial Light).</span></em></p><p class="fine-print"><em><span>Loren Fardell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A Harry Potter nightwalk experience at a wildlife sanctuary on the Mornington Peninsula has raised concern for wildlife. Evidence suggests the fears are well-founded.Jaana Dielenberg, University Fellow, Charles Darwin UniversityEuan Ritchie, Professor in Wildlife Ecology and Conservation, School of Life & Environmental Sciences, Deakin UniversityLoren Fardell, Research Fellow, The University of QueenslandTherésa Jones, Professor in Evolution and Behaviour, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2213872024-01-30T16:01:27Z2024-01-30T16:01:27ZThe surprising reason why insects circle lights at night: They lose track of the sky<figure><img src="https://images.theconversation.com/files/571170/original/file-20240124-21-ynct7x.png?ixlib=rb-1.1.0&rect=30%2C20%2C6679%2C4446&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A multiple-exposure photograph of insects circling a light at night.</span> <span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>It’s an observation as old as humans gathering around campfires: Light at night can draw an erratically circling crowd of insects. In art, music and literature, this spectacle is an enduring metaphor for <a href="https://roundglasssustain.com/wildvaults/moths">dangerous but irresistible attractions</a>. And watching their frenetic movements really gives the sense that something is wrong – that instead of finding food and evading predators, these nocturnal pilots are trapped by a light.</p>
<p>Sadly, centuries of witnessing what happens have produced little certainty about why it happens. How does a simple light change fast, precise navigators into helpless, flittering captives? We are researchers examining <a href="https://scholar.google.co.uk/citations?user=wG5HGs8AAAAJ&hl=en">flight</a>, <a href="https://scholar.google.com/citations?user=4i4wRGgAAAAJ&hl=en">vision</a> and <a href="https://scholar.google.co.in/citations?user=X-j5RnwAAAAJ&hl=en">evolution</a>, and we have used high-speed tracking techniques in <a href="https://www.nature.com/articles/s41467-024-44785-3">newly published research</a> to provide an answer.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/FxNRDxlVyxk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The reason insects fly around light will surprise you.</span></figcaption>
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<h2>Moths to a flame?</h2>
<p>Many old explanations for this hypnotic behavior have not fully panned out. An early notion was that the insects might be attracted to the heat of a flame. This was interesting, as some insects really <a href="https://doi.org/10.1016/j.foreco.2022.120629">are pyrophilic</a>: They are attracted to fire and have evolved to take advantage of conditions in recently burned areas. But most insects around a light are not in this category, and cool lights attract them quite well. </p>
<p>Another thought was that insects were just directly attracted to light, a <a href="https://doi.org/10.1007/s13355-013-0219-x">response called phototaxis</a>. Many insects move toward light, perhaps as a way to escape dark or entrapping surroundings. But if this were the explanation for the clusters around a light, you might expect them to bump straight into the source. This theory does little to explain the wild circling behavior.</p>
<p>Still another idea was that insects might mistake a nearby light for the Moon, as they attempted to use <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">celestial navigation</a>. Many insects reference the Moon to keep their course at night.</p>
<p>This strategy relies on how objects at great distance seem to hover in place as you move along a straight path. A steady Moon indicates that you have not made any unintentional turns, as you might if you were buffeted by a gust of wind. Nearer objects, however, don’t appear to follow you in the sky but drift behind as you move past.</p>
<p>The celestial navigation theory held that insects worked to keep this light source steady, turning sharply in a failed attempt to fly straight. An elegant idea, but this model predicts that many flights will spiral inward to a collision, which doesn’t usually match the orbits we see. So what’s really going on?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several cameras face a bright light on a stand in a forest setting at night." src="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists used high-speed stereo motion capture to document how the presence of artificial light at night affects insects’ flight behavior.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<h2>Turning their backs to the light</h2>
<p>To examine this question in detail, we and our colleagues captured high-speed videos of insects around different light sources to precisely determine flight paths and body postures, both in the lab at <a href="https://www.imperial.ac.uk">Imperial College London</a> and at two field sites in Costa Rica, <a href="https://www.ciee.org/go-abroad/college-study-abroad/locations/costa-rica/monteverde">CIEE</a> and the <a href="https://www.estacionbiologica.com/">Estación Biológica</a>. We found that their flight patterns weren’t a close match for any existing model. </p>
<p>Rather, a broad swath of insects consistently pointed their backs toward the lights. This is a known behavior called the <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">dorsal light response</a>. In nature, assuming that more light comes down from the sky than up from the ground, this response helps keep insects in the proper orientation to fly.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qECYfEN70qs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Artificial light at night interrupts the normal flight patterns of insects. This compilation video shows an orbiting behavioral motif in which insects circle the light.</span></figcaption>
</figure>
<p>But pointing their backs toward nearby artificial lights alters their flight paths. Just as airplanes bank to turn, sometimes rolling until the ground seems nearly straight out your window, banking insects turn as well. When their backs orient to a nearby light, the resulting bank loops them around the light, circling but rarely colliding. </p>
<p>These orbiting paths were only one of the behaviors we observed. When insects flew directly under a light, they often arched upward as it passed behind them, keeping their backs to the bulb until, eventually flying straight up, they stalled and fell out of the air. And even more compelling, when flying directly over a light, insects tended to flip upside down, again turning their backs to the light but then abruptly crashing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagrams show insects rolling vertically or horizontally or inverting in the presence of artificial light." src="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three different observed turning behaviors in which flying insects turn their backs to artificial light.</span>
<span class="attribution"><span class="source">Jamie Theobald</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why have a dorsal light response?</h2>
<p>Although light at night can harm <a href="https://www.jstor.org/stable/43597777">other animals</a> – for example, by <a href="https://doi.org/10.1073/pnas.1708574114">diverting migrating birds into urban areas</a> – larger animals don’t seem to lose their vertical orientation. So why do insects, the oldest and most species-rich group of flyers, rely on a response that leaves them so vulnerable?</p>
<p>It may have to do with their small size. Larger animals can sense gravity directly with sensory organs pulled by its acceleration, or any acceleration. Humans, for example, use the <a href="https://www.ncbi.nlm.nih.gov/books/NBK279394/">vestibular system of our inner ear</a>, which regulates our sense of balance and usually gives us a good sense of which way is down.</p>
<p>But insects have only small sensory structures. And especially as they perform rapid flight maneuvers, acceleration offers only a poor indication of which way is down. Instead, they seem to bet on the brightness of the sky. </p>
<p>Before modern lighting, the sky was usually brighter than the ground, day or night, so it provided a fairly reliable cue for a small active flyer hoping to keep a steady orientation. The artificial lights that sabotage this ability, by cueing insects to fly in circles, are relatively recent. </p>
<h2>The growing problem of nighttime lighting</h2>
<p>As new technology spreads, lights that pervade the night are <a href="https://doi.org/10.3390/rs13163311">proliferating faster then ever</a>. With the introduction of cheap, bright, <a href="https://www.energy.gov/eere/ssl/led-basics">broad-spectrum LEDs</a>, many areas, such as large cities, never see a dark night.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A view upward through treetops to a starry dark sky, with a bright light at the top of the screen from a light bulb near the ground." src="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This upward view at the authors’ field research site in Monteverde, Costa Rica, shows how artificial light competes with the night sky.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Insects aren’t the only creatures affected. Light pollution disrupts circadian rhythms and physiological processes in other <a href="https://darksky.org/resources/what-is-light-pollution/effects/wildlife-ecosystems/">animals, plants</a> and <a href="https://darksky.org/resources/what-is-light-pollution/effects/human-health/">humans</a>, often with <a href="https://theconversation.com/new-atlas-shows-extent-of-light-pollution-what-does-it-mean-for-our-health-60836">serious health consequences</a></p>
<p>But insects trapped around a light seem to get the worst of it. Unable to secure food, easily spotted by predators and prone to exhaustion, many die before the morning comes.</p>
<p>In principle, light pollution is one of the easiest things to fix, often by just <a href="https://www.youtube.com/watch?v=EfhuU5Ceo_w">flipping a switch</a>. <a href="https://darksky.org/what-we-do/advancing-responsible-outdoor-lighting/">Restricting outdoor lighting</a> to useful, targeted warm light, no brighter than necessary, and for no longer than necessary, can greatly improve the health of nocturnal ecosystems. And the same practices that are good for insects help restore views of the night sky: Over one-third of the world population lives in areas where the <a href="http://dx.doi.org/10.1126/sciadv.1600377">Milky Way is never visible</a>. </p>
<p>Although insects circling around a light are a fascinating spectacle, it is certainly better for the insects and the <a href="https://www.si.edu/spotlight/buginfo/benefits">benefits they provide to humans</a> when we leave the night unlit and let them go about the activities they so masterfully perform under the night sky.</p><img src="https://counter.theconversation.com/content/221387/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samuel Fabian receives funding from the European Research Council and a National Geographic Explorer Grant.</span></em></p><p class="fine-print"><em><span>Jamie Theobald receives funding from the National Science Foundation and the U.S. Air Force Office of Scientific Research.</span></em></p><p class="fine-print"><em><span>Yash Sondhi receives funding from the Florida International University Graduate School, the Susan Levine Foundation, a National Geographic Explorer Grant, the American Philosophical Society, and the Kimberly-Green Latin-American and Caribbean Center.</span></em></p>A new study shows how artificial light at night scrambles insects’ normal flight patterns, pulling them off course into orbit around the light.Samuel Fabian, Postdoctoral Research Associate in Bioengineering, Imperial College LondonJamie Theobald, Associate Professor of Biological Sciences, Florida International UniversityYash Sondhi, Postdoctoral Research Associate in Entomology, Mcguire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2194642023-12-14T13:12:30Z2023-12-14T13:12:30ZArtificial light lures migrating birds into cities, where they face a gauntlet of threats<figure><img src="https://images.theconversation.com/files/565500/original/file-20231213-21-30h0uo.jpg?ixlib=rb-1.1.0&rect=33%2C33%2C7315%2C4869&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The New York City borough of Manhattan at night, viewed from the Rockefeller Center observation deck.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/manhattan-skyline-with-view-to-empire-state-building-from-news-photo/1749117051">Sergi Reboredo/VW Pics/Universal Images Group via Getty Images</a></span></figcaption></figure><p>Light pollution has steadily intensified and expanded from urban areas, and with the <a href="https://doi.org/10.1582/LEUKOS.2010.06.04001">advent of LED lighting</a>, it is growing in North America by <a href="http://dx.doi.org/10.1126/science.abq7781">up to 10% per year</a>, as measured by the visibility of stars in the night sky. In our <a href="https://doi.org/10.1038/s41467-023-43046-z">recent study</a>, we found that the glow from cities and urban outskirts can powerfully attract migratory birds, drawing them into developed areas where food is scarcer and they face threats such as colliding with glass buildings.</p>
<p>Each spring and fall, migratory birds journey to or from their breeding grounds, <a href="https://www.allaboutbirds.org/guide/Bobolink/maps-range">sometimes traveling thousands of miles</a>. En route, most birds need to <a href="http://dx.doi.org/10.1111/ele.13618">make stopovers</a> to rest and feed. Some species burn off half of their body mass during migration.</p>
<p>Migratory stopover sites are not random, and birds typically use the same locations from year to year. Because migration takes place on a continental scale, with <a href="https://abcbirds.org/blog/north-american-bird-flyways/">billions of birds crossing North America</a> each migratory season, it’s important for scientists to understand what attracts birds to these locations. </p>
<p>We found that light pollution was a top predictor of the density of migrating birds at stopover locations for both spring and fall migration across the continental U.S.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/H6Avo9T45xk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Artificial light at night is an expanding threat to migrating birds, drawing them into developed areas where they can die from collisions with buildings and are exposed to other threats.</span></figcaption>
</figure>
<h2>Why it Matters</h2>
<p>Nearly all birds in North America – some 80% – migrate each spring and fall. And of those species that migrate, <a href="https://doi.org/10.1002/fee.2029">70% travel at night</a>. </p>
<p>Nocturnal migration has many adaptive benefits: For example, the weather conditions are better, and fewer predators are active. But it makes most migratory birds highly susceptible to light pollution. In North America alone, it is estimated that up to 1 billion migrating birds <a href="https://doi.org/10.1650/CONDOR-13-090.1">die each year from collisions with buildings</a>. </p>
<p>Scientists don’t yet know why nocturnally migrating birds are attracted to artificial light, but research has shown that light pollution <a href="https://doi.org/10.1016/j.tree.2022.12.006">acts as an amplifying agent</a> that draws more songbirds into urbanized areas. It often <a href="https://doi.org/10.1111/geb.13466">co-occurs with other environmental threats</a>, such as water and air pollution and noise. All of these stressors disrupt birds’ behavioral and physiological processes during journeys that already are extremely taxing.</p>
<p>Lighting is part of the fabric of human structures, yet many people don’t think of it as a pollutant or perceive its harmful effects on nature – until events like the <a href="https://chicago.suntimes.com/2023/10/6/23906778/birds-killed-migration-collision-mccormick-place-lakeside-center">mass bird loss in Chicago</a> on Oct. 4-5, 2023, when nearly 1,000 birds were killed after colliding with the McCormick Place Convention Center, make the problem impossible to ignore.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black bird with an orange underside perches on a branch next to half an orange placed there for feeding." src="https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=445&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=445&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=445&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=560&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=560&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565502/original/file-20231213-15-ti0ti3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=560&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Baltimore orioles migrate twice yearly between their wintering grounds in Florida, the Caribbean and Latin America and their summer breeding zones, which stretch from Louisiana into central Canada.</span>
<span class="attribution"><span class="source">Kyle Horton</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>How we did our work</h2>
<p>With colleagues at Colorado State University, Michigan State University, the University of Delaware, the Cornell Lab of Ornithology, Princeton University, the University of Massachusetts Amherst and the National Park Service, we sought to understand the complex drivers and large-scale patterns of stopover density by combining remote sensing data with geospatial tools. Mapping stopover locations has been a bird conservation priority for many years; now, for the first time, we have a complete view of where these stopovers are across the United States.</p>
<p>We were able to make novel maps at a continental scale using <a href="https://www.ncei.noaa.gov/products/radar/next-generation-weather-radar">U.S. NEXRAD weather surveillance data</a> – information from the same radars that meteorologists draw on to predict weather patterns on television and weather apps. We created 2,500 models using roughly 1 million locations across the U.S. and 49 predictor variables, including forest cover, precipitation, temperature, elevation and <a href="https://www.energy.gov/eere/ssl/text-alternative-version-what-sky-glow">skyglow</a> – diffuse brightness in the night sky from artificial light.</p>
<p>These maps capture fine-scale details that allow us to see increased densities of migrating birds following the winding banks of the Mississippi River, which provide an important refuge for depleted migrants to rest and refuel. We also created fall and spring hotspot maps highlighting regions where especially high numbers of birds made stopovers. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radar imagery showing masses of light and dark blue above a map of St. Louis." src="https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565636/original/file-20231213-21-au4a3l.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radar detecting migrating birds lifting off from the St. Louis landscape on the night of May 10, 2023. Density of bird flocks increases from light blue to dark blue to green.</span>
<span class="attribution"><span class="source">Kyle Horton</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We found that the presence of light pollution was a better predictor of bird densities than temperature, precipitation or tree canopy cover. These all were variables that we had expected to correlate with periods when birds would be on the ground, or with high-quality habitats where birds would be likely to stop over. </p>
<p>Other variables were associated with areas that birds were unlikely to use as stopovers. One example was the presence of agricultural crops, such as corn or soybeans. Fields planted with a single crop <a href="https://doi.org/10.1073/pnas.2203511120">don’t provide adequate food or shelter for many bird species</a>, so migrants are unlikely to rest there.</p>
<p>Light pollution is a human-induced change to the environment that may act as an <a href="https://doi.org/10.1016/j.cois.2021.02.004">ecological trap</a>, drawing birds into substandard habitats and increasing their risk of collisions with buildings. Happily, its immediate effects can be quickly reversed with the flip of a switch. </p>
<p>Working to reduce artificial light through <a href="https://tx.audubon.org/urbanconservation/lights-out-texas">Lights Out campaigns</a> and <a href="https://aeroecolab.com/uslights">migration alerts</a>, <a href="http://dx.doi.org/10.1111/cobi.13740">understanding when birds will be in airspaces</a> and <a href="https://www.audubon.org/bird-friendly-buildings">using bird-friendly glass</a> that has patterns across its surface to make it more visible to birds, will reduce bird deaths from light pollution. Understanding the drivers and macro-scale patterns of stopover densities across the continental U.S. will better inform conservation actions like these. </p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take on interesting academic work.</em></p><img src="https://counter.theconversation.com/content/219464/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyle Horton receives funding from the National Science Foundation and the National Aeronautics and Space Administration. </span></em></p><p class="fine-print"><em><span>Carolyn S. Burt does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Migrating birds need stopover locations en route where they can rest and feed. A new study shows that artificial light draws them away from sites they would normally use and into risky zones.Carolyn S. Burt, Convergence Research Coordinator, Department of Fish, Wildlife, and Conservation Biology, Colorado State UniversityKyle Horton, Assistant Professor of Fish, Wildlife, and Conservation Biology, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189312023-12-11T19:02:41Z2023-12-11T19:02:41Z8 ways to tone down the Christmas lights to help wildlife – and why we should<figure><img src="https://images.theconversation.com/files/563148/original/file-20231204-17-esyf9q.jpg?ixlib=rb-1.1.0&rect=32%2C5%2C3551%2C2018&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Christmas_lights_galore.jpg">Agnostic Preachers Kid/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The Australian government has launched a campaign asking people to “<a href="https://www.dcceew.gov.au/campaign/light-pollution">switch off light pollution” to protect wildlife</a>. So, what does the science say? Should we rethink Christmas lights? </p>
<p>In <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife.pdf">our latest report</a>, we reviewed research into the effects of artificial light at night on mammals, frogs, birds and reptiles. We found artificial lights cause problems for a wide range of species, and energy-efficient <a href="https://www.pnas.org/doi/10.1073/pnas.2309539120">LED lights</a> often <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jez.2163">make matters worse</a>. </p>
<p>Most people don’t realise their outdoor lights can harm wildlife. <a href="https://digitalcommons.usu.edu/hwi/vol16/iss1/12/">At Christmas the problem grows</a> because many people put up more decorative lights. </p>
<p>Here we offer eight easy ways to reduce light pollution at Christmas while still showing your festive spirit.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VAJf3iWqJo0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Bright flashing Christmas lights make our gardens stressful for wildlife (The Biodiversity Council)</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/getting-smarter-about-city-lights-is-good-for-us-and-nature-too-69556">Getting smarter about city lights is good for us and nature too</a>
</strong>
</em>
</p>
<hr>
<h2>Easy ways to help</h2>
<p>These eight <a href="https://darksky.org/resources/guides-and-how-tos/lighting-principles/">simple actions</a> will help you support local wildlife while also enjoying festive decorations. Most will save electricity too. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A big red bow on a tree in front of a house" src="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563520/original/file-20231205-17-pubb03.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Daytime decorations are a great way to be festive without contributing to light pollution.</span>
<span class="attribution"><span class="source">Jaana Dielenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<ol>
<li><p>Switch to daytime decorations such as big red bows on trees. Better still, plant a <a href="https://flowerhub.com.au/eduhub/article/7-Native-Australian-Flowers-Associated-with-Christmas">garden with festive colour</a>. Bottlebrush, woolly bush, Christmas bush and Christmas bells are all gorgeous native Australian plants that bloom brightly over Christmas.</p></li>
<li><p>Instead of covering your house and fence, which can also trap animals and block their movement, make your decorative lights window displays. At bedtime, close your curtains so indoor lights cannot disturb either sleeping or active animals outside.</p></li>
<li><p>Don’t leave lights on all night. Pick a short period, and avoid dusk or dawn when animals can be most active. Timers are helpful.</p></li>
<li><p>Instead of bright white or blue lights, use warm colours such as amber or red, as they are less harmful to wildlife. </p></li>
<li><p>Use low-intensity lights – they are supposed to look pretty, not light up a surgery.</p></li>
<li><p>When using spotlights, keep them angled downward and focused on where you need them. Use shields to stop light shining into the sky or nearby vegetation.</p></li>
<li><p>Leave your trees and shrubs as dark refuges for nocturnal wildlife – don’t load them up with lights.</p></li>
<li><p>Camping or travelling? Minimising your light pollution is a great way to help animals in the bush and along the coast. Thousands of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110114">young seabirds</a> and <a href="https://www.dcceew.gov.au/campaign/light-pollution/turtles">baby turtles</a> die on their first trip because artificial lights attract them and cause them to move in the wrong direction. </p></li>
</ol>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bright red botttlebrush flowers against a blue sky" src="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563519/original/file-20231205-27-dxt5r6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plants like bottlebrushes and Christmas bells can add a festive feel to gardens.</span>
<span class="attribution"><span class="source">Zeynel Cebeci/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bright-city-lights-are-keeping-ocean-predators-awake-and-hungry-68965">Bright city lights are keeping ocean predators awake and hungry</a>
</strong>
</em>
</p>
<hr>
<h2>Why get involved?</h2>
<p>Research in Australia and overseas has found artificial light at night has a <a href="https://biodiversitycouncil.org.au/media/uploads/2023_12/biodiversity_council_2023_impacts_of_artificial_light_on_wildlife.pdf">wide range of harmful effects</a> on many types of animals, from making them <a href="https://www.sciencedirect.com/science/article/pii/S0269749121003559">stressed</a> and <a href="https://digitalcommons.usu.edu/hwi/vol16/iss1/12/">more vulnerable to predators</a>, to changing their <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0085069">reproduction</a> and making migrating birds more likely to <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2101666118">crash into windows</a>. </p>
<p>It’s such a significant issue for our wildlife that the Australian government launched the “<a href="https://www.dcceew.gov.au/campaign/light-pollution/mammals">Let’s switch off light pollution</a>” campaign in November.</p>
<p>You might not realise how <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.12404">important</a> your garden is to wildlife, because most of our mammals and frogs, and many birds and reptiles, are active at night and are great at hiding as they try to stay out of sight of predators. </p>
<p>Depending on where you live, your yard may be visited at night by <a href="https://www.environment.nsw.gov.au/get-involved/sydney-nature/wildlife/mammals-in-sydney">possums, bats, bettongs</a>, <a href="https://www.australiangeographic.com.au/topics/wildlife/2017/10/the-native-animals-youll-find-in-an-aussie-backyard/">bandicoots</a>, gliders, antechinus, echidnas, koalas, owls, tawny frogmouths, bush stone curlew, frogs, snakes, moths and geckos. </p>
<p>You can help these animals by minimising the amount of <a href="https://www.dcceew.gov.au/sites/default/files/documents/fs-light-pollution-guidelines.pdf">artificial light</a> you shine outdoors. </p>
<p>By stopping lights shining up into the sky or out into the distance, you can also help animals further away. <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1708574114">Migrating birds</a> flying high overhead, <a href="https://www.aims.gov.au/information-centre/news-and-stories/blinded-light-tracking-baby-sea-turtles">baby sea turtles</a> and even <a href="https://www.science.org/content/article/blinding-nemo-artificial-lights-prevent-clownfish-eggs-hatching#:%7E:text=Experiment%20suggests%20light%20pollution%20threatens%20sea%20creatures&text=The%20experiment%20included%2010%20clownfish,them%20hatched%2C%20National%20Geographic%20reports.">fish</a> in the coast can be disturbed by artificial <a href="https://link.springer.com/article/10.1007/s11252-021-01149-9">sky glow</a>, which they <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017307">see from far away</a>. </p>
<p>Unfortunately, increasingly common energy-efficient <a href="https://www.pnas.org/doi/10.1073/pnas.2309539120">LED lights</a> appear to have <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/jez.2163">greater impacts</a> on many animal species <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12758">than other lighting types</a> because they are rich in short-wavelength white and blue light. That means minimising the amount of scattered light has become more important than ever. </p>
<p>Blue light at night is a <a href="https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side">problem for humans too</a> and can make it hard to sleep, which is why many mobile phones have a night-light setting that reduces blue light and makes the phone glow appear orange-tinted. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large tree covered in fairy lights at night" src="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563523/original/file-20231205-21-aco7ia.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Trees provide vital habitat for wildlife, but when they are lit like this few animals can use them.</span>
<span class="attribution"><span class="source">Mick Haupt/Unsplash</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/yes-the-state-of-the-environment-is-grim-but-you-can-make-a-difference-right-in-your-own-neighbourhoood-187259">Yes, the state of the environment is grim, but you can make a difference, right in your own neighbourhoood</a>
