tag:theconversation.com,2011:/us/topics/rivers-1725/articlesRivers – The Conversation2024-03-28T10:23:50Ztag:theconversation.com,2011:article/2267852024-03-28T10:23:50Z2024-03-28T10:23:50ZBaltimore Key Bridge: how a domino effect brought it down in seconds<p>The <a href="https://www.bbc.co.uk/news/live/world-us-canada-68663071">collapse of the Francis Scott Key Bridge</a> in Baltimore on 26 March was a shocking and tragic event. Six people remain unaccounted for in the disaster, which saw the world’s third largest continuous truss bridge fall into the Patapsco river.</p>
<p>The cause was Singapore-flagged container ship, the Dali, which veered off course, <a href="https://www.cbsnews.com/news/baltimore-bridge-collapse-ship-what-caused-crash-francis-scott-key-dali/">colliding with one of the bridge’s supports</a>, or piers. As the 300 metre-long vessel slammed into the structure, it triggered what’s known as a <a href="https://www.sciencedirect.com/science/article/pii/S2590123023002177">progressive collapse</a>, where a domino effect leads to the entire structure failing. The bridge, built more than 45 years ago, crashed down into the frigid water at 1:28am eastern standard time (5:28 UTC).</p>
<p>But how could one ship bring down this 366m (1,200 ft) structure within seconds of the collision? </p>
<p>A progressive collapse involves the failure of a single element, like the pier, and results in the sequential failure of other connected components. These can include the metallic truss and the bridge’s deck. This type of collapse can have catastrophic consequences in terms of the risk to human life, as well as to the economy of an area and the local environment. </p>
<p>Although it’s impossible to account for every scenario, bridges can be built with inherent features that enhance their resistance to progressive collapse. Typically, bridges can withstand some degree of damage to a pier or part of the superstructure. The bridge deck can even remain safe for vehicles depending on the circumstances.</p>
<p>However, in the case of the Baltimore bridge collapse, the metallic truss was designed <a href="https://www.washingtonpost.com/local/2024/03/26/francis-scott-key-bridge-history-baltimore/">as one continuous system</a>. The space between each support, or pier, is known as the truss span. The collapse of one of the piers effectively doubled the truss span to the next support. This dramatic increase in span exerted a much larger force on the remaining truss structure. </p>
<p>While continuous truss systems are favoured because they can redistribute weight in the event of damage, in this case, the remaining truss elements couldn’t withstand all that extra force after the pier failed. </p>
<p>This resulted in the complete collapse of the truss section above the damaged
pier. The collapse didn’t stop there, however. Due to the interconnected nature of the trusses, the remaining section was initially pulled upwards. The sudden release of this tension created a powerful dynamic effect, ultimately causing the entire bridge to collapse.</p>
<h2>Rare event</h2>
<p>It’s certainly not unknown for ships to strike bridge supports. On May 9, 1980, <a href="https://www.fox13news.com/news/sunshine-skyway-bridge-francis-scott-key-baltimore-tampa-st-pete-florida-pinellas-hillsborough-collapse-boat-freighter">a strikingly similar event</a> took place when a freighter <a href="https://eu.jacksonville.com/picture-gallery/news/state/2019/05/08/photos-sunshine-skyway-bridge-disaster/809810007/">collided with a support pier of the Sunshine Skyway Bridge</a> in Tampa Bay, Florida. As a result, the bridge failed over a similar distance as the Baltimore collapse.</p>
<p>But while bridge designers are acutely aware of the potential for collisions, these are – at the same time – rather rare events. The impact forces on a support pier are also highly variable. A higher speed or heavier ship will significantly increase the force on the pier. And higher vessel traffic in the water boosts the probability of a collision.</p>
<p>In addition, the current method used in the US for calculating the collision force of a ship is based on <a href="https://www.taylorfrancis.com/chapters/edit/10.1201/b15621-9/vessel-collision-design-bridges-michael-knott-zolan-prucz">research conducted between 1967 and 1976</a>. However, a different method would have been used for the Key Bridge, which opened in 1977. Needless to say, vessels as heavy and fast as the Dali were not a common sight in 1977. </p>
<p>In fact, the collision force under some scenarios is likely to be <a href="https://www.newcivilengineer.com/latest/baltimores-366m-span-steel-truss-bridge-collapses-after-being-struck-by-container-ship-26-03-2024/">well beyond the capacity of bridge piers to withstand</a>. This is why bridges have other systems of protection, such as dolphins – a group of pilings situated in the water near a pier, which serve to deflect a vessel or take the energy out of a collision.</p>
<p>There isn’t any information about the system that was installed when the Key Bridge opened in 1977. And some observers have questioned whether the <a href="https://www.nytimes.com/2024/03/26/us/baltimore-key-bridge-structure-support-pier.html">protective barriers around the Baltimore bridge were sufficient</a>.</p>
<p>Regular structural assessments and retrofits are crucial to ensure a bridge meets current safety standards. Concrete and steel, the primary materials in this bridge, are susceptible to deterioration from factors like corrosion and other environmental conditions. </p>
<p>In general, insufficient maintenance or inadequate retrofits can be contributing factors when bridges collapse. However, it must be said there is no evidence this was a factor in this case – and the Key Bridge <a href="https://web.archive.org/web/20240326081517/https://www.cnn.com/2024/03/26/us/baltimore-key-bridge-collapse-tuesday/index.html">was said to be “up to code”</a> when the disaster occurred. </p>
<p>There will be more detail to come on this dramatic and tragic event. And the findings will surely inform future approaches to the design and protection of bridges across busy waterways.</p><img src="https://counter.theconversation.com/content/226785/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Mohamed Shaheen 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>We’ll need to learn the lessons from this disaster.Dr Mohamed Shaheen, Lecturer in Structural Engineering, Loughborough UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2246762024-03-12T17:51:20Z2024-03-12T17:51:20ZHigh levels of PFAS forever chemicals found flowing into River Mersey – new study<figure><img src="https://images.theconversation.com/files/580908/original/file-20240311-18-qst8cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heavy industry and dense urban populations both contribute to high levels of effluent containing toxic forever chemicals that don't biodegrade. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/iconic-image-liverpool-130521821">Shaun Jeffers/Shutterstock</a></span></figcaption></figure><p>Huge volumes of toxic and cancer-causing forever chemicals are flowing into the River Mersey in north-west England. With a busy, industrialised skyline and both <a href="https://www.merseyrivers.org/index.php/about/who-we-are">Manchester and Liverpool</a> nearby, it’s the <a href="https://www.nature.com/articles/s41561-018-0080-1">second-most populated</a> river catchment in the UK after the Thames. </p>
<p><a href="https://theriverstrust.org/key-issues/state-of-our-rivers#:%7E:text=No%20single%20stretch%20of%20river,every%20stretch%20of%20English%20rivers.">None of England’s rivers</a> are in good chemical health. The recent <a href="https://theriverstrust.org/key-issues/state-of-our-rivers">State of Our Rivers 2024</a> report from The Rivers Trust found that one of the most concerning groups of synthetic chemicals, per- and polyfluorinated substances (PFAS), contaminates almost every river in England. </p>
<p>Known as forever chemicals because they can take <a href="https://www.unep.org/topics/chemicals-and-pollution-action/pollution-and-health/persistent-organic-pollutants-pops/and">thousands of years</a> to break down, PFAS <a href="https://enveurope.springeropen.com/articles/10.1186/s12302-023-00721-8">persist</a> in the <a href="https://www.theguardian.com/environment/2022/feb/14/forever-chemicals-pcb-pfas-use-marine-life-to-travel-world-by-sea">environment</a> and accumulate in living things. They <a href="https://chemtrust.org/wp-content/uploads/PFAS_Brief_CHEMTrust_2019.pdf">threaten ecosystems and human health</a>, not just in the Mersey, but in every industrialised river around the world. </p>
<p>My team of hydrologists and I found that levels of two <a href="https://www.iarc.who.int/faq/iarc-monographs-evaluate-the-carcinogenicity-of-perfluorooctanoic-acid-pfoa-and-perfluorooctanesulfonic-acid-pfos/#:%7E:text=PFOA%20is%20carcinogenic%20to%20humans,and%20immunosuppression%20in%20exposed%20humans">cancer-causing PFAS</a> washing off the land and into the Mersey – perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)– are among the highest in the world. Both PFOS and PFOA, now <a href="https://chm.pops.int/Implementation/IndustrialPOPs/PFAS/Overview/tabid/5221/Default.aspx">banned in most countries</a>, were used to make many consumer and <a href="https://www.theguardian.com/environment/2021/sep/14/forever-chemicals-the-hidden-threat-from-the-pfas-toxins-on-your-shelf">industrial products</a> including furniture, cookware and fire-fighting foams.</p>
<p><a href="https://pubs.acs.org/doi/10.1021/acs.estlett.4c00017#:%7E:text=The%20total%20%E2%88%918PFAS,year">Our study</a> established that around 50% of PFOS, a type of PFAS that’s classed as probably carcinogenic, in the River Mersey was coming from supposedly clean water discharges from 44 different wastewater treatment works. PFAS are found in treated water because they are very difficult to remove using current water treatment technologies. Almost all wastewater treatment work effluents in the UK <a href="https://pubmed.ncbi.nlm.nih.gov/34412376/">contain PFAS</a>.</p>
<p>Our research highlights that we don’t really know where the remaining 50% of that PFOS is coming from. Other potential sources include runoff from <a href="https://pfas-exchange.org/wp-content/uploads/PFAS-Exchange-Firefighting-Foam-6.pdf">airports</a> where big amounts of fire-fighting foams are used,
<a href="https://pubs.acs.org/doi/10.1021/acs.estlett.1c00750">agricultural land</a> and <a href="https://www.theguardian.com/environment/2024/feb/01/seventeen-landfills-in-england-make-toxic-liquid-hazardous-to-drinking-water">landfills</a>. Some PFAS could contaminate groundwater or surface waters used as <a href="https://www.usgs.gov/news/national-news-release/tap-water-study-detects-pfas-forever-chemicals-across-us#:%7E:text=At%20least%2045%25%20of%20the,by%20the%20U.S.%20Geological%20Survey.">drinking water</a>. </p>
<p><a href="https://theconversation.com/pfas-you-cant-smell-see-or-taste-these-chemicals-but-they-are-everywhere-and-theyre-highly-toxic-to-humans-196168">PFAS chemicals</a> are all around us and impossible to avoid. Found in everything from food packaging to cosmetic products, they are also used to manufacture <a href="https://www.acea.auto/news/importance-of-fluoropolymers-for-the-clean-energy-transition-and-the-eus-net-zero-industry/">green energy technologies</a> like electric cars and wind turbines. </p>
<p>Whenever PFAS are used to make <a href="https://greensciencepolicy.org/harmful-chemicals/pfas/">these products</a> they end up draining into rivers, so wildlife and humans living in the river basin are exposed to them. We don’t really know the long-term <a href="https://chemtrust.org/pfas/">implications</a> of the current exposure levels. But these chemicals will persist. If we keep discharging them into the environment, PFAS exposure levels – and potential risk to humans – can increase through drinking water contamination and accumulation in the food chain. </p>
<p>Pinpointing exactly where, how and when these chemicals enter rivers is not straightforward so scientists and governments don’t really have the regulatory measures and tools to hold <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969721034628">polluters to account</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial shot of round water treatment container, gree water, spinning filters with grey infrastructure" src="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.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">Significant PFAS levels were found in effluent from 44 wastewater treatment plants flowing into the River Mersey.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-treatment-solution-industrial-aerial-top-1241037328">Avigator Fortuner/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Dilute, disperse and detect</h2>
<p>Since the 1850s, <a href="https://www.merseybasin.org.uk/archive/assets/5/original/MERSEY_6_MINUTE_EXPERT.pdf">the Mersey</a> has been a hub of industry, particularly for <a href="https://www.liverpoolmuseums.org.uk/city-built-cotton">cotton manufacturing</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969703000949">chemical production</a>. Most cities, including Liverpool and Manchester, have been built close to rivers and seas, partly to dilute pollution and <a href="https://onlinelibrary.wiley.com/doi/10.1002/rvr2.7">transport it away</a>. Out of sight, out of mind. </p>
<p>Today, enormous volumes of toxic waste are discharged into rivers and seas because dilution reduces chemical concentrations to extremely low or undetectable levels. But undetectable does not mean toxic chemicals are not present. </p>
<p>PFAS are ubiquitous. These forever chemicals have been detected almost everywhere we look, including in <a href="https://pubs.acs.org/doi/10.1021/acs.est.2c02592">Antarctica</a>, in <a href="https://www.ewg.org/news-insights/news/2023/02/wildlife-warning-more-330-species-contaminated-forever-chemicals">whales and polar bears</a> and in <a href="https://pubs.acs.org/doi/10.1021/acs.est.2c02765">rainwater</a>. <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00106-7/fulltext">Most people on Earth</a> probably have detectable concentrations of PFAS in their blood. An estimated [<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483690/">97% of the US population</a>] have PFAS in their blood, according to one study of 1,682 people.</p>
<h2>A state of flux</h2>
<p>Governments need to <a href="https://echa.europa.eu/hot-topics/perfluoroalkyl-chemicals-pfas">phase out PFAS</a> from society to reduce human exposure and halt their accumulation in the environment and wildlife. The development of safer, healthier, greener alternatives is essential. </p>
<p>Even if the tap gets turned off immediately, the PFAS already in the environment, and in the River Mersey, will persist for thousands of years. To prevent further PFAS entering our rivers, more needs to be known about how they move into and through river systems. As part of our study, we measured this flux. </p>
<p>Instead of measuring a chemical’s concentration, flux is a measure of how much PFAS, for example in kilograms per year, flows off the land and out to sea. By measuring PFAS flux at multiple locations across a river basin like the Mersey, we can distinguish different sources of PFAS to the river, such as runoff from landfills, and establish how much comes from that source. </p>
<p>Governments and environmental regulators need more data like this to develop strategies that will prevent PFAS entering rivers. Our study not only confirmed wastewater treatment works effluents as a source of PFAS to the Mersey, we established exactly how much is coming from that source. This direct accountability is required to effectively target regulations and apply measures that make a difference. </p>