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</em>
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<hr>
<h2>Your lighting choices make a difference</h2>
<p>At Christmas and year-round, minimising light pollution is a great way to help wildlife. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563518/original/file-20231205-17-3fl8q5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bandicoots occur in many urban areas around Australia. Artificial lighting disturbs the bandicoot’s vision and makes them more visible to predators.</span>
<span class="attribution"><span class="source">Mark Gillow/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Light pollution is not the only problem facing our wildlife, but it can make it much harder for animals to survive other pressures. </p>
<p>For some species, such as <a href="https://www.jstor.org/stable/44973632">seabirds</a>, light pollution is one of the biggest threats to their survival. </p>
<p>Even though urban areas are already <a href="https://www.science.org/doi/full/10.1126/sciadv.1600377">bright at night</a>, your <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2101666118">actions still make a difference</a>. </p>
<p>Like other types of pollution such as carbon emissions, <a href="https://darksky.org/news/light-is-energy-estimating-the-impact-of-light-pollution-on-climate-change/">light pollution adds up</a>. This means every <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110114">light you can turn off</a>, turn down or stop pointing into nature helps. If many people get involved, the difference we can make will be enormous. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/artificial-light-at-night-can-change-the-behaviour-of-all-animals-not-just-humans-183028">Artificial light at night can change the behaviour of all animals, not just humans</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/218931/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaana Dielenberg works for the Biodiversity Council. The Biodiversity Council was founded by 11 universities and receives support from The Ian Potter Foundation, The Ross Trust, Trawalla Foundation, The Rendere Trust, Isaacson Davis Foundation, Coniston Charitable Trust and Angela Whitbread. Jaana is employed by The University of Melbourne and is a Charles Darwin University Fellow.</span></em></p><p class="fine-print"><em><span>Sarah Bekessy receives funding from the Australian Research Council, the National Health and Medical Research Council, the Ian Potter Foundation and the European Commission. She is a lead councillor of the Biodiversity Council, a board member of Bush Heritage Australia, a member of WWF's Eminent Scientists Group and a member of the Advisory Group for Wood for Good.</span></em></p><p class="fine-print"><em><span>Loren Fardell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new report from the Biodiversity Council reveals the disturbing effects of artificial light on
Australia’s nocturnal animals. Here’s how you can help wildlife at Christmas and all year round.Jaana Dielenberg, University Fellow, Charles Darwin UniversityLoren Fardell, Research Fellow, The University of QueenslandSarah Bekessy, Professor in Sustainability and Urban Planning, Leader, Interdisciplinary Conservation Science Research Group (ICON Science), RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145042023-10-11T16:28:21Z2023-10-11T16:28:21ZSleepless cities: how urban noise and light keep us up at night<figure><img src="https://images.theconversation.com/files/550599/original/file-20230913-15-jd0c8a.jpg?ixlib=rb-1.1.0&rect=126%2C0%2C3799%2C2922&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/woman-lies-bed-covers-her-head-2151060329">My July/Shutterstock</a></span></figcaption></figure><p>Living in cities that never sleep has its price: inhabitants are getting less, worse quality, sleep. We cannot forget that sleep, though often undervalued, is a fundamental part of staying in good health. It is well established that if <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8194472/">we don’t get enough, we end up getting sick</a>.</p>
<p>But how much is enough? It depends on age, but a healthy adult needs, on average, <a href="https://sleepeducation.org/sleep-faqs/#:%7E:text=Children%201%20to%202%20years,24%20hours%20(including%20naps).&text=Children%203%20to%205%20years,24%20hours%20(including%20naps).&text=Children%206%20to%2012%20years,12%20hours%20per%2024%20hours.&text=Teenagers%2013%20to%2018%20years,10%20hours%20per%2024%20hours">7 to 9 hours per day</a>. The number is more for children, who might need anything from 9 to 16 hours per day.</p>
<p>Another question is when we should sleep. Since we are diurnal animals, we sleep at night. There are variations, of course, due to what are known as different <a href="https://pubmed.ncbi.nlm.nih.gov/36868368/">chronotypes</a>. Some of us are night owls, who tend to go to bed later and get up later, while others are larks, preferring to get up earlier and go to bed earlier. </p>
<p>Despite individual differences, the night is generally the time our bodies reserve for sleep. Over millions of years we have evolved to organise our physiological processes according to altering states of light and darkness. However, our nights have changed enormously in just a century and a half thanks to the widespread use of electric light. Now, in most built up areas, the night is no longer dark. Light has allowed humans, whose eyes are adapted to daylight, to colonise the night by getting rid of darkness and, as a consequence, extend our activity period well into the small hours. </p>
<h2>Light keeps us up at night</h2>
<p>Artificial light is considered to be, in and of itself, <a href="https://theconversation.com/contaminacion-luminica-por-que-la-falta-de-oscuridad-nos-sale-tan-cara-187370">a form of pollution</a>, bringing with it a range of health problems. Primarily, it makes us sleep less. There are now studies showing that, among <a href="https://pubmed.ncbi.nlm.nih.gov/31627155/">adults</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/35461841/">elderly people</a>, the higher the level of artificial light during the night, the less they sleep. It has also been observed that artificial light at night –both inside and outside the home– can <a href="https://pubmed.ncbi.nlm.nih.gov/36228789/">increase sleep problems by 22%</a>. Artificial light is the enemy of sleep because it confuses the internal clock that regulates it: it tells us that it is daytime and that it is not time to go to bed yet.</p>
<p>Light pollution not only reduces the hours of sleep that we get (which is bad enough in itself), but too much artificial light at night may also have <a href="https://www.tandfonline.com/doi/abs/10.1080/09291016.2022.2151763?journalCode=nbrr20">other serious health consequences</a>. These include an increased likelihood of cardiovascular and metabolic conditions (obesity or diabetes), mental health disorders, and even some types of cancer, such as breast, prostate or colon cancer. Controlled laboratory studies leave no doubt as to the harmfulness of artificial light at night. </p>
<p>However, in clinical terms there is some <a href="https://www.sciencedirect.com/science/article/abs/pii/S1001074222003291">dispute due to the inconsistency of the results</a>. This is due, above all, to so-called “confounding factors”: circumstances specific to the most well-lit areas that make it impossible to differentiate whether damage is done by night-time light or other factors.</p>
<h2>Traffic and nightlife</h2>
<p>One of these confounding factors is noise, another obstacle to a good night’s sleep. By colonising darkness with electric light, we have made nights noisy, depriving ourselves of the peace and quiet that we need to fall and stay asleep. Noise leaking into our homes at any time of day is bad for our health, regardless of whether it bothers us or not. But at night, it can also interfere with our sleep.</p>
<p>According to the European Environment Agency, prolonged exposure to background noise contributes to 48,000 new cases of heart disease and 12,000 premature deaths every year in Europe. Additionally, 22 million people suffer from chronically disrupted sleep, and 6.5 million suffer from major chronic sleep disorders. It has been calculated that <a href="https://www.who.int/publications/i/item/9789289002295">every year, one million years of healthy life are collectively lost due to the effects of noise</a>. Coronary heart disease and sleep disorders make up <a href="https://www.eea.europa.eu/highlights/number-of-europeans-exposed-to">the largest proportion of noise-related diseases</a>.</p>
<p>The negative consequences of traffic noise have been widely proven. However, in cities at night there are other significant sources of noise. One of the biggest is nightlife. In fact, noise maps are currently being made of several Spanish cities, although corrective measures to combat the problem thus far have, more often than not, fallen short.</p>
<p>What is more, the noise generated by nightlife is on the rise due to an increase in outdoor terrace seating in bars, much of it as a result of the COVID-19 pandemic. For example, <a href="https://www.lavanguardia.com/vida/20230228/8790860/terrazas-barcelona-superan-30-000-mesas-62-mas-2019.html">in Barcelona the number of outdoor tables has increased by 62% since 2019</a>, and <a href="https://www.eldiario.es/madrid/somos/noticias/madrid-suma-5-700-nuevas-mesas-terraza-durante-pandemia-mitad-aparcamientos_1_7951191.html">5,700 new tables have appeared in Madrid</a>, bringing the total to 60,912.</p>
<p>Street cleaning, often done at night or well into the early morning, is another factor. Somewhat ironically, we could say that nightly street cleaning impacts the cleaning effects that the <a href="https://pubmed.ncbi.nlm.nih.gov/25947369/">glymphatic system</a> has on our brains while we are sleeping.</p>
<h2>How can local authorities protect our sleep?</h2>
<p>Many of the barriers to a good night’s sleep could be remedied with greater awareness and empathy on the part of citizens. But we also need a suitable legal framework that is, above all, effectively enforced by local authorities. </p>
<p>As well as national noise regulations, there are municipal bylaws that regulate different causes of noise. But how can a town or city help its citizens to sleep better? To begin with, we must start from the premise that sleep, which is closely linked to health, should always take precedence over other activities such as nightlife. For this reason, some proposed measures would be:</p>
<ol>
<li><p>Place limits on the times when loud street cleaning equipment can be used. Even if a vehicle’s motor is electric and silent, water pumps are not. They should not be used at night. </p></li>
<li><p>Substitute noisy public transport vehicles for electric models, and ensure that private vehicles comply with regulations.</p></li>
<li><p>Reduce the timetables and number of tables at bars, cafes and restaurants in residential areas, informing managers and owners of the need to respect the rest needed by local residents. </p></li>
<li><p>Reduce the permitted volume in noisy premises (which is often harmful to the hearing of users as well as local residents) and avoid night-time opening in residential areas. This will not only avoid the transmission of noise through walls, but also large numbers of people accumulating outside.</p></li>
<li><p>Avoid organising live shows that create a lot of noise in areas close to people’s homes, especially at night.</p></li>
<li><p>Review the placement of streetlights and other sources of light to reduce overall levels of light pollution, especially that which enters homes through windows.</p></li>
</ol>
<p>Lastly, and most importantly, an understanding is needed –on both an institutional and individual level– that building a healthier society depends fundamentally on creating an environment that facilitates both our own sleep and that of our neighbours.</p><img src="https://counter.theconversation.com/content/214504/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>María Ángeles Bonmatí Carrión has received funding from the Séneca Foundation and the Ministry of Education and Science, as well as from the Ministry of Economy and Competitiveness, the Carlos III Health Institute through Ciberfes (CB16/10/00239), the Ministry of Science, Innovation and Universities, and the State Agency for Research through RTI2018-093528-B-I00 and Call H2020-Sc1-Bhc-2018-2020 (Grant Agreement 825546, Diabfrail-Latam), co-financed by the European Regional Development Fund (FEDER). She has recently been awarded a scholarship by the Spanish Sleep Society.</span></em></p>Too much light and noise at night in cities makes us sleep less and, as a consequence, worsens our health. Here are some of the measures that local authorities should take to remedy this problem.María Ángeles Bonmatí Carrión, Investigadora postdoctoral CIBERFES y profesora colaboradora UMU, Universidad de MurciaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2075142023-06-13T22:11:47Z2023-06-13T22:11:47ZLight pollution is taking the sparkle out of glow-worm mating<figure><img src="https://images.theconversation.com/files/531628/original/file-20230613-19-yocc54.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5283%2C3519&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Female glow-worms attract males with a chemical reaction in their abdomen.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-shot-lampyris-noctiluca-glowworm-on-2010347432">Wirestock Creators/Shutterstock</a></span></figcaption></figure><p>The invention of electric light has extended our lives deeper into the night: street lamps help us travel more safely outdoors, while lighting indoors lets us work and play for longer. Entire stadiums are drenched in light so that people can watch sport at night. Even your garden may be lit up to accentuate its finer features.</p>
<p>Light generated outside of the natural cycle of the sun and moon can have unwanted effects, however, and is actually a form of pollution. Like other kinds, light pollution can harm animals, particularly nocturnal ones. Some predators which would otherwise turn in for the day are instead now choosing to <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2012.0216">hunt after dusk</a> and disrupting entire food webs.</p>
<p>Artificial light at night can have particularly severe consequences for insects. For example, large numbers of moths distracted by the allure of street lighting were discovered to have been neglecting their nocturnal pollinating duties according to <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.13371">one study</a>, with potentially severe consequences for the wider ecosystem.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fatal-attraction-how-street-lights-prevent-moths-from-pollinating-60331">Fatal attraction: how street lights prevent moths from pollinating</a>
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</em>
</p>
<hr>
<p>How some insects are responding to the sudden brightening of their night-time habitat is still poorly understood. Common glow-worms (<em>Lampyris noctiluca</em>) are another nocturnal insect and they use bioluminescent signalling during mating. Female glow-worms stay put and use a chemical reaction to produce green bioluminescence in their abdomen, which attracts flying males.</p>
<p>Several <a href="https://doi.org/10.1242/jeb.229146">field studies</a> have shown that white light similar to that produced by modern LED street lighting can reduce the numbers of males that manage to find females. My research team and I wanted to find out what’s going on, so we brought <a href="https://journals.biologists.com/jeb/article/226/11/jeb245760/313487/Artificial-light-impairs-local-attraction-to">glow-worm mating into the lab</a>. </p>
<figure class="align-center ">
<img alt="A residential street with a row of lamp posts shining white light." src="https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531662/original/file-20230613-29-hngfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">White-light LEDS are replacing older lamps in many areas.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/small-residential-street-modern-led-lights-782091265">Milan Noga/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Wherefore art thou?</h2>
<p>We collected male glow-worms from a meadow near our laboratory. Back in the lab, we transferred each male to a Y-shaped maze in the dark. One arm of the maze contained a green LED that acted as a dummy female. Once the LED was turned on, males typically hurried towards the glow. We then switched on a light that mimicked artificial lighting at night and repeated the experiment. </p>
<p>In darkness, the males could easily find the dummy female. But at the dimmest level of white light we used, which is roughly equivalent to street lighting, just 70% of males found the green LED. This dropped to 21% at the brightest light levels, which equates to the lighting used to illuminate monuments in town squares and parks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A composite image of a glow-worm on wood in bright light and one of a green, luminous abdomen in the dark." src="https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531588/original/file-20230613-25-u9zbno.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Not so alluring: a female glow worm lit by a camera flash (left) and in the dark (right).</span>
<span class="attribution"><span class="source">Jeremy Niven</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Monitoring male glow-worms in the Y-maze allowed us to examine their behaviour in detail. White light increased the time they took to reach the dummy female: males in darkness took around 48 seconds and about a minute at the lowest level of white light. </p>
<h2>Blinded by the light</h2>
<p>We also noticed that the males lingered before entering one of the arms when they were exposed to white light. These males spent just 32 seconds on average in the base of the Y-maze in darkness, but this increased to 81 seconds in the brightest white light. </p>
<p>This hesitance may be because the glow-worms were dazzled. The insects retracted their head and compound eyes beneath a shield-like structure on their head when they were exposed to white light. In darkness, the males kept their head beneath the eye shield for just 0.5% of a trial’s duration – this rose to 25% in white light. More than half of the males kept their head shielded throughout the lit trials. </p>
<figure class="align-center ">
<img alt="A beetle on the stem of a plant." src="https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531633/original/file-20230613-21-358kwd.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">White light delayed the advances of male glow-worms.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Lampyris_noctiluca#/media/File:Lampyridae_-_Lampyris_noctiluca.JPG">Hectonichus/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We think the head shield acts like a pair of sunglasses, reducing how much light reaches the eyes. This may not be enough to protect them from the effects of the white light though, as males with their head retracted seemed far less likely to approach a dummy female. This suggests that artificial lighting at night could prevent a male from finding females, not only by making a potential mate’s bioluminescent signal harder to detect, but also by stunning them into stasis.</p>
<p>These sorts of detailed experiments into insect behaviour help us understand what glow-worms go through as a result of artificial lighting at night, complementing ecological studies that have been done in the field. Both lines of evidence tell us that reducing light pollution – by installing covers on street lights or changing the wavelengths of light they emit – can help insects go about their lives at night as we continue to go about ours.</p>
<hr>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Jeremy Niven receives funding from UKRI (BBSRC). </span></em></p>Artificial light is making it harder for male glow-worms to find bioluminescent females.Jeremy Niven, Professor of Zoology (Evolution, Behaviour and Environment), University of SussexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1993942023-03-23T12:40:17Z2023-03-23T12:40:17ZScientists are using machine learning to forecast bird migration and identify birds in flight by their calls<figure><img src="https://images.theconversation.com/files/516482/original/file-20230320-447-474etl.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C2998%2C1994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sandhill cranes flying above the Platte River in Nebraska.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/e6HkFZ">shannonpatrick17/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>With chatbots like ChatGPT <a href="https://theconversation.com/the-chatgpt-chatbot-is-blowing-people-away-with-its-writing-skills-an-expert-explains-why-its-so-impressive-195908">making a splash</a>, machine learning is playing an increasingly prominent role in our lives. For many of us, it’s been a mixed bag. We rejoice when our Spotify For You playlist finds us a new jam, but groan as we scroll through a slew of targeted ads on our Instagram feeds.</p>
<p>Machine learning is also changing many fields that may seem surprising. One example is <a href="https://www.researchgate.net/profile/Miguel-Jimenez-18">my discipline, ornithology – the study of birds</a>. It isn’t just solving some of the biggest challenges associated with studying bird migration; more broadly, machine learning is expanding the ways in which people engage with birds. As spring migration picks up, here’s a look at how machine learning is influencing ways to research birds and, ultimately, to protect them.</p>
<h2>The challenge of conserving migratory birds</h2>
<p>Most birds in the Western Hemisphere <a href="https://www.allaboutbirds.org/news/the-basics-how-why-and-where-of-bird-migration/#">migrate twice a year</a>, flying over entire continents between their breeding and nonbreeding grounds. While these journeys are awe-inspiring, they expose birds to many hazards en route, including <a href="https://www.nasa.gov/topics/earth/features/migratory-birds.html">extreme weather</a>, <a href="https://www.audubon.org/news/deadly-algal-bloom-could-cause-food-shortage-bay-area-migrating-waterbirds">food shortages</a> and <a href="https://news.un.org/en/story/2022/05/1118262">light pollution</a> that can attract birds and cause them to collide with buildings. </p>
<p>Our ability to protect migratory birds is only as good as the science that tells us where they go. And that science <a href="https://theconversation.com/birds-migrate-along-ancient-routes-here-are-the-latest-high-tech-tools-scientists-are-using-to-study-their-amazing-journeys-187967">has come a long way</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3_CqIJbZx4I?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">People in Alaska, Washington state and Mexico explain what migratory birds mean to them.</span></figcaption>
</figure>
<p>In 1920, the U.S. Geological Survey launched the <a href="https://www.usgs.gov/labs/bird-banding-laboratory">Bird Banding Laboratory</a>, spearheading an effort to put bands with unique markers on birds, then recapture the birds in new places to figure out where they traveled. Today researchers can deploy a variety of lightweight tracking tags on birds to discover their migration routes. These tools have uncovered the spatial patterns of <a href="https://explorer.audubon.org/home?legend=collapse&layersPanel=expand">where and when birds of many species migrate</a>.</p>
<p>However, tracking birds has limitations. For one thing, over <a href="https://doi.org/10.1038/s41559-018-0666-4">4 billion birds migrate</a> across the continent every year. Even with increasingly affordable equipment, the number of birds that we track is a drop in the bucket. And even within a species, migratory behavior may vary across sexes or populations. </p>
<p>Further, tracking data tells us where birds have been, but it doesn’t necessarily tell us where they’re going. Migration is dynamic, and the climates and landscapes that birds fly through are constantly changing. That means it’s crucial to be able to predict their movements. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"795735116232396800"}"></div></p>
<h2>Using machine learning to forecast migration</h2>
<p>This is where machine learning comes in. Machine learning is a subfield of artificial intelligence that gives computers the ability to learn tasks or associations without explicitly being programmed. We use it to train algorithms that tackle various tasks, from <a href="https://theconversation.com/ai-and-machine-learning-are-improving-weather-forecasts-but-they-wont-replace-human-experts-182498">forecasting weather</a> to <a href="https://theconversation.com/this-march-madness-were-using-machine-learning-to-predict-upsets-91618">predicting March Madness upsets</a>.</p>
<p>But applying machine learning requires data – and the more data the better. Luckily, scientists have inadvertently compiled decades of data on migrating birds through the <a href="https://www.ncei.noaa.gov/products/radar/next-generation-weather-radar">Next Generation Weather Radar system</a>. This network, known as NEXRAD, is used to measure weather dynamics and help predict future weather events, but it also picks up signals from birds as they fly through the atmosphere. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tall metal tower with a spherical radar receiver on top." src="https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516489/original/file-20230320-20-ozjvkn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A NEXRAD radar at an operation center in Norman, Okla.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/NEXRAD#/media/File:LabNexrad.jpg">Andrew J. Oldaker/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://birdcast.info/about/">BirdCast</a> is a collaborative project of Colorado State University, the Cornell Lab of Ornithology and the University of Massachusetts that seeks to leverage that data to quantify bird migration. Machine learning is central to its operations. Researchers have known since the 1940s that <a href="https://doi.org/10.1038/156446a0">birds show up on weather radar</a>, but to make that data useful, we need to remove nonavian clutter and identify which scans contain bird movement. </p>
<p>This process would be painstaking by hand – but by training algorithms to identify bird activity, we have automated this process and unlocked decades of migration data. And machine learning allows the BirdCast team to take things further: By training an algorithm to learn what atmospheric conditions are associated with migration, we can use predicted conditions to produce <a href="http://dx.doi.org/10.1126/science.aat7526">forecasts of migration across the continental U.S.</a> </p>
<p>BirdCast began broadcasting these forecasts in 2018 and has become <a href="https://www.allaboutbirds.org/news/heres-how-to-use-the-new-migration-forecast-tools-from-birdcast/">a popular tool in the birding community</a>. Many users may recognize that radar data helps produce these forecasts, but fewer realize that it’s a product of machine learning.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/bpQ3rFlxTQE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">BirdCast provides summaries of radar-based measurements of nocturnal bird migration for the continental U.S., including estimates of numbers of birds migrating and their directions, speeds and altitudes.</span></figcaption>
</figure>
<p>Currently these forecasts can’t tell us what species are in the air, but that could be changing. Last year, researchers at the Cornell Lab of Ornithology published an automated system that uses machine learning to <a href="https://doi.org/10.1111/1365-2664.14342">detect and identify nocturnal flight calls</a>. These are species-specific calls that birds make while migrating. Integrating this approach with BirdCast could give us a more complete picture of migration.</p>
<p>These advancements exemplify how effective machine learning can be when guided by expertise in the field where it is being applied. As a <a href="https://scholar.google.com/citations?user=G8OvEN4AAAAJ&hl=en&oi=ao">doctoral student</a>, I joined <a href="https://aeroecolab.com/">Colorado State University’s Aeroecology Lab</a> with a strong ornithology background but no machine learning experience. Conversely, <a href="https://scholar.google.com/citations?user=WBov7GQAAAAJ&hl=en&oi=ao">Ali Khalighifar</a>, a postdoctoral researcher in our lab, has a background in machine learning but has never taken an ornithology class. </p>
<p>Together, we are working to enhance the models that make BirdCast run, often leaning on each other’s insights to move the project forward. Our collaboration typifies the convergence that allows us to use machine learning effectively.</p>
<h2>A tool for public engagement</h2>
<p>Machine learning is also helping scientists engage the public in conservation. For example, forecasts produced by the BirdCast team are often used to inform <a href="https://www.audubon.org/lights-out-program">Lights Out</a> campaigns. </p>
<p>These initiatives seek to reduce artificial light from cities, which attracts migrating birds and increases their chances of <a href="https://theconversation.com/cities-can-help-migrating-birds-on-their-way-by-planting-more-trees-and-turning-lights-off-at-night-152573">colliding with human-built structures</a>, such as buildings and communication towers. Lights Out campaigns can mobilize people to help protect birds at the flip of a switch. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CjAuRkrMEgk/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>As another example, <a href="https://merlin.allaboutbirds.org/">the Merlin bird identification app</a> seeks to create technology that makes birding easier for everyone. In 2021, the Merlin staff released a feature that automates song and call identification, allowing users to identify what they’re hearing in real time, like an <a href="https://www.shazam.com/home">ornithological version of Shazam</a>.</p>
<p>This feature has opened the door for millions of people to engage with their natural spaces in a new way. Machine learning is a big part of what made it possible. </p>
<p>“Sound ID is our biggest success in terms of replicating the magical experience of going birding with a skilled naturalist,” Grant Van Horn, a staff researcher at the Cornell Lab of Ornithology who helped develop the algorithm behind this feature, told me. </p>
<h2>Taking flight</h2>
<p>Opportunities for applying machine learning in ornithology will only increase. As billions of birds migrate over North America to their breeding grounds this spring, people will engage with these flights in new ways, thanks to projects like BirdCast and Merlin. But that engagement is reciprocal: The data that birders collect will open new opportunities for applying machine learning. </p>