<p>Greater understanding of the flux and movement of PFAS in rivers and seas will help ensure better monitoring and regulation of these toxic forever chemicals – especially in hotspots like the Mersey that should be a top priority for enforcement. </p>
<hr>
<figure class="align-right ">
<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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/224676/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patrick Byrne receives funding from the UKRI Natural Environment Research Council. </span></em></p>Huge amounts of PFAS come from wastewater treatment plants, new study finds.Patrick Byrne, Reader in Hydrology and Environmental Pollution, Liverpool John Moores UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2248692024-03-05T15:02:19Z2024-03-05T15:02:19ZArctic rivers face big changes with a warming climate, permafrost thaw and an accelerating water cycle − the effects will have global consequences<figure><img src="https://images.theconversation.com/files/579392/original/file-20240303-24-mmw6cz.jpg?ixlib=rb-1.1.0&rect=0%2C1333%2C9000%2C6157&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Water from the Mackenzie River, seen from a satellite, carries silt and nutrients from land to the Arctic Ocean.</span> <span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/90703/mackenzie-meets-beaufort">Jesse Allen/NASA Earth Observatory</a></span></figcaption></figure><p>As the Arctic warms, its mighty rivers are changing in ways that could have vast consequences – not only for the Arctic region but for the world.</p>
<p>Rivers represent the land branch of the earth’s hydrological cycle. As rain and snow fall, rivers transport freshwater runoff along with dissolved organic and particulate materials, including carbon, to coastal areas. With the Arctic now warming nearly <a href="https://theconversation.com/arctic-is-warming-nearly-four-times-faster-than-the-rest-of-the-world-new-research-188474">four times faster</a> than the rest of the world, the region <a href="https://doi.org/10.1175/2010JCLI3421.1">is seeing more precipitation</a> and the permafrost is thawing, leading to stronger river flows.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows major rivers and their water sheds, primarily in Russia, Alaska and Canada." src="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=596&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=596&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=596&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=749&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=749&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=749&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Major river basins of the Arctic region.</span>
<span class="attribution"><a class="source" href="https://www.pmel.noaa.gov/arctic-zone/detect/land-river.shtml">NOAA Arctic Report Card</a></span>
</figcaption>
</figure>
<p>We’re climate scientists who study how warming is influencing the water cycle and ecosystems. <a href="https://doi.org/10.5194/tc-18-1033-2024">In a new study</a> using historical data and sophisticated computer models of Earth’s climate and hydrology, we explored how climate change is altering Arctic rivers. </p>
<p>We found that thawing permafrost and intensifying storms will change how water moves into and through Arctic rivers. These changes will affect coastal regions, the Arctic Ocean and, potentially, the North Atlantic, as well as the climate.</p>
<h2>Thawing permafrost: Big changes in Arctic soils</h2>
<p>Permafrost thaw is one of the most consequential changes that the Arctic is experiencing as temperatures rise. </p>
<p>Permafrost is soil that has been <a href="https://climate.mit.edu/explainers/permafrost">frozen for at least two years</a> and often for millennia. It covers approximately 8.8 million square miles (about 22.8 million square kilometers) in Earth’s Northern Hemisphere, but that area is shrinking as the permafrost thaws.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people stand on a cliff with permafrost evident." src="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.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">Erosion reveals ice-rich permafrost near Teshekpuk Lake, Alaska.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgeologicalsurvey/12116729705">Brandt Meixell/USGS</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows where permafrost is found, both in ground and below the ocean." src="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.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"></a>
<figcaption>
<span class="caption">Known permafrost zones in the Northern Hemisphere.</span>
<span class="attribution"><a class="source" href="https://www.grida.no/resources/13519">GRID-Arendal/Nunataryuk</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Historically, most water going into Arctic rivers flows atop frozen permafrost soils in spring. Scientists call this “overland runoff.” </p>
<p>However, our results suggest that as warming continues, an increasing fraction of annual river flow will come from under the surface, through thawed soils in the degrading permafrost. As the overall flow increases with more precipitation, as much as 30% more of it could be moving underground by the end of this century as subsurface pathways expand.</p>
<p>When water flows through soil, it picks up different chemicals and metals. As a result, water coming into rivers will likely have a different chemical character. For example, it may carry more nutrients and dissolved carbon that can affect coastal zones and the global climate. The fate of that mobilized carbon is an active area of study.</p>
<p>More carbon in river water could end up “outgassed” upon reaching placid coastal waters, increasing the amount of carbon dioxide released into the atmosphere, which further drives <a href="https://doi.org/10.1038/nature14338">climate warming</a>. The thaw is also revealing other nasty surprises, such as the <a href="https://www.usatoday.com/story/news/politics/2023/11/18/arctic-permafrost-thawing-deadly-pathogens/71581668007/">emergence of long-frozen viruses</a>. </p>
<h2>More rain and snow, more runoff</h2>
<p>The Arctic’s water cycle is also ramping up as temperatures rise, meaning more precipitation, evaporation, plant transpiration and river discharge. This is primarily due to a warmer atmosphere’s inherent ability to hold more moisture. It’s the same reason that <a href="https://theconversation.com/why-a-warming-climate-can-bring-bigger-snowstorms-176201">bigger snowstorms are occurring</a> as the climate warms. </p>
<p>Our study found that the bulk of the additional precipitation will occur across far northern parts of the Arctic basin. As sea ice disappears in a warming climate, computer models agree that a more open Arctic Ocean will feed more water to the atmosphere, where it will be transported to adjacent land areas to fall as precipitation. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps show increasing snow and rainfall" src="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=410&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Changes projected this century in annual rainfall and snowfall simulated by the computer model used in the study. Red areas represent increases.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.5194/tc-18-1033-2024">Rawlins and Karmalkar, 2024</a></span>
</figcaption>
</figure>
<p>More snow in northern Alaska, Siberia and Canada will lead to more water flowing in rivers, potentially up to 25% more under a high-warming scenario based on our research. There is more carbon in the soil in northern parts of the Arctic compared with the south. With permafrost thaw, those regions will also see more water coming into rivers from below the surface, where additional soil carbon can leach into the water and become dissolved organic carbon.</p>
<p>More <a href="https://doi.org/10.1088/1748-9326/aaa1fe">old carbon is already showing up</a> in samples gathered from Arctic rivers, attributed to permafrost thaw. Carbon dating shows that some of this carbon has been frozen for thousands of years. </p>
<h2>Impacts will cascade through Arctic ecosystems</h2>
<p>So, what does the future hold? </p>
<p>One of the most notable changes expected involves the transport of fresh water and associated materials, such as dissolved organic carbon and heat energy, to Arctic coastal zones. </p>
<figure class="align-center ">
<img alt="A scientist in a rain jacket and cap holds up a water sample in a jar." src="https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.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">James McClelland of the Beaufort Lagoon Ecosystems Long Term Ecological Research program examines a water sample from a stream near Utqiagvik on Alaska’s North Slope. The brown tint is dissolved organic matter.</span>
<span class="attribution"><span class="source">Michael A. Rawlins</span></span>
</figcaption>
</figure>
<p><a href="https://ble.lternet.edu/">Coastal lagoons</a> may become fresher. This change would affect organisms up and down the food chain, though <a href="https://doi.org/10.3389/fmars.2022.738363">our current understanding</a> of the potential affects of changes in fresh water and dissolved organic carbon is still murky.</p>
<p>River water will also be warmer as the climate heats up and has the potential to melt coastal sea ice earlier in the season. Scientists <a href="https://theconversation.com/arctic-report-card-2023-from-wildfires-to-melting-sea-ice-the-warmest-summer-on-record-had-cascading-impacts-across-the-arctic-218872">observed this in spring 2023</a>, when unusually warm water in Canada’s Mackenzie River carried heat to the Beaufort Sea, contributing to early coastal sea ice melting.</p>
<figure class="align-center ">
<img alt="A satellite view of the Arctic coast showing a river and sea ice breaking up." src="https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.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">Fresh water flowing from rivers such as Canada’s Mackenzie River, at the bottom center of the satellite image, into the Beaufort Sea can break up sea ice early.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/83271/river-discharge-alters-arctic-sea-ice">NASA Earth Observatory</a></span>
</figcaption>
</figure>
<p>Finally, more river water reaching the coast has the potential to freshen the Arctic Ocean, particularly along northern Eurasia, where big Russian rivers export massive amounts of fresh water each year. </p>
<p>There are concerns that <a href="https://arctic.noaa.gov/report-card/report-card-2021/river-discharge/">rising river flows in that region</a> are influencing the Atlantic Meridional Overturning Circulation, the currents that circulate heat from the tropics, up along the U.S. East Coast and toward Europe. Evidence is mounting that these currents <a href="https://theconversation.com/the-atlantic-oceans-major-current-system-is-slowing-down-but-a-21st-century-collapse-is-unlikely-214647">have been slowing in recent years</a> as more fresh water enters the North Atlantic. If the circulation shuts down, it would <a href="https://theconversation.com/atlantic-ocean-is-headed-for-a-tipping-point-once-melting-glaciers-shut-down-the-gulf-stream-we-would-see-extreme-climate-change-within-decades-study-shows-222834">significantly affect temperatures</a> across North America and Europe.</p>
<p>At the coast, changing river flows will also affect the plants, animals and Indigenous populations that call the region home. For them and for the global climate, our study’s findings highlight the need to closely watch how the Arctic is being transformed and take steps to mitigate the effects.</p><img src="https://counter.theconversation.com/content/224869/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael A. Rawlins receives funding from The Department of Energy, the National Aeronautics and Space Administration and the U.S. National Science Foundation. </span></em></p><p class="fine-print"><em><span>Ambarish Karmalkar receives funding from the Department of Energy and the United States Geological Survey. </span></em></p>A new study shows how thawing permafrost and intensifying storms will change how water moves into and through Arctic rivers.Michael A. Rawlins, Associate Director, Climate System Research Center and Associate Professor of Climatology, UMass AmherstAmbarish Karmalkar, Assistant Professor of Geosciences, University of Rhode IslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239542024-03-04T13:41:22Z2024-03-04T13:41:22ZRiver pollution is causing harmful outbreaks of sewage fungus in the UK<figure><img src="https://images.theconversation.com/files/577615/original/file-20240223-22-5xtkj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sewage fungus outbreaks are a sign that our freshwater ecosystems are unhealthy and polluted. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/draining-sewage-pipe-into-river-pollution-2163327235">Dmitriy Prayzel</a></span></figcaption></figure><p>The pollution of the UK’s waterways and coastlines with sewage is throwing its ecosystems out of balance. One well documented example is the spread of microscopic bacteria that can multiply rapidly into <a href="https://theconversation.com/extensive-algal-blooms-in-englands-lakes-heres-why-189481">algal blooms</a>, causing extensive dead zones once oxygen in the water has been used up. </p>
<p>But there’s another pollution problem that has been largely overlooked, until now. Dangerous outbreaks of <a href="https://besjournals.onlinelibrary.wiley.com/action/getFTRLinkout?url=http%3A%2F%2Fscholar.google.com%2Fscholar_lookup%3Fhl%3Den%26volume%3D5%26publication_year%3D1971%26pages%3D281-296%26journal%3DWater%2BResearch%26author%3DE.%2BJ.%2BC.%2BCurtis%26author%3DD.%2BW.%2BHarrington%26title%3DOccurrence%2Bof%2Bsewage%2Bfungus%2Bin%2Brivers%2Bin%2Bthe%2BUnited%2BKingdom&doi=10.1002%2F2688-8319.12277&doiOfLink=10.1016%2F0043-1354%2871%2990173-4&linkType=gs&linkLocation=Reference&linkSource=FULL_TEXT">sewage fungus</a> are becoming a big problem for the UK’s rivers, ponds and lakes. </p>
<p>While working at the University of Oxford with associate professor Michelle Jackson, my aquatic ecology colleagues and I studied how to detect sewage fungus in polluted rivers. We also investigated how changes in a river’s chemical and physical characteristics might be related with the spread of sewage fungus, for example, the high concentration of nitrates <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.16934">from fertilisers</a> coming from farmland. </p>
<p>Healthy rivers are crucial for ecosystems, drinking water, biodiversity and our wellbeing. But <a href="https://www.ox.ac.uk/news/2023-09-22-new-study-finds-sewage-release-worse-rivers-agriculture">sewage pollution</a>, and the sewage fungus within it, threaten all of this, endangering aquatic life, human health and our economy. </p>
<p>Frequent <a href="https://www.theguardian.com/environment/2024/jan/30/english-rivers-pollution-sewage-agriculture-uk">sewage fungus outbreaks</a> indicate how badly polluted our environment is. Our rivers are in trouble and governments, water companies and regulators need to act fast to protect them before it is too late. </p>
<p>Sewage fungus isn’t actually a fungus. It’s a mix of microscopic bacteria, viruses and organisms that can form visible masses in water. Despite their fungus-like appearance, these masses of threads are made up of tiny single rod-shaped cells. </p>
<p>These bacteria multiply quickly in <a href="https://books.google.co.uk/books?hl=en&lr=&id=T6biHTO4E3kC&oi=fnd&pg=PA113&dq=Kator,+H.,+%26+Rhodes,+M.+(2003).+Handbook+of+water+and+wastewater+microbiology.&ots=hVSd4St48d&sig=HLDrK3mfL2GNIS4p6TQxk0kHIKI&redir_esc=y#v=onepage&q=Kator%2C%20H.%2C%20%26%20Rhodes%2C%20M.%20(2003).%20Handbook%20of%20water%20and%20wastewater%20microbiology.&f=false">nutrient-rich environments</a>, such as <a href="https://www.sciencedirect.com/science/article/pii/0043135469900840">rivers contaminated</a> with <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.122%20or%20animal%20slurry77">sewage effluent</a>. More than 100 types of sewage fungus have been identified, with two known as <em>Sphaerotilus natans</em> and <em>Beggiatoa alba</em> commonly found in <a href="https://www.sciencedirect.com/science/article/pii/0043135471901734">most English rivers</a>.</p>