<p>Computers can’t do this work themselves. “Any successful machine learning project has a huge human component to it. That is the reason these projects are succeeding,” Van Horn said to me.</p><img src="https://counter.theconversation.com/content/199394/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Miguel Jimenez receives funding from the National Aeronautics and Space Administration. </span></em></p>Machine learning may not seem to have much connection with wildlife, but it’s starting to play a central role in bird conservation.Miguel Jimenez, Ph.D. student in Ecology, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2020472023-03-20T19:23:17Z2023-03-20T19:23:17ZSatellites and space junk may make dark night skies brighter, hindering astronomy and hiding stars from our view<figure><img src="https://images.theconversation.com/files/516258/original/file-20230320-183-8rlygz.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C1680%2C1050&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.esa.int/ESA_Multimedia/Images/2013/04/Distribution_of_debris">ESA</a></span></figcaption></figure><p>Since time immemorial, humans around the world have gazed up in wonder at the night sky. The starry night sky has not only inspired countless works of music, art and poetry, but has also played an important role in timekeeping, navigation and agricultural practices in <a href="https://doi.org/10.1017/s1743921310004783">many traditions</a>.</p>
<p>For many cultures, the night sky, with its stars, planets and the Milky Way, is considered <a href="https://doi.org/10.1016/j.polgeo.2020.102218">just as important</a> a part of the natural environment as the forests, lakes and mountains below. Countless people around the world gaze at the night sky: not only amateur and professional astronomers, but also casual observers who enjoy looking up at the stars to contemplate our place in the cosmos.</p>
<p>However, the night sky is changing. Not only is ground-based light pollution <a href="https://theconversation.com/night-skies-are-getting-9-6-brighter-every-year-as-light-pollution-erases-stars-for-everyone-199383">increasing rapidly</a>, but <a href="https://astronomy.com/magazine/news/2023/03/megaconstellations-are-changing-the-night-sky">growing numbers of satellites</a> and space debris in orbit around Earth are also impacting the night sky.</p>
<p><a href="https://academic.oup.com/mnrasl/article/504/1/L40/6188393">Earlier research</a> showed that satellites and space debris may increase the overall brightness of the night sky. In <a href="https://www.nature.com/articles/s41550-023-01904-2">a new paper</a> in Nature Astronomy, my colleagues and I applied this knowledge to predicting the performance of a major astronomical sky survey. We found this phenomenon may make the survey 7.5% less efficient and US$21.8 million more expensive.</p>
<h2>A brighter sky</h2>
<p>As a cultural astronomer, I am interested in the role of the night sky in <a href="https://tpt.pbslearningmedia.org/resource/cultural-cosmos-a-cultural-astronomers-view-video/northern-nights-starry-skies/">cultural traditions</a> around the world. In particular, I am interested in how <a href="http://spica.org.uk/index.php/2019/11/09/the-night-sky-in-the-lives-of-amateur-and-professional-astronomers/">light pollution</a> and increasing satellite numbers affect different communities.</p>
<p>The number of satellites in orbit is growing rapidly. Since 2019, the number of functional satellites in orbit has <a href="https://www.ucsusa.org/resources/satellite-database">more than doubled</a> to <a href="https://www.space-track.org/auth/login">around 7,600</a>. The increase is mostly due to SpaceX and other companies <a href="https://www.science.org/content/article/satellite-swarms-are-threatening-night-sky-creating-new-zone-environmental-conflict">launching large groups of satellites</a> to provide high-speed internet communications around the world. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516260/original/file-20230320-16-z160am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Starlink satellites already leave streaks on astronomical photographs – but growth in satellites and debris will make the whole sky brighter.</span>
<span class="attribution"><a class="source" href="https://noirlab.edu/public/images/ann21021c/">Rafael Schmall / NOIRLab</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>By the end of this decade, we estimate, there may be 100,000 satellites in orbit around the Earth. Collisions that generate space debris are <a href="https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JA083iA06p02637">more likely</a> as space fills with new satellites. Other sources of debris include the <a href="https://doi.org/10.1016/j.actaastro.2023.02.043">intentional destruction of satellites</a> in space warfare tests. </p>
<p>Increasing numbers of satellites and space debris reflect ever more sunlight towards the night side of Earth. This will almost certainly change the appearance of the night sky and <a href="https://aas.org/sites/default/files/2020-08/SATCON1-Report.pdf">make it harder for astronomers</a> to do research.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/thousands-of-satellites-are-polluting-australian-skies-and-threatening-ancient-indigenous-astronomy-practices-173840">Thousands of satellites are polluting Australian skies, and threatening ancient Indigenous astronomy practices</a>
</strong>
</em>
</p>
<hr>
<p>One way satellites impact astronomy is by appearing as moving points of light, which show up as streaks across astronomers’ images. Another is by increasing <a href="https://academic.oup.com/mnrasl/article/504/1/L40/6188393">diffuse night sky brightness</a>. This means all the satellites that are too dim or small to be seen individually, as well as all the small bits of space debris, still reflect sunlight, and their collective effect is to make the night sky appear less dark.</p>
<h2>Hard times for astronomers</h2>
<p>In <a href="https://doi.org/10.1038/s41550-023-01904-2">our research</a>, we present the first published calculations of the aggregate effects of satellites and space debris in low-Earth orbit on major ground-based astronomy research facilities. </p>
<p>We looked at the effect on the planned <a href="https://www.lsst.org/science">large-scale survey of the night sky</a> to be carried out at the Vera Rubin Observatory starting in 2024. We found that, by 2030, reflected light from objects in low-Earth orbit will likely increase the diffuse background brightness for this survey by at least 7.5% compared to an unpolluted sky.</p>
<p>This would diminish the efficiency of this survey by 7.5% as well. Over the ten-year lifetime of the survey, we estimate this would add some US$21.8 million to the total project cost. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/starlink-amazon-and-others-are-racing-to-fill-the-sky-with-bigger-satellites-to-deliver-mobile-coverage-everywhere-on-earth-190237">Starlink, Amazon and others are racing to fill the sky with bigger satellites to deliver mobile coverage everywhere on Earth</a>
</strong>
</em>
</p>
<hr>
<p>Brighter night skies mean longer exposures through telescopes are needed to see distant objects in the cosmos. This will mean that for projects with a fixed amount of observing time, less science will be accomplished, and there will be increased competition for telescope access.</p>
<p>In addition, brighter night skies will also reduce the detection limits of sky surveys, and dimmer objects may not be detected, resulting in missed research opportunities. </p>
<p>Some astrophysical events are rare and if researchers are unable to view them when they occur, there might not be an opportunity to easily see a given event again during a survey’s operational period. One example of faint objects is near-Earth objects – comets and asteroids in orbits close to Earth. Brighter night skies make it more likely such potentially hazardous objects may remain undetected.</p>
<h2>A dramatic and unprecedented tranformation</h2>
<p>Increases in diffuse night sky brightness will also change how we see the night sky with the unaided eye. As the human eye cannot resolve individual small objects as well as a telescope can, an increase in satellites and space debris will create an even greater increase in the apparent brightness of the night sky. (When using a telescope or binoculars, one would be able to make out more of the dimmer satellites individually.)</p>
<p>The projected increase in night sky brightness will make it increasingly difficult to see fainter stars and the Milky Way, both of which are important in <a href="https://doi.org/10.48550/ARXIV.2008.05266">various cultural traditions</a>. Unlike “ground-based” light pollution (which tends to be the worst near large cities and heavily populated areas), the changes to the sky will be visible from essentially everywhere on Earth’s surface.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516261/original/file-20230320-26-r24sy7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There may be 100,000 satellites in orbit around Earth by 2030.</span>
<span class="attribution"><a class="source" href="https://noirlab.edu/public/images/ann22005a/">M Lewinsky / NOIRLab</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Our models give us a conservative lower limit for a likely increase in night sky brightness. If numbers of satellites and space debris continue to grow at the expected rate, the impacts will be even more pronounced.</p>
<p>As we note in our paper, “we are witnessing a dramatic, fundamental, and perhaps semi-permanent transformation of the night sky without historical precedent and with limited oversight”. Such a transformation will have profound consequences for professional astronomy as well as for anyone who wishes to view an unpolluted night sky.</p><img src="https://counter.theconversation.com/content/202047/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica Heim does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Tens of thousands of satellites orbiting Earth will hamper astronomers’ efforts to study the Universe and spot dangerous asteroids, as well as brightening the sky and hiding stars from the rest of us.Jessica Heim, PhD researcher, University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1993532023-03-03T13:24:40Z2023-03-03T13:24:40ZRadio interference from satellites is threatening astronomy – a proposed zone for testing new technologies could head off the problem<figure><img src="https://images.theconversation.com/files/513013/original/file-20230301-20-knf7oq.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1281%2C1281&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Radio observatories like the Green Bank Telescope are in radio quiet zones that protect them from interference.</span> <span class="attribution"><a class="source" href="https://public.nrao.edu/gallery/green-bank-telescope/">NRAO/AUI/NSF</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Visible light is just one part of the electromagnetic spectrum that astronomers use to study the universe. The <a href="https://theconversation.com/the-james-webb-space-telescope-is-finally-ready-to-do-science-and-its-seeing-the-universe-more-clearly-than-even-its-own-engineers-hoped-for-184989">James Webb Space Telescope</a> was built to see infrared light, other <a href="https://swift.gsfc.nasa.gov/">space telescopes capture X-ray images</a>, and observatories like the <a href="https://greenbankobservatory.org/science/telescopes/gbt/">Green Bank Telescope</a>, the <a href="https://public.nrao.edu/telescopes/VLA/">Very Large Array</a>, the <a href="http://www.almaobservatory.org/">Atacama Large Millimeter Array</a> and dozens of other observatories around the world work at radio wavelengths. </p>
<p>Radio telescopes are facing a problem. All satellites, whatever their function, use radio waves to transmit information to the surface of the Earth. Just as <a href="https://theconversation.com/night-skies-are-getting-9-6-brighter-every-year-as-light-pollution-erases-stars-for-everyone-199383">light pollution can hide a starry night sky</a>, radio transmissions can swamp out the radio waves astronomers use to learn about black holes, newly forming stars and the evolution of galaxies.</p>
<p>We are three scientists who work in <a href="https://www.researchgate.net/profile/Christopher-De-Pree">astronomy</a> and <a href="https://scholar.google.com/citations?user=y5L4A3gAAAAJ&hl=en&oi=ao">wireless</a> <a href="https://scholar.google.com/citations?user=eEqTPcwAAAAJ&hl=en&oi=ao">technology</a>. With <a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">tens of thousands of satellites</a> expected to go into orbit in the coming years and increasing use on the ground, the radio spectrum is getting crowded. Radio quiet zones – regions, usually located in remote areas, where ground-based radio transmissions are limited or prohibited – have protected radio astronomy in the past.</p>
<p>As the problem of radio pollution continues to grow, scientists, engineers and policymakers will need to figure out how everyone can effectively share the limited range of radio frequencies. One solution that we have been working on for the past few years is to create a facility where astronomers and engineers <a href="https://beta.nsf.gov/funding/opportunities/spectrum-innovation-initiative-national-radio">can test new technologies</a> to prevent radio interference from blocking out the night sky.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing what wavelengths of light correspond with different types of radiation." src="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513004/original/file-20230301-22-mo36il.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Different telescopes capture different parts of the electromagnetic spectrum, with radio telescopes collecting radiation of the longest wavelengths.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:EM_Spectrum_Properties_edit.svg">InductiveLoad/NASA/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Astronomy with radio waves</h2>
<p>Radio waves are the longest wavelength emissions on the electromagnetic spectrum, meaning that the distance between two peaks of the wave is relatively far apart. Radio telescopes collect radio waves in wavelengths from millimeter to meter wavelengths. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An orange ring surrounding a dark center." src="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513010/original/file-20230301-1800-alvapb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The first direct image of a black hole was created using the Event Horizon Telescope, combining observations from eight radio telescopes.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Black_hole_-_Messier_87_crop_max_res.jpg#/media/File:Black_hole_-_Messier_87_crop_max_res.jpg">European Southern Observatory/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Even if you are unfamiliar with radio telescopes, you have probably heard about some of the research they do. The fantastic <a href="https://public.nrao.edu/gallery/astronomers-capture-first-image-of-a-black-hole/">first images of accretion disks</a> around <a href="https://theconversation.com/say-hello-to-sagittarius-a-the-black-hole-at-the-center-of-the-milky-way-galaxy-183008">black holes</a> were both produced by the <a href="https://eventhorizontelescope.org/about">Event Horizon Telescope</a>. This telescope is a global network of eight radio telescopes, and each of the individual telescopes that make up the Event Horizon Telescope is located in a place with very little radio frequency interference: a radio quiet zone.</p>
<p>A radio quiet zone is a region where ground-based transmitters, like cellphone towers, are required to lower their power levels so as not to affect sensitive radio equipment. The U.S. has two such zones. The largest is the <a href="https://info.nrao.edu/do/spectrum-management/national-radio-quiet-zone-nrqz-1">National Radio Quiet Zone</a>, which covers 13,000 square miles (34,000 square kilometers) mostly in West Virginia and Virginia. It contains the <a href="https://greenbankobservatory.org">Green Bank Observatory</a>. The other, <a href="https://its.ntia.gov/research-topics/table-mountain/tm-home/">the Table Mountain Field Site and Radio Quiet Zone</a>, in Colorado, supports research by a number of federal agencies.</p>
<p>Similar radio quiet zones are home to telescopes in <a href="https://www.csiro.au/en/about/facilities-collections/atnf/mro">Australia</a>, <a href="https://www.sarao.ac.za/science/meerkat/about-meerkat/">South Africa</a> and <a href="https://doi.org/10.1109/APEMC.2013.7360597">China</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pgysWWwESfU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Large satellite constellations, like those of Starlink, can be seen marching in lines across night skies and harm both visible and radio astronomy.</span></figcaption>
</figure>
<h2>A satellite boom</h2>
<p>On Oct. 4, 1957, the Soviet Union launched Sputnik into orbit. As the small satellite circled the globe, amateur radio enthusiasts all over the world were able to <a href="https://ethw.org/Sputnik">pick up the radio signals</a> it was beaming back to Earth. Since that historic flight, wireless signals have become part of almost every aspect of modern life – from aircraft navigation to Wi-Fi – and the <a href="https://theconversation.com/how-many-satellites-are-orbiting-earth-166715">number of satellites has grown exponentially</a>. </p>
<p>The more radio transmissions there are, the more challenging it becomes to deal with <a href="https://researchrepository.wvu.edu/etd/11467/">interference in radio quiet zones</a>. Existing laws do not protect these zones from satellite transmitters, which can have devastating effects. In one example, transmissions from an Iridium satellite <a href="https://nap.nationalacademies.org/catalog/12800/spectrum-management-for-science-in-the-21st-century">completely obscured</a> the observations of a faint star made in a protected band allocated to radio astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One chart showing a single object and another showing a mess of lines." src="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512917/original/file-20230301-16-2at6pw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Two images from the Very Large Array in New Mexico show what a faint star looks like to a radio telescope without satellite interference, left, and with satellite interference, right.</span>
<span class="attribution"><span class="source">G. Taylor, UNM</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Satellite internet networks like Starlink, OneWeb and others will eventually be flying over every location on Earth and transmitting radio waves down to the surface. Soon, no location will be truly quiet for radio astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The light pollution of a large city against the night sky." src="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513008/original/file-20230301-22-stgk35.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Just as with light pollution, the more development there is on Earth and in the sky, the more radio interference there will be.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:San_Tan_Mountain_Lights.jpg">Gppercy/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Interference in the sky and on the ground</h2>
<p>The <a href="https://science.nrao.edu/facilities/vla/docs/manuals/obsguide/rfi">problem of radio interference is not new</a>.</p>
<p>In the 1980s, the Russian <a href="https://glonass-iac.ru/en/about_glonass/">Global Navigation Satellite System</a> – essentially the Soviet Union’s version of GPS – <a href="http://www.iucaf.org/sschool/procs/glonass.pdf">began transmitting at a frequency</a> that was officially protected for <a href="https://hal-enac.archives-ouvertes.fr/hal-01022448/document">radio astronomy</a>. Researchers <a href="https://arxiv.org/abs/astro-ph/0002516">recommended a number of fixes</a> for this interference. By the time operators of the Russian navigation system agreed to change the transmitting frequency of the satellites, <a href="https://adsabs.harvard.edu/full/1994PASP..106..807C">a lot of harm</a> had already been done due to the lack of testing and communication.</p>
<p>Many satellites look down at Earth using parts of the radio spectrum to monitor characteristics like <a href="https://land.copernicus.eu/global/products/ssm">surface soil moisture</a> that are important for weather prediction and climate research. The frequencies they rely on are protected under <a href="https://www.itu.int/rec/R-REC-RA.769-2-200305-I/en">international agreements</a> but are also under threat from radio interference. </p>
<p>A recent study showed that a large fraction of NASA’s soil moisture measurements <a href="https://doi.org/10.1109/TGRS.2013.2281266">experience interference</a> from ground-based radar systems and consumer electronics. There are systems in place to <a href="https://salinity.oceansciences.org/smap-radiometer.htm">monitor and account for the interference</a>, but avoiding the problem altogether through international communication and prelaunch testing would be a better option for astronomy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A number of satellite dishes in a remote desert." src="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513011/original/file-20230301-424-ivg4js.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Most radio telescopes, like the Atacama Large Millimeter Array in Chile, are in areas far from any source of interference. But a new site designed to test technologies and interference solutions could prevent future problems.</span>
<span class="attribution"><a class="source" href="http://www.eso.org/public/images/potw1111a/">ALMA (ESO/NAOJ/NRAO), J. Guarda</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Solutions to a crowded radio spectrum</h2>
<p>As the radio spectrum continues to <a href="https://whyy.org/segments/our-gadgets-increasingly-crowd-the-radio-spectrum-theyre-crowding-out-science-too/">get more crowded</a>, users will have to share. This could involve sharing in time, in space or in frequency. Regardless of the specifics, solutions will need to be tested in a controlled environment. There are early signs of cooperation. The National Science Foundation and SpaceX recently announced an <a href="https://beta.nsf.gov/news/statement-nsf-astronomy-coordination-agreement">astronomy coordination agreement</a> to benefit radio astronomy.</p>
<p>Working with astronomers, engineers, software and wireless specialists, and with the support of the National Science Foundation, we have been <a href="https://www.cs.albany.edu/nrdz-ra/index.html">leading a series of workshops</a> to develop what a national radio dynamic zone could provide. This zone would be similar to existing radio quiet zones, covering a large area with restrictions on radio transmissions nearby. Unlike a quiet zone, the facility would be outfitted with sensitive spectrum monitors that would allow astronomers, satellite companies and technology developers to test receivers and transmitters together at large scales. The goal would be to support creative and cooperative uses of the radio spectrum. For example, a zone established near a radio telescope could test schemes to provide broader bandwidth access for both active uses, like cell towers, and passive uses, like radio telescopes.</p>
<p>For <a href="https://doi.org/10.1109/MCOM.005.2200389">a new paper our team just published</a>, we spoke with users and regulators of the radio spectrum, ranging from radio astronomers to satellite operators. We found that most agreed that a radio dynamic zone could help solve, and potentially avoid, many critical interference issues in the coming decades.</p>
<p>Such a zone doesn’t exist yet, but our team and many people across the U.S. are working to refine the concept so that radio astronomy, Earth-sensing satellites and government and commercial wireless systems can find ways to share the precious natural resource that is the radio spectrum.</p><img src="https://counter.theconversation.com/content/199353/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Gordon De Pree has received funding from National Science Foundation. </span></em></p><p class="fine-print"><em><span>Christopher R. Anderson receives funding from the National Science Foundation, Office of Naval Research, and National Telecommunications and Information Administration. </span></em></p><p class="fine-print"><em><span>Mariya Zheleva receives funding from the National Science Foundation. </span></em></p>Many telescopes use the radio spectrum to learn about the cosmos. Just as human development leads to more light pollution, increasing numbers of satellites are leading to more radio interference.Christopher Gordon De Pree, Deputy Electromagnetic Spectrum Manager, National Radio Astronomy ObservatoryChristopher R. Anderson, Associate Professor of Electrical Engineering, United States Naval AcademyMariya Zheleva, Assistant Professor of Computer Science, University at Albany, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1993832023-02-23T13:15:36Z2023-02-23T13:15:36ZNight skies are getting 9.6% brighter every year as light pollution erases stars for everyone<figure><img src="https://images.theconversation.com/files/510410/original/file-20230215-24-phgv5z.jpg?ixlib=rb-1.1.0&rect=747%2C249%2C5060%2C1458&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All human development, from large cities to small towns, shines light into the night sky. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/evobenny/38510489362/">Benny Ang/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510596/original/file-20230216-18-s7y17h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For most of human history, the stars blazed in an otherwise dark night sky. But starting around the Industrial Revolution, as artificial light increasingly lit cities and towns at night, the stars began to disappear.</p>
<p>We are <a href="https://scholar.google.com/citations?user=OrRLRQ4AAAAJ&hl=en&oi=ao">two</a> <a href="https://noirlab.edu/science/about/scientists-at-noirlab">astronomers</a> who depend on dark night skies to do our research. For decades, astronomers have been <a href="https://about.ifa.hawaii.edu/facility/mauna-kea-observatories/">building telescopes</a> in the <a href="https://www.smithsonianmag.com/travel/star-trekking-chile-astronomy-180955798/">darkest places</a> on Earth to <a href="https://doi.org/10.1007/s00159-010-0032-2">avoid light pollution</a>. </p>
<p>Today, most people live in cities or suburbs that <a href="https://doi.org/10.1038/457027a">needlessly shine light into the sky at night</a>, dramatically reducing the <a href="https://doi.org/10.1126/sciadv.1600377#body-ref-R3">visibility of stars</a>. Satellite data suggests that light pollution over North America and Europe has remained <a href="https://www.science.org/doi/10.1126/sciadv.1701528">constant or has slightly decreased</a> over the last decade, while <a href="https://www.mdpi.com/2072-4292/9/8/798">increasing in other parts of the world</a>, such as Africa, Asia and South America. However, satellites miss the blue light of LEDs, which are <a href="http://dx.doi.org/10.2760/759859">commonly used for outdoor lighting</a> – resulting in an underestimate of light pollution.</p>
<p>An international citizen science project called <a href="https://globeatnight.org">Globe at Night</a> aims to measure how everyday people’s view of the sky is changing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A number of panels showing different numbers of stars." src="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510429/original/file-20230215-15-f11qnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Globe at Night survey asks users to select which panel – each representing different levels of light pollution – best matches the sky above them.</span>
<span class="attribution"><a class="source" href="https://globeatnight.org/webapp/">The Globe at Night</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Measuring light pollution over time</h2>
<p>Relying on citizen scientists makes it much easier to take multiple measurements of the night sky over time from many different places. </p>
<p>To provide data to the project, volunteers enter the date and time, their location and local weather conditions into an <a href="https://globeatnight.org/webapp/">online reporting page</a> anytime an hour or more after sunset on certain nights each month. The page then shows eight panels, each displaying a constellation visible at that time of year – like Orion in January and February, for example. The first panel, representing a light-polluted night sky, only shows the few brightest stars. Each panel shows progressively more and fainter stars, representing darker and darker skies. The participant then matches what they see in the sky with one of the panels. </p>
<p>The Globe at Night team launched the report page as an online app in 2011, just at the beginning of widespread adoption of LEDs. In <a href="https://doi.org/10.1126/science.abq7781">the recent paper</a>, the team filtered out data points taken during twilight, when the Moon was out, when it was cloudy or when the data was unreliable for any other reason. This left around 51,000 data points, mostly taken in North America and Europe. </p>
<p>The data shows that the night sky got, on average, <a href="https://doi.org/10.1126/science.abq7781">9.6% brighter every year</a>. For many people, the night sky today is twice as bright as it was eight years ago. The brighter the sky, the fewer stars you can see.</p>
<p>If this trend continues, a <a href="https://eos.org/articles/starry-nights-are-disappearing">child born today</a> in a place where 250 stars are visible now would only be able to see 100 stars on their 18th birthday. </p>
<h2>Causes, impacts and solutions</h2>
<p>The main culprits driving increasing brightness of the night sky are urbanization and the growing use of <a href="http://dx.doi.org/10.2760/759859">LEDs for outdoor lighting</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two pictures of the constellation Orion with one showing many times more stars." src="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510413/original/file-20230215-28-33uihp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The more light pollution there is, the fewer stars a person can see when looking at the same part of the night sky. The image on the left depicts the constellation Orion in a dark sky, while the image on the right is taken near the city of Orem, Utah, a city of about 100,000 people.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/79297308@N00/3180280752">jpstanley/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The loss of dark skies, both from light pollution and also from <a href="https://doi.org/10.1093/mnrasl/slab030">increasing numbers of satellites orbiting Earth</a>, threatens our ability as astronomers to do <a href="https://doi.org/10.1007/s00159-021-00138-3">good science</a>. But everyday people feel this loss too, as the degradation of dark skies is also a loss of human <a href="https://www.darksky.org/light-pollution/night-sky-heritage/">cultural heritage</a>. Starry night skies have inspired artists, writers, musicians and philosophers for thousands of years. For many, a star-filled sky provides an irreplaceable sense of awe.</p>
<p>Light pollution also interferes with the daily cycle of light and dark that <a href="https://ec.europa.eu/research-and-innovation/en/horizon-magazine/light-pollution-altering-plant-and-animal-behaviour">plants and animals</a> use to regulate sleep, nourishment and reproduction. Two-thirds of the world’s key biodiversity areas are <a href="https://www.upi.com/Science_News/2019/02/11/Light-pollution-affects-most-of-the-planets-key-wildlife-areas/1451549899187">affected by light pollution</a>.</p>
<p>Individuals and their communities can make simple changes to <a href="https://www.darksky.org/light-pollution/light-pollution-solutions/">reduce light pollution</a>. The secret is using the right amount of light, in the right place and at the right time. Shielding outdoor light fixtures so they shine downward, using bulbs that emit more yellow-colored light instead of white light and putting lights on timers or motion sensors can all help reduce light pollution.</p>
<p>The next time you are far away from a major city or another source of light pollution, look up at the night sky. A view of the roughly <a href="https://www.theatlantic.com/technology/archive/2013/11/how-many-stars-are-there-in-the-sky/281641/">2,500 stars you can see with the naked eye</a> in a truly dark sky might convince you that dark skies are a resource worth saving.</p><img src="https://counter.theconversation.com/content/199383/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Impey receives funding from the National Science Foundation and Epic Games.</span></em></p><p class="fine-print"><em><span>Connie Walker works for NSF's NOIRLab and the International Astronomical Union. She is a member of the American Astronomical Society's COMPASSE and on the Board of Directors for the International Dark-Sky Association.</span></em></p>With the help of thousands of citizen scientists, a new study measured exactly how much brighter night skies are getting every year.Chris Impey, University Distinguished Professor of Astronomy, University of ArizonaConnie Walker, Scientist, National Optical-Infrared Astronomy Research LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1980352023-02-09T16:59:27Z2023-02-09T16:59:27ZLight pollution has cut humanity’s ancient connection with the stars – but we can restore it<figure><img src="https://images.theconversation.com/files/508340/original/file-20230206-31-b29opi.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C2991%2C1994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/milky-way-rises-over-pine-trees-384983128">Andrey Prokhorov/Shutterstock</a></span></figcaption></figure><p>Humans are naturally afraid of the dark. We sometimes imagine monsters under the bed and walk faster down unlit streets at night. To conquer our fears, we may leave a night light on to scare away the monsters and a light over the porch to deter break-ins. </p>
<p>Yet, in huddling for safety under our pools of light, we have lost our connection to the night sky. Star counts by public awareness campaign <a href="https://www.globeatnight.org/">Globe at Night</a> revealed that, between 2011 and 2022, the world’s night sky <a href="https://www.theguardian.com/environment/2023/jan/19/light-pollution-rapidly-reducing-stars-visible-naked-eye-study-finds">more than doubled in artificial brightness</a>. Yet local interventions can create meaningful change. </p>
<p>Light pollution is cutting us off from one of nature’s greatest wonders, harming wildlife and blocking research that could help fight climate change. Stars are more than pretty glimmers in the night sky. They have shaped the mythology of every human civilisation. They guide birds on their astonishing migratory journeys. And now we need to do our bit to prevent light pollution so stars can be part of our future. </p>
<p><a href="https://skyandtelescope.org/astronomy-blogs/how-many-stars-night-sky-09172014/">The human eye can detect around 5,000</a> stars in the night sky. But the light emitted by skyscrapers, street lamps, and houses obscures all but a handful of the brightest stars. </p>
<p>Our ancestors used the rising and setting of the constellations as <a href="https://www.britannica.com/science/calendar/Time-determination-by-stars-Sun-and-Moon">calendars</a>. They also <a href="https://theconversation.com/how-far-theyll-go-moana-shows-the-power-of-polynesian-celestial-navigation-72375#:%7E:text=The%20position%20of%20Moana's%20hand,are%20travelling%20exactly%20due%20East.&text=Later%20in%20the%20film%2C%20we,by%20following%20Maui's%20fish%20hook.">navigated by the stars</a> as they searched for new lands or traced nautical trade routes. Sailors don’t normally use the stars to navigate any more, but they are still taught how to, <a href="https://www.popularmechanics.com/military/research/a36078957/celestial-navigation/">in case their navigation systems break down</a>. </p>
<p>Migratory animals, including birds and insects, are <a href="https://www.darksky.org/light-pollution/wildlife/">drawn away from their natural flight paths</a> by the beckoning “sky glow” of cities. In the summer of 2019, Las Vegas was <a href="https://www.smithsonianmag.com/smart-news/las-vegas-was-inundated-46-million-grasshoppers-single-night-2019-180977395/">invaded</a> by millions of migrating grasshoppers, while the beams of New York’s <a href="https://www.nytimes.com/2018/09/10/opinion/9-11-tribute-in-light-birds.html">9/11 Tribute in Light</a> are a magnet for flocks of migrating songbirds flying at night. </p>
<p>Disoriented by the bright city lights, birds crash into towering skyscrapers. Insect numbers are collapsing worldwide and light pollution is making matters worse by <a href="https://www.smithsonianmag.com/smart-news/light-pollution-contributes-insect-apocalypse-180973642/">disrupting their nocturnal life cycles</a>.</p>
<h2>What is light pollution</h2>
<p>Light pollution is caused by the same <a href="https://spaceplace.nasa.gov/blue-sky/en/">physics that turns the sky blue during the day</a>. Sunlight is made up of all the colours of the rainbow and each colour has a different wavelength. The air that surrounds us is composed of tiny particles (such as oxygen and carbon dioxide molecules). </p>
<p>As light from the Sun makes its way through the air, it is scattered by these particles in random directions. Blue light (with shorter wavelengths) is scattered more than red light (which has longer wavelengths). As a result, our eyes receive more blue light from every direction in the sky. </p>
<p>At night, light scattered by the same air particles causes the sky to shine down on us. A small fraction of this sky glow is caused by natural sources, such as starlight and the Earth’s atmosphere. But most of the light that creates sky glow is artificial. </p>
<figure class="align-center ">
<img alt="The constellation Orion, imaged at left from dark skies, and at right from the teeming metropolis of Orem, UT comprising about half a million people." src="https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509173/original/file-20230209-22-xf5oal.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Light pollution is not pretty.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Light_pollution_It%27s_not_pretty.jpg">Jeremy Stanley/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Light pollution also affects our ability to study the universe. Even modern observatories, built on remote mountaintops, are affected by the encroaching sky glow from growing, sprawling cities. Light pollution is so widespread that <a href="https://www.space.com/major-observatories-suffering-light-pollution">three quarters of all observatories</a> are affected. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/h0RKQmVAeQM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Migrating birds flying through Tribute in Light in 2015.</span></figcaption>
</figure>
<h2>Looking up</h2>
<p>There is no reason to despair, though. We created light pollution; we can fix it.</p>
<p>Around the world, <a href="https://www.darksky.org/">dark sky</a> <a href="https://www.darkskydiscovery.org.uk/">associations</a> are working to educate the public about the hazards of light pollution, to lobby for <a href="https://www.allaboutbirds.org/news/new-york-city-passes-landmark-lights-out-laws/">legislation to protect dark sky reserves</a> and encourage people to reignite their connection with <a href="https://www.darksky.org/our-work/lighting/">dark, star-studded skies</a>.</p>
<p><a href="https://theconversation.com/turn-off-the-porch-light-6-easy-ways-to-stop-light-pollution-from-harming-our-wildlife-132595">Fighting light pollution begins at home.</a> If you need to keep outside lights on for security, use shielded lamps that only shine downwards. Use light bulbs that do not emit violet and blue light as this is harmful to wildlife. Smart lighting controls will also help reduce your house’s effect on wildlife and make it easier for you to observe the night sky.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=267&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=267&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=267&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=336&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=336&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505372/original/file-20230119-16-5t6mrz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=336&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">2016 world map of artificial sky brightness. 80% of the world’s population is now affected by light pollution. Credit: Falchi et al., Science Advances, 2016;2:e160037.</span>
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</figure>
<p>You will also find <a href="https://www.lightpollutionmap.info">interactive maps</a> that show how polluted the skies are in your area. These maps are created from data gathered by satellites and by citizen scientists taking part in annual star counts. You can help darken our skies, too. </p>
<p>In the UK, the 2023 annual star count will take place on <a href="https://www.cpre.org.uk/what-we-care-about/nature-and-landscapes/dark-skies/star-count-2023/">February 17-24</a>. And, wherever you are in the world, you can always take part in the year-long <a href="https://globeatnight.org/">Globe at Night</a> star count whenever you want. </p>
<p>The task is simple: step outside on a clear night, count how many stars you can see in a well-known constellation, such as Orion, and report back. </p>
<p>To defeat light pollution, we need to know how severe it is and what difference national policies and local interventions (such as replacing the street lights in your town) make. In the UK, for example, star counts show light pollution may have <a href="https://www.cpre.org.uk/news/night-skies-outlook-is-bright-our-star-count-results-suggest/">peaked in 2020</a> and has started to decline. </p>
<p>Perhaps the most important aspect of star counts is that they shine a light on our vanishing night skies and galvanize us to take action. Ultimately, it’s up to each and every one of us to reduce our effect on the sky, by changing the way we light our homes and neighbourhoods and by lobbying our representatives to pass <a href="https://www.allaboutbirds.org/news/new-york-city-passes-landmark-lights-out-laws/#">dark sky legislation</a>. </p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Or Graur does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People travel hundreds or thousands of miles and spend a fortune to see the night sky in all its splendor. But we are literally blocking out the cosmic beauty above our homes.Or Graur, Reader in Astrophysics, University of PortsmouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1965252023-01-05T11:54:10Z2023-01-05T11:54:10ZUrban light pollution is a danger for marine ecosystems – new research<figure><img src="https://images.theconversation.com/files/501350/original/file-20221215-15-2eals8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5982%2C3979&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artificial light is an emerging threat for marine ecosystems in coastal waters (Kochi, India).</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/marine-drive-kochi-kerala-india-784637686">Vinu Sebastian/Shutterstock</a></span></figcaption></figure><p>Cities are artificially lit to allow humans to make use of the night. This light pollution means that stars are often barely visible in urban skies. But reduced stargazing is not the only <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13927">impact of artificial light at night</a>. </p>
<p>Urban development in coastal areas is increasingly exposing marine ecosystems to artificial light. This exposure is particularly acute in and near some of the world’s largest coastal cities and may carry physiological and behavioural consequences for the organisms that inhabit their coastal waters. </p>
<p>The <a href="https://pml.ac.uk/">Plymouth Marine Laboratory</a>, where I lead the Marine Biogeochemistry team, last year published an atlas of <a href="https://online.ucpress.edu/elementa/article/9/1/00049/119144/A-global-atlas-of-artificial-light-at-night-under">artificial light at night under the sea</a>. The atlas reveals that at a depth of 1 metre, light pollution affects 1.9 million sq km of the world’s coastal seas. This is equivalent to 3.1% of global <a href="https://emodnet.ec.europa.eu/en/map-week-%E2%80%93-exclusive-economic-zones#:%7E:text=This%20is%20called%20a%20country's,lies%20its%20Exclusive%20Economic%20Zone.">exclusive economic zones</a> (the areas of the ocean owned by coastal nations). </p>
<p>Such research has confirmed that light pollution is widespread and expanding. But the difference between the intensity and cycles of natural and unnatural light has to this point been understudied. Quantifying this would allow a better understanding of the impact of expansive urbanised coastlines on the ecology of marine ecosystems. </p>
<p>Together with colleagues from the Universities of Plymouth and Strathclyde, <a href="https://online.ucpress.edu/elementa/article/10/1/00042/194863/Disruption-of-marine-habitats-by-artificial-light">we quantified</a> the magnitude of the natural and unnatural light reaching the marine ecosystems of a group of seven coastal cities with more than 10 million inhabitants: Tokyo, Shanghai, Mumbai, New York, Buenos Aires, Lagos and Los Angeles. </p>
<p>Our research showed that for these cities, dosages of artificial light at night on the surface of the sea are up to six times greater than moonlight. Moonlight intensity only exceeded artificial lighting within a period of three days from the brightest full moons.</p>
<figure class="align-center ">
<img alt="Shanghai skyline at night from the sea." src="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501346/original/file-20221215-22-hf7guc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Shanghai’s skyline illuminated at night.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shanghai-bund-garden-bridge-lujiazui-skyline-190208075">ArtisticPhoto/Shutterstock</a></span>
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<h2>Illuminating coastal waters</h2>
<p>Our model, which included inputs for lunar, artificial light and both daylight and twilight solar sources alongside seasonal and tidal changes in the distribution of light, was applied to each city over the course of 2020. In 15-minute time intervals we then determined the intensity of these light sources both above the sea’s surface and in the intertidal zone. This refers to the points on the shore which are covered, generally twice a day, by the tide. </p>
<p>We also applied the model to Plymouth, a coastal city in the west of England with a population of 230,000. Natural and artificial light sources have been studied here from 2001 to 2020 in order to capture the variability in tidal and lunar cycles. This fieldwork allowed us to ensure that our model provided accurate predictions.</p>
<p>In Plymouth, artificial light at night dosages generally ranked sixth across all of the cities studied. The city has a relatively northerly latitude, meaning it has long nights during the autumn and winter months. Yet summertime full moons in Plymouth shine with an intensity close to that of artificial light because the moon is close to the horizon all night with a longer atmospheric path length.</p>
<p>But the marine ecosystems likely to be most affected by light pollution are those in the coastal waters of Los Angeles, New York, Buenos Aires, Shanghai and Mumbai. Factors including tidal range and water clarity interact with the high intensity brightness of artificial urban lighting to impact marine ecosystems in these locations.</p>
<h2>Impact on marine ecosystems</h2>
<p>Natural sources of light at night have seasonal cycles. Nighttime light exposure has therefore historically been dependent on the moon and its cycle of waxing, waning and elevation in the sky. Artificial light sources, in contrast, have a fixed position irrespective of the season and shine with the same intensity throughout the night and all year round. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16264">Scientific research</a> has shown that light pollution can mask the natural cycle of the moon and can affect coastal organisms. This occurs at a variety of scales, from a hyperlocal (underneath street lights) to a regional and even global scale.</p>
<p>Marine organisms, including coral reefs, rely on natural light cycles to regulate their physiological and biological processes. Several coral species simultaneously <a href="https://www.sciencedirect.com/science/article/pii/S0960982220315827">release their reproductive cells</a> – called gametes – on cues from the lunar cycle.</p>
<p>Key maintenance processes in coral, such as <a href="https://www.frontiersin.org/articles/10.3389/fphys.2021.695083/full">symbiosis</a>, can also be sensitive to artificial lighting. Symbiosis describes the close relationship between the two organisms that make up coral. </p>
<p>The spectral composition of artificial light at night (its red, green and blue light components) illuminating seafloor habitats may also disrupt <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.14146">visually guided ecological processes</a>. Predators that usually feed in the day such as the herring gull may be able to see prey that would ordinarily be camouflaged at night, such as marine snails. </p>
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<img alt="A yellow and black street sign warning people that turtles are nesting on the beach and that street lights will be turned off." src="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501347/original/file-20221215-12-2u9juc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Artificial light can disorientate turtle hatchlings.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fort-lauderdale-florida-january-23-2014-175410500">Serenethos/Shutterstock</a></span>
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<p>Illuminating coastal environments can also alter the bodily functions of many marine animals. Exposure to artificial light can reduce the <a href="http://dx.doi.org/10.1098/rsbl.2019.0272">reproductive success of fish</a>. And research has also found that it can <a href="http://dx.doi.org/10.1016/0006-3207(91)90053-C">disorientate turtle hatchlings</a> and affect their ability to reach the safety of the ocean.</p>
<p>Some species are highly sensitive to even low levels of light. The daily migration of zooplankton, which are a key part of the marine food chain, can be disrupted by artificial light. <a href="https://www.nature.com/articles/s42003-020-0807-6">Research in the Arctic</a> has observed that zooplankton move away from the working light of a ship at depths of at least 200 metres.</p>
<p>Measuring light pollution in nature is a challenge because of the low intensities of light encountered. This is particularly true at greater depths. </p>
<p>But overcoming these challenges is essential to facilitate a better understanding of the ecological impact of light pollution. Research such as ours will guide biologists on future research into the impact of light pollution on marine ecosystems. It will also provide urban planners with the information necessary to balance coastal urban development with the protection of marine ecosystems.</p><img src="https://counter.theconversation.com/content/196525/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Smyth receives funding from the UK Natural Environment Research Council (grants NE/S003568/1 and NE/X006271/1).</span></em></p>Artificial lighting from cities illuminates coastal waters and can change the physiology and behaviour of marine organisms.Tim Smyth, Head of Science: Marine Biogeochemistry and Observations, Plymouth Marine LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1956422022-12-01T00:30:08Z2022-12-01T00:30:08ZBlueWalker 3, an enormous and bright communications satellite, is genuinely alarming astronomers<figure><img src="https://images.theconversation.com/files/498115/original/file-20221129-20-xgedg.jpeg?ixlib=rb-1.1.0&rect=65%2C11%2C3808%2C2646&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Trail from BlueWalker 3 above Kitt Peak telescope in Arizona.</span> <span class="attribution"><a class="source" href="https://www.iau.org/public/images/detail/iau2211a/">KPNO/NOIRLab/IAU/SKAO/NSF/AURA/R. Sparks</a></span></figcaption></figure><p>The night sky is a shared wilderness. On a dark night, away from the city lights, you can see the stars in the same way as your ancestors did centuries ago. You can see the Milky Way and the constellations associated with stories of mythical hunters, sisters and journeys. </p>
<p>But like any wilderness, the night sky can be polluted. Since Sputnik 1 in 1957, <a href="https://sdup.esoc.esa.int/discosweb/statistics/">thousands of satellites</a> and pieces of space junk have been launched into orbit. </p>
<p>For now, satellites crossing the night sky are largely a curiosity. But with the advent of satellite constellations – containing hundreds or thousands of satellites – this could change. </p>
<p>The recent launch of <a href="https://ast-science.com/spacemobile-network/bluewalker-3/">BlueWalker 3</a>, a prototype for a satellite constellation, raises the prospect of bright satellites contaminating our night skies. At 64 square metres, it’s the <a href="https://cosmosmagazine.com/technology/bluewalker-launched-spacex-largest-satellite-astronomers/">largest commercial communications satellite</a> in low Earth orbit – and very bright. </p>
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Read more:
<a href="https://theconversation.com/starlink-amazon-and-others-are-racing-to-fill-the-sky-with-bigger-satellites-to-deliver-mobile-coverage-everywhere-on-earth-190237">Starlink, Amazon and others are racing to fill the sky with bigger satellites to deliver mobile coverage everywhere on Earth</a>
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<h2>Pollution of the night sky</h2>
<p>While spotting satellites in the night sky has been a curiosity, the accelerating number of satellites in orbit means pollution of the night sky could become a serious problem.</p>
<p>On a clear night, particularly near twilight, you can see satellites travelling across the night sky. These satellites are in low Earth orbit, just a few hundred kilometres above Earth and travelling almost 8 kilometres every second. </p>
<p><a href="https://apps.apple.com/us/app/night-sky/id475772902">Apps</a> and <a href="https://www.heavens-above.com">websites</a> allow you to identify or predict the arrival of particular satellites overhead. And it is genuinely fun to see the <a href="https://spotthestation.nasa.gov">International Space Station</a> travelling by, realising that on that speck of light there’s a crew of astronauts. </p>
<p>But in the past few years, the pace of satellite launches has accelerated. SpaceX has made satellite launches cheaper, and it has been launching thousands of Starlink satellites that provide internet services. </p>
<p>Roughly 50 Starlink satellites are launched into orbit by each Falcon 9 rocket, and initially produce a bright train of satellites. These initially produced <a href="https://www.cnet.com/science/a-ufo-sighting-boom-is-coming-thanks-to-spacex-and-oneweb/">UFO reports</a>, but are now sufficiently common to not be particularly newsworthy.</p>
<p>Once the Starlink satellites disperse and move to their operational orbits, they are near the limit of what can be seen with the unaided eye.</p>
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Read more:
<a href="https://theconversation.com/lights-in-the-sky-from-elon-musks-new-satellite-network-have-stargazers-worried-117829">Lights in the sky from Elon Musk's new satellite network have stargazers worried</a>
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<p>However, such satellites are bright enough to produce trails in images taken with telescopes. These trails overwrite the stars and galaxies underneath them, which can only be remedied by taking additional images. Short transient phenomena, such as a brief flash from a <a href="https://www.nasa.gov/mission_pages/swift/bursts/brightest_grb.html">gamma ray burst</a>, could potentially be lost. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A geometric composite image of black night sky with dots of stars and bright lines across them" src="https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=543&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=543&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=543&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=682&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=682&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498206/original/file-20221130-14-t67ynz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=682&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An image from the Blanco 4-meter Telescope with 19 trails from Starlink satellites.</span>
<span class="attribution"><span class="source">CTIO/NOIRLab/NSF/AURA/DECam DELVE Survey</span></span>
</figcaption>
</figure>
<h2>BlueWalker 3</h2>
<p>While Starlink is the largest satellite constellation in service, with thousands of satellites in orbit, others are planned.</p>
<p>Amazon’s Blue Origin plans to launch more than 3,200 <a href="https://www.blueorigin.com/news/amazon-selects-new-glenn-for-kuiper/">Project Kuiper</a> satellites, and <a href="https://ast-science.com/spacemobile-network/">AST SpaceMobile</a> plans to launch <a href="https://www.datacenterdynamics.com/en/news/ast-spacemobile-delays-first-five-constellation-satellites-by-six-months/">100 BlueBird</a> satellites (and perhaps more). </p>
<p>The recently launched BlueBird prototype, BlueWalker 3, has produced genuine alarm among astronomers. </p>
<p>While BlueWalker 3 was initially quite faint, it unfolded a 64 square metre communications array – roughly the size of a squash court. This vast surface is very good at reflecting sunlight, and BlueWalker 3 is now as bright as some of the brightest stars in the night sky.</p>
<p>It’s possible the operational BlueBird satellites <a href="https://twitter.com/steve_larrison/status/1429121796599533572">could be even bigger</a> and brighter. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A starry sky with a black background and a white line trailing across it" src="https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498117/original/file-20221129-16-2d4cyv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">BlueWalker 3 passing over Oukaimeden Observatory on November 16 2022. At its brightest, BlueWalker 3 is brighter than all but a few stars in the night sky.</span>
<span class="attribution"><a class="source" href="https://www.iau.org/public/images/detail/iau2211c/">CLEOsat/Oukaimeden Observatory/IAU CPS/A.E. Kaeouach</a></span>
</figcaption>
</figure>
<p>Large numbers of satellites this bright could be bad – very bad. If there were thousands of satellites this bright, sometimes you would be unable to look at the night sky without seeing bright satellites.</p>
<p>We would lose that sense of wilderness, with an almost constant reminder of technology in our sky.</p>
<p>There could be a big impact on professional astronomy. Brighter satellites do more damage to astronomical images than faint satellites. </p>
<p>Furthermore, many of these satellites broadcast at radio frequencies that could interfere with radio astronomy, transmitting <a href="https://www.iau.org/news/announcements/detail/ann19035/">radio waves</a> above remote sites where <a href="https://www.industry.gov.au/science-technology-and-innovation/space-and-astronomy/co-hosting-ska-telescope/australian-radio-quiet-zone-wa">radio observatories observe the heavens</a>. </p>
<h2>A precipice?</h2>
<p>What happens next is uncertain. <a href="https://www.iau.org/public/themes/satellite-constellations/">The International Astronomical Union</a> has communicated its alarm about satellite constellations, and <a href="https://www.iau.org/news/pressreleases/detail/iau2211/">BlueWalker 3</a> in particular. </p>
<p>However, the approval of satellite constellations by the <a href="https://www.fcc.gov/document/fcc-moves-facilitate-satellite-broadband-competition">US Federal Communications Commission</a> has had relatively little consideration of environmental impacts.</p>
<p>This has recently been flagged as a major problem by the <a href="https://www.gao.gov/products/gao-23-105005">US Government Accountability Office</a>, but whether this leads to concrete change is unclear.</p>
<p>We may be on the edge of a precipice. Will the night sky be cluttered with bright artificial satellites for the sake of internet or 5G? Or will we pull back and preserve the night sky as a globally shared wilderness? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The night sky in charcoal and dark yellow tones, with the Milky Way streaking across on a diagonal" src="https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498210/original/file-20221130-19-bvoyfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For now, under dark skies, we can see the Milky Way and Dark Emu as people have seen them for millennia.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/cafuego/52176359423">cafuego/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/thousands-of-satellites-are-polluting-australian-skies-and-threatening-ancient-indigenous-astronomy-practices-173840">Thousands of satellites are polluting Australian skies, and threatening ancient Indigenous astronomy practices</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/195642/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael J. I. Brown receives research funding from the Australian Research Council and Monash University.