<p>Sewage fungus predominantly lives in polluted waters with high levels of nutrients. That’s typically in areas with poor water quality or inadequate sewage treatment.</p>
<p>That includes ponds and reservoirs near urban areas with high levels of sewage run-off or polluted rivers and streams where untreated or treated sewage is <a href="https://www.sciencedirect.com/science/article/pii/0043135469900840">discharged regularly</a>. Sewage fungus also grows naturally in wastewater treatment plants due to the high concentrations of organic material present.</p>
<p>Sewage fungus, although not always visible to the naked eye, is likely to be present in rivers that receive sewage discharge. Most common methods used to detect it rely on visual inspection of the river, so it is hard to identify early or smaller growth, and we don’t have accurate figures on how widespread the problem is. </p>
<p>However, more hi-tech approaches such as machine learning combined with microscopy can detect and quantify sewage fungus filaments, even before they <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12277">become visible</a>. We have applied one such technique, using a machine called <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12277">FlowCam</a> which made it possible to quickly identify and count fungus filaments.</p>
<h2>Dangerous for wildlife and humans</h2>
<p>High levels of sewage fungus indicate poor water quality. Sewage fungus can harm freshwater environments by reducing oxygen levels in the water, affecting aquatic life, reducing the numbers of sensitive organisms and disrupting the natural balance of rivers. </p>
<p>Fish and shellfish can become stressed due to low oxygen levels, making them more prone to disease and ultimately leading to <a href="https://www.tandfonline.com/doi/abs/10.1080/15287390500259483?casa_token=nN1JI8PAlZ0AAAAA:rOF_RBf9gCTuS-LXo8FCDhvv18tf-HGcEDEM8IldMR6k1b_hrQ2Rp6I6m9mEry-3nBVhRxkfHWiIQg">their death</a>. </p>
<p>High levels of sewage fungus can also have negative effects on human health. If contaminated water is used for swimming or fishing this can lead to human sickness, because some of the microorganisms can include <a href="https://www.sciencedirect.com/science/article/pii/S2405676623000239">human parasites</a> </p>
<p>Sewage fungus effects can interact with other types of human pollution, including agricultural and <a href="https://www.sciencedirect.com/science/article/pii/S0048969718318333#bb0545">urban runoff</a>. The full impact of these interactions is not yet well understood. </p>
<p>But it is important to consider all sources of pollution, from sewage to agricultural run-off, when estimating the effect sewage fungus might have on ecosystems. By doing so, water companies and environmental groups can work towards more effective management and protection of rivers and freshwater resources.</p>
<h2>What to do about it</h2>
<p>By using more advanced detection methods, regulatory bodies and water companies can monitor rivers more efficiently. More timely action could help limit the source of pollution and prevent future outbreaks of sewage fungus, protecting both freshwater ecosystems and human health.</p>
<p>On a local level, people can report pollution incidents, including sewage fungus outbreak, to the respective authorities: <a href="https://www.gov.uk/report-an-environmental-incident">Environment Agency</a> in England, <a href="https://naturalresources.wales/about-us/contact-us/report-an-incident/?lang=en">Natural Resources Wales</a>, the <a href="https://www.mygov.scot/report-environmental-incident">Scottish Environment Protection Agency</a> or the <a href="https://www.nidirect.gov.uk/information-and-services/environment-and-outdoors/environmental-quality-your-area">Department of Agriculture, Environment and Rural Affairs for Northern Ireland</a>. </p>
<p>Before calling those authorities, it is useful to collect details about the date, time and precise location of the sewage fungus. Passing this information on to the authorities will hopefully encourage more comprehensive monitoring in the future.</p><img src="https://counter.theconversation.com/content/223954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dania Albini received funding from the University of Oxford, the John Fell Fund (University of Oxford), a UK water company and a NERC Discipline Hopping Grant
</span></em></p>Sewage fungus is actually not a fungus. Our expert explains what it is, where it lives and what can be done to reduce outbreaks in polluted rivers.Dania Albini, Postdoctoral Research Fellow, Aquatic Ecology, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207402024-02-07T13:26:16Z2024-02-07T13:26:16ZGhana: Kumasi city’s unplanned boom is destroying two rivers – sewage, heavy metals and chemical pollution detected<p>Ghana’s urban population has <a href="https://www.worldbank.org/en/news/opinion/2015/05/14/rising-through-cities-in-ghana-the-time-for-action-is-now-to-fully-benefit-from-the-gains-of-urbanization">more than tripled</a> in the past three decades, from 4 million to nearly 14 million people. Competition for land in cities has increased among various land uses. These trends have led to encroachment in ecologically sensitive areas such as wetlands.</p>
<p><a href="https://www.britannica.com/place/Kumasi">Kumasi</a>, Ghana’s second largest city, has a high level of encroachment and this has led to the pollution of water bodies. Kumasi’s population growth has been rapid because of its central and strategic location and its functions as a major commercial, traditional and administrative centre. In 2022, the <a href="https://worldpopulationreview.com/world-cities/kumasi-population">population of Kumasi</a> was 3,630,326 with a growth rate of 4.02%. The city’s growth puts pressure on its natural assets.</p>
<p>As scholars of urban planning and chemistry, we conducted a <a href="https://www.tandfonline.com/doi/full/10.1080/19463138.2022.2146121">study</a> in the <a href="https://www.luspa.gov.gh/media/plan/EIJR13206_Greater_Kumasi_01.pdf">greater Kumasi metropolis</a> to understand the extent of encroachment and pollution of two rivers, Subin and Wiwi. We wanted to understand how cities can be developed and functional without destroying natural resources. We also wanted to know more about the extent of water pollution, land-use dynamics and water resources regulations, and how they influence the quality of water resources. </p>
<p>We found that people were building homes in informal settlements along the rivers. Liquid and solid waste was being dumped into the rivers. People were using land on the river banks for agriculture and industrial activities, which had a negative effect on water quality. </p>
<p>We recommend that the city authorities monitor what is happening better and do more to prevent degradation of Kumasi’s water bodies.</p>
<h2>Effects of land use on the quality of water bodies</h2>
<p>We discovered that, in the greater Kumasi metropolis, more land alongside the rivers was being used for industrial, residential and commercial purposes than for green spaces. City authorities were ineffective in controlling development in these areas despite the fact that <a href="https://www.luspa.gov.gh/media/document/ZONING_GUIDELINES_final_DESIGN.pdf">Ghana’s zoning guidelines</a> say there should be a buffer of 100 feet (30 metres) along water bodies. </p>
<p>Land values in Kumasi are increasing due to rapid urban growth, but values are lower for wetlands. This difference has contributed to city residents building in wetlands. Also, the intense pressure of urbanisation on the available land has resulted in a <a href="https://www.modernghana.com/news/483045/wetlands-in-kumasi-metropolis-under-siege.html">high level of encroachment</a> in wetlands. The study revealed that 35.4% of the land uses within the <a href="https://www.researchgate.net/figure/River-Wiwi-and-some-other-streams-that-drain-the-Kumasi-Metropolis-Department-of_fig2_257939998">River Wiwi</a> buffers were residential development. </p>
<p>This research further confirmed that the Wiwi and Subin rivers had been heavily polluted with faecal coliforms over the years. <a href="https://www.sciencedirect.com/topics/nursing-and-health-professions/fecal-coliform">Coliform counts</a> are an indicator of possible faecal contamination, and reflect hygiene standards. </p>
<p>The mean of the coliform counts surpassed the limits of 400 total coliforms/100ml and 10 faecal coliforms/100ml allowed by the <a href="https://www.who.int/publications/i/item/9241546743">World Health Organization standard</a>. The two rivers are extremely polluted with faecal matter. </p>
<p>The research also confirmed that heavy metals in the water bodies were above the <a href="https://www.ncbi.nlm.nih.gov/books/NBK535301/table/ch8.tab2/">WHO’s recommended standard</a> of 0.01mg/litre. For example, the average concentration of lead (Pb) recorded in the Wiwi and Subin rivers was 0.018–0.031 mg/l and 0.035–0.055, respectively. Exposure to lead is <a href="https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health">dangerous</a> to health. </p>
<p>As a result of limited investment in sewage plants, most of the city’s untreated waste water is discharged into the surface water bodies. This has implications for the quality and sustainability of these water bodies. </p>
<p>The study also showed that some city residents dump their <a href="https://www.ghanaweb.com/GhanaHomePage/features/Resolving-dying-water-bodies-Dealing-with-waste-pollutants-through-lucrative-means-569358">waste near the city’s wetlands</a>. During heavy rains, the refuse runs off into the water, affecting water quality and flow. </p>
<p>The inability of city authorities to enforce land-use regulations and legislation has allowed people to carry out agricultural activities close to the rivers. The use of agrochemicals threatens aquatic habitats. Chemicals such as pesticides, herbicides and fertilisers are likely to seep or be washed into the rivers. The use of polluted water from the rivers for irrigation also poses a threat to human health. </p>
<p>The industrial activities along the water bodies include washing bays, auto-mechanical activities, welding and wood processing. These pose a threat of chemical pollution due to likely seepage of petroleum products into the water.</p>
<h2>Time for Kumasi to wake up</h2>
<p>The development of sustainable cities relies on the ability of city authorities to plan for social, environmental and economic growth. Urban growth can coexist with natural resources if human activities located near water bodies don’t threaten their quality and continued existence. </p>
<p>Our study shows that Kumasi has developed with little regard for its natural assets. This is a threat to the city’s sustainability. City authorities ought to put in place measures to clean the water bodies and convert buffer areas into parks and green spaces. Environmentally friendly urban agriculture can also be promoted along the water bodies. </p>
<p>Activities such as disposal of liquid and solid waste must be stopped. <a href="https://www.lse.ac.uk/granthaminstitute/explainers/what-is-the-polluter-pays-principle/#:%7E:text=The%20%27polluter%20pays%27%20principle%20is,human%20health%20or%20the%20environment">The “polluter must pay” principle</a> must be applied to people who contravene environmental regulations. </p>
<p>Urban centres in Ghana need a water resource management policy. Regulatory institutions such as the Physical Planning Department and the <a href="https://www.epa.gov.gh/epa/">Environmental Protection Agency</a> should be restructured and equipped to respond to emerging complex environmental problems in cities. There should be continuous environmental monitoring and regulations must be strictly enforced. The <a href="https://westindiacommittee.org/historyheritageculture/wp-content/uploads/2020/07/Contents-and-Introduction.pdf">River Thames Policing model</a> in the UK can be adopted to ensure the continuous monitoring of the water bodies. To monitor and enforce the zoning regulations, city authorities and policy-makers must invest in technologies such as drones. </p>
<p>The <a href="https://www.luspa.gov.gh/media/document/ZONING_GUIDELINES_final_DESIGN.pdf">Zoning Guideline and Planning Standards</a> provide standard setback average distances for a buffer zone of 50–100 feet from the water bodies. We recommend that the buffer should rather be 100 feet (30 metres) away from the wetland. The wetlands are an important <a href="https://www.ramsar.org/sites/default/files/documents/library/services_00_e.pdf">ecosystem service</a> that needs to be protected. Ecologically sensitive areas that are 100 feet away from wetlands should be compulsorily acquired as natural assets for the public interest.</p><img src="https://counter.theconversation.com/content/220740/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors 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>The inability of city authorities to enforce land-use regulations has allowed people to carry out ecologically unfriendly activities along the water bodies.Stephen Appiah Takyi, Senior Lecturer, Department of Planning, Kwame Nkrumah University of Science and Technology (KNUST)Owusu Amponsah, Senior Lecturer, Department of Planning, Kwame Nkrumah University of Science and Technology (KNUST)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201502024-01-10T18:54:04Z2024-01-10T18:54:04Z‘Legal animism’: when a river or even nature itself goes to court<figure><img src="https://images.theconversation.com/files/566558/original/file-20231004-26-deen3k.jpg?ixlib=rb-1.1.0&rect=130%2C32%2C5324%2C3582&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Aerial view of a waterfall in the valley of Vilcabamba, Ecuador, where an historic lawsuit was won by a river in 2011.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/fr/image-photo/ecuador-waterfall-aerial-view-mountain-waterall-2150891681">Curioso.Photography/Shutterstock</a></span></figcaption></figure><p>On 30 March 2011, a truly <a href="https://ejatlas.org/conflict/first-successful-case-of-rights-of-nature-ruling-vilcabamba-river-ecuador/">unprecedented event</a> took place at a provincial court in Loja, Equator, located some 270 miles from the capital of Quito. The Vilcabamba River, a plaintiff in a <a href="https://mariomelo.files.wordpress.com/2011/04/proteccion-derechosnatura-loja-11.pdf">trial there</a>, convinced the tribunal that its own rights were being undermined by a road development project. The project was then halted due because it would have jeopardised the river’s flow.</p>
<p>I was fortunate to be able to both attend this trial and examine what has been termed “legal animism” in two pioneering countries in the field, Ecuador and Bolivia.</p>