</span></em></p>The stars, planets and Milky Way we see at night are part of a wilderness shared across the globe and across centuries. But does BlueWalker 3 herald a night sky polluted with bright satellites?Michael J. I. Brown, Associate Professor in Astronomy, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1830282022-07-28T02:59:44Z2022-07-28T02:59:44ZArtificial light at night can change the behaviour of all animals, not just humans<figure><img src="https://images.theconversation.com/files/474010/original/file-20220714-9357-wgdrw3.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6016%2C4016&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/indian-softshell-turtle-trying-cross-road-742958275">shutterstock</a></span></figcaption></figure><p>As the Moon rises on a warm evening in early summer, thousands of baby turtles emerge and begin their precarious journey towards the ocean, while millions of moths and fireflies take to the air to begin the complex process of finding a mate. </p>
<p>These nocturnal behaviours, and many others like it, evolved to take advantage of the darkness of night. Yet today, they are under a increasing threat from the presence of artificial lighting.</p>
<p>At its core, artificial light at night (such as from street lights) masks natural light cycles. Its presence blurs the transition from day to night and can dampen the natural cycle of the Moon. Increasingly, we are realising this has dramatic physiological and behavioural consequences, including altering hormones associated with day-night cycles of some species and their seasonal reproduction, and changing the timing of daily activities such as <a href="https://www.nature.com/articles/s41559-020-01322-x">sleeping, foraging or mating</a>. </p>
<p>The increasing intensity and spread of artificial light at night (<a href="https://www.mdpi.com/2072-4292/13/16/3311/htm">estimates suggest 2-6% per year</a>) makes it one of the fastest-growing global pollutants. Its presence has been linked to changes in the <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2012.0216">structure of animal communities</a> and <a href="https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(10)00221-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0169534710002211%3Fshowall%3Dtrue">declines in biodiversity</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-attached-tracking-devices-to-west-africas-green-turtles-this-is-what-we-learnt-183858">We attached tracking devices to West Africa's green turtles. This is what we learnt</a>
</strong>
</em>
</p>
<hr>
<h2>How animals are affected by artificial lighting</h2>
<p>Light at night can both attract and repel. Animals living alongside urban environments are often attracted to artificial lights. Turtles can turn away from the safety of the oceans and head inland, where they may be run over by a vehicle or drown in a swimming pool. Thousands of moths and other invertebrates become trapped and disoriented around urban lights until they drop to the ground or die without ever finding a mate. Female fireflies produce bioluminescent signals to attract a mate, but this light can’t compete with street lighting, so they too may fail to reproduce.</p>
<p>Each year it is estimated <a href="https://www.annualreviews.org/doi/10.1146/annurev-ecolsys-112414-054133">millions of birds</a> are harmed or killed because they are trapped in the beams of bright urban lights. They are disoriented and slam into brightly lit structures, or are drawn away from their <a href="https://www.pnas.org/doi/full/10.1073/pnas.1708574114">natural migration pathways</a> into urban environments with limited resources and food, and more predators.</p>
<p>Other animals, such as bats and small mammals, shy away from lights or may avoid them altogether. This effectively reduces the habitats and resources available for them to live and reproduce. For these species, street lighting is a form of habitat destruction, where a light rather than a road (or perhaps both) cuts through the darkness required for their natural habitat. Unlike humans, who can return to their home and block out the lights, wildlife may have no option but to leave.</p>
<p>For some species, light at night does provide some benefits. Species that are typically only active during the day can extend their foraging time. Nocturnal spiders and geckos frequent areas around lights because they can feast on the multitude of insects they attract. However, while these species may gain on the surface, this doesn’t mean there are no hidden costs. Research with insects and spiders suggests exposure to light at night can affect <a href="https://pubmed.ncbi.nlm.nih.gov/30720239/">immune function</a> and health and alter their <a href="https://pubmed.ncbi.nlm.nih.gov/30324009/">growth, development and number of offspring</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1526201563999522817"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sex-on-the-beach-might-be-fun-for-people-but-its-bad-for-dunes-and-wildlife-171591">Sex on the beach might be fun for people – but it's bad for dunes and wildlife</a>
</strong>
</em>
</p>
<hr>
<h2>How can we fix this?</h2>
<p>There are some real-world examples of effective mitigation strategies. In Florida, many urban beaches use amber-coloured lights (which are less attractive to turtles) and <a href="https://myfwc.com/wildlifehabitats/wildlife/sea-turtle/lighting/">turn off street lights</a> during the turtle nesting season. On Philip Island, Victoria, home to more than a million short-tailed shearwaters, many new street lights are also amber and are <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110114">turned off along known migration pathways</a> during the fledging period to reduce deaths. </p>
<p>In New York, the Tribute in Light (which consists of 88 vertical searchlights that can be seen nearly 100km away) is <a href="https://nycaudubon.org/our-work/conservation/project-safe-flight">turned off for 20-minute periods</a> to allow disoriented birds (and bats) to escape and to reduce the attraction of the structure to migrating animals. </p>
<p>In all cases, these strategies have reduced the ecological impact of night lighting and saved the lives of countless animals.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1542965769444679681"}"></div></p>
<p>However, while these targeted measures are effective, they do not solve what might be yet another global biodiversity crisis. Many countries have outdoor lighting standards, and several independent guidelines have been written but these are not always enforceable and often open to interpretation.</p>
<p>As an individual there are things you can do to help, such as:</p>
<ol>
<li><p>default to darkness: only light areas for a specific purpose</p></li>
<li><p>embrace technology: use sensors and dimmers to manage lighting frequency and intensity</p></li>
<li><p>location, location, location: keep lights close to the ground, shield at the rear, and direct light below the horizontal</p></li>
<li><p>respect the spectrum: choose low-intensity lights that limit the blue, violet and ultraviolet wavelengths. Wildlife is less sensitive to red, orange and amber light</p></li>
<li><p>all that glitters: choose non-reflective finishes for your home. This reduces the scattered light that contributes to sky glow.</p></li>
</ol>
<p>In one sense, light pollution is relatively easy to fix – we can simply not turn on the lights and allow the night to be illuminated naturally by moonlight. </p>
<p>Logistically, this is mostly not feasible as lights are deployed for the benefit of humans who are often reluctant to give them up. However, while artificial light allows humans to exploit the night for work, leisure and play, in doing so we catastrophically change the environment for many other species.</p>
<p>In the absence of turning off the lights, there are other management approaches we can take to mitigate their impact. We can limit their number; reduce their intensity and the time they are on; and, potentially change their colour. Animal species differ in their sensitivity to different colours of light and research suggests some colours (ambers and reds) may be less harmful than the blue-rich white lights becoming commonplace around the world.</p><img src="https://counter.theconversation.com/content/183028/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Therésa Jones receives funding from the Australian Research Council (DP210101915). She is a co-director of the Australasian Dark Sky Alliance (ADSA). </span></em></p><p class="fine-print"><em><span>Kathryn McNamara is employed as a research associate on an ARC grant awarded to Therésa Jones (DP210101915). </span></em></p>While artificially illuminating the night allows humans to make use of the the night, in doing so we catastrophically change the environment for all other species. How can we fix this?Therésa Jones, Associate Professor in Evolution and Behaviour, The University of MelbourneKathryn McNamara, Post-doctoral research associate, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1847302022-07-12T12:33:24Z2022-07-12T12:33:24ZLight pollution is disrupting the seasonal rhythms of plants and trees, lengthening pollen season in US cities<figure><img src="https://images.theconversation.com/files/473427/original/file-20220711-13-xmyjzd.jpg?ixlib=rb-1.1.0&rect=0%2C1772%2C3712%2C2160&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some cities never sleep.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/light-trails-on-city-street-against-sky-at-night-royalty-free-image/1311603238">Noam Cohen/EyeEm via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>City lights that blaze all night are profoundly disrupting urban plants’ phenology – shifting when their buds open in the spring and when their leaves change colors and drop in the fall. New research I coauthored shows how nighttime lights are <a href="https://doi.org/10.1093/pnasnexus/pgac046">lengthening the growing season in cities</a>, which can affect everything from <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">allergies</a> to local economies.</p>
<p>In our study, my colleagues and I analyzed trees and shrubs at about 3,000 sites in U.S. cities to see <a href="https://doi.org/10.1093/pnasnexus/pgac046">how they responded</a> under different lighting conditions over a five-year period. Plants use <a href="https://islandpress.org/books/ecological-consequences-artificial-night-lighting">the natural day-night cycle</a> as a signal of seasonal change along with <a href="https://doi.org/10.1073/pnas.1911117117">temperature</a>.</p>
<p>We found that artificial light alone <a href="https://doi.org/10.1093/pnasnexus/pgac046">advanced the date that leaf buds broke</a> in the spring by an average of about nine days compared to sites without nighttime lights. The timing of the fall color change in leaves was more complex, but the leaf change was still delayed on average by nearly six days across the lower 48 states. In general, we found that the more intense the light was, the greater the difference.</p>
<p><iframe id="gSKIJ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/gSKIJ/9/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>We also projected the future influence of nighttime lights for five U.S. cities – Minneapolis, Chicago, Washington, Atlanta and Houston – based on different scenarios for future global warming and up to a 1% annual increase in nighttime light intensity. We found that increasing nighttime light would likely continue to shift the start of the season earlier, though its influence on the fall color change timing was more complex.</p>
<h2>Why it matters</h2>
<p>This kind of shift in plants’ biological clocks has important implications for the <a href="https://doi.org/10.1016/j.tourman.2018.08.021">economic</a>, <a href="https://theconversation.com/satellites-zoom-in-on-cities-hottest-neighborhoods-to-help-combat-the-urban-heat-island-effect-182925">climate</a>, <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">health</a> and <a href="https://doi.org/10.1098/rsbl.2014.0586">ecological</a> services that urban plants provide.</p>
<p>On the positive side, longer growing seasons could allow urban farms to <a href="https://doi.org/10.2134/jeq2013.01.0031">be active over longer periods of time</a>. Plants could also provide shade to cool neighborhoods earlier in spring and later in fall as global temperatures rise.</p>
<p>But changes to the growing season could also increase plants’ <a href="https://doi.org/10.1038/s41586-018-0399-1">vulnerability to spring frost damage</a>. And it can create a mismatch with the timing of other organisms, <a href="https://doi.org/10.1042/ETLS20190139">such as pollinators</a>, that some urban plants rely on.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Charts show the intensity of urban light in seven representative cities" src="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473542/original/file-20220712-22-1d5slr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Urban light intensity varies among cities, and among neighborhoods within cities.</span>
<span class="attribution"><span class="source">Yuyu Zhou</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>A longer active season for urban plants also suggests an earlier and longer pollen season, which can exacerbate asthma and other breathing problems. A study in Maryland found a <a href="https://doi.org/10.1001/jamanetworkopen.2020.7551">17% increase</a> in hospitalizations for asthma in years when plants bloomed very early.</p>
<h2>What still isn’t known</h2>
<p>How the fall color timing will change going forward as night lighting increases and temperatures rise is less clear. Temperature and artificial light together influence the fall color in a complex way, and our projections suggested that the delay of coloring date due to climate warming might stop midcentury and possibly reverse because of artificial light. This will require more research.</p>
<p>How urban artificial light will change in the future also remains to be seen.</p>
<p>One study found that urban light at night had increased <a href="https://doi.org/10.1126/sciadv.1701528">by about 1.8% per year</a> worldwide from 2012-2016. However, many cities and states are <a href="https://www.ncsl.org/research/environment-and-natural-resources/states-shut-out-light-pollution.aspx">trying to reduce light pollution</a>, including requiring shields to control where the light goes and shifting to LED street lights, which use less energy and have <a href="https://doi.org/10.1111/1365-2664.12927">less of an effect</a> on plants than traditional streetlights with <a href="https://doi.org/10.1038/35036500">longer wavelengths</a>.</p>
<figure class="align-center ">
<img alt="Cars are parked on an old brick residential street at dusk with street lights and trees lining the sidewalks." src="https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/473435/original/file-20220711-14-a2ls8a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Baltimore has been converting its streetlights to LED to save money on energy. LEDs also have less of an impact on plants.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cobblestone-street-and-fells-point-neighborhood-at-royalty-free-image/1179432549">Cyndi Monaghan via Getty Images</a></span>
</figcaption>
</figure>
<p>Urban plants’ phenology may also be influenced by other factors, such as carbon dioxide and soil moisture. Additionally, the faster increase of temperature at night compared to the daytime could lead to different day-night temperature patterns, which might <a href="https://doi.org/10.1016/j.agrformet.2019.107832">affect plant phenology in complex ways</a>.</p>
<p>Understanding these interactions between plants and artificial light and temperature will help scientists <a href="https://doi.org/10.1038/s41558-022-01331-7">predict changes in plant processes under a changing climate</a>. Cities are already serving as natural laboratories.</p><img src="https://counter.theconversation.com/content/184730/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yuyu Zhou receives funding from the College of Liberal Arts and Sciences at Iowa State University. </span></em></p>Artificial light is upending trees’ ability to use the natural day-night cycle as a signal of seasonal change.Yuyu Zhou, Associate Professor of Environmental Science, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1704272021-11-30T21:27:11Z2021-11-30T21:27:11ZSoon, 1 out of every 15 points of light in the sky will be a satellite<figure><img src="https://images.theconversation.com/files/434031/original/file-20211125-13-13t3ndk.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3000%2C1998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Starlink satellites are quite visible in the night sky.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/soon--1-out-of-every-15-points-of-light-in-the-sky-will-be-a-satellite" width="100%" height="400"></iframe>
<p>I’m outside at my rural Saskatchewan farm, chatting with my neighbours who I’ve invited over to appreciate the night sky through my telescope. After exclamations and open-mouthed wonder over Saturn’s rings, and light that has been travelling through space for more than two million years to reach our eyes from the Andromeda Galaxy, our conversation inevitably turns to the pandemic, our work-from-home arrangements and complaints about rural internet. My neighbour casually mentions they’ve just switched to using Starlink for their internet provider.</p>
<p>I glance up and notice a bright satellite moving across the sky, almost certainly a Starlink, since they now make up almost <a href="https://www.unoosa.org/oosa/osoindex/search-ng.jspx?lf_id=#?c=%7B%22filters%22:%5B%7B%22fieldName%22:%22en%23object.status.inOrbit_s1%22,%22value%22:%22Yes%22%7D%5D,%22sortings%22:%5B%7B%22fieldName%22:%22object.launch.dateOfLaunch_s1%22,%22dir%22:%22desc%22%7D%5D%7D">half of the nearly 4,000 operational satellites</a> and they’re extremely bright. I take a deep breath and carefully consider how to discuss the substantial cost that we’re all going to have to pay for Starlink internet.</p>
<p>I don’t blame my neighbours for switching. Here, as in many rural parts of North America, there aren’t <a href="https://www.npr.org/2021/02/16/968457180/how-a-project-to-get-humans-to-mars-could-solve-the-rural-internet-problem">great internet options</a>, and with many people working and taking classes from home during the pandemic, anything that makes life easier is immediately accepted.</p>
<p>But I know exactly how high this cost could be. My paper, forthcoming in <em>The Astronomical Journal</em>, has <a href="https://arxiv.org/pdf/2109.04328.pdf">predictions for what the night sky will look like if satellite companies follow through on their current plans</a>. I also know that because of the geometry of sunlight and the orbits that have been chosen, 50 degrees north, where I live, will be the most severely affected part of the world.</p>
<p>With no regulation, I know that in the near future, <a href="https://www.sciencenews.org/article/satellite-mega-constellations-night-sky-stars-simulations">one out of every 15 points</a> you can see in the sky will actually be relentlessly crawling satellites, not stars. This will be devastating to research astronomy, and will completely change the night sky worldwide.</p>
<h2>The future is too, too bright</h2>
<p>In order to find out how badly the night sky is going to be affected by sunlight reflected from planned satellite megaconstellations, we built an <a href="https://github.com/hannorein/megaconstellations">open-source computer model to predict satellite brightnesses</a> as seen from different places on Earth, at different times of night, in different seasons. We also built a simple <a href="http://megaconstellations.hanno-rein.de/">web app based on this simulation</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UieVD0nuKkY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A simulation of the brightness and number of satellites during a full night for 50 degrees north on the summer solstice.</span></figcaption>
</figure>
<p>Our model uses 65,000 satellites on the orbits filed by four megaconstellation companies: SpaceX Starlink and Amazon Kuiper (United States), OneWeb (United Kingdom) and StarNet/GW (China). We calibrated our simulation to match <a href="https://arxiv.org/pdf/2109.12494.pdf">telescope measurements of Starlink satellites</a>, since they are by far the most numerous.</p>
<p>Starlink has so far made some strides toward dimming their satellites since their first launch, but most are <a href="https://arxiv.org/pdf/2101.00374.pdf">still visible to the naked eye</a>.</p>
<p>Our simulations show that from everywhere in the world, in every season, there will be dozens to hundreds of satellites visible for at least an hour before sunrise and after sunset. Right now, it’s relatively easy to escape urban light pollution for dark skies while camping or visiting your cabin, but our simulations show that you can’t escape this new satellite light pollution anywhere on Earth, even at the North Pole.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/spacexs-starlink-satellites-are-about-to-ruin-stargazing-for-everyone-149516">SpaceX's Starlink satellites are about to ruin stargazing for everyone</a>
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<p>The most severely affected locations on Earth will be 50 degrees north and south, near cities like London, Amsterdam, Berlin, Prague, Kiev, Vancouver, Calgary and my own home. On the summer solstice, from these latitudes, there will be close to 200 satellites visible to the naked eye all night long.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of the night sky showing telegraph wires, trees and streaks of light" src="https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434032/original/file-20211125-17-e7wdrr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Megaconstellations of satellites will be a visible distraction at night.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jabberwock/49863305786/">(Steve Elliott/flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>I study orbital dynamics of the Kuiper Belt, <a href="https://solarsystem.nasa.gov/news/792/10-things-to-know-about-the-kuiper-belt/">a belt of small bodies beyond Neptune</a>. My research relies on long time-exposure, wide-field imaging to <a href="https://theconversation.com/how-we-discovered-840-minor-planets-beyond-neptune-and-what-they-can-tell-us-96431">discover and track these small bodies</a> to learn about the history of our Solar System.</p>
<p>The telescope observations that are key to learning about our universe are about to get <a href="https://www.lsst.org/content/lsst-statement-regarding-increased-deployment-satellite-constellations">much, much harder</a> because of unregulated development of space. </p>
<p>Astronomers are creating some <a href="https://regmedia.co.uk/2021/11/04/satcon2_working_groups_reports.pdf">mitigation strategies</a>, but they will require time and effort that should be paid for by megaconstellation companies.</p>
<h2>Unknown environmental costs</h2>
<p>Starlink internet might appear cheaper than other rural options, but this is because <a href="https://doi.org/10.1038/s41598-021-89909-7">many costs are offloaded</a>. One immediate cost is <a href="https://www.theguardian.com/science/2021/jul/19/billionaires-space-tourism-environment-emissions">atmospheric pollution</a> from the hundreds of rocket launches required to build and maintain this system. </p>
<p>Every satellite deployment dumps spent rocket bodies and other debris into already-crowded low Earth orbit, increasing <a href="http://astriacss03.tacc.utexas.edu/ui/min.html">collision risks</a>. Some of this space junk will eventually fall back to Earth, and those parts of the globe with the highest overhead satellite densities will also be the <a href="https://www.smithsonianmag.com/smart-news/after-fiery-display-spacex-debris-landed-washington-farm-180977494/">most likely to be literally impacted</a>.</p>
<p>Starlink plans to replace each of the 42,000 satellites after five years of operation, which will require de-orbiting an average 25 satellites per day, about six tons of material. The mass of these satellites won’t go away — it will be <a href="https://www.space.com/starlink-satellite-reentry-ozone-depletion-atmosphere">deposited in the upper atmosphere</a>. Because satellites comprise mostly aluminium alloys, they may form alumina particles as they vaporize in the upper atmosphere, potentially destroying ozone and causing global temperature changes. </p>
<p>This has not yet been studied in-depth because low Earth orbit is not currently subject to any environmental regulations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A rocket with a large white cloud trail against a bright blue sky" src="https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434034/original/file-20211125-15-1xf2vkj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A SpaceX Falcon 9 rocket lifts off from Cape Canaveral, Fla., with satellites for SpaceX’s Starlink broadband network.</span>
<span class="attribution"><span class="source">(AP Photo/John Raoux)</span></span>
</figcaption>
</figure>
<h2>Regulating the sky</h2>
<p>Currently, low Earth orbit, where all of these satellites are planned to operate, is almost completely unregulated. There are no rules about light pollution, atmospheric pollution from launches, atmospheric pollution from re-entry, or collisions between satellites.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-not-too-late-to-save-the-night-sky-but-governments-need-to-get-serious-about-protecting-it-158394">It's not too late to save the night sky, but governments need to get serious about protecting it</a>
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<hr>
<p>These megaconstellations might not even be <a href="https://arxiv.org/pdf/2011.05168.pdf">financially viable over the long term</a>, and internet speeds may slow to a crawl when <a href="https://doi.org/10.1109/ACCESS.2021.3119634">many users connect at the same time</a> or when <a href="https://www.doi.org/10.1126/science.acx9299">it rains</a>.</p>
<p>But companies are launching satellites right now at a frenetic pace, and the damage they do to the night sky, the atmosphere and the safety of low Earth orbit will not be undone even if the operators go bankrupt.</p>
<p>There’s no doubt that rural and remote internet users in many places have been left behind by internet infrastructure development. But there are many other options for internet delivery that will not result in such extreme costs.</p>
<p>We can’t accept the <a href="https://www.vice.com/en/article/k78mnz/spacexs-satellite-megaconstellations-are-astrocolonialism-indigenous-advocates-say">global loss of access to the night sky</a>, which we’ve been able to see and connect with for as long as we’ve been human.</p>
<p>With co-operation instead of competition between satellite companies, we could have many fewer in orbit. By changing the design of satellites, they could be made much fainter, having less of an impact on the night sky. We shouldn’t have to make a choice between astronomy and the internet. </p>
<p>But without regulations requiring these changes, or strong pressure from consumers indicating the importance of the night sky, our view of the stars will soon be changed forever.</p><img src="https://counter.theconversation.com/content/170427/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samantha Lawler receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>Megaconstellations of satellites will visually clutter the night sky, disrupting astronomical research. And the environmental damage caused by these satellites is still unknown.Samantha Lawler, Assistant professor of astronomy, University of ReginaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1651102021-07-29T15:12:38Z2021-07-29T15:12:38ZSkyglow forces dung beetles in the city to abandon the Milky Way as their compass<figure><img src="https://images.theconversation.com/files/413110/original/file-20210726-17-7nasuh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A dung beetle climbs atop its precious ball to orient itself using the night skies.</span> <span class="attribution"><span class="source">Chris Collingridge</span></span></figcaption></figure><p>Globally, nights are <a href="https://www.nationalgeographic.com/science/article/nights-are-getting-brighter-earth-paying-the-price-light-pollution-dark-skies">becoming ever brighter</a>. Increasing urbanisation and the installation of new streetlights, security floodlights and outdoor ornamental lighting all contribute to growing light pollution. </p>
<p>This light floods directly into the eyes of animals that are active at night and also into the skies. There a proportion of it is redirected back downwards towards an earthbound observer. This is known as “<a href="https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightpollution/skyglow.asp">skyglow</a>”, an omnipresent sheet of light across the night sky in and around cities that can block all but the very brightest stars from view.</p>
<p>We wanted to understand how this change in night brightness would affect animals that rely on the sky as their compass. Would their sensitive eyes be blinded by bright city lights? Would the disappearance of stars from the night sky cause them to lose their way? So we used the well-studied “sky compass” of the nocturnal dung beetle, <em>Scarabaeus satyrus</em>, to <a href="https://doi.org/10.1016/j.cub.2021.06.038">compare orientation</a> under pristine and light polluted skies.</p>
<p><a href="https://doi.org/10.1016/j.cub.2021.06.038">Our study</a> compared the dung-rolling performance of beetles in a rural part of Limpopo province with that of beetles at the University of Witwatersrand in inner city Johannesburg, both in South Africa. Our findings confirm that beetles exposed to light pollution – both directly through the glare of bright artificial lights and indirectly via skyglow that obscures the stars – are forced to change strategy. They abandon their sky compass and rely instead on earthbound artificial lights as beacons.</p>
<p>This change in strategy comes at a cost. </p>
<h2>Light pollution</h2>
<p>These beetles, found across southern Africa, collect dung from various animals, fashioning it into a ball. By rolling this ball away from the dung pile they need not share it with other insects. But even when rolling their ball they are not safe from competition. Their best option is to leave the dung pile as quickly as possible, by using their internal compass to travel in a straight line away from it.</p>
<p>Before rolling the dung away to an area where it can safely dig into the ground, rest and feed, each beetle climbs on top of its ball and performs a brief pirouette termed the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3261170/">orientation “dance”</a>. It scans the scene for features it can use to hold its course. Since it starts each night in unfamiliar territory, the most reliable references are those in the sky that stay stable while the beetle maintains the same heading. On starlit nights, the Milky Way acts as these beetles’ primary reference. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/theres-still-so-much-we-dont-know-about-the-star-gazing-beetle-with-a-tiny-brain-117709">There's still so much we don't know about the star-gazing beetle with a tiny brain</a>
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<p>When the beetles relied on artificial lights to navigate, they all rolled towards them – numerous beetles rolling in the same direction. Under natural conditions, they almost always roll in different directions. Rolling towards artificial lights makes them more likely to encounter one another and fights may break out as the beetles try to steal each other’s dung balls. </p>
<p>Artificial light is also more likely to guide beetles into the concrete and asphalt regions of their immediate environment, where they may find themselves unable to dig into the ground and bury their ball. </p>
<p>It’s not just dung beetles that could be affected by light pollution in this way. Even species that can rely on other compass references may still suffer from the loss of the stars. <a href="https://journals.biologists.com/jeb/article/220/9/1578/19610/Compass-cues-used-by-a-nocturnal-bull-ant-Myrmecia">Nocturnal ants</a> use landmarks for outbound journeys, but need their sky compass when returning home. Migratory birds have a magnetic compass, with which they check latitude and magnetic North, but use their sky compass to calibrate their magnetic compass to geographic North. </p>
<p>In the worst case, animals that need the stars to find their home or breeding site may never make it. But even with their backup systems, starless skies may cause them to gradually deviate off course, wasting energy and risking predator encounters. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/monarch-butterflies-navigate-using-magnetism-28440">Monarch butterflies navigate using magnetism</a>
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</em>
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<hr>
<h2>Country beetle and city beetle</h2>
<p>We collected two sets of ten beetles at the same site, then transported them to our chosen locations.</p>
<p>When the skies were clear at both locations, beetles rolled their ball to the edge of a circular arena. Each beetle could be collected with its ball at the arena’s edge and replaced at the centre ten times in row, without losing its focus. This allowed us to record ten exit bearings for each beetle, to measure the accuracy of their compass under both pristine and light-polluted skies.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people, both in dark clothing, are standing alongside two cameras. One is squatting, one is standing. The sky is full of stars, and the people are gazing at a small object on a lit-up pink circle on the ground" src="https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/413118/original/file-20210726-13-hz2kca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dr James Foster and Prof. Marie Dacke performing orientation experiments at a dark-sky site in rural Limpopo.</span>
<span class="attribution"><span class="source">Chris Collingridge</span></span>
</figcaption>
</figure>
<p>We also recorded the experimental conditions using a camera with a fisheye lens pointed up towards the sky. By post-processing these images, we could estimate what compass information should be available to a beetle when it performs its orientation dance. These images revealed that Johannesburg skies were between ten and 100 times brighter than those in rural Limpopo. The Milky Way and most other star patterns were almost completely obscured by skyglow in Johannesburg.</p>
<p>In spite of this dramatic loss of sky compass references, the beetles in Johannesburg performed at least as well as those in rural Limpopo. They maintained the same heading direction across sequential trials with remarkable accuracy. But on closer inspection it appeared that they were using different strategies to hold their course. </p>
<p>Beetles under pristine skies were relying on the Milky Way, as evidenced by a slight tendency to choose headings towards its brightest region. Those under light-polluted skies rolled towards brightly lit buildings. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-moon-and-stars-are-a-compass-for-nocturnal-animals-but-light-pollution-is-leading-them-astray-142301">The Moon and stars are a compass for nocturnal animals – but light pollution is leading them astray</a>
</strong>
</em>
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<p>In our follow-up experiments, the same set of beetles changed their behaviour when exposed to a single floodlight under pristine skies. They rolled towards the floodlight when it was switched on but dispersed away from one another when the light was switched off. </p>
<p>We also confirmed our worst fears about light-polluted skies. When bright lights were blocked from view, beetles in Johannesburg became completely disoriented. The light-polluted sky was of no use to them. Those viewing pristine skies remained comparatively better oriented. </p>
<h2>Solutions exist</h2>
<p>There is a remarkably simple solution to reducing animals’ experience of direct and indirect light pollution: turning off unnecessary lights at night. Where lights cannot be turned off, they can be shielded so that they do not shed light into the surrounding environment and sky.</p>
<p>The International Dark-Skies Association has certified more than 130 “<a href="http://www.darksky.org/our-work/conservation/idsp">International Dark Sky Places</a>”, where artificial lighting has been adjusted to reduce skyglow and light trespass. However, nearly all are in developed countries in the northern hemisphere. </p>
<p>This gap should be addressed. Less-developed regions are often both species-rich and, currently, less light-polluted, presenting an opportunity to invest in lighting solutions before animals there are seriously affected.</p><img src="https://counter.theconversation.com/content/165110/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Foster received funding from the Wallenberg Foundation, the Swedish Science Foundation (VR 2014-4623), the European Research Council (817535-UltimateCOMPASS), National Geographic (NGS-56504R-19), and travel grants to from the Royal Physiographic Society of Lund and Royal Swedish Academy of Sciences to support this work. He is currently supported by the German Science Foundation (DFG).</span></em></p>On starlit nights, the Milky Way acts as these beetles’ primary reference. But light pollution gets in the way.James Foster, Research Fellow, Julius Maximilian University of WürzburgLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1624022021-06-10T11:39:22Z2021-06-10T11:39:22ZWhy so many Iranians plan not to vote this month – podcast<p>In this episode of <a href="https://theconversation.com/uk/topics/the-conversation-weekly-98901">The Conversation Weekly</a>, ahead of Iran’s presidential elections later this month, we look at why so many Iranians are planning not to vote. And why light pollution is ruining the romantic mood for fireflies – and how you can help. </p>