<p>Today, nations from <a href="https://notreaffaireatous.org/amendement-du-parlement-ougandais-du-national-environment-act-2019/">Uganda</a> to <a href="https://www.earthlaws.org.au/aelc/rights-of-nature/new-zealand/">New Zealand</a> are following suit by opening up their criminal justice systems to this type of jurisprudence that enables a natural entity, be it an ecosystem or indeed nature itself, to become a legal person and thus have rights. These innovations are raising hopes among some environmental activists, but they also remind us of the law’s malleability. From animals being called to stand trial in the <a href="https://www.wired.com/2014/09/fantastically-wrong-europes-insane-history-putting-animals-trial-executing/">Middle Ages</a> to the Indian lawyer who <a href="https://www.bbc.com/news/world-asia-india-35489971">sued a god</a>, we have sculpted our laws in creative ways throughout the eras. Indeed, no one finds it odd nowadays that a business is considered a legal person.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505718/original/file-20230122-28471-kntkja.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"></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=431&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=431&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=431&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=542&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=542&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499989/original/file-20221209-29206-wsoxgj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=542&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Illustration of a sow and her piglets on trial for the murder of a child. The trial is believed to have taken place in 1457.</span>
<span class="attribution"><a class="source" href="https://fr.wikipedia.org/wiki/Proc%C3%A8s_d%27animaux#/media/Fichier:Trial_of_a_sow_and_pigs_at_Lavegny.png">Wikimedia</a></span>
</figcaption>
</figure>
<h2>When two worldviews collide</h2>
<p>By delving into the origin and development of the innovations in Ecuador and Bolivia, we can also observe how legal animism plays out in all its various guises, possibilities and limits. This is what I intend to do in this article.</p>
<p>South America may have blazed the trail, but the expression “legal animism” actually appeared for the first time in the writings of French legal researcher <a href="https://journals.openedition.org/insituarss/1338">Marie-Angèle Hermitte</a>. Right off the bat, this compound term connotes a meeting of two worlds and two philosophical traditions. In one corner, we have the animist worldview, which some Western schools of thought have portrayed as their antithesis; in the other, a system that forms the bedrock of European modernity.</p>
<p>In Ecuador and in Bolivia, we can find a common undercurrent of influences or frictions that pervades these two colliding worldviews. All at once, influences from North American environmental lawyers meld with the use of the divine Earth Mother figure present in Andean cosmogony.</p>
<h2>Constituent Assembly: the moment when the natural world became redefined</h2>
<p>Another commonality between these two nations is the rather specific context of the constituent assembly. In 2006 and 2007, respectively, Bolivia and Ecuador essentially wiped the slate clean by introducing assemblies tasked with drafting new constitutions. In doing so, they each witnessed a watershed moment of redefining their entire national identity.</p>
<p>Supported or even long awaited by Native communities in both countries, these changes led to a rising prominence of the figure of Pachamama, the embodiment of Mother Earth in Andean myth. Also evoking a meeting of two worlds, this name is a portmanteau of <em>pacha</em>, the Quechua and Aymara word for “world”, and <em>mama</em>, the Spanish word for “mother”. Out of these circumstances soon came a wave of aspirations to endow nature with a legal status.</p>
<figure class="align-center ">
<img alt="Mother Earth, or Pachamama, is a mythical figure found throughout Latin America. Shown here in Andean cosmology according to Juan de Santa Cruz Pachacuti Yamqui Salcamayhua (1613)." src="https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=657&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=657&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=657&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=826&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=826&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552055/original/file-20231004-24-8ro2p2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=826&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mother Earth, or Pachamama, is a mythical figure present across Latin America. This depiction of her is taken from Andean cosmology, drawn by Juan de Santa Cruz Pachacuti Yamqui Salcamayhua (1613) based on an image from the Qorikancha (</span>
<span class="attribution"><a class="source" href="https://fr.wikipedia.org/wiki/Pachamama#/media/Fichier:Santa_Cruz_Pachacuti_Yamqui_Pachamama.jpg">Domaine public</a></span>
</figcaption>
</figure>
<p>In Ecuador, legal animism was brought into the constituent assembly by intellectuals aligned with new theories of the law. They’re influenced by the concepts of US legal expert Christopher Stone, who proposed, as early as <a href="https://global.oup.com/academic/product/should-trees-have-standing-9780199736072">1972</a>, that trees should have rights. To ground these ideas within the constitutional context, the advocates relied on reinterpretations of the country’s Indigenous knowledge. In fact, 80% of Ecuadorians are mixed-race European and Native, but <a href="https://www.pewresearch.org/religion/2014/11/13/religion-in-latin-america/">virtually the entire population</a> identifies as Christian. It was out of these disparate influences that Article 71 of the Constitution was born. It stipulates:</p>
<blockquote>
<p>“Nature, or Pachamama where life is reproduced and occurs, has the right to integral respect for its existence and for the maintenance and regeneration of its life cycles, structure, functions and evolutionary processes. All persons, communities, peoples and nations can call upon public authorities to enforce the rights of nature.”</p>
</blockquote>
<p>Article 72 evokes the right for an ecosystem to be restored, while Article 73 cites the requirement to enforce the precautionary principle for activities that might lead to the extinction of species, the destruction of ecosystems and the permanent alteration of natural cycles.</p>
<h2>The figure of Pachamama</h2>
<p>In Bolivia, constituents found themselves debating Pachamama’s specific attributes. On one side were residents from the highlands, who honour this deity each day; on the other were people from the lowlands and the south of the country, who had an altogether much more nebulous notion.</p>
<p>Pachamama’s scope of enforcement was also the subject of fierce discussion. If Mother Earth is omnipresent, must all living things be included in her definition? What are her limits? I had the chance to attend a debate that sought to ascertain whether, if Pachamama were considered a legal person, it would be possible – or indeed desirable – to sue a mosquito for biting a human.</p>
<p>These discussions culminated in a conceptualisation of Pachamama as an open-ended, collective entity; a Mother Earth across all planes of existence who should therefore be protected as such. This was to avoid the endless back-and-forth of determining what could or could not be included in her definition. Thus regarded as the mother of all things, her definition extends to every entity in the world. In the new constitution of 22 January 2010, no fewer than 10 articles mention Mother Earth based on these terms:</p>
<blockquote>
<p>“Mother Earth is a dynamic living system comprising an indivisible community of all living systems and living organisms, interrelated, interdependent and complementary, which share a common destiny. Mother Earth is considered sacred, from the worldviews of nations and indigenous peoples.” (Article 3)</p>
</blockquote>
<p>Articles 5 and 6 set out the legal framework of Mother Earth as a “collective public interest”, affirming that all Bolivians can exercise the rights of Mother Earth, provided that they also respect individual and collective rights.</p>
<p>Article 7 then goes on to list the seven rights of Mother Earth, which are the right to life, to the diversity of life, to water, to clean air, to equilibrium, to restoration and to pollution-free living.</p>
<hr>
<p><em>This article is brought to you in partnership with <a href="https://shows.acast.com/654a3366cce18a0012315d73">“Your Planet”</a>, an AFP audio podcast. A creation to explore initiatives in favour of ecological transition, all over the planet. <a href="https://shows.acast.com/654a3366cce18a0012315d73">Subscribe</a></em></p>
<iframe src="https://embed.acast.com/$/654a3366cce18a0012315d73/carbon-capture-is-it-really-the-miracle-solution?feed=true" frameborder="0" width="100%" height="110px" allow="autoplay"></iframe>
<hr>
<h2>The permutations and limits of nature’s newfound rights</h2>
<p>With this new relationship to nature being enshrined in the two constitutions, what real-world consequences and applications have followed on from the legal tools that they have inspired? Again, Bolivia and Ecuador differ somewhat.</p>
<p>The Ecuadorian constituents’ desire to offer practical legal tools quickly gave way to legal actions, the first of which was the case of the Vilcabamba River. This trial was spurred by environmental activists who back in 2011 were already well versed in the law’s new potential, but we have since seen <a href="https://www.derechosdelanaturaleza.org.ec/casos-ecuador/">other proceedings led by a diverse cross-section of Ecuadorian society</a>.</p>
<p>The tools proposed by the new constitution soon outstripped the limits expected of them by ecological struggles across the world. In this respect, it was presumed that it would be tricky to isolate responsibility for cases concerning the environment. For instance, how could a project, organisation or person be held accountable for environmental damages if those damages were suffered beyond the borders of the offending country? The Ecuadorian justice system has managed to extricate itself from these issues by invoking the precautionary principle and <a href="https://www.erudit.org/en/journals/mlj/2014-v60-n1-mlj01619/1027721ar/">universal jurisdiction</a>.</p>
<p>In November 2010, citizens from Ecuador, as well as India, Colombia and Nigeria, pressed charges against British Petroleum before the Constitutional Court of Ecuador. After the company caused a colossal oil spill in the Gulf of Mexico, the plaintiffs demanded that it release information on the ecological disaster and its impact, and that it repair the damages caused. These citizens were not direct victims of the oil spill and were therefore not suing on behalf of their own rights, but of those of the ocean. Although the complaint was heard, the judges ultimately decided to dodge the issue, citing another constitutional framework that imposed a notion and scope of territoriality on legal cases.</p>
<p>By comparison, the Bolivian constituent assembly has done little in the way of offering simple recourse to the law for defending the rights of nature. Nevertheless, the drafting of the new constitution centred on the figure of Pachamama has not been a futile exercise.</p>
<p>In particular, there has been some disillusionment regarding the gap between the ambitious ideals built upon the rights of Mother Earth and the reality of ongoing projects to exploit natural resources. This has put the government in a difficult position. It declares Mother Earth as sacred on the one hand, but on the other, it has also been entrusted with managing business as usual – or even developing it further – across all economic sectors.</p>
<p>This disparity has a fuelled a certain anger, with the figure of Pachamama being used as a cornerstone of several struggles. Among them is the movement to stop the construction of a road leading to the region of TIPNIS, a natural reserve of the Bolivian Amazon. Against the “developmentalist” arguments of the Bolivian government, farmers’ organisations, Natives and civic committees alike have cited the rights of Mother Earth as guaranteed in the nation’s constitution.</p>
<figure class="align-center ">
<img alt="Manifestants contre le projet de route de TIPNIS arrivant à La Paz, en octobre 2011" src="https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552048/original/file-20231004-17-83ds1u.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">Demonstrators protesting against plans to build a road from TIPNIS to La Paz in October 2011.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/mywayaround/6262323419/">Szymon Kochański/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Backed by <a href="https://www.sciencespo.fr/opalc/node/712/index.html">citizen support</a>, particularly during two marches toward the capital, this movement saw an <a href="https://www.courrierinternational.com/breve/2011/09/27/evo-morales-recule-sur-le-projet-de-route-du-tipnis">initial victory</a> when a law was passed to establish the national park as an “intangible zone” and when plans to build the motorway were scrapped in October 2011. However, this was <a href="https://www.courrierinternational.com/article/bolivie-le-projet-controverse-dune-route-au-milieu-de-lamazonie-refait-surface">reversed in 2017</a>. President <a href="https://theconversation.com/fr/topics/evo-morales-78519">Evo Morales</a>, for his part, lost considerable support from Native populations throughout this case.</p>
<h2>Backtracking and side-tracking in all directions</h2>
<p>What can we learn? Such legal innovations may well have sparked a number of legal and political actions, but the law cannot do everything. It remains, above all, subject to the whims of political situations, as malleable for environmental struggles as it is for the demands of extractivism.</p>
<p>It can be common for backtracking to occur. In Australia in 2019, the Aṉangu Aboriginal population decided to ban <a href="https://ici.radio-canada.ca/espaces-autochtones/2002324/autochtones-lieux-touristiques-land-back">tours of Uluru</a> despite the substantial financial boon that these visits represented. This was because mass tourism to this sacred site was exacerbating erosion and groundwater pollution.</p>
<figure class="align-center ">
<img alt="Panorama du Mont Uluru" src="https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=522&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=522&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552057/original/file-20231004-15-6nov55.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=522&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Uluru, a mountain where tourist access has been prohibited.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/fr/photos/1GFUOji-yck">Photoholgic/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>In recent years, Ecuador and Bolivia have stayed true to their reputation as breeding grounds of legal innovation. For instance, the Bolivian Mother Earth Authority, headed by Benecio Quispe, considered potentially expanding the law to include rights for objects.</p>
<p>Confronted with the global problem of waste management, the Mother Earth Authority opened up discussions with chiefs of Native communities and trade union leaders on the subject of <a href="https://arbre-bleu-editions.com/heritage-et-anthropocene.html">legal rights for manufactured objects and goods</a>. These included the right to a maximum lifespan, care, repair, non-abandonment and so forth. While this avenue ultimately led to nothing, it once more demonstrated the ability of legal tools to help redefine our relationship with ecosystems and the modern world.</p>
<hr>
<p><em>This article is part of a project between The Conversation France and AFP Audio, supported financially by the European Journalism Centre, as part of the Bill and Melinda Gates Foundation “Solutions Journalism Accelerator” initiative. AFP and The Conversation France have maintained their editorial independence at every stage of the project.</em></p><img src="https://counter.theconversation.com/content/220150/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Diego Landivar ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Some countries have managed to elevate nature and ecosystems to the status of legal entities. Do these innovations really help to protect the environment?Diego Landivar, Enseignant Chercheur en Economie, Directeur d'Origens Media Lab, ESC Clermont Business SchoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207882024-01-10T16:37:57Z2024-01-10T16:37:57ZExtreme UK flood levels are happening much more often than they used to, analysis shows<p>Heavy rain across southern Britain meant that most rivers in England swelled at the beginning of 2024, prompting widespread flooding. </p>
<p>The River Trent was among the most severely affected. Water levels at the Drakelow gauging station in the west Midlands reached <a href="https://check-for-flooding.service.gov.uk/station/2108">3.88 metres</a> on January 4 – well above the previous record set less than four years earlier in February 2020.</p>
<p>Are floods growing larger and happening more often <a href="https://doi.org/10.1029/2020GL091824">in the UK</a>? There are two ways to answer this question. One is to consult computer models which project Earth’s climate in the future, and the other is to search the historical record. </p>
<p>Climate projections are important but highly uncertain as they indicate a wide range of potential futures <a href="https://eip.ceh.ac.uk/hydrology/cc-impacts/">for any given river</a>. Projections also only tell part of the story as they do not reflect the patterns of water use, changes to <a href="https://iopscience.iop.org/article/10.1088/1748-9326/acbecc/meta">groundwater levels</a> or to the <a href="https://doi.org/10.1016/j.jhydrol.2022.128417">urban environment</a> that can decide flooding on a particular river. </p>
<p>That’s why we give equal importance to historical data, although we cannot project past changes directly into the future. <a href="https://nrfa.ceh.ac.uk/data/station/peakflow/28019">Historical archives</a> of river monitoring data can help us understand how the largest floods are changing on the River Trent. </p>
<p>For instance, how is the 50-year water level (the highest point a river would be expected to reach in 50 years on average) changing? On the River Trent at Drakelow, the 50-year water level has risen from about 3.46 metres in 1959 to 3.83 metres in 2024. This means the largest floods are indeed getting bigger.</p>
<h2>How the January 2024 floods compare</h2>
<p>The flood water level on the Trent at the start of January 2024 was actually higher than what scientists would consider a once-in-50-year event in today’s warmer climate.</p>
<p>Another way to understand how much floods have changed is to consider how often they happen today compared with the past. If we look at the 50-year level from 1959 (about 3.46 metres), how often would such a flood occur in today’s climate?</p>
<p>On the Trent, a 3.46-metre flood level would now be expected to occur every 9.38 years, on average, in 2024. This makes sense, considering there have already been six events in which the river level exceeded 3.5 metres since the 1980s. The historical data shows that extreme water levels are being reached more frequently on the Trent.</p>
<p>Our analysis of the Trent aligns with results from a previous study which looked at rivers across <a href="https://doi.org/10.1029/2020GL091824">the rest of the UK</a>. In many places, 50-year floods are now happening less than every ten years, on average. </p>
<p>This is partly due to climate change and also partly due to <a href="https://www.carbonbrief.org/guest-post-are-uk-floods-becoming-worse-due-to-climate-change/">natural variations in the climate</a> which see rivers cycle through spells of more and less flooding. The UK went through a “flood-poor” period in the 1960s, 70s and 80s, and has been going through a “flood-rich” period since then. </p>
<h2>Prepare for worse</h2>
<p>It is worth noting that there are caveats to this type of <a href="https://doi.org/10.5194/hess-25-3897-2021">analysis</a> which tries to assess how extreme events are changing over time. Caution must be exercised when looking at long records of river levels given <a href="https://iwaponline.com/hr/article/43/3/203/31252/The-Thames-flood-series-a-lack-of-trend-in-flood">changes in river management practices</a> and measurement techniques over time. </p>
<p>It should also be noted that these results use a different methodology to the <a href="https://www.ceh.ac.uk/our-science/projects/flood-estimation-handbook">industry standard</a> for flood estimation. </p>
<p>But what matters is not the precise changes in the frequency of major floods (from 50 years down to nine or even two-and-a-half years, according to some statistical methods). It is understanding that the frequency of large floods is changing fast.</p>
<p>For many UK rivers with more extensive historical archives of river level measurements, floods appear to be occurring far more frequently than before. In a smaller number of places, they are occurring less frequently.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/v0Z-OodTIYQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>We need to better understand how flood risk will evolve in response to further human-induced warming. The UK’s efforts to predict and prepare for future floods are supported by the Environment Agency’s <a href="https://www.gov.uk/flood-and-coastal-erosion-risk-management-research-reports/flood-hydrology-roadmap">flood hydrology roadmap</a>, which is mobilising a wide community of researchers and practitioners.</p>
<p>Overall, the UK must prepare to live with bigger floods and be able to predict <a href="https://doi.org/10.1029/2022GL100650">flood-rich periods</a> several years ahead. This starts with an understanding of how the severity and frequency of such events is changing. </p>
<p>To support this effort, we are preparing a range of tools to guide flood planners, including an interactive map allowing users to explore how flood return periods are changing across the UK. Being better prepared for extreme events in a warming climate starts with understanding what it will mean for your local area.</p>
<hr>
<figure class="align-right ">
<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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/220788/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Slater is Professor of Hydroclimatology at Oxford University and a Future Leaders Fellow funded by UK Research and Innovation (UKRI). Slater leads the Hydroclimate Extremes research group which studies how floods and other extreme events are changing over time. She is also a member of the UK Flood Hydrology Scientific and Technical Advisory Group.</span></em></p><p class="fine-print"><em><span>Jamie Hannaford is a Principal Hydrologist and Group Leader at the Centre for Ecology & Hydrology. He is also a visiting Associate Professor at the Irish Climate And Research Units (ICARUS) at Maynooth University, Ireland. Hannaford is the scientific lead for the UK Centre for Ecology and Hydrology’s water monitoring work in the programme UK-SCAPE. He is also the scientific lead for the UK National River Flow Archive (NRFA) and the UK Hydrological Outlook.</span></em></p>On one stretch of Nottingham’s River Trent, floods that arrived every 50 years now return in ten.Louise Slater, Professor of Hydroclimatology, University of OxfordJamie Hannaford, Principal Hydrologist, UK Centre for Ecology & HydrologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2193332023-12-13T23:53:27Z2023-12-13T23:53:27ZWhen the heat hits, inland waters look inviting. Here’s how we can help people swim safely at natural swimming spots<figure><img src="https://images.theconversation.com/files/564158/original/file-20231207-21-tzvzwq.png?ixlib=rb-1.1.0&rect=0%2C0%2C1532%2C1022&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.nsw.gov.au/visiting-and-exploring-nsw/penrith-beach">Penrith Beach/NSW government</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>People love to hang out around water, especially on hot summer days. And, for those who aren’t near the ocean, Australia is blessed with beautiful inland waterways. In New South Wales, the government wants to increase access to these “blue” natural environments, especially for people living far from the coast. </p>
<p>One of these swimming sites is <a href="https://www.nsw.gov.au/visiting-and-exploring-nsw/penrith-beach">Penrith Beach</a>, which has just opened to the public for the summer. This new site in the heart of Western Sydney is part of the state government’s <a href="https://www.planning.nsw.gov.au/policy-and-legislation/open-space/open-spaces-program/places-to-swim">Places to Swim</a> program. It’s likely to be an important refuge for locals to seek relief from <a href="https://www.news.com.au/national/nsw-act/news/top-urban-planners-grim-warning-western-sydney-will-be-hottest-place-on-earth-within-months/news-story/8b4e1a6b9bb4564bda2d704330bc6f92">intense summer heat</a>.</p>
<p>Our recently published <a href="https://researchdirect.westernsydney.edu.au/islandora/object/uws:73705">research</a> informed the government’s new <a href="https://www.planning.nsw.gov.au/sites/default/files/2023-11/places-to-swim-guideline-draft-public.pdf">Places to Swim guide</a>. Now out for public consultation, the draft guide aims to help anyone involved in establishing or managing a swim site.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/rcF5S-vE0i4?wmode=transparent&start=30" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A new public beach has been opened at Penrith in Western Sydney.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/olympic-swimming-in-the-seine-highlights-efforts-to-clean-up-city-rivers-worldwide-210714">Olympic swimming in the Seine highlights efforts to clean up city rivers worldwide</a>
</strong>
</em>
</p>
<hr>
<h2>People want natural swimming spots, but are they safe?</h2>
<p>The <a href="https://www.planning.nsw.gov.au/policy-and-legislation/open-space/open-spaces-program/places-to-swim">Places to Swim</a> program responds to two government surveys, covering <a href="https://www.planning.nsw.gov.au/policy-and-legislation/open-space-and-parklands/the-greater-sydney-outdoors-study">Greater Sydney</a> and <a href="https://www.planning.nsw.gov.au/policy-and-legislation/open-space-and-parklands/nsw-regional-outdoor-survey">regional NSW</a>. These showed:</p>
<ul>
<li><p>people see access to water as very important – about half enjoy outdoor water recreation activities at least once a week</p></li>
<li><p>swimming in natural areas is growing in popularity </p></li>
<li><p>demand for access points and storage facilities for activities such as kayaking and paddle-boarding is increasing.</p></li>
</ul>
<p>But are natural waterways safe to use? Recreation involving waterways inherently entails risks like <a href="https://theconversation.com/its-hot-and-your-local-river-looks-enticing-but-is-too-germy-for-swimming-198506">exposure to waterborne contaminants</a> and potential for injury and drowning. As new swim sites are opened, the risks need to be identified, monitored and managed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/its-hot-and-your-local-river-looks-enticing-but-is-too-germy-for-swimming-198506">It’s hot, and your local river looks enticing. But is too germy for swimming?</a>
</strong>
</em>
</p>
<hr>
<h2>Time spent in ‘blue’ nature has many benefits</h2>
<p>Our report, prepared by the <a href="https://www.westernsydney.edu.au/urban-transformations">Urban Transformations Research Centre</a>, outlined the benefits of opening swim sites across the state. </p>
<p>Spending time in “blue” nature has many <a href="https://theconversation.com/from-microbes-to-forest-bathing-here-are-4-ways-healing-nature-is-vital-to-our-recovery-from-covid-19-188458">physical</a> and <a href="https://theconversation.com/blue-space-access-to-water-features-can-boost-city-dwellers-mental-health-122995">mental</a> benefits. Other social, cultural, economic and ecological spin-offs are equally valuable. </p>
<p>These natural sites are freely available to all (and pleasingly chemical-free). People come together at these places, which strengthens sense of community and belonging.</p>
<p>Economic multipliers arise from the increase in visitors to an area.</p>
<p>An increased public focus on ensuring the water is clean also benefits the wider ecosystems that depend on it.</p>
<p>We also provided a checklist of things to consider when setting up or managing a swim site. These include:</p>
<ul>
<li><p>the need to assess upfront, and then continually monitor, <a href="https://theconversation.com/its-hot-and-your-local-river-looks-enticing-but-is-too-germy-for-swimming-198506">water quality</a></p></li>
<li><p><a href="https://theconversation.com/parks-and-green-spaces-are-important-for-our-mental-health-but-we-need-to-make-sure-that-everyone-can-benefit-142322">equitable physical access</a> and transport points</p></li>
<li><p>risks and hazards in what can be physically tricky sites</p></li>
<li><p>environmental considerations, including any critical habitats, in what might otherwise be an undisturbed natural environment</p></li>
<li><p>any required planning processes and formal approvals </p></li>
<li><p>ongoing governance arrangements, which might involve more than one body.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-do-we-love-the-great-outdoors-new-research-shows-part-of-the-answer-is-in-our-genes-175995">Why do we love the great outdoors? New research shows part of the answer is in our genes</a>
</strong>
</em>
</p>
<hr>
<h2>Learning from the best</h2>
<p><a href="https://researchdirect.westernsydney.edu.au/islandora/object/uws:73705">Our report</a> also offered six case studies of projects in Australia and New Zealand, Canada and Europe. These provide good examples of how to proceed. </p>
<p>The case study from New Zealand’s <a href="https://www.lawa.org.nz/explore-data/swimming/">Can I swim here?</a> program has an <a href="https://www.lawa.org.nz/explore-data/swimming/">interactive map</a> to help people find the best places to swim across the country. This public advice, provided by the <a href="https://www.lawa.org.nz/about">Land, Air, Water Aotearoa</a> partnership, includes weekly water quality test results.</p>
<p>In Canada, <a href="https://greatlakes.guide/ideas/citizen-science-in-the-great-lakes-toronto">Toronto on Lake Ontario</a> showcases innovative water-quality monitoring that directly involves the community. It’s done by volunteer “citizen scientists” co-ordinated by a government-funded charity, Swim Drink Fish.</p>
<p>As confirmed by research on <a href="https://theconversation.com/building-a-second-nature-into-our-cities-wildness-art-and-biophilic-design-88642">biophilia</a> – our innate affinity with nature – bringing people closer to nature is not just about direct benefits to individuals. It also encourages us to look after the natural ecosystems on which we ultimately depend. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/many-urban-waterways-were-once-waste-dumps-restoration-efforts-have-made-great-strides-but-theres-more-to-do-to-bring-nature-back-206407">Many urban waterways were once waste dumps. Restoration efforts have made great strides – but there's more to do to bring nature back</a>
</strong>
</em>
</p>
<hr>
<p>Recognition of the benefits of spending time in “blue” nature will continue to grow. We therefore need to put more effort into designing water-based activities as part of life in our cities and towns. It’s especially important for those without ready access to coastal beaches. </p>
<p>It’s time to get more active in promoting and improving these great water resources. These facilities will also need to be closely monitored and managed. The investment is worth it.</p><img src="https://counter.theconversation.com/content/219333/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicky Morrison received funding from the NSW government. </span></em></p><p class="fine-print"><em><span>Ian A. Wright received funding from the NSW government.</span></em></p>People love natural swimming spots, but it’s important to manage them well to protect both swimmers and the environment.Nicky Morrison, Professor of Planning and Director of Urban Transformations Research Centre, Western Sydney UniversityIan A. Wright, Associate Professor in Environmental Science, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2172862023-11-29T23:11:39Z2023-11-29T23:11:39ZNew unified theory shows how past landscapes drove the evolution of Earth’s rich diversity of life<p>Earth’s surface is the living skin of our planet – it connects the physical, chemical and biological systems.</p>