<iframe src="https://embed.acast.com/60087127b9687759d637bade/60c0d3c17c2da000131ee87a?cover=true" frameborder="0" allow="autoplay" width="100%" height="110"></iframe>
<p><iframe id="tc-infographic-561" class="tc-infographic" height="100" src="https://cdn.theconversation.com/infographics/561/4fbbd099d631750693d02bac632430b71b37cd5f/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Iranians are about to get the chance to vote for a new president on June 18. Hassan Rouhani, president since 2013, is stepping down after serving two terms in office. The frontrunner to succeed him is Ebrahim Raisi, an ultra-conservative and current head of the judiciary. </p>
<p>It’s the first election since <a href="https://www.nytimes.com/2019/12/01/world/middleeast/iran-protests-deaths.html">a wave of protests</a> hit the country in November 2019, followed by a brutal crackdown by security services in which an <a href="https://www.reuters.com/article/us-iran-protests-specialreport-idUSKBN1YR0QR">estimated 1,500 people were killed.</a> </p>
<p>Getting information about how Iranians view their society and its political leaders is notoriously difficult. People can be scared to answer freely, particularly if they’re called up on the phone by a government-backed pollster. In this episode we speak to two academics in the Netherlands who take a different approach – anonymous online surveys. And they’re getting tens of thousands of people to participate. </p>
<p>Ammar Maleki, assistant professor in public law and governance at Tilburg University, and Pooyan Tamimi Arab, assistant professor of religious studies at Utrecht University carried out <a href="https://gamaan.org/wp-content/uploads/2021/06/GAMAAN-Election-Survey-2021-English-Final.pdf">a new survey</a> about voting intentions in late May, via the <a href="https://gamaan.org/english/">Group for Analyzing and Measuring Attitudes in Iran</a>, a non-profit, independent research organisation. They received responses from 68,000 Iranians living in Iran and found that only 25% plan to vote. Compared to the <a href="https://www.bbc.co.uk/news/world-middle-east-39984066">more than 70%</a> who voted in the last presidential elections in 2017, that’s a dramatic decrease. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-iranians-wont-vote-new-survey-reveals-massive-political-disenchantment-162374">Why Iranians won’t vote: new survey reveals massive political disenchantment</a>
</strong>
</em>
</p>
<hr>
<p>They unpick why so many Iranians plan to abstain and what’s causing this massive political disenchantment. And they explain what some of their previous <a href="https://theconversation.com/irans-secular-shift-new-survey-reveals-huge-changes-in-religious-beliefs-145253">surveys</a> reveal about a growing secular shift in Iran and whether it’s affecting people’s willingness to participate in elections. “This is the miracle of the Islamic Republic,” says Tamimi Arab, “secularisation to this extent would never have been possible under a secular regime.” </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/irans-secular-shift-new-survey-reveals-huge-changes-in-religious-beliefs-145253">Iran's secular shift: new survey reveals huge changes in religious beliefs</a>
</strong>
</em>
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<p>Our second story (26m20s) provides advice on how to ensure future generations continue to enjoy one of nature’s greatest wonders: fireflies. Their glowing light comes from a biochemical reaction in their abdomen and they use it during courtship as a way to communicate. But the light shows up best in the dark – and as Avalon Owens, a PhD candidate in biology at Tufts University, tells us, its effects are dimmed by artificial light. She explains her new research into what actually happens, and how we can help to keep the fireflies blinking in their search for love. </p>
<p>And Haley Lewis, culture and society editor at The Conversation in Ottawa, gives us some recommended reading about the 215 First Nations children found in a mass unmarked grave at a former residential school in British Columbia, Canada (36m10s). </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-longer-the-disappeared-mourning-the-215-children-found-in-graves-at-kamloops-indian-residential-school-161782">No longer 'the disappeared': Mourning the 215 children found in graves at Kamloops Indian Residential School</a>
</strong>
</em>
</p>
<hr>
<p>The Conversation Weekly is produced by Mend Mariwany and Gemma Ware, with sound design by Eloise Stevens and Mau Loseto. Our theme music is by Neeta Sarl. You can find us on Twitter <a href="https://twitter.com/TC_Audio">@TC_Audio</a>, on Instagram at <a href="https://www.instagram.com/theconversationdotcom/?hl=en">theconversationdotcom</a>. or via email on podcast@theconversation.com. You can also sign up to <a href="https://theconversation.com/newsletter?utm_campaign=PodcastTCWeekly&utm_content=newsletter&utm_source=podcast">The Conversation’s free daily email here</a>.</p>
<p>News clips in this episode are from <a href="https://www.youtube.com/watch?v=P7Q2bSpZTBk">France</a> <a href="https://www.youtube.com/watch?v=QSf8gDhTMNk">24</a>, <a href="https://www.youtube.com/watch?v=o7qTFdhbhMI">Al</a> <a href="https://www.youtube.com/watch?v=tZssOvZaMnU">Jazeera</a>, <a href="https://www.youtube.com/watch?v=K4WZ_PloiV0">Channel 4</a>, <a href="https://www.youtube.com/watch?v=12nLyhaXQH0">CBC News</a>, <a href="https://www.youtube.com/watch?v=KL4h4dGzqck">CNN</a>, <a href="https://www.youtube.com/watch?v=ZPyR8wDjmZo">Democracy</a> <a href="https://www.youtube.com/watch?v=ZPyR8wDjmZo&t=74s">Now</a>, <a href="https://www.youtube.com/watch?v=-csyrkV4oU0">AP News</a>, <a href="https://www.youtube.com/watch?v=4r6jmLP3ukU">The Telegraph</a> and <a href="https://www.youtube.com/watch?v=CPWiEkvawz4">Salaam Times</a>. </p>
<p><em>You can listen to The Conversation Weekly via any of the apps listed above, our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a>, or find out how else to <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">listen here</a>.</em></p><img src="https://counter.theconversation.com/content/162402/count.gif" alt="The Conversation" width="1" height="1" />
Plus, why fireflies need dark nights and what you can do about it. Listen to episode 19 of The Conversation Weekly.Gemma Ware, Head of AudioDaniel Merino, Associate Breaking News Editor and Co-Host of The Conversation Weekly PodcastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1582852021-05-20T12:27:23Z2021-05-20T12:27:23ZFireflies need dark nights for their summer light shows – here’s how you can help<figure><img src="https://images.theconversation.com/files/401360/original/file-20210518-15-jn05i2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4897%2C3220&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fireflies light up a June night in central Maine.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/o6LHoG">Mike Lewinski/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Before humans invented fire, the only things that lit up the night were the moon, the stars and <a href="https://oceanservice.noaa.gov/facts/biolum.html">bioluminescent</a> creatures – including fireflies. These ambassadors of natural wonder are soft-bodied beetles that emit “cold light,” using <a href="https://theconversation.com/how-fireflies-glow-and-what-signals-theyre-sending-118574">a biochemical reaction</a> housed in their abdominal lanterns.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two fireflies on a leaf, back ends touching." src="https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1073&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1073&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1073&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1349&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1349&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401739/original/file-20210519-19-9m1u0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1349&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fireflies mating.</span>
<span class="attribution"><span class="source">Sara Lewis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Fireflies exchange bioluminescent courtship signals as a precursor to mating. In doing so, they construct spectacular light shows that inspire joy and delight in people <a href="https://doi.org/10.1111/csp2.391">all around the world</a>. Unfortunately, human activities threaten to extinguish these silent sparks.</p>
<p>In recent decades, fireflies have vanished from many places where they were once found. Like other insects, fireflies are <a href="https://doi.org/10.1093/biosci/biz157">threatened by habitat loss and pesticide use</a>. They are also uniquely vulnerable to the harmful effects of <a href="https://www.darksky.org/light-pollution/">light pollution</a>.</p>
<p>As scientists who study <a href="https://scholar.google.com/citations?user=-Dg42W8AAAAJ&hl=en">fireflies</a> and how they are <a href="https://scholar.google.com/citations?user=LLRndSkAAAAJ&hl=en">affected by artificial light</a>, we want to make sure that future generations can continue to enjoy one of nature’s greatest wonders.</p>
<h2>A life in the dark</h2>
<p>Fireflies evolved some <a href="https://onlinelibrary.wiley.com/doi/10.1111/syen.12132">100 million years ago</a> and have blossomed into more than 2,200 species that are found on every continent except Antarctica. Here in North America, nearly 150 different species of flashing firefly light up our summer nights.</p>
<p><a href="https://open.spotify.com/episode/58x6G2G2V7tOdeObJGobT2?si=Nsx37tL1QqqBTCz67FJ1Eg&t=1587&context=spotify%3Aepisode%3A58x6G2G2V7tOdeObJGobT2&dl_branch=1"><img src="https://images.theconversation.com/files/405690/original/file-20210610-27-14d8zsk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=212&fit=crop&dpr=1" alt="Promotional image for podcast" width="100%"></a>
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<em>Find other ways to listen to <a href="https://theconversation.com/why-so-many-iranians-plan-not-to-vote-this-month-podcast-162402%22%22">The Conversation Weekly podcast</a> here.</em></p>
<p>Most North American species have a two- to four-week mating season. Each evening, males and females engage in a dash of light flirtation. The males fly around, producing a species-specific pattern of flashes. Females, perched in the undergrowth, discreetly respond when they are interested with flashes of their own.</p>
<p>For the vast majority of evolutionary history, nighttime light sources were predictable and short-lived: The sun set, and the moon waned. But as advances in technology made it cheaper and easier for humans to light up their environment, light pollution has become a constant presence in urban, suburban and rural habitats.</p>
<p>Human-caused light sources – house lights, path lights, streetlights – often shine all night, year-round. Humans can use curtains to block out a neighbor’s annoying LED floodlight, but nocturnal animals aren’t so fortunate. The more we light up the night, the less space we leave for the firefly flash dance.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/0BOjTMkyfIA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Synchronous fireflies, native to the U.S. Southeast, coordinate their flashes into bursts that ripple through groups of insects.</span></figcaption>
</figure>
<h2>Blinded by the light</h2>
<p>We and <a href="https://fireflyersinternational.net/">other firefly researchers</a> have become increasingly worried about the future of these remarkable insects. More than a decade of <a href="https://doi.org/10.1002/ece3.4557">scientific research</a> offers ample evidence that light pollution is a threat to firefly reproduction. </p>
<p>The fundamental problem is visibility: Fireflies use their bioluminescence to flirt in the dark. It doesn’t work so well with the lights on.</p>
<p>Scientists have known for some time that direct illumination from a nearby streetlight <a href="http://dx.doi.org/10.4236/ae.2015.31004">makes male fireflies flash less</a>, but that is only half the story. As with most animals that engage in complex courtship rituals, female fireflies are the choosy ones – and they are watching the show with the rest of us. When a female sees a male she likes, she flashes back. He zips over, and that’s when the magic happens.</p>
<p>Our <a href="https://doi.org/10.1111/icad.12487">recent lab study</a> shows that females of a common New England firefly species are even more sensitive to direct illumination than their male counterparts. Under artificial light, males flash about half as often, while females rarely, if ever, flash back. </p>
<p><iframe id="LA5D5" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/LA5D5/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>It may be that female fireflies are quite literally blinded by the light shining down into their eyes. Or even if they do manage to pick out a male flash pattern here and there, they might not think it worth a reply. Previous research shows that <a href="https://doi.org/10.1146/annurev.ento.53.103106.093346">female fireflies prefer bright flashes over dim ones</a>, and background light can turn an otherwise bright flash into one that is dull and unimpressive.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Female firefly on a stem, flashing her light." src="https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401766/original/file-20210519-17-i0xmdb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A female firefly signals.</span>
<span class="attribution"><a class="source" href="https://fireflyexperience.org/">Radim Schreiber/Firefly Experience</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The brightness of the artificial light source makes a big difference, but its dominant color is also a factor. Fireflies don’t see blue or red light very well because they have evolved to focus in on the <a href="https://science.sciencemag.org/content/210/4469/560">particular yellow-green hue that they use to communicate</a>. Amber light, which has a yellow-orange hue, is most disruptive to firefly courtship – even more so than white light – because it approaches the color of firefly bioluminescence. </p>
<h2>Help fireflies reclaim the night</h2>
<p>Current research supports a few simple <a href="https://xerces.org/publications/fact-sheets/firefly-friendly-lighting">firefly-friendly lighting guidelines</a> that can help protect both fireflies and <a href="https://www.treehugger.com/worlds-first-bat-friendly-town-turns-night-red-4868381">other animals</a> that need the dark.</p>
<p>First, remove unnecessary light. Lights left on in the middle of the night – especially in natural habitats like backyards, parks and reserves – too often go unused by anyone. Install motion detectors, timers and shielding to ensure that light goes only where people need it, when they need it. These devices can <a href="https://www.darksky.org/light-pollution/energy-waste/">pay for themselves</a> over the long term. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic showing the cost of excess outdoor lighting." src="https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/401369/original/file-20210518-15-35pnhy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In addition to harming nocturnal wildlife, light pollution wastes energy and money.</span>
<span class="attribution"><a class="source" href="https://www.darksky.org/wp-content/uploads/2016/03/Energy-waste-web.jpg">International Dark Sky Association</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>Second, keep necessary light as dim as possible. Modern LEDs tend to be <a href="https://www.darksky.org/our-work/lighting/lighting-for-citizens/led-guide/">much brighter than they need to be</a> for public safety. To easily dim an LED, cover it with a few sheets of paper or layers of painter’s tape. For older lighting types, which can overheat when covered, use heat-resistant cellophane or acrylic gel filters instead.</p>
<p>Finally, remember this: The redder the better! When buying new outdoor lights, opt for monochrome red LEDs. Some lighting manufacturers have begun to tout amber LEDs as “insect-friendly,” but they are not thinking about fireflies. And while <a href="https://www.thespruce.com/yellow-bug-away-lights-2175146">it’s true</a> that amber light doesn’t attract as many flying insects as white light, red light attracts <a href="https://doi.org/10.1002/jez.2188">even fewer</a>.</p>
<p>As with any harmful environmental pollutant, limiting how much artificial light we create will always be more effective than trying to lessen its impact. Fortunately, light pollution is instantly and completely reversible, which means that we can change things for the better for fireflies with the flip of a switch. </p>
<p>Fireflies give us so much, and don’t demand a lot in return – just a bit of dark night to call their own.</p>
<p>[<em>The Conversation’s science, health and technology editors pick their favorite stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-favorite">Weekly on Wednesdays</a>.]</p><img src="https://counter.theconversation.com/content/158285/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Avalon Owens received a 2019 Environmental Fellowship from the Robert & Patricia Swizter Foundation, and is a member of the IUCN SSC Firefly Specialist Group and Zoological Lighting Association.</span></em></p><p class="fine-print"><em><span>Sara Lewis co-chairs the IUCN SSC Firefly Specialist Group. </span></em></p>Fireflies’ summer evening light shows are a delight for humans, but for the insects they are a crucial mating ritual – and human-caused light pollution is a buzz kill.Avalon C.S. Owens, PhD Candidate in Biology, Tufts UniversitySara Lewis, Professor of Biology, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1564832021-03-25T18:54:24Z2021-03-25T18:54:24ZHow shipping ports can become more sustainable<figure><img src="https://images.theconversation.com/files/391285/original/file-20210323-22-1yyu56o.jpg?ixlib=rb-1.1.0&rect=152%2C38%2C8299%2C3015&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Growth in the port industry is expected to continue, and will intensify the adverse environmental effects on marine ecosystems and coastal communities.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p><a href="https://doi.org/10.1016/B978-0-12-805052-1.00030-9">Marine shipping drives 90 per cent of global trade</a>, moving over <a href="https://unctad.org/system/files/official-document/rmt2019_en.pdf">11 billion tonnes of containers, solid and liquid bulk cargo across the world’s seas annually</a>. Almost all consumer products we buy — or the raw materials required to make them — arrive at Canadian ports via ship.</p>
<p>Each year, Canadian port facilities handle about 340 million tonnes of goods, worth about $400 billion. Roughly <a href="https://doi.org/10.1016/j.marpol.2019.103519">25 per cent of Canadian exports and imports</a>, by value, are transported by marine shipping.</p>
<p>Despite their economic importance, ports have adverse effects on the environment, including local air and water pollution, greenhouse gas emissions, noise and air pollution, traffic congestion and <a href="https://doi.org/10.1016/j.marpol.2015.08.018">widespread contamination of sediments</a>. </p>
<p>Society increasingly expects Canadian ports to balance economic growth with social and environmental impacts — and some Canadian ports are already integrating elements of sustainability into their operations. But others could do more.</p>
<h2>Environmental impacts of ports and shipping</h2>
<p>Marine shipping is responsible for <a href="https://doi.org/10.1016/B978-0-12-409548-9.09270-8">two to three per cent of global greenhouse gas emissions</a>. These are predicted to increase to 17 per cent by 2050 if left unchecked. Given these projections, it becomes increasingly important to mitigate <a href="https://theconversation.com/why-decarbonizing-marine-transportation-might-not-be-smooth-sailing-116949">energy use and greenhouse gas emissions of this industry</a> in the face of climate change.</p>
<p>Port activities, such as berthing (mooring), can have environmental impacts including oil spills, local air, noise and light pollution. And <a href="https://doi.org/10.1080/01441647.2014.891162">intermodal transport of cargo in containers on trucks, trains or smaller ships to their final destination</a> also releases carbon dioxide, sulfur dioxide, black carbon and other environmentally harmful greenhouse gases and particulates. </p>
<figure class="align-center ">
<img alt="Stacked cargo containers in front of port cargo lifts." src="https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391499/original/file-20210324-17-fwal3x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cargo containers sit on idle trains at port in Vancouver.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Darryl Dyck</span></span>
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</figure>
<p>Ship traffic produces <a href="https://theconversation.com/quieter-ships-could-help-canadas-endangered-orcas-recover-107515">underwater noise pollution</a>. Ships <a href="https://science.sciencemag.org/content/358/6364/730.2">can strike marine megafauna</a>, such as <a href="https://theconversation.com/new-fishing-rules-aim-to-protect-gulf-of-st-lawrence-right-whales-96158">the North Atlantic right whales in the Gulf of St. Lawrence</a>. Ships may also release <a href="https://tc.canada.ca/en/marine-transportation/marine-safety/ballast-water-defined">ballast water</a> containing aquatic invasive species as they move from one port to another.</p>
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Read more:
<a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">Arctic Ocean: climate change is flooding the remote north with light – and new species</a>
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<h2>Improving environmental performance</h2>
<p>The North American marine industry can participate in voluntary environmental certification programs such as the <a href="https://doi.org/10.1016/j.marpolbul.2016.02.029">Green Marine program</a> to measure and improve environmental performance. <a href="https://green-marine.org/">The program</a> addresses key environmental issues, such as reductions in air pollution and greenhouse gas emissions, through 14 performance indicators. Participants can be shipowners, ports, terminals, seaway corporations and shipyards.</p>
<p>Shore power and alternative fuels have recently gained popularity among global ports because of <a href="https://doi.org/10.1016/j.rtbm.2015.10.008">stringent international regulations to reduce air emissions from ships</a>. </p>
<figure class="align-center ">
<img alt="Looking at a large blue container ship through the window of a smaller boat" src="https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391498/original/file-20210324-15-7ql4tj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A container ship is unloaded in the harbour of Rotterdam, Netherlands, in September 2018.</span>
<span class="attribution"><span class="source">(AP Photo/Peter Dejong)</span></span>
</figcaption>
</figure>
<p>Shore power allows ships to shut off their diesel-powered engines when berthed and connect to the electricity grid to reduce local air pollution and greenhouse gas emissions. </p>
<p>Ports that provide liquified natural gas (LNG) for ship refuelling can also help reduce air pollutants and greenhouse gas emissions. Cargo and cruise ships need to refuel or “bunker,” as it is referred to in the marine industry, when they arrive at a port. Some Canadian ports, including those in Halifax, Montréal and Vancouver, already provide shore power and LNG fuelling facilities. </p>
<p>Ports and port infrastructure stand to be disproportionately affected by sea-level rise, extreme weather and other impacts of climate change and implementing <a href="https://doi.org/10.1007/s10584-011-0043-7">environmental initiatives such as offering shore power for ships to reduce greenhouse gas emissions will become increasingly important</a>.</p>
<p>Currently, all <a href="https://tc.canada.ca/en/marine-transportation/ports-harbours-anchorages/list-canada-port-authorities">18 Canadian major ports</a> participate in the Green Marine program. Several, including the ports of Halifax, Montréal and Vancouver, consistently achieve environmental excellence — the highest possible score. Despite widespread participation in the Green Marine program, only seven ports proactively integrate other elements of sustainability into their operations.</p>
<h2>What about sustainable ports?</h2>
<p>Green ports and sustainable ports are related, but are not quite the same. </p>
<p><a href="https://www.aapa-ports.org/">Port sustainability</a> is defined as the strategies and activities that a port undertakes to meet current and future needs of those who use it, while protecting and sustaining human and natural resources. Similarly, <a href="https://doi.org/10.1080/13675567.2015.1027150">green ports</a> are defined as those engaged in the proactive development, execution and monitoring practices targeted at reducing environmental effects beyond compliance. Whereas <a href="https://doi.org/10.1080/03088839.2020.1736354">green ports only focus on environmental issues</a>, port sustainability considers <a href="https://doi.org/10.1016/j.jclepro.2019.02.098">social, economic and environmental issues</a>.</p>
<p>Generally, <a href="https://doi.org/10.1016/j.ocecoaman.2020.105435">European ports are global leaders when it comes to adopting sustainability initiatives</a>. For example, the <a href="https://www.portofrotterdam.com/en/news-and-press-releases/leading-port-authorities-combine-forces-in-climate-action-program">Port of Rotterdam, in the Netherlands, is the largest port in Europe</a>, handling 461 million tonnes of cargo in 2016. Despite its size, the port endeavours to be the world’s most sustainable and is striving for net-zero emissions by 2050. It supplies LNG to tenants, incentivizes use of shore power for ships and includes renewable energy in its electricity mix.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Globe containers holding liquid natural gas" src="https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391500/original/file-20210324-19-1lw8oxz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Containers of liquid natural gas in the Port of Rotterdam.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>However, the Port of Rotterdam is facing increasingly stiff competition in its sustainability aspirations from the Port of Vancouver, Canada’s largest port. In 2016, the Port of Vancouver handled about 142 million tonnes of cargo from 170 countries, and strives to be “<a href="https://www.portvancouver.com/about-us/sustainability/">the most sustainable port in the world</a>.” It offers incentives such as reduced port fees to ship owners that reduce emissions and other environmental effects.</p>
<p>Vancouver’s recent “Port 2050” plan includes programs to monitor and report air pollution emissions, water quality, noise levels, habitat and wildlife impacts. The port measures ambient noise levels in real-time, and has used underwater noise levels to assess their impact on at-risk whales, which prompted the the port <a href="https://theconversation.com/quieter-ships-could-help-canadas-endangered-orcas-recover-107515">to reduce underwater noise levels</a>.</p>
<h2>How can other Canadian ports become more sustainable?</h2>
<p>Growth in the port industry is expected to continue. This growth will intensify adverse environmental effects on marine ecosystems and coastal communities. As society becomes increasingly aware of environmental issues, effective environmental management in port operations becomes essential.</p>
<p>With increasing social and economic demands, along with environmental challenges, port authorities must continue to adopt measures to improve environmental performance and achieve sustainability in port operations. Although all Canadian ports recognize that Green Marine certification can help improve their environmental stewardship, few are proactive at taking additional sustainability initiatives to improve environmental performance as compared to their European peers.</p>
<p>Canadian port authorities must ensure Canadian ports continue to participate in the Green Marine program and improve environmental performance. However, to remain competitive in the global maritime supply chain, they will need to take on more of a leadership role to integrate sustainability measures — beyond that of a single environmental lens. </p>
<p><em>Tahazzud Hossain, an environmental protection officer with the Government of Newfoundland and Labrador, co-authored this article.</em></p><img src="https://counter.theconversation.com/content/156483/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tony Robert Walker receives funding from a Partnership Development Grant from the Canadian Social Sciences and Humanities Research Council (SSHRC).</span></em></p><p class="fine-print"><em><span>Michelle Adams has received funding from a Partnership Development Grant from the Canadian Social Sciences and Humanities Research Council (SSHRC).</span></em></p>Marine shipping generates about three per cent of global greenhouse gas emissions, and port activities can add to local pollution. Ports are now taking action to reduce their environmental impacts.Tony Robert Walker, Associate Professor, School for Resource and Environmental Studies, Dalhousie UniversityMichelle Adams, Associate professor, School for Resource and Environmental Studies, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1564172021-03-04T11:54:07Z2021-03-04T11:54:07ZDiving in the icy depths: the scientists studying what climate change is doing to the Arctic Ocean – The Conversation Weekly podcast<figure><img src="https://images.theconversation.com/files/387534/original/file-20210303-22-udbxj8.jpg?ixlib=rb-1.1.0&rect=17%2C110%2C5652%2C3663&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Arctic is warming two to three times faster than any other place on Earth. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/arctic-ocean-sea-ice-1099602824">Kevin Xu Photography via Shutterstock</a></span></figcaption></figure><p>In this week’s episode of <a href="https://theconversation.com/uk/topics/the-conversation-weekly-98901">The Conversation Weekly</a> podcast, two experts explain how melting ice in the far north is bringing more light to the Arctic Ocean and what this means for the species that live there. And we hear from a team of archaeologists on their new research in Tanzania’s Olduvai Gorge that found evidence of just how adaptable early humans were to the changing environment. </p>
<iframe src="https://embed.acast.com/60087127b9687759d637bade/603fd2cb60fb3d4ddced9015?cover=true&ga=false" frameborder="0" allow="autoplay" width="100%" height="110"></iframe>
<p><iframe id="tc-infographic-561" class="tc-infographic" height="100" src="https://cdn.theconversation.com/infographics/561/4fbbd099d631750693d02bac632430b71b37cd5f/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Every summer, the sea ice in the Arctic melts – but it’s melting more and more each year. In September 2020, the ice covered <a href="https://www.nasa.gov/feature/goddard/2020/2020-arctic-sea-ice-minimum-at-second-lowest-on-record">3.74 million square kilometres</a> in the Arctic. That might sound like a lot, but it was actually the second smallest measurement ever – and roughly half of what was measured in 1980. This dramatic loss is because the Arctic is warming two to three times faster than the rest of the planet. </p>
<p>Scientists are studying what climate change means for the various species that live in the Arctic Ocean. One of the things they’re looking at is light: as the sea ice shrinks, that means more light can get down to the depths, but also more ships can venture into the far north, bringing with them more artificial light. </p>
<p>We speak to two researchers who spend their time diving down into the ocean to study what this increase in light means. Karen Filbee-Dexter, research fellow in the School of Biological Sciences at the University of Western Australia, talks to us about how the increase in sunlight is good news for the Arctic’s <a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">underwater kelp forests</a>. “We’re already way into the climate change future along our Arctic coastlines,” she says, “so it’s not surprising that our ecosystems are responding because these changes are really dramatic and they’re noticeable.”</p>
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Read more:
<a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">Arctic Ocean: climate change is flooding the remote north with light – and new species</a>
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<p>And Jørgen Berge, professor of Arctic marine ecology, at the University of Tromsø in Norway, says that even during the polar night, when the Sun doesn’t come up for months, light plays an important role. “The polar night is certainly not just dark. It’s actually all about different kinds of lights, both background illumination from the Sun, the aurora borealis, the Moon, also biological lights.” He explains his <a href="https://www.nature.com/articles/s42003-020-0807-6.epdf?author_access_token=AhjhVJ9T-Ho3FU8ewme7A9RgN0jAjWel9jnR3ZoTv0NEMXGytZWyu7pRWgNA-Ls9S-OwEeIlQT_1cG84LQxJkHVlTII3ANzs3zXmrS-cLPS7or6UYLjEnyWFmnSN748A-DMYCYQKXSVtuY0VaRAieg%253D%253D">recent research</a> which found out just how disruptive artificial light can be to the creatures that live in these ecosystems. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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</figure>
<p><strong><em>This research is part of <a href="https://theconversation.com/uk/topics/oceans-21-96784">Oceans 21</a></em></strong>
<br><em>Our series on the global ocean opened with <a href="https://oceans21.netlify.app/">five in-depth profiles</a>. Look out for new articles on the state of our oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.</em></p>
<p>In our second story, we head to the warmer climes of the Olduvai Gorge in Tanzania, known as the birthplace of humanity. We speak to a team of researchers, Julio Mercader, professor of anthropology and archaeology at the University of Calgary in Canada, and Pastory Bushozi, director of Humanities Research Centre and Makarius Peter Itambu, lecturer in the College of Humanities, both at the University of Dar es Salaam in Tanzania, about <a href="https://www.nature.com/articles/s41467-020-20176-2">their recent discoveries</a> in the gorge. They found new evidence of just how adaptable early humans were to the changing environment around 2 million years ago. </p>
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Read more:
<a href="https://theconversation.com/finds-in-tanzanias-olduvai-gorge-reveal-how-ancient-humans-adapted-to-change-150755">Finds in Tanzania's Olduvai Gorge reveal how ancient humans adapted to change</a>
</strong>
</em>
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<p>And Laura Hood, politics editor and assistant editor at The Conversation in London, recommends a couple of stories by academics in the UK. </p>
<p>The Conversation Weekly is produced by Mend Mariwany and Gemma Ware, with sound design by Eloise Stevens. Our theme music is by Neeta Sarl.</p>
<p>News clips in this episode from <a href="https://www.youtube.com/watch?v=4tAYdrQadaA">Euronews</a>, <a href="https://www.youtube.com/watch?v=iAXKN3y4SYs">Global News</a> and <a href="https://www.youtube.com/watch?v=hjhj7lEVFZU">DW News</a>. </p>
<p>A transcript of this <a href="https://theconversation.com/climate-change-is-flooding-the-arctic-ocean-with-light-what-it-means-for-the-species-that-live-there-156526">episode is available here</a>.</p>
<p><em>You can listen to The Conversation Weekly via any of the apps listed above, our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a>, or find out how else to <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">listen here</a>.</em></p><img src="https://counter.theconversation.com/content/156417/count.gif" alt="The Conversation" width="1" height="1" />
Plus, new discoveries about early humans in Tanzania’s Olduvai Gorge. Listen to episode 5 of The Conversation Weekly podcast.Gemma Ware, Head of AudioDaniel Merino, Associate Breaking News Editor and Co-Host of The Conversation Weekly PodcastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1525732021-01-15T13:17:05Z2021-01-15T13:17:05ZCities can help migrating birds on their way by planting more trees and turning lights off at night<figure><img src="https://images.theconversation.com/files/378880/original/file-20210114-21-cd2a7a.jpeg?ixlib=rb-1.1.0&rect=50%2C0%2C5568%2C3642&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tennessee warblers (_Leiothlypis peregrina_) breed in northern Canada and spend winters in Central and South America.