<p>Over geological time, this surface evolves. Rivers fragment the landscape into an environmentally diverse range of habitats. These rivers also transfer sediments from the mountains to the continental plains and ultimately the oceans. </p>
<p>The idea that landscapes have influenced the trajectory of life on our planet has a long history, dating back to the early 19th century scientific narratives of German polymath <a href="https://learningfromlandscapes.com/2019/06/11/humboldt-the-invention-of-nature/">Alexander von Humboldt</a>. While we’ve learnt more since then, many aspects of biodiversity evolution remain enigmatic. For example, it’s still unclear why there is a 100-million-year gap between the explosion of marine life and the development of plants on continents.</p>
<p>In research <a href="https://www.nature.com/articles/s41586-023-06777-z">published in Nature</a> today, we propose a new theory that relates the evolution of biodiversity over the past 540 million years to sediment “pulses” controlled by past landscapes.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Uxutnt44NKU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<h2>10 years of computational time</h2>
<p>Our simulations are based on an open-source code released as part of a <a href="https://theconversation.com/scientists-just-revealed-the-most-detailed-geological-model-of-earths-past-100-million-years-200898">Science paper</a> published earlier this year.</p>
<p>To drive the evolution of the landscape through space and time in our computer model, we used a series of reconstructions for what the climate and tectonics were like in the past.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two colourful computer simulated Earth globes side by side" src="https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=291&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=291&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=291&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=365&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=365&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558304/original/file-20231108-27-yqmk6n.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=365&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These two globes from our simulation show landscapes 200 million years ago (just before the Pangea supercontinent broke up, left) and 15 million years ago (right), after the formation of the Andes, Alps and Himalayas.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>We then compared the results of our global simulations with reconstructions of marine and continental biodiversity over the past 540 million years.</p>
<p>To perform our computer simulations, we took advantage of Australia’s <a href="https://nci.org.au/">National Computational Infrastructure</a> running on several hundreds of processors. The combined simulations presented in our study are equivalent to ten years of computational time.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-the-earths-last-supercontinent-broke-apart-to-form-the-world-we-have-today-131632">How the Earth's last supercontinent broke apart to form the world we have today</a>
</strong>
</em>
</p>
<hr>
<h2>Marine life and river sediment were closely linked</h2>
<p>In our model, we discovered that the more sediment rivers carried into the oceans, the more the sea life diversified (a positive correlation). You can see this tracked by the red line in the chart below. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=222&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=222&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=222&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=279&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=279&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560720/original/file-20231121-3914-t01a3j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=279&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Reconstructed sediment fluxes to the oceans (red line) versus diversity of marine animals (black line, adapted from C. Bentley using Sepkoski’s compendium) from the Cambrian through to the Neogene.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>As the continents weather, rivers don’t just carry sediment into the oceans, they also bring a large quantity of nutrients. These nutrients, such as carbon, nitrogen and phosphorus, are essential to the <a href="https://www.britannica.com/science/biogeochemical-cycle">biological cycles</a> that move vital elements through all living things.</p>
<p>This is why we think rivers delivering more or less nutrients to the ocean – on a geological timescale of millions of years – is related to the diversification of marine life.</p>
<p>Perhaps even more surprisingly, we found that episodes of mass extinctions in the oceans happened shortly after significant decreases in sedimentary flow. This suggests that a lack or deficiency of nutrients can destabilise biodiversity and make it vulnerable to catastrophic events (like asteroid impacts or volcanic eruptions).</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-a-mass-extinction-and-are-we-in-one-now-122535">What is a 'mass extinction' and are we in one now?</a>
</strong>
</em>
</p>
<hr>
<h2>Landscapes also drove the diversity of plants</h2>
<p>On the continents, we designed a variable that integrates sediment cover and landscape ruggedness to describe the continents’ capacity to host diverse species. </p>
<p>Here we also found a striking correlation (see below) between our variable and plant diversification for the past 400 million years. This highlights how changes in landscape also have a strong influence on species diversifying on land. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=232&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=232&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=232&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=291&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=291&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560719/original/file-20231121-27-hlx0p3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=291&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sediment cover in continental regions (black line) versus the long-term trend in land-plant diversity. Illustrations from Rebecca Horwitt.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<p>We hypothesise that as Earth’s surface was gradually covered with thicker soil, richer in nutrients deposited by rivers, plants could develop and diversify with more elaborate root systems. </p>
<p>As plants slowly expanded across the land, the planet ended up hosting varied environments and habitats with favourable conditions for plant evolution, such as the emergence of flowering plants some 100 million years ago.</p>
<h2>A living planet</h2>
<p>Overall, our findings suggest the diversity of life on our planet is strongly influenced by landscape dynamics. At any given moment, Earth’s landscapes determine the maximum number of different species continents and oceans can support.</p>
<p>This shows it’s not just tectonics or climates, but their interactions that determine the long-term evolution of biodiversity. They do this through sediment flows and changes to the landscapes at large.</p>
<p>Our findings also show that biodiversity has always evolved at the pace of plate tectonics. That’s a pace incomparably slower than the current rate of extinction caused by human activity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/five-ways-you-can-help-stop-biodiversity-loss-in-your-area-and-around-the-world-196746">Five ways you can help stop biodiversity loss in your area – and around the world</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/217286/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research was undertaken with resources from the National Computational Infrastructure supported by the Australian Government and from Artemis HPC supported by the University of Sydney. This work was supported by an Australian Research Council grant.</span></em></p><p class="fine-print"><em><span>Beatriz Hadler Boggiani, Laurent Husson, and Manon Lorcery 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>For decades, scientists have tried to uncover the cause of long-term changes in Earth’s biodiversity. New simulations point at geography playing a critical role.Tristan Salles, Senior Lecturer, University of SydneyBeatriz Hadler Boggiani, PhD Candidate, University of SydneyLaurent Husson, Earth sciences researcher, Université Grenoble Alpes (UGA)Manon Lorcery, PhD Candidate, Université Grenoble Alpes (UGA)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170022023-11-27T04:12:56Z2023-11-27T04:12:56ZThe government’s Murray-Darling bill is a step forward, but still not enough<figure><img src="https://images.theconversation.com/files/561714/original/file-20231126-21-rluebs.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C3058%2C2032&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/sunrise-on-murray-river-near-kingstononmurray-1207917046">Philip Schubert, Shutterstock</a></span></figcaption></figure><p>This week, the Senate is debating changes to Australia’s most important water laws. These changes seek to rescue the ailing A$13 billion Murray-Darling Basin Plan to improve the health of our nation’s largest river system. </p>
<p>The <a href="https://www.aph.gov.au/Parliamentary_Business/Bills_Legislation/Bills_Search_Results/Result?bId=r7076">Water Amendment (Restoring Our Rivers) Bill 2023</a> is a crucial step forward. It proposes to lift the Coalition-era cap on water buybacks, allowing the federal government to recover more water for the environment through the voluntary purchase of water entitlements from irrigators.</p>
<p>It also proposes to extend the deadlines for the many beleaguered water-offsetting projects put forward by state governments.</p>
<p>Through the Wentworth Group of Concerned Scientists – an independent group working to secure the long-term health of Australia’s land, water and biodiversity – we strive to restore river health for the basin’s communities, industries and ecosystems. Here we ask whether the bill can fulfil the Albanese government’s <a href="https://anthonyalbanese.com.au/media-centre/labors-plan-to-future-proof-australias-water-resources-butler">2022 election promise</a> to deliver the plan.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1728928333243781591"}"></div></p>
<h2>Securing support of the Greens and crossbenchers</h2>
<p>The bill is central to Prime Minister Anthony Albanese’s <a href="https://anthonyalbanese.com.au/media-centre/labors-plan-to-future-proof-australias-water-resources-butler">five-point election promise</a> to deliver the plan, and Federal Water Minister Tanya Plibersek’s <a href="https://www.tanyaplibersek.com/media/media-releases/media-release-plibersek-decade-of-liberal-national-sabotage-puts-murray-darling-basin-plan-behind/">subsequent commitment</a> to implement the Murray-Darling Basin Plan in full.</p>
<p>With the Coalition <a href="https://www.aph.gov.au/Parliamentary_Business/Bills_Legislation/Bills_Search_Results/Result?bId=r7076">voting against the bill</a> in the lower house, the federal government <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-strengthening-restoring-our-rivers-bill">secured the support</a> of the Greens with measures that considerably strengthen the bill.</p>
<p>It is now up to key crossbench Senators to secure passage through parliament. But they have said the bill doesn’t go far enough, citing serious concerns it <a href="https://www.lidiathorpe.com/mr_water_legislation">excludes First Nations water rights and interests</a> and <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/MDBAWaterBill2023/Report">ignores climate change</a>.</p>
<p>The federal government must pass the bill in the next two sitting weeks to avoid triggering a statutory deadline, after which unfinished water offset projects would be cancelled and water recovery would be required instead.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/labors-new-murray-darling-basin-plan-deal-entrenches-water-injustice-for-first-nations-212261">Labor’s new Murray-Darling Basin Plan deal entrenches water injustice for First Nations</a>
</strong>
</em>
</p>
<hr>
<h2>Water Act and Basin Plan: where are we at?</h2>
<p>Born of the crisis of the Millennium drought, the Water Act 2007 was announced by the Howard government to “<a href="https://www.theaustralian.com.au/news/howards-full-speech-to-the-national-press-club/news-story/cfd6aa4761027929545602a96dc04254">once and for all</a>” address over-allocation of water in the Murray-Darling Basin.</p>
<p>Five years later, the Basin Plan 2012 was established to recover 3,200 billion litres of water for the environment from other uses, or to implement projects that deliver “equivalent” outcomes. That includes securing 450 billion litres for the health of the River Murray, Coorong and Lower Lakes.</p>
<p>But this volume of water fell substantially short of the Murray-Darling Basin Authority’s best estimate of what was needed to “<a href="http://www6.austlii.edu.au/cgi-bin/viewdoc/au/legis/cth/consol_act/wa200783/s3.html">ensure the return to environmentally sustainable levels of extraction</a>”, and did not take climate change into account.</p>
<p>All water recovery targets were expected to be met by June 2024. But while some progress has been made, water recovery has <a href="https://wentworthgroup.org/2017/11/review-of-water-reform-in-the-murray-darling-basin/">almost stalled</a> in the past decade.</p>
<p>Only <a href="https://www.dcceew.gov.au/water/policy/mdb/progress-recovery">26 billion litres have been recovered</a> of the crucial 450 billion litres. </p>
<p>Of the 36 water offset projects meant to be operational by 2024, <a href="https://www.mdba.gov.au/sites/default/files/publications/2023-sdlam-annual-assurance-report.pdf">16 are not likely to be complete</a>, contributing to a likely shortfall of between 190 billion and 315 billion litres.</p>
<p>No onground work has commenced to alleviate flow “constraints”, leaving thousands of hectares of floodplain forests in the River Murray disconnected from their channels and at risk of drying out and dying.</p>
<p>The Water Act and the plan <a href="https://www.abc.net.au/news/2023-11-14/lawyers-academics-first-nations-rights-murray-darling-basin-plan/103098066">do not provide for First Nations people’s water rights and interests</a>. And they <a href="https://openresearch-repository.anu.edu.au/bitstream/1885/67496/2/01_Pittock_The_Murray-Darling_Basin_Plan_2015.pdf">fail to deal with climate change</a>.</p>
<p>Reforms to both the legislation and the plan are desperately needed to address these major shortcomings.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/murray-darling-basin-plan-to-be-extended-under-a-new-agreement-without-victoria-but-an-uphill-battle-lies-ahead-212002">Murray-Darling Basin Plan to be extended under a new agreement, without Victoria – but an uphill battle lies ahead</a>
</strong>
</em>
</p>
<hr>
<h2>Voluntary buybacks are necessary</h2>
<p>The new bill represents a clear step towards the first of the Albanese government’s <a href="https://anthonyalbanese.com.au/media-centre/labors-plan-to-future-proof-australias-water-resources-butler">five-point promises</a> to “deliver on water commitments” by removing the cap on buybacks.</p>
<p>Without buybacks, it is unlikely the federal government will be able to deliver the 3,200 billion-litre plan in full.</p>
<p>While the <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/MDBAWaterBill2023/Report">Senate Committee</a> acknowledged the impacts of buybacks on communities, the committee found some concerns were “overinflated and not supported by the high-quality evidence base”, referring to a <a href="https://www.mdba.gov.au/sites/default/files/publications/mdb-outlook-economic-literature-review2.pdf">literature review</a>.</p>
<p>The Wentworth Group has <a href="https://wentworthgroup.org/2010/06/sustainable-diversions-in-the-murray-darling-basin/">long argued</a> for funding to establish a regional transition fund to support impacted communities through these reforms. As part of these reforms, “significant transitional assistance” was <a href="https://minister.dcceew.gov.au/plibersek/speeches/speech-introducing-restoring-our-rivers-bill">announced</a> by Plibersek.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1728946516616962316"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/water-buybacks-are-back-on-the-table-in-the-murray-darling-basin-heres-a-refresher-on-how-they-work-200529">Water buybacks are back on the table in the Murray-Darling Basin. Here's a refresher on how they work</a>
</strong>
</em>
</p>
<hr>
<h2>Statutory guarantees are needed</h2>
<p>The bill requires <a href="https://wentworthgroup.org/2023/10/submission-to-senate_inquiry_water_amendment_bill_2023/">additional measures</a> to guarantee the unfinished business to which parliament agreed more than a decade ago:</p>
<ol>
<li><p><strong>a legally binding 450 billion litre water recovery target</strong>. The public needs a legal recourse if governments fail to deliver the full volume. We understand the intent of today’s <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-strengthening-restoring-our-rivers-bill">announcement</a> is to make the target a statutory requirement, in line with other water recovery targets under the plan.</p></li>
<li><p><strong>improved integrity of the water offset method and withdrawal of unviable water offset projects</strong> The <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-strengthening-restoring-our-rivers-bill">agreement</a> reached today allows the Commonwealth to remove non-viable projects. <a href="https://www.publish.csiro.au/mf/Fulltext/MF22082">Significant flaws</a> in the method used to calculate water offsets still need to be addressed. </p></li>
<li><p><strong>milestones in the bill’s proposed “constraints roadmap”</strong> which specify targets linked to incentive payments.</p></li>
<li><p><strong>transparency and accountability measures</strong> to restore public confidence in water reform, such as whole-of-basin hydrological modelling, water accounting and auditing, and validation of annual permitted take models. </p></li>
</ol>
<p>Several of these measures were <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-strengthening-restoring-our-rivers-bill">announced today</a>. We’re yet to see details but the high-level agreement is encouraging.</p>
<h2>Urgent reforms can’t wait to 2027</h2>
<p>Australia’s water laws have <a href="https://theconversation.com/labors-new-murray-darling-basin-plan-deal-entrenches-water-injustice-for-first-nations-212261">failed to address</a> the rights and interests of Indigenous people. Indigenous peoples <a href="https://www.sciencedirect.com/science/article/pii/S0264837719319799">own a mere 0.2%</a> of surface water entitlements in the Murray-Darling Basin.</p>
<p>In 2022, the Albanese government <a href="https://anthonyalbanese.com.au/media-centre/labors-plan-to-future-proof-australias-water-resources-butler">committed</a> to “increasing First Nations ownership of water entitlements and participation in decision making”.</p>
<p>The <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/MDBAWaterBill2023/Report">Senate Committee</a> found “overwhelming support […] that significantly more needs to be done to incorporate the values and interests of First Nations people in Basin Plan management”.</p>
<p>Many solutions can be readily incorporated into the bill. It should be amended so the legislation is consistent with the United Nations Declaration on the Rights of Indigenous Peoples, and recommendations of Indigenous organisations, such as the Murray-Lower Darling Rivers Indigenous Nations.</p>
<p>The $100 million <a href="https://minister.dcceew.gov.au/plibersek/media-releases/joint-media-release-strengthening-restoring-our-rivers-bill">announced</a> today for the Aboriginal Water Entitlement Program is welcome, although much was already <a href="https://www.tonyburke.com.au/media-releases/2019/5/6/media-release-labornbspwillnbspget-the-basin-plan-back-on-tracknbsp">committed</a> and the remainder won’t make up for the lost value given entitlement prices, according to <a href="https://mldrin.org/wp-content/uploads/2023/08/WEB_20230829-MLDRIN-Slide-Deck-FINAL-STC.pdf">analysis</a> commissioned by the Murray-Lower Darling Rivers Indigenous Nations.</p>
<p>The bill also needs to provide greater clarity for basin communities on how climate change will be incorporated into the Basin Plan review, and strategies for adapting to climate change. This cannot wait until 2027 – communities need to prepare now for their future.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/victorias-plans-for-engineered-wetlands-on-the-murray-are-environmentally-dubious-heres-a-better-option-204116">Victoria’s plans for engineered wetlands on the Murray are environmentally dubious. Here’s a better option</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/217002/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Celine Steinfeld is Director of the Wentworth Group of Concerned Scientists.</span></em></p><p class="fine-print"><em><span>Michael Vanderzee is a Water Policy Analyst with the Wentworth Group of Concerned Scientists. He is a former water policy adviser to the Victorian goverment with more than 12 years experience in national and Murray-Darling Basin water reform.</span></em></p>With the support of the Greens, there’s a chance the ‘Restoring Our Rivers’ Bill will pass. Will it be enough to put the Murray-Darling Basin Plan back on track?Celine Steinfeld, Director, Wentworth Group of Concerned Scientists & Adjunct Lecturer, UNSW SydneyMichael Vanderzee, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2031422023-11-13T02:49:40Z2023-11-13T02:49:40ZMurray-Darling water buybacks won’t be enough if we can’t get water to where it’s needed<p>When it was clear the Murray-Darling Basin Plan could not be completed on time, Federal Water Minister Tanya Plibersek <a href="https://minister.dcceew.gov.au/plibersek/media-releases/historic-deal-struck-guarantee-future-murray-darling-basin">announced a new agreement</a> (without Victoria) to deliver in full the plan’s aim of restoring the health of this vast river system.</p>
<p>The new agreement required changes to the Water Act to allow more water for the environment to be purchased from irrigators (<a href="https://theconversation.com/water-buybacks-are-back-on-the-table-in-the-murray-darling-basin-heres-a-refresher-on-how-they-work-200529">water buybacks</a>). Concerns about these changes prompted a Senate inquiry. </p>
<p>The <a href="https://www.aph.gov.au/Parliamentary_Business/Tabled_Documents/4142">report</a> from that inquiry, released on Friday, <a href="https://www.abc.net.au/news/rural/2023-11-10/murray-darling-senate-inquiry-more-offset-project-scrutiny/103084420">supports buybacks</a> but also makes key recommendations to remove “constraints” to water delivery. These are physical constraints or limits to the movement of water through the river system. Managers can only deliver so much water before it spills out of the river onto private land. </p>
<p>The report goes so far as to ask whether constraints should be removed before more water is recovered. This is a question we have been asking in our research. And our results suggest the answer is yes.</p>
<p>Currently, we cannot physically deliver all of the water recovered from other uses for the environment (known as <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780128039076000012">environmental water</a>) to where it’s needed without flooding private property along the way. And the government is not prepared to do that. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1722838583894307201"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/murray-darling-basin-plan-to-be-extended-under-a-new-agreement-without-victoria-but-an-uphill-battle-lies-ahead-212002">Murray-Darling Basin Plan to be extended under a new agreement, without Victoria – but an uphill battle lies ahead</a>
</strong>
</em>
</p>
<hr>
<h2>Basin health is improving but challenges remain</h2>
<p>Under the <a href="https://www.mdba.gov.au/water-management/basin-plan">Basin Plan</a>, about 20% of water used for irrigation a decade ago is now used for environmental purposes. This has improved river health, encouraging fish to spawn and plants to grow, and reduced salt levels in the Lower Lakes and Coorong. </p>
<p>These benefits rely on the river’s <a href="https://www.jstor.org/stable/1313099">flow regime</a>, not just the annual volume. Higher flows inundate wetlands, move sediment down the river, and provide natural triggers for various species to breed or migrate. </p>
<p>But raising water levels in the river channel isn’t enough to get environmental water everywhere it’s needed. Sometimes larger flows are required. Unfortunately, sending more water down the river runs the risk of inundating private property or damaging infrastructure such as low-lying pumps on floodplains. </p>
<p>Restoring the river’s health requires not only recovering water but also completing projects that allow more of this water to flow despite physical constraints such as a narrow stretch of river. These <a href="https://www.dcceew.gov.au/water/policy/mdb/policy/sdl-adjustment-mechanism">projects</a> might involve modifying or improving infrastructure such as low-lying roads and bridges, as well as working with communities to limit damage and compensate for flooding of private property.</p>
<p>The Senate inquiry report highlights the challenges for these projects. It also supports improving the approach to delivering these projects across the southern basin. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1722811013907599559"}"></div></p>
<h2>Challenges, priorities and solutions may differ</h2>
<p><a href="https://www.frontiersin.org/articles/10.3389/fenvs.2021.789206/full">Our research</a> on the Goulburn River in Victoria’s part of the Murray-Darling Basin shows recovery of additional water for the environment does not guarantee environmental outcomes. </p>
<p>This is because the amount of water that can be sent down the river is constrained. So having more environmental water at your disposal does not help, because it is physically impossible to get all the water to where it is needed, when it is needed, without risking inundation of private property.</p>
<p>Current river system operations, including rules and physical constraints, prevent the full volume of environmental water held in Goulburn River being delivered at the right time and in the right way to achieve the best environmental outcomes.</p>
<p>Narrow sections of the river and adjacent private development limit releases from Lake Eildon. River managers are not allowed to deliberately inundate the floodplain if it risks private property. </p>
<p>So the volume of environmental water available in the Goulburn River is not the issue – delivering this water is the challenge. In this regard, <a href="https://theconversation.com/murray-darling-basin-plan-to-be-extended-under-a-new-agreement-without-victoria-but-an-uphill-battle-lies-ahead-212002">Victoria’s refusal</a> to sign up to the new basin deal is understandable, because more water buybacks would potentially cause more pain to the local community than gain to the local environment. </p>
<p>However, neither Victoria nor New South Wales has addressed these capacity constraint issues, significantly limiting the ability to get better environmental outcomes with less water. So the challenge is much more complex than simply redistributing entitlements and buying back environmental water. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1722827130860605468"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/water-buybacks-are-back-on-the-table-in-the-murray-darling-basin-heres-a-refresher-on-how-they-work-200529">Water buybacks are back on the table in the Murray-Darling Basin. Here's a refresher on how they work</a>
</strong>
</em>
</p>
<hr>
<h2>The elephant in the room: climate change</h2>
<p>Temperature, rainfall and streamflow have already changed in parts of the Murray-Darling Basin. Over the coming decade these changes will become more pronounced, <a href="https://www.sciencedirect.com/science/article/pii/S002216942300313X">widespread and entrenched</a>, causing more frequent floods and droughts. </p>
<p>While the precise consequences for water availability remain to be seen, the impact on the basin will be immense. </p>
<p>But climate change simply adds to the need to have difficult conversations around the future of communities along the Murray-Darling. Focusing on whether buyback targets have been achieved does not resolve this. In many regions, there will not be enough water, with or without buybacks, to achieve <a href="https://cdn.environment.sa.gov.au/environment/docs/6.8.1-Preliminary-adaptation-pathways-for-the-Coorong-Lower-Lakes-and-Murray-Mouth.pdf">current management objectives</a>. </p>
<p>Buybacks should be placed in the context of this imminent threat. In rivers like the Goulburn, addressing capacity constraints provides the <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2021.789206/full">single best climate adaptation option</a> to improve environmental outcomes in the short and medium term. </p>
<p>Removing these constraints would allow more water onto the lower Goulburn River floodplain, with due care for land and infrastructure that could be affected. For example, projects may offer landholders <a href="https://www.gbcma.vic.gov.au/our-region/waterway-floodplain-management/waterways/constraints-management-strategy">options to avoid or compensate for any water damage and associated costs</a>. </p>
<p>This is because removing constraints gives river managers more flexibility, which can increase the resilience of the environment to a wider range of future climates. More water from buybacks provides very limited additional benefit because it doesn’t change how environmental water can be delivered. </p>
<p>The senate report emphasises the need to embed consideration of climate change in the Water Act and Basin Plan. The decisions we are making now on water recovery and constraints relaxation will have big impacts on communities.</p>
<p>Our work shows considering climate change is essential to ensuring lasting benefits and resilient outcomes for the rivers and communities that rely on them.</p>
<p>The first basin plan took a big step towards sustainable management of the vast Murray-Darling river system. But it was always meant to be the first step in an adaptive policy process. Priorities and solutions will look different across the basin. We need a holistic approach where buybacks may very well be part of the solution, but are not the whole solution. We also need to ensure we can deliver this water where and when the environment needs it. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/victorias-plans-for-engineered-wetlands-on-the-murray-are-environmentally-dubious-heres-a-better-option-204116">Victoria’s plans for engineered wetlands on the Murray are environmentally dubious. Here’s a better option</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/203142/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Avril Horne receives funding from the Victorian Government Department of Energy, Environment and Climate Action.