</span> <span class="attribution"><span class="source">Kyle Horton</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Millions of birds travel between their breeding and wintering grounds during spring and autumn migration, creating one of the greatest spectacles of the natural world. These journeys often span incredible distances. For example, the <a href="https://doi.org/10.1098/rsbl.2014.1045">Blackpoll warbler</a>, which weighs less than half an ounce, may travel up to 1,500 miles between its nesting grounds in Canada and its wintering grounds in the Caribbean and South America.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing Blackpoll warbler range" src="https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378931/original/file-20210114-15-x2w6zs.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blackpoll warbler abundance in breeding, non-breeding and migration seasons.</span>
<span class="attribution"><a class="source" href="https://ebird.org/science/status-and-trends/bkpwar/abundance-map?forceLogin=true">Cornell Lab of Ornithology</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For many species, these journeys take place at night, when skies typically are calmer and predators are less active. Scientists do not have a good understanding yet of how birds navigate effectively at night over long distances. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blackpoll warbler" src="https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=362&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=362&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=362&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=455&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=455&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378934/original/file-20210114-23-qtz9i8.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=455&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blackpoll warbler.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Blackpoll_warbler#/media/File:Blackpoll_Warbler_PJT.JPG">PJTurgeon/Wikipedia</a></span>
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<p>We study bird migration and how it is being affected by factors ranging from <a href="https://scholar.google.com/citations?user=S04C3UMAAAAJ&hl=en">climate change</a> to <a href="https://scholar.google.com/citations?user=pPk38-8AAAAJ&hl=en">artificial light at night</a>. In a recent study, we used millions of bird observations by citizen scientists to document the <a href="https://doi.org/10.1016/j.envpol.2020.116085">occurrence of migratory bird species in 333 U.S. cities</a> during the winter, spring, summer and autumn. </p>
<p>We used this information to determine how the number of migratory bird species varies based on each city’s level of <a href="https://www.britannica.com/science/light-pollution">light pollution</a> – brightening of the night sky caused by artificial light sources, such as buildings and streetlights. We also explored how species numbers vary based on the quantity of tree canopy cover and impervious surface, such as concrete and asphalt, within each city. Our findings show that cities can help migrating birds by planting more trees and reducing light pollution, especially during spring and autumn migration.</p>
<h2>Declining bird populations</h2>
<p>Urban areas contain numerous dangers for migratory birds. The biggest threat is the risk of <a href="https://doi.org/10.1650/CONDOR-13-090.1">colliding with buildings or communication towers</a>. Many migratory bird populations have <a href="http://dx.doi.org/10.1126/science.aaw1313">declined over the past 50 years</a>, and it is possible that light pollution from cities is contributing to these losses.</p>
<p>Scientists widely agree that light pollution can <a href="https://doi.org/10.1073/pnas.1708574114">severely disorient migratory birds</a> and make it hard for them to navigate. Studies have shown that birds will cluster around brightly lit structures, much like insects flying around a porch light at night. Cities are the <a href="https://doi.org/10.1002/fee.2029">primary source of light pollution for migratory birds</a>, and these species tend to be more abundant within cities <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.13792">during migration</a>, especially in <a href="https://doi.org/10.1016/j.landurbplan.2020.103892">city parks</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Satellite image of U.S. at night with cities brightly lit" src="https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=482&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=482&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378884/original/file-20210114-24-svu1yl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=482&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Composite image of the continental U.S. at night from satellite photos.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/sites/default/files/thumbnails/image/2016-north-america-usa.jpg">NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center</a></span>
</figcaption>
</figure>
<h2>The power of citizen science</h2>
<p>It’s not easy to observe and document bird migration, especially for species that migrate at night. The main challenge is that many of these species are very small, which limits scientists’ ability to use electronic tracking devices. </p>
<p>With the growth of the internet and other information technologies, new data resources are becoming available that are making it possible to overcome some of these challenges. <a href="https://doi.org/10.1038/d41586-018-07106-5">Citizen science initiatives</a> in which volunteers use online portals to enter their observations of the natural world have become an important resource for researchers.</p>
<p>One such initiative, <a href="https://ebird.org/home">eBird</a>, allows bird-watchers around the globe to share their observations from any location and time. This has produced one of the <a href="https://doi.org/10.1111/ecog.04632">largest ecological citizen-science databases in the world</a>. To date, eBird contains over 922 million bird observations compiled by over 617,000 participants.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/StF19Qdgqn0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Large clusters of birds (blue and green splotches) captured by weather radar during spring migration, April-May 2019.</span></figcaption>
</figure>
<h2>Light pollution both attracts and repels migratory birds</h2>
<p>Migratory bird species have evolved to use certain migration routes and types of habitat, such as forests, grasslands or marshes. While humans may enjoy seeing migratory birds appear in urban areas, it’s generally not good for bird populations. In addition to the many hazards that exist in urban areas, cities typically lack the food resources and cover that birds need during migration or when raising their young. As scientists, we’re concerned when we see evidence that migratory birds are being drawn away from their traditional migration routes and natural habitats.</p>
<p>Through our analysis of eBird data, we found that cities contained the greatest numbers of migratory bird species during spring and autumn migration. Higher levels of light pollution were associated with more species during migration – evidence that light pollution attracts migratory birds to cities across the U.S. This is cause for concern, as it shows that the influence of light pollution on migratory behavior is strong enough to increase the number of species that would normally be found in urban areas.</p>
<p>In contrast, we found that higher levels of light pollution were associated with fewer migratory bird species during the summer and winter. This is likely due to the scarcity of suitable habitat in cities, such as large forest patches, in combination with the adverse affects of light pollution on bird behavior and health. In addition, during these seasons, migratory birds are active only during the day and their populations are largely stationary, creating few opportunities for light pollution to attract them to urban areas.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/08ET47-b13o?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Darkening skies at night during migration season makes it easier for birds to navigate.</span></figcaption>
</figure>
<h2>Trees and pavement</h2>
<p>We found that tree canopy cover was associated with more migratory bird species during spring migration and the summer. Trees provide important habitat for migratory birds during migration and the breeding season, so the presence of trees can have a strong effect on the number of migratory bird species that occur in cities. </p>
<p>Finally, we found that higher levels of impervious surface were associated with more migratory bird species during the winter. This result is somewhat surprising. It could be a product of the <a href="https://www.epa.gov/heatislands">urban heat island effect</a> – the fact that structures and paved surfaces in cities absorb and reemit more of the sun’s heat than natural surfaces. Replacing vegetation with buildings, roads and parking lots can therefore make cities significantly warmer than surrounding lands. This effect could reduce cold stress on birds and increase food resources, such as insect populations, during the winter.</p>
<p>Our research adds to our understanding of how conditions in cities can both help and hurt migratory bird populations. We hope that our findings will inform urban planning initiatives and strategies to reduce the harmful effects of cities on migratory birds through such measures as <a href="https://www.arborday.org/programs/treecityusa/index.cfm">planting more trees</a> and initiating <a href="https://aeroecolab.com/uslights">lights-out programs</a>. Efforts to make it easier for migratory birds to complete their incredible journeys will help maintain their populations into the future.</p><img src="https://counter.theconversation.com/content/152573/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frank La Sorte receives funding from The Wolf Creek Charitable Foundation and the National Science Foundation (DBI-1939187).</span></em></p><p class="fine-print"><em><span>Kyle Horton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Cities are danger zones for migrating birds, but there are ways to help feathered visitors pass through more safelyFrank La Sorte, Research Associate, Cornell Lab of Ornithology, Cornell UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1501572020-12-06T10:01:21Z2020-12-06T10:01:21ZArctic Ocean: climate change is flooding the remote north with light – and new species<figure><img src="https://images.theconversation.com/files/372024/original/file-20201130-15-bi9r3q.jpg?ixlib=rb-1.1.0&rect=62%2C62%2C2932%2C1926&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A boat navigates at night next to large icebergs in eastern Greenland.</span> <span class="attribution"><span class="source">(AP Photo/Felipe Dana)</span></span></figcaption></figure><p>At just over 14 million square kilometres, the Arctic Ocean is the smallest and shallowest of the world’s oceans. It is also the coldest. An expansive raft of sea ice floats near its centre, expanding in the long, cold, dark winter, and contracting in the summer, as the Sun climbs higher in the sky. </p>
<p>Every year, usually in September, the sea ice cover shrinks to its lowest level. The tally in 2020 was a meagre <a href="https://www.nasa.gov/feature/goddard/2020/2020-arctic-sea-ice-minimum-at-second-lowest-on-record">3.74 million square kilometres</a>, the second-smallest measurement in 42 years, and roughly half of what it was in 1980. Each year, as the climate warms, the Arctic is holding onto less and less ice. </p>
<p>The effects of global warming are being felt around the world, but nowhere on Earth are they as dramatic as they are in the Arctic. The Arctic is warming <a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">two to three times faster</a> than any other place on Earth, ushering in far-reaching changes to the Arctic Ocean, its ecosystems and the 4 million people who live in the Arctic.</p>
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<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>This story is part of <a href="https://theconversation.com/uk/topics/oceans-21-96784">Oceans 21</a></em></strong>
<br><em><a href="https://oceans21.netlify.app/">Five profiles open our series on the global ocean</a>, delving into ancient <a href="https://theconversation.com/exploring-the-indian-ocean-as-a-rich-archive-of-history-above-and-below-the-water-line-133817">Indian Ocean</a> trade networks, <a href="https://theconversation.com/it-might-be-the-worlds-biggest-ocean-but-the-mighty-pacific-is-in-peril-150745">Pacific</a> plastic pollution, <a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">Arctic</a> light and life, <a href="https://theconversation.com/the-atlantic-the-driving-force-behind-ocean-circulation-and-our-taste-for-cod-146534">Atlantic</a> fisheries and the <a href="https://theconversation.com/an-ocean-like-no-other-the-southern-oceans-ecological-richness-and-significance-for-global-climate-151084">Southern Ocean</a>’s impact on global climate. Look out for new articles in the lead up to COP26. Brought to you by The Conversation’s international network.</em></p>
<p>Some of them are unexpected. The warmer water is pulling some species further north, into higher latitudes. The thinner ice is carrying more people through the Arctic on cruise ships, cargo ships and research vessels. Ice and snow can almost entirely black out the water beneath it, but climate change is allowing more light to flood in.</p>
<h2>Artificial light in the polar night</h2>
<p>Light is very important in the Arctic. The algae which form the foundation of the Arctic Ocean’s food web convert sunlight into sugar and fat, feeding fish and, ultimately, whales, polar bears and humans.</p>
<p>At high latitudes in the Arctic during the depths of winter, the Sun stays below the horizon for 24 hours. This is called the polar night, and at the North Pole, the year is simply one day lasting six months, followed by one equally long night.</p>
<p>Researchers studying the effects of ice loss deployed moored observatories – anchored instruments with a buoy — in an Arctic fjord in the autumn of 2006, before the fjord froze. When sampling started in the spring of 2007, the moorings had been in place for almost six months, collecting data throughout the long and bitter polar night.</p>
<p>What they detected changed everything.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man on a boat stands with a torch, looking into the polar night." src="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The polar night can last for weeks and even months in the high Arctic.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Life in the dark</h2>
<p>At that time, scientists assumed the polar night was utterly uninteresting. A dead period in which life lies dormant and the ecosystem sinks into a dark and frigid standby mode. Not much was expected to come of these measurements, so researchers were surprised when the data showed that life doesn’t pause at all. </p>
<p>Arctic zooplankton — tiny microscopic animals that eat algae — take part in something called diel vertical migration beneath the ice and in the dead of the polar night. Sea creatures in all the oceans of the world do this, migrating to depth during the day to hide from potential predators in the dark, and surfacing at night to feed. </p>
<p>Organisms use light as a cue to do this, so they shouldn’t logically be able to during the polar night. We now understand the polar night to be a riot of <a href="https://www.springer.com/gp/book/9783030332075">ecological activity</a>. The normal rhythms of daily life continue in the gloom. Clams open and close cyclically, seabirds hunt in almost total darkness, ghost shrimps and sea snails gather in kelp forests to reproduce, and deep-water species such as the <a href="http://www.seawater.no/fauna/cnidaria/periphylla.html">helmet jellyfish</a> surface when it’s dark enough to stay safe from predators. </p>
<p>For most of the organisms active during this period, the Moon, stars and aurora borealis likely give important cues that guide their behaviour, especially in parts of the Arctic not covered by sea ice. But as the <a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">Arctic climate warms</a> and human activities in the region ramp up, these natural light sources will in many places be invisible, crowded out by much stronger artificial light.</p>
<figure class="align-center ">
<img alt="A band of turquoise light in the sky is reflected in the Norwegian fjord below." src="https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=345&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=345&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=345&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=434&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=434&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=434&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The northern lights dance in the sky over Tromsø, Norway.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/northern-lights-aurora-borealis-sky-over-1667574898">Muratart/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Artificial light</h2>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/27386582/">Almost a quarter</a> of all land masses are exposed to scattered artificial light at night, as it’s <a href="https://theconversation.com/the-moon-and-stars-are-a-compass-for-nocturnal-animals-but-light-pollution-is-leading-them-astray-142301">reflected back</a> to the ground from the atmosphere. Few truly dark places remain, and light from cities, coastlines, roads and ships is visible as far as <a href="https://theconversation.com/aliens-could-light-and-noise-from-earth-attract-attention-from-outer-space-121073">outer space</a>. </p>
<p>Even in sparsely populated areas of the Arctic, light pollution is noticeable. Shipping routes, oil and gas exploration and fisheries extend into the region as the sea ice retreats, drawing artificial light into the otherwise inky black polar night. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large ship covered in yellow lights illuminates the icy water." src="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Creatures which have adapted to the polar night over millions of years are now suddenly exposed to artificial light.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>No organisms have had the opportunity to properly adapt to these changes – evolution works on a much longer timescale. Meanwhile, the harmonic movements of the Earth, Moon and Sun have provided reliable cues to Arctic animals for millennia. Many biological events, such as migration, foraging and breeding are highly attuned to their gentle predictability.</p>
<p>In <a href="https://www.nature.com/articles/s42003-020-0807-6.epdf?author_access_token=AhjhVJ9T-Ho3FU8ewme7A9RgN0jAjWel9jnR3ZoTv0NEMXGytZWyu7pRWgNA-Ls9S-OwEeIlQT_1cG84LQxJkHVlTII3ANzs3zXmrS-cLPS7or6UYLjEnyWFmnSN748A-DMYCYQKXSVtuY0VaRAieg%253D%253D">a recent study</a> carried out in the high Arctic archipelago of Svalbard, between mainland Norway and the north pole, the onboard lights of a research vessel were found to affect fish and zooplankton at least 200 metres down. Disturbed by the sudden intrusion of light, the creatures swirling beneath the surface reacted dramatically, with some swimming towards the beam, and others swimming violently away. </p>
<p>It’s difficult to predict the effect artificial light from ships newly navigating the ice-free Arctic will have on polar night ecosystems that have known darkness for longer than modern humans have existed. How the rapidly growing human presence in the Arctic will affect the ecosystem is concerning, but there are also unpleasant questions for researchers. If much of the information we’ve gathered about the Arctic came from scientists stationed on brightly lit boats, how “natural” is the state of the ecosystem we have reported?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seen from a sea ice floe, a large ship on the horizon beams white light into the sky." src="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Research in the Arctic could change considerably over the coming years to reduce light pollution.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Arctic marine science is about to enter a new era with autonomous and remotely operated platforms, capable of operating without any light, making measurements in complete darkness.</p>
<hr>
<p><em>Listen to interviews with two the scientists studying artificial light and kelp forests in the Arctic Ocean in <a href="https://theconversation.com/diving-in-the-icy-depths-the-scientists-studying-what-climate-change-is-doing-to-the-arctic-ocean-the-conversation-weekly-podcast-156417">The Conversation Weekly podcast</a>.</em> </p>
<iframe src="https://embed.acast.com/60087127b9687759d637bade/603fd2cb60fb3d4ddced9015?cover=true&ga=false" frameborder="0" allow="autoplay" width="100%" height="110"></iframe>
<hr>
<h2>Underwater forests</h2>
<p>As sea ice retreats from the shores of Greenland, Norway, North America and Russia, periods with open water are getting longer, and more light is reaching the sea floor. Suddenly, coastal ecosystems that have been hidden under ice for 200,000 years are seeing the light of day. This could be very good news for marine plants like kelp – large brown seaweeds that thrive in cold water with enough light and nutrients. </p>
<p>Anchored to the sea floor and floating with the tide and currents, some species of kelp can grow up to <a href="https://www.montereybayaquarium.org/animals/animals-a-to-z/giant-kelp#:%7E:text=Giant%20kelp%20often%20grows%20in,to%20sway%20in%20ocean%20currents.">50 metres</a> (175 feet) – about the same height as Nelson’s Column in Trafalgar Square, London. But kelp are typically excluded from the highest latitudes because of the shade cast by sea ice and its scouring effect on the seabed. </p>
<figure class="align-center ">
<img alt="Large greeny-brown and frilled fronds of seaweed snake across a gravelly seabed." src="https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Badderlocks, or winged kelp, off the coast of Nunavut in the Canadian Arctic.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These lush underwater forests are set to grow and thrive as sea ice shrinks. <a href="https://deeply.thenewhumanitarian.org/arctic/articles/2016/04/13/let-them-eat-kelp-spinning-gold-from-seaweed">Kelp are not a new arrival to the Arctic though</a>. They were once part of the traditional Greenlandic diet, and polar researchers and explorers observed them along northern coasts more than a century ago. </p>
<p>Some species of kelp may have colonised Arctic coasts after the last ice age, or <a href="https://www.pnas.org/content/117/36/22590">spread out from small pockets</a> where they’d held on. But most kelp forests in the Arctic are smaller and more restricted to patches in deeper waters, compared to the vast swathes of seaweed that line coasts like California’s in the US.</p>
<figure class="align-center ">
<img alt="A scuba diver swims through kelp fronds." src="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A diver explores a four-metre-high sugar kelp forest off Southampton Island, Canada.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Recent evidence from <a href="https://www.pnas.org/content/109/35/14052">Norway</a> and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2012.02765.x">Greenland</a> shows kelp forests are already expanding and increasing their ranges poleward, and these ocean plants are expected to get bigger and grow faster as the Arctic <a href="https://doi.org/10.1016/j.gloplacha.2018.09.005">warms</a>, creating more nooks for species to live in and around. The full extent of Arctic kelp forests remains largely unseen and uncharted, but modelling can help determine how much they have shifted and grown in the Arctic since the 1950s.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the Arctic Circle showing how kelp forests will expand further north as the world warms." src="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=534&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=534&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=534&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=671&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=671&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=671&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Known locations of kelp forests and global trends in predicted average summer surface temperature increase over next two decades, according to IPCC models.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1016/j.gloplacha.2018.09.005">Filbee-Dexter et al. (2018)</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A new carbon sink</h2>
<p>Although large seaweeds come in all shapes and sizes, many are remarkably similar to trees, with long, trunk-like but flexible bodies called stipes. The kelp forest canopy is filled with the flat blades like leaves, while holdfasts act like roots by anchoring the seaweed to rocks below.</p>
<p>Some types of Arctic kelp can grow over <a href="https://www.arctickelp.ca/post/finding-forests">ten metres</a> and form large and complex canopies suspended in the water column, with a shaded and protected understorey. Much like forests on land, these marine forests provide habitats, nursery areas and feeding grounds for many animals and fish, including cod, pollack, crabs, lobsters and sea urchins. </p>
<figure class="align-center ">
<img alt="A cloud of shrimp surrounds a large path of kelp." src="https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Kelp forests offer lots of nooks and crannies and surfaces to settle on, making them rich in wildlife.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Kelp are fast growers, storing carbon in their leathery tissue as they do. So what does their expansion in the Arctic mean for the global climate? Like restoring forests on land, growing underwater kelp forests can help to slow climate change by diverting carbon from the atmosphere.</p>
<p>Better yet, some kelp material breaks off and is swept out of shallow coastal waters and into the deep ocean where it’s effectively removed from the Earth’s carbon cycle. Expanding kelp forests along the Earth’s extensive Arctic coasts could become a growing carbon sink that captures the CO₂ humans emit and locks it away in the deep sea. </p>
<p>What’s happening with kelp in the Arctic is fairly unique – these ocean forests are <a href="https://www.pnas.org/content/113/48/13785.short">embattled</a> in most other parts of the world. Overall, the global extent of kelp forests is on a <a href="https://www.washingtonpost.com/news/theworldpost/wp/2018/10/23/ocean/">downward trend</a> because of ocean heatwaves, pollution, warming temperatures, and outbreaks of grazers like <a href="https://theconversation.com/restore-large-carnivores-to-save-struggling-ecosystems-21828">sea urchins</a>.</p>
<p>Unsurprisingly, it’s not all good news. Encroaching kelp forests could push out unique wildlife in the high Arctic. Algae living under the ice will have nowhere to go, and could disappear altogether. More temperate kelp species may replace endemic Arctic kelps such as <em>Laminaria solidungula</em>.</p>
<figure class="align-center ">
<img alt="A bright orange crab nestles in a thicket of dark brown seaweed." src="https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A crab finds refuge on <em>Laminaria solidungula</em> – the only kelp species endemic to the Arctic.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But kelp are just one set of species among many pushing further and deeper into the region as the ice melts.</p>
<h2>Arctic invasions</h2>
<p>Milne Inlet, on north Baffin Island, Nunavut, Canada, sees <a href="https://doi.org/10.1371/journal.pone.0211815">more marine traffic than any other port in Arctic Canada</a>. Most days during the open-water period, 300-metre-long ships leave the port laden with iron ore from the nearby Mary River Mine. Between <a href="https://www.baffinland.com/_resources/2019_NIRB_AnnualReport.pdf">71 and 82 ships</a> pass through the area annually, most heading to — or coming from <a href="https://tc.canada.ca/en/marine-transportation/marine-safety/ship-safety-bulletins/updates-canadian-ballast-water-reporting-form-ssb-no-07-2018">ports in northern Europe</a>.</p>
<p>Cruise ships, coast guard vessels, pleasure yachts, research icebreakers, cargo supply ships and rigid inflatable boats full of tourists also glide through the area. Unprecedented warming and declining sea ice has attracted new industries and other activities to the Arctic. Communities like Pond Inlet have seen marine traffic <a href="https://doi.org/10.14430/arctic4698">triple in the past two decades</a>.</p>
<figure class="align-center ">
<img alt="Ships anchored offshore in icy water with small group of passengers standing on a point of land." src="https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Passengers from a cruise ship arrive in Pond Inlet, Nunavut.</span>
<span class="attribution"><span class="source">Kimberly Howland</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These ships come to the Arctic from all over the world, carrying a host of aquatic hitchhikers picked up in Rotterdam, Hamburg, Dunkirk and elsewhere. These species — some too small to see with the naked eye — are hidden in the ballast water pumped into on-board tanks to stabilise the ship. They also <a href="https://cdnsciencepub.com/doi/10.1139/cjfas-2014-0473">stick to the hull and other outer surfaces</a>, called “biofouling.” </p>
<p>Some survive the voyage to the Arctic and are released into the environment when the ballast water <a href="http://semaphore.uqar.ca/id/eprint/1481/1/Antoine_Dispas_fevrier2019.pdf">is discharged and cargo loaded</a>. Those that maintain their hold on the outer surface may release eggs, sperm or larvae.</p>
<p>Many of these organisms are innocuous, but some may be invasive newcomers that can cause harm. <a href="https://cdnsciencepub.com/doi/10.1139/cjfas-2014-0473">Research in Canada</a> and <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.12566">Norway</a> has already shown non-native invasive species like bay and acorn barnacles can survive ship transits to the Arctic. This raises a risk for Arctic ecosystems given that invasive species are <a href="http://dx.doi.org/10.1098/rsbl.2015.0623">one of the top causes for extinctions worldwide</a>. </p>
<h2>Expanded routes</h2>
<p>Concern about invasive species extends far beyond the community of Pond Inlet. Around 4 million people live in the Arctic, many of them along the coasts that provide nutrients and critical habitat for a wide array of animals, from Arctic char and ringed seals to polar bear, bowhead whales and millions of migratory birds.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=694&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=694&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=694&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=872&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=872&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=872&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As the Arctic sea ice melts during the summer months, shipping routes are opening up along the Russian coast and through the Northwest Passage. Some say a trans-Arctic route might soon be navigable.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>As waters warm, the shipping season is becoming longer, and new routes, like the Northwest Passage and the Northern Sea Route (along Russia’s Arctic coast), are opening up. Some researchers expect a <a href="https://doi.org/10.1002/2016GL069315">trans-Arctic route across the North Pole might be navigable by mid-century</a>. The increased ship traffic <a href="https://doi.org/10.1111/gcb.15159">magnifies the numbers and kinds of organisms transported into Arctic waters</a>, and the progressively more hospitable conditions improve their odds of survival.</p>
<p>Prevention is the number one way to <a href="https://doi.org/10.1016/j.marpolbul.2007.01.005">keep invasive species out</a> of the Arctic. Most ships must treat their ballast water, using <a href="https://www.imo.org/en/About/Conventions/Pages/International-Convention-for-the-Control-and-Management-of-Ships%27-Ballast-Water-and-Sediments-(BWM).aspx">chemicals or other processes, and/or exchange it</a> to limit the movement of harmful organisms to new locations. Guidelines also recommend ships use special coatings on the hulls and clean them regularly <a href="https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/RESOLUTIONMEPC.207%5B62%5D.pdf">to prevent biofouling</a>. But these prevention measures are not always reliable, and their efficacy in colder environments is <a href="https://waves-vagues.dfo-mpo.gc.ca/Library/40817817.pdf">poorly understood</a>. </p>
<p>The next best approach is to <a href="http://www.stoppinginvasives.com/dotAsset/3a05e4d0-bb25-40ff-a72a-c25a486bb90f.pdf">detect invaders as soon as possible once they arrive</a>, to improve chances for eradication or suppression. But early detection requires widespread monitoring, which can be challenging in the Arctic. Keeping an eye out for the arrival of a new species can be akin to searching for a needle in a haystack, but northern communities may offer a solution.</p>
<p>Researchers in Norway, <a href="https://accs.uaa.alaska.edu/invasive-species/bering-sea-marine-invasives/">Alaska</a> and Canada have found a way to make that search easier by singling out species that have <a href="https://doi.org/10.1007/s10530-017-1553-7">caused harm elsewhere</a> and that could endure Arctic environmental conditions. Nearly two dozen potential invaders show a high chance for <a href="https://doi.org/10.1111/gcb.15159">taking hold in Arctic Canada</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The red king crab was intentionally introduced to the Barents Sea in the 1960s, but is now spreading south along the Norwegian coast.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Among these is the cold-adapted red king crab, native to the Sea of Japan, Bering Sea and North Pacific. It was intentionally introduced to the Barents Sea in the 1960s to establish a fishery and is now spreading south <a href="https://www.researchgate.net/publication/226380427_The_Invasive_History_Impact_and_Management_of_the_Red_King_Crab_Paralithodes_camtschaticus_off_the_Coast_of_Norway">along the Norwegian coast and in the White Sea</a>. It is a large, voracious predator <a href="https://www.cabi.org/isc/datasheet/71549">implicated in substantial declines</a> of harvested shellfish, sea urchins and other larger, slow moving bottom species, with a high likelihood of <a href="https://doi.org/10.1371/journal.pone.0211815">surviving transport in ballast water</a>. </p>
<p>Another is the common periwinkle, which <a href="https://www.cabi.org/isc/datasheet/76460">ruthlessly grazes on lush aquatic plants</a> in shoreline habitats, leaving behind bare or encrusted rock. It has also introduced a parasite on the east coast of North America that causes <a href="https://invasions.si.edu/nemesis/calnemo/SpeciesSummary.jsp?TSN=70419">black spot disease in fishes</a>, which stresses adult fishes and makes them unpalatable, kills juveniles and causes intestinal damage to birds and mammals that eat them. </p>
<h2>Tracking genetic remnants</h2>
<p>New species like these could affect the fish and mammals people hunt and eat, if they were to arrive in Pond Inlet. After just a few years of shipping, a handful of possibly non-native species have <a href="https://www.baffinland.com/_resources/document_portal/1663724-197-R-Rev0-24000-BIM-2019-MEEMP-27AUG-20-cs.pdf">already been discovered</a>, including the invasive <a href="https://invasions.si.edu/nemesis/browseDB/SpeciesSummary.jsp?TSN=-47">red-gilled mudworm (<em>Marenzellaria viridis</em>)</a>, and a <a href="https://invasions.si.edu/nemesis/browseDB/SpeciesSummary.jsp?TSN=93600">potentially invasive tube dwelling amphipod</a>. Both are known to reach high densities, alter the characteristics of the seafloor sediment and compete with native species.</p>
<figure class="align-center ">
<img alt="An orange ship sits in icy water with a rocky slope behind it." src="https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A cargo ship passes through Milne Inlet, Nunavut.</span>
<span class="attribution"><span class="source">Kimberly Howland</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Baffinland, the company that runs the Mary River Mine, is seeking to <a href="https://www.cbc.ca/news/canada/north/hunters-inuit-knowledge-ignored-nunavut-mine-environmental-study-1.5726454">double its annual output</a> of iron ore. If the expansion proceeds, up to 176 ore carriers will pass through Milne Inlet during the open-water season. </p>
<p>Although the future of Arctic shipping remains uncertain, it’s an upward trend that needs to be watched. In Canada, researchers are working with Indigenous partners in communities with high shipping activity — including Churchill, Manitoba; Pond Inlet and Iqaluit in Nunavut; Salluit, Quebec and Nain, Newfoundland — to establish an invasive species monitoring network. One of the approaches includes collecting water and testing it for <a href="https://doi.org/10.1038/s41598-018-27048-2">genetic remnants</a> shed from scales, faeces, sperm and other biological material. </p>
<figure class="align-center ">
<img alt="A group of people sit on shore learning to use sampling equipment." src="https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Members of the 2019 field team from Pond Inlet and Salluit filter eDNA from water samples collected from Milne Inlet.</span>
<span class="attribution"><span class="source">Christopher Mckindsey</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This environmental DNA (eDNA) is easy to collect and can help detect organisms that might otherwise be difficult to capture or are in low abundance. The technique has also <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/edn3.35">improved baseline knowledge of coastal biodiversity</a> in other areas of high shipping, a fundamental step in detecting future change. </p>
<p>Some non-native species have already been detected in the Port of Churchill using eDNA surveillance and other sampling methods, including <a href="http://semaphore.uqar.ca/id/eprint/1481/1/Antoine_Dispas_fevrier2019.pdf">jellyfish, rainbow smelt and an invasive copepod species</a>.</p>
<p>Efforts are underway to expand the network across the Arctic as part of the Arctic Council’s <a href="https://arctic-council.org/en/projects/invasive/">Arctic Invasive Alien Species Strategy</a> to reduce the spread of invasive species. </p>
<p>The Arctic is often called the frontline of the climate crisis, and because of its rapid rate of warming, the region is beset by invasions of all kinds, from new species to new shipping routes. These forces could entirely remake the ocean basin within the lifetimes of people alive today, from frozen, star-lit vistas, populated by unique communities of highly adapted organisms, to something quite different.</p>
<p>The Arctic is changing faster than scientists can document, yet there will be opportunities, such as growing carbon sinks, that could benefit the wildlife and people who live there. Not all changes to our warming world will be wholly negative. In the Arctic, as elsewhere, there are winners and losers.</p><img src="https://counter.theconversation.com/content/150157/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jørgen Berge receives funding from the Norwegian Research Council (300333).</span></em></p><p class="fine-print"><em><span>Carlos Duarte receives funding from King Abdullah University of Science and Technology and the Independent Research Fund of Denmark.</span></em></p><p class="fine-print"><em><span>Dorte Krause-Jensen receives funding from various governmental research funds, such as the Independent Research Fund, Denmark, and private research funds, including the Velux Foundations.</span></em></p><p class="fine-print"><em><span>Karen Filbee-Dexter receives funding from ArcticNet, the Norwegian Blue Forest Network, the Australian Research Council, and the Norwegian Research Council (BlueConnect).</span></em></p><p class="fine-print"><em><span>Kimberly Howland receives funding from Fisheries and Ocean Canada; Natural Resources Canada and Polar Knowledge Canada.</span></em></p><p class="fine-print"><em><span>Philippe Archambault receives funding from ArcticNet.</span></em></p>The Arctic has been a remote place for much of its history. But climate change is bringing global problems and opportunities to its door.Jørgen Berge, Vice Dean for Research, Arctic and Marine Biology, University of TromsøCarlos M. Duarte, Adjunct Professor of Marine Ecology, King Abdullah University of Science and TechnologyDorte Krause-Jensen, Professor, Marine Ecology, Aarhus UniversityKaren Filbee-Dexter, Research Fellow, School of Biological Sciences, The University of Western AustraliaKimberly Howland, Research Scientist/Adjunct University Professor, Université du Québec à Rimouski (UQAR)Philippe Archambault, Professor & CoScientific Director of ArcticNet, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1405562020-09-03T20:02:51Z2020-09-03T20:02:51ZPredators, prey and moonlight singing: how phases of the Moon affect native wildlife<figure><img src="https://images.theconversation.com/files/356253/original/file-20200903-24-onf90z.png?ixlib=rb-1.1.0&rect=113%2C0%2C3814%2C1994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Wes Mountain/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Humans have long been inspired and transfixed by the Moon, and as we’re discovering, moonlight can also change the behaviour of Australian wildlife. </p>
<p>A collection of recently published research has illuminated how certain behaviours of animals – including potoroos, wallabies and quolls – change with variation in ambient light, phases of the Moon and cloud cover. </p>
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Read more:
<a href="https://theconversation.com/how-big-is-the-moon-let-me-compare-118840">How big is the Moon? Let me compare ...</a>
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<p>One <a href="https://www.publish.csiro.au/am/AM19070">study</a> found small mammals were more active on cloudy nights. <a href="https://www.publish.csiro.au/am/AM19056">Another</a> found variation in moonlight led to differing amounts of species captured in non-lethal traps. And a study on willie wagtails found males just love <a href="https://link.springer.com/article/10.1007/s00265-020-02888-z">singing on a full moon</a>. </p>
<p>These findings are interesting from a natural history perspective. But they’ll also help ecologists and conservation scientists better locate and study nocturnal animals, and learn how artificial light pollution is likely changing where animals can live and how they behave. </p>
<h2>Moonlit predator-prey games of hide and seek</h2>
<p>Most of Australia’s mammals are nocturnal, and some smaller species are thought to use the <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.12148">cover of darkness</a> to avoid the attention of hungry predators. However, there’s much we don’t know about such relationships, especially because it can be difficult to study these interactions in the wild. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355672/original/file-20200901-18-1bofr19.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Eastern barred bandicoots became more active on darker nights.</span>
<span class="attribution"><span class="source">Simon Gorta</span></span>
</figcaption>
</figure>
<p>In the relatively diverse mammal community at <a href="https://www.mtrothwell.com.au/">Mt Rothwell</a>, Victoria, we examined how variation in ambient light affected species’ activity, and how this might influence species interactions. Mt Rothwell is a fenced conservation reserve free of feral cats and foxes, and with minimal light pollution. </p>
<p>Over two years, <a href="https://www.publish.csiro.au/am/AM19070">we surveyed</a> the responses of predator and prey species to different light levels from full, half and new moon phases. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/one-little-bandicoot-can-dig-up-an-elephants-worth-of-soil-a-year-and-our-ecosystem-loves-it-132266">One little bandicoot can dig up an elephant's worth of soil a year – and our ecosystem loves it</a>
</strong>
</em>
</p>
<hr>
<p>Potential prey species in our study included <a href="https://theconversation.com/one-little-bandicoot-can-dig-up-an-elephants-worth-of-soil-a-year-and-our-ecosystem-loves-it-132266">eastern barred</a> and <a href="https://theconversation.com/rockin-the-suburbs-bandicoots-live-among-us-in-melbourne-95423">southern brown</a> bandicoots, <a href="https://theconversation.com/cats-wreak-havoc-on-native-wildlife-but-weve-found-one-adorable-species-outsmarting-them-132265">long-nosed potoroos</a>, brushtailed <a href="https://www.zoo.org.au/fighting-extinction/local-threatened-species/brush-tailed-rock-wallaby-southern-population/">rock-wallabies</a>, and <a href="https://theconversation.com/hidden-housemates-when-possums-go-bump-in-the-night-57478">brushtail</a> and common <a href="https://australian.museum/learn/animals/mammals/common-ringtail-possum/">ringtail possums</a>. <a href="https://theconversation.com/eastern-quolls-edge-closer-to-extinction-but-its-not-too-late-to-save-them-65882">Eastern</a> and <a href="https://australian.museum/learn/animals/mammals/spotted-tailed-quoll/">spotted-tailed quolls</a> are their potential predators. </p>
<p>Just as we predicted, <a href="https://www.publish.csiro.au/am/AM19070">we found</a> that while there does appear to be relationships between cloud cover, Moon phase and mammal activity, these interactions depend on the sizes and types of mammals involved. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Spotted tail quoll" src="https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=353&fit=crop&dpr=1 600w, https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=353&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=353&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/356247/original/file-20200903-14-1p3w5r3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The spotted-tailed quoll, a meat-eating marsupial, hunts smaller prey at night.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Both predators and prey generally increased their activity in darker conditions.
Smaller, prey species increased their activity when cloud cover was higher, and predators increased their activity during the half and new moon phases.</p>
<p>This suggests their deadly game of hide and seek might intensify on darker nights. And prey might have to trade off foraging time to reduce their chances of becoming the evening meal. </p>
<h2>What happens in the wild?</h2>
<p>It’s important to acknowledge that studies in sanctuaries such as Mt Rothwell might not always reflect well what goes on in the wild, including in areas where introduced predators, such as feral cats and red foxes, are found. </p>
<p>Another recent <a href="https://www.publish.csiro.au/am/AM19056">study</a>, this time of small mammals in the wilds of Victoria’s Mallee region, sheds further light on the situation. The authors tested if variation in weather and Moon phase affected the numbers of five small mammal species – <a href="https://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=10684">Bolam’s mouse</a>, common <a href="https://australian.museum/learn/animals/mammals/common-dunnart/">dunnart</a>, house <a href="https://australian.museum/learn/animals/mammals/house-mouse/">mouse</a>, southern <a href="https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10560">ningaui</a>, and western <a href="https://www.australiangeographic.com.au/blogs/creatura-blog/2014/09/western-pygmy-possum-burramyidae/">pygmy possum</a> – captured in pitfall traps. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355822/original/file-20200901-24-2ozl6g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Ningauis are less likely to be caught in ecological surveys with increasing moonlight.</span>
<span class="attribution"><span class="source">Kristian Bell</span></span>
</figcaption>
</figure>
<p><a href="https://www.animalethics.org.au/policies-and-guidelines/wildlife-research/pitfall-traps">Pitfall traps</a> are long fences small animals can’t climb over or through, so follow along the side until they fall into a bucket dug in the ground. Ecologists typically use these traps to capture and measure animals and then return them to the wild, unharmed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/eastern-quolls-edge-closer-to-extinction-but-its-not-too-late-to-save-them-65882">Eastern quolls edge closer to extinction – but it’s not too late to save them</a>
</strong>
</em>
</p>
<hr>
<p>At more than 260 sites and over more than 50,000 trap nights, they found wind speed, temperature and moonlight influenced which species were caught and in what numbers. </p>
<p>For example, captures of a small native rodent, Bolam’s mouse, and carnivorous marsupial, southern ningaui, decreased with more moonlight, whereas captures of pygmy possums were higher with more moonlight.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355920/original/file-20200902-18-bwigq7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Variation in the moon phase and associated light can change how active mammals are.</span>
<span class="attribution"><span class="source">Aaron Greenville</span></span>
</figcaption>
</figure>
<h2>Moonlight songbird serenades</h2>
<p><a href="https://link.springer.com/article/10.1007/s00265-020-02888-z">Research</a> from last month has shown even species normally active by day may change their behaviour and activity by night. </p>
<p>It’s not uncommon to hear bird song by night, including the quintessentially Aussie warbling of <a href="https://www.abc.net.au/radionational/programs/offtrack/magpie-behaviour-is-not-just-black-and-white/6746240">magpies</a>. Using bioacoustic recorders and song detection software, these researchers show the willie wagtail – another of Australia’s most recogisable and loved birds – is also a nighttime singer, particularly during the breeding season. </p>
<p>While both male and female wagtails sing by day, it is the males that are most vocal by night. And it seems the males aren’t afraid of a little stage-lighting either, singing more with increasing moonlight, with performances peaking during full moons. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355422/original/file-20200830-24-1gftca2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">While characteristically playful by day, male willie wagtails can really turn on a vocal performance by night.</span>
<span class="attribution"><span class="source">Jim Bendon/Flickr</span></span>
</figcaption>
</figure>
<p>This work provides insight into the importance and potential role of nocturnal song for birds, such as mate attraction or territory defence, and helps us to better understand these behaviours more generally.</p>
<h2>Moonlight affects wildlife conservation</h2>
<p>These studies, and others, can help inform wildlife conservation, as practically speaking, ecological surveys must consider the relative brightness of nights during which work occurred. </p>
<p>Depending on when and where we venture out to collect information about species, and what methods we use (camera traps, spotlighting, and non-lethal trapping) we might have higher or lower chances of detecting certain species. And this might affect our insights into species and ecosystems, and how we manage them. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/355809/original/file-20200901-18-mt1pxa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artificial lighting can change the behaviour of wildlife.</span>
<span class="attribution"><span class="source">Kenny Louie</span></span>
</figcaption>
</figure>
<p>As dark skies become rarer in many places around the world, it also begs a big question. To what extent is <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/1540-9295%282004%29002%5B0191%3AELP%5D2.0.CO%3B2">all the artificial light pollution</a> in our <a href="https://theconversation.com/getting-smarter-about-city-lights-is-good-for-us-and-nature-too-69556">cities</a> and peri-urban areas <a href="https://www.darksky.org/light-pollution/wildlife/">affecting wildlife and ecosystems</a>? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/turn-off-the-porch-light-6-easy-ways-to-stop-light-pollution-from-harming-our-wildlife-132595">Turn off the porch light: 6 easy ways to stop light pollution from harming our wildlife</a>
</strong>
</em>
</p>
<hr>
<p>Pipistrelle <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/acv.12635?campaign=wolearlyview">bats</a>, for example, will be roughly half as active around well-lit bridges than unlit bridges. They’ll also keep further away from well-lit bridges, and fly faster when near them. </p>
<p>This means artificial light might reduce the amount and connectivity of habitat available to some bat species in urban areas. This, in turn could affect their populations. </p>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.12948?campaign=wolearlyview">Research is underway</a> around the world, examining the conservation significance of such issues in more detail, but it’s another timely reminder of the profound ways in which we influence the environments we share with other species. </p>
<hr>
<p><em>We would like to acknowledge Yvette Pauligk, who contributed to our published work at Mt Rothwell, and that the traditional custodians of this land are the Wathaurong people of the Kulin nation.</em></p><img src="https://counter.theconversation.com/content/140556/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Euan Ritchie receives funding from the Australian Research Council, The Australia and Pacific Science Foundation, Australian Geographic, Parks Victoria, Department of Environment, Land, Water and Planning, and the Bushfire and Natural Hazards CRC. Euan Ritchie is a Director (Media Working Group) of the Ecological Society of Australia, and a member of the Australian Mammal Society.</span></em></p><p class="fine-print"><em><span>Courtney Marneweck and Grant Linley do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Three recent studies shed new light, as understanding how the behaviour of Australia’s wildlife changes at night can help scientists better protect them.Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin UniversityCourtney Marneweck, Postdoctoral Researcher in Carnivore Ecology, Clemson UniversityGrant Linley, PhD Candidate, Charles Sturt UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1446472020-08-26T12:21:40Z2020-08-26T12:21:40Z5 ways families can enjoy astronomy during the pandemic<figure><img src="https://images.theconversation.com/files/354734/original/file-20200825-22-dm4gus.jpg?ixlib=rb-1.1.0&rect=53%2C0%2C6000%2C3934&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">With the proper equipment, you can enjoy the beauty of the night sky. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/happy-family-are-watching-meteor-shower-nigh-sky-royalty-free-image/826077456?adppopup=true">Allexxandar via iStock/GettyImages</a></span></figcaption></figure><p>This is a challenging time for families. Schools across the U.S. are struggling to provide a meaningful online experience. The coronavirus pandemic has cut off or restricted many entertainment options. As an <a href="https://scholar.google.com/citations?user=OrRLRQ4AAAAJ&hl=en&oi=ao">astronomer</a>, I believe a great way for families to fill the void and have a meaningful science experience in the time of COVID-19 is to turn their attention to the stars they can see right outside their homes.</p>
<p>The night sky is, and always has been, safe and free.</p>
<p>Here are five ways you can get started.</p>
<h2>Naked eye</h2>
<figure class="align-left ">
<img alt="Three people point up to the night sky to look at beautiful constellations." src="https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354735/original/file-20200825-14-646g1a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=534&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If you travel to the right places, you can witness goregous constellations at night.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/colorful-milky-way-with-silhouette-of-a-family-royalty-free-image/539946058">den-belitsky via iStock/GettyImages</a></span>
</figcaption>
</figure>
<p>You can see a lot with just your eyes. But the night sky is a strange landscape to most people. Just as you would when traveling somewhere unfamiliar, you’ll need a map. <a href="https://skyandtelescope.org/">Sky and Telescope</a> – an astronomy news publication – has a guide to get started, with <a href="https://skyandtelescope.org/wp-content/uploads/GettingStartedNorth.pdf">printable sky maps</a> for any month. The objects of the night sky migrate through a complete cycle over the course of a year.</p>
<p>As the Earth moves around the sun, different stars and constellations come into view, so you can enjoy new sights all through the year. You may find it more convenient to have a planisphere, or sky wheel, a rotating plastic disk that <a href="http://skymaps.com/store/cat04.html">shows the night sky for any date and time</a>. They can be bought for US$10-$20 online.</p>
<p>Spotting planets is trickier since they move among the stars, but there are interactive maps online that show them in the <a href="https://skyandtelescope.org/interactive-sky-chart/">night sky for any time at any location</a>. Your view of the night sky depends on your latitude, so it varies with your specific location. Even easier, there are <a href="https://www.goodhousekeeping.com/life/g26089673/best-stargazing-apps/">smartphone apps</a> that take all the work – and maybe also the fun – out of navigating the night sky.</p>
<p>Hold your phone up and the apps identify stars and overlay the constellation shapes. Some respond to voice commands and add detailed information on celestial objects or show the <a href="https://www.nasa.gov/mission_pages/station/main/index.html">International Space Station</a> as it whizzes overhead. </p>
<h2>Binoculars</h2>
<p>You probably have a pair of binoculars somewhere in your house. If you don’t or you want an upgrade, new binoculars cost anywhere from $35 to over $500, and the lower end of the range is just <a href="https://www.space.com/26021-best-binoculars.html">fine for stargazing</a>. </p>
<p>Perhaps you use them at concerts or for bird-watching. Well, they’re also <a href="https://earthsky.org/human-world/top-tips-for-using-ordinary-binoculars-for-stargazing">perfect for stargazing</a>. There are two numbers on binoculars. They represent the magnification and the lens diameter, so 7 x 50 will magnify an image by a factor of 7 using 50-millimeter lenses. At a dark location, your naked eye will see about 3000 stars. With binoculars this number goes up to 100,000.</p>
<p>The <a href="https://stardate.org/sites/default/files/pdfs/teachers/ObservingTheMoon.pdf">moon is spectacular through binoculars</a>. It’s fun for kids to track a cycle of the moon phases over a month, and then do an <a href="https://www.youtube.com/watch?v=wz01pTvuMa0&list=PLyO4---4Ijl_NS0JabRyGQJmF1iFES433&index=3&t=0s">activity that shows why the moon has phases</a>.</p>
<h2>Small telescopes</h2>
<figure class="align-right ">
<img alt="A young boy and his father view the night sky next to a telescope." src="https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C383%2C255&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354643/original/file-20200825-16-15820bg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Using telescopes one can view hundreds of stars from miles away.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/father-and-son-watching-stars-royalty-free-image/80464402">DAJ/GettyImages</a></span>
</figcaption>
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<p>If you want to make a bigger commitment to exploring the night sky, consider getting a small telescope. Peering through a telescope opens up a world of star clusters, galaxies and nebulae. You can see Saturn’s rings and the moons of Jupiter.</p>
<p>It’s a good idea to <a href="https://skyandtelescope.org/wp-content/uploads/AboutScopes.pdf">read a guide</a> before you take the plunge. Small telescopes range from a hundred to several thousand dollars, but you can get a <a href="https://www.space.com/31229-best-beginner-telescopes.html">good starter one</a> for as little as $200. These basic telescopes usually have a viewfinder attached to help locate objects, but you’ll need sky maps to get the most out of them.</p>
<p>If you can shell out at least $400, you can acquire what are called “GoTo” telescopes that have motors and are computer controlled, where the <a href="https://theplanets.org/best-telescopes-buying-guide/">telescope does the work of finding the deep sky objects</a>. You just have to type the name in or choose from a list. Now you’ll be ready to learn <a href="https://cosmicpursuits.com/1943/how-to-see-averted-vision-and-dark-adaptation/">tricks of the trade</a>, like using a red LED flashlight to preserve your night vision, and looking slightly to the side, which lets you see deeper because the cells near the edge of your retina are more sensitive to low light levels.</p>
<h2>Online resources</h2>
<p>The internet is a great resource for backyard astronomy. You might want to start with a <a href="https://www.youtube.com/watch?v=L-Wtlev6suc&t=266s">Crash Course</a> in naked-eye astronomy. In addition to reviews of apps and binoculars and telescopes, there are <a href="https://skyandtelescope.org/astronomy-news/new-videos-sky-telescopes-skywatching-series-12192014/">tutorials on how to use your new telescope</a>.</p>
<p>You’ll also want to check out Sky and Telescope’s weekly <a href="https://skyandtelescope.org/observing/sky-at-a-glance/">“Sky at a Glance.”</a> BBC’s <a href="https://www.skyatnightmagazine.com/">Sky at Night magazine</a> has a <a href="https://www.youtube.com/channel/UCNXzteckwM7bKNNLwWu5OLw">longer monthly summary</a> of what you can observe.</p>
<p>And if you just want to be inspired by the <a href="https://www.youtube.com/watch?v=xTvvQ65jWVs&t=57s">visual splendor</a> of a dark night sky, there are a number of <a href="https://www.youtube.com/watch?v=Z3xkHmC-KQE">time-lapse videos</a> you can enjoy.</p>
<h2>Dark skies</h2>
<p>Hopefully you’re excited about backyard astronomy, but what you can actually see will depend on where you live.</p>
<p>For tens of thousands of years, the night sky was a familiar friend to our ancestors, and they used it to navigate, tell time and project their myths into the stars and constellations. But the glories of the night sky have been steadily eroded by industrial activity and artificial lights.</p>
<p>[<em>The Conversation’s science, health and technology editors pick their favorite stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-favorite">Weekly on Wednesdays</a>.]</p>
<p>You can see recent measures of night sky brightness in a <a href="https://cires.colorado.edu/Artificial-light">zoomable map</a> of the U.S., where it’s clearly harder to find a dark sky in the eastern half of the country.</p>
<p>To measure how sky brightness affects what you can see, amateur astronomers use something called the <a href="https://nightskypix.com/bortle-scale/">Bortle scale</a>, where 9 is an inner city and 1 is a pristine wilderness. <a href="https://www.darksky.org/light-pollution/">Light pollution</a> is the effect of artificial lighting on the night sky, and you can also see how it affects the familiar <a href="https://academo.org/demos/bortle-scale/">Big Dipper and Orion</a> constellations. </p>
<p><a href="https://www.npca.org/articles/1806-celebrate-dark-skies-at-these-27-national-parks">National parks</a> are great places to enjoy the sky because they try to protect it from artificial lights, and in normal times many national parks offer <a href="https://www.nps.gov/subjects/nightskies/stargaze.htm">astronomy programs</a>. Many are also beginning to <a href="https://www.nps.gov/subjects/nightskies/events.htm">resume those programs</a> with COVID-19 restrictions in place.</p>
<p>If you want to contribute to the effort to raise awareness of light pollution by monitoring the sky brightness where you live, the U.S. national observatories run a project called “<a href="https://www.globeatnight.org/about.php">Globe at Night</a>.”</p>
<p>Anyone can collect data and help a research project by doing <a href="https://scistarter.org/citizen-science">citizen science</a>, which is when non-scientists gather data and contribute to a collective research effort. You can become a citizen scientist and submit your own observations from a computer or smartphone.</p><img src="https://counter.theconversation.com/content/144647/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Impey does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>COVID-19 may have messed up school and shut down a lot of entertainment venues. But you can still brighten things up by doing a little stargazing at night, an astronomer says.Chris Impey, University Distinguished Professor of Astronomy, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.