Avril has recently been appointed as a member of the Murray-Darling Basin Authority Advisory Committee on Social Economic and Environmental Sciences.</span></em></p><p class="fine-print"><em><span>Andrew John receives funding from the Victorian Government Department of Energy, Environment and Climate Action. </span></em></p>Buying back water from irrigators across the Murray-Darling Basin will not be enough to restore river health because we have big problems getting this ‘environmental water’ to where it’s needed most.Avril Horne, Research fellow, Department of Infrastructure Engineering, The University of MelbourneAndrew John, Research fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2149492023-11-02T22:49:19Z2023-11-02T22:49:19ZIn the 1800s, colonial settlers moved Ballarat’s Yarrowee River. The impacts are still felt today<p>The discovery of gold in Ballarat in 1851 transformed its landscape to a staggering degree. Within days, and despite the news being initially suppressed, hundreds of men had gathered along the Yarrowee River. </p>
<p>They sluiced the clay and soil, turning the once pristine waters into what writer William Bramwell Withers <a href="https://catalogue.nla.gov.au/catalog/2937612">described</a> as</p>
<blockquote>
<p>liquid, yellow as the yellowest Tiber flood, and its banks grew to be long shoals of tailings.</p>
</blockquote>
<p>Over the next few weeks, the waterways of the Yarrowee River and of Gnarr Creek were diverted into water courses to support the search for gold.</p>
<p>The river was moved to make way for the town population boom, which was driven by a lust for gold. The end result was that the original, serpentine path of the river – originally across floodplains equipped to handle the natural ebb and flow of water and seasonal flooding – eventually came to be a much straighter line. Part of the river now runs underground through a tunnel.</p>
<p><iframe id="tc-infographic-953" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/953/c2d23cd95a72326c661068837565617ee1bd0f41/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Our new interactive map, <a href="https://yarrowee.cerdi.edu.au/">Yarrowee River History: Peel to Prest</a> (which takes its name from the two streets that serve as borders for the mapping), interrogates the long-term effects of this water diversion on community and Country.</p>
<p>A collaboration between Federation University, the Wadawurrung Traditional Owners Aboriginal Corporation and the city of Ballarat, our project overlays historical maps with Google Maps to illustrate how the area changed.</p>
<p><iframe id="tc-infographic-952" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/952/5616d6e1226fe77e975d562937b50a1c71283eee/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/victorias-gold-rush-ended-in-the-19th-century-so-why-are-people-still-finding-so-much-gold-202846">Victoria’s gold rush ended in the 19th century. So why are people still finding so much gold?</a>
</strong>
</em>
</p>
<hr>
<h2>‘We inherit the scars of this trauma’</h2>
<p>In Ballarat, water is deeply significant to the culture of the area’s First Nations inhabitants, the Wadawurrung people, who stewarded these lands and waterways for millennia.</p>
<p>So we wanted people using our interactive map to ponder the cultural significance of these gold rush impacts to the Wadawurrung people and the environment.</p>
<p>For the Wadawurrung people, the watercourse now known as the Yarrowee River carries profound historical meaning. </p>
<p>This river bore the names Yaramlok and Narmbool, and these names were used interchangeably to reference different segments of the Yarrowee. </p>
<p>The river wasn’t merely a physical entity – it was a symbol of spiritual and cultural significance, the life force which flows through Country.</p>
<p>It supported fishing, agriculture and food gathering. It symbolised the deep and harmonious connection with dja (Country) and the precious resource of ngubitj (water). </p>
<p>The river diversion affected the Wadawurrung profoundly. As two of us (Shannen Mennen and Kelly Ann Blake) write on the <a href="https://yarrowee.cerdi.edu.au/">Yarrowee River History: Peel to Prest</a> site:</p>
<blockquote>
<p>Colonisation and mining in Ballarat led to devastation and destruction of Wadawurrung dja, including the Yarrowee River. Settlement was built upon our living spaces and as a result Wadawurrung people were displaced. </p>
<p>The withholding of cultural rights and obligations further increased the dispossession of our people, who were unforgivingly forced to adapt to change. Still today we inherit the scars of this trauma.</p>
</blockquote>
<p>Colonial settlers altered the river</p>
<blockquote>
<p>in a way which excluded the knowledge Wadawurrung people had built upon for many thousands of years […] The habitat surrounding the Yarrowee was removed or altered, damaging animal, fish and insect populations.</p>
<p>The destruction of the waterway continues to impact our people today. However, the spirit of this land remains within us and we continue as Wadawurrung people to live alongside the Yarrowee whilst working to restore its health and vitality.</p>
</blockquote>
<p>The Wadawurrung people involved in this project hope it fosters interconnectedness between the waterway, our human ancestors, creator beings and all living things. </p>
<p>It is also crucial in working towards reconciliation by helping people understand the devastating environmental destruction wrought by the gold rush for the First Nations people of the region and the deep connection between culture, heritage and the landscape.</p>
<h2>Effluent, flooding and typhoid</h2>
<p>When one looks at the sheer scale of the transformation of Ballarat and district wrought by the gold rush, the level of environmental destruction is almost beyond comprehension.</p>
<p>Vast forested tracts of land were felled of trees, the topsoil dug up and blown away, the earth ripped open by deep tunnelling. Imported sheep began to harden the soil (disrupting native plants) and consuming the Murrnong plants, whose roots were a staple of the Wadawurrung people.</p>
<p>Moving the river made the area prone to disastrous flooding as water was diverted away from floodplains. Land was polluted by effluent and chemical residue from mining. This led to multiple outbreaks of disease. As one contributor to the Ballarat Star wrote at the time:</p>
<blockquote>
<p>The smell from this creek for a quarter of a mile on each side is most frightful — the bed of the creek looking and smelling like the refuse pigs’ droppings mixing with their liquid manure. Nearly one-half of the children, and even adults, have been swept off between the Gnarr Creek and the Cemetery, from typhoid fever.</p>
</blockquote>
<p>This project aims to draw attention to the absolute centrality of the waterways to Australia’s history and continual sustainable environmental management. </p>
<p>Mapping the transformation of Australia’s waterways since colonisation is crucial to understanding the long term effects of changes we make to our environment.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/flashers-femmes-and-other-forgotten-figures-of-the-eureka-stockade-20939">Flashers, femmes and other forgotten figures of the Eureka Stockade</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214949/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kelly Ann Blake works for Wadawurrung Traditional Owners Aboriginal Corporation as a Biodiversity Project Officer.</span></em></p><p class="fine-print"><em><span>Shannen Mennen works for Wadawurrung Traditional Owners Aboriginal Corporation as a Project Officer.</span></em></p><p class="fine-print"><em><span>David Waldron 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>The river wasn’t merely a physical entity – it was a symbol of spiritual and cultural significance, serving as the life force which flows through Country.David Waldron, Senior Lecturer in History, Federation University AustraliaKelly Ann Blake, Gherrang/Biodiversity Project Officer, Wadawurrung Traditional Owners Aboriginal Corporation, Indigenous KnowledgeShannen Mennen, Project Officer Wadawurrung Traditional Owners Aboriginal Corporation, Indigenous KnowledgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126902023-11-02T19:12:25Z2023-11-02T19:12:25ZTaming wild northern rivers could harm marine fisheries and threaten endangered sawfish<figure><img src="https://images.theconversation.com/files/556797/original/file-20231031-23-pl3bb0.JPG?ixlib=rb-1.1.0&rect=26%2C0%2C2198%2C1504&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Google Earth Image Landsat/Copernicus</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Australia’s tropical northern rivers still run wild and free. These relatively pristine areas have so far avoided extensive development. But this might not last. There are <a href="https://www.dcceew.gov.au/water/policy/national/northern-australia">ongoing scoping studies exploring irrigating agricultural land</a> using water from these rivers.</p>
<p>Our <a href="https://www.nature.com/articles/s41893-023-01238-x">new research</a> in the journal Nature Sustainability shows disturbing the delicate water balance upstream can have major consequences downstream, even hundreds of kilometres away.</p>
<p>Using our latest computer modelling, we found northern water resource development would have substantial effects on prawn, mud crab and barramundi fisheries in the Gulf of Carpentaria. These are valuable Australian marine fisheries which depend on healthy estuaries. Reducing river flows would also disturb mangrove and seagrass habitats and threaten the iconic endangered largetooth sawfish.</p>
<p>Freshwater flows to the sea play a crucial role, boosting the productivity of marine, estuarine and freshwater systems. These complex interactions must be carefully considered in the assessment of future development plans.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic illustrating how altering river flow influences downstream estuarine and marine species and habitats" src="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=379&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=379&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=379&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556412/original/file-20231029-25-tiz5y6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Changing the natural river flow regime has consequences for estuarine and marine species and fisheries.</span>
<span class="attribution"><span class="source">James Chen in Plaganyi et al (2023) Nature Sustainability</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-we-protect-mangroves-we-protect-our-fisheries-our-towns-and-ourselves-214390">If we protect mangroves, we protect our fisheries, our towns and ourselves</a>
</strong>
</em>
</p>
<hr>
<h2>Rivers are our lifeblood</h2>
<p>Worldwide, few wild running rivers remain. Their future is uncertain given <a href="https://turningthetide.watercommission.org/">growing demand for water</a>. </p>
<p>Climate change is putting extra pressure on rivers as temperatures rise, rainfall patterns shift and <a href="https://theconversation.com/marine-heatwaves-are-getting-hotter-lasting-longer-and-doing-more-damage-95637">extreme events</a> become more frequent. </p>
<p>Rivers are the lifeblood of ecosystems and communities. They connect land, estuaries and the sea. But assessments of river developments <a href="https://www.science.org/doi/epdf/10.1126/science.abj4017">often focus narrowly on local effects</a>. They ignore the fact downstream estuaries and marine systems depend on freshwater flows. Few studies have calculated the costs of upstream catchment developments to downstream estuarine and marine ecosystems and fisheries.</p>
<p>We must avoid the <a href="https://theconversation.com/damming-northern-australia-we-need-to-learn-hard-lessons-from-the-south-53885">mistakes made in southern Australia</a> where <a href="https://theconversation.com/excessive-water-extractions-not-climate-change-are-most-to-blame-for-the-darling-river-drying-192621">too much water has been taken out of the system</a> for growing crops. That means carefully evaluating the design of dams or irrigation schemes, considering when, where and how much water should be taken – and the likely trade-offs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing many common banana prawns on a trawler. This is one of several species caught by the Northern Prawn Fishery" src="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556413/original/file-20231029-25-u36qo0.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">Yields of common banana prawn vary depending on river flows from multiple catchments.</span>
<span class="attribution"><span class="source">NPF Industry Pty Ltd, Australian Council of Prawn Fisheries Ltd, Austral Fisheries and Raptis Seafoods</span></span>
</figcaption>
</figure>
<h2>Why should we care about northern rivers?</h2>
<p>Australia’s remote northern rivers are one of the last strongholds for endangered species such as the <a href="https://theconversation.com/australian-endangered-species-largetooth-sawfish-24558">largetooth sawfish</a>. These iconic species are born in estuaries before spending their first few years of life upstream in freshwater rivers. </p>
<p>Flows from these rivers also sustain extensive mangrove forests and seagrass beds. Periodic floods <a href="https://www.abc.net.au/news/2020-10-30/barramundi-banana-prawns-could-be-threatened-gulf-of-carpentaria/12828280">boost the food supply</a> for many prized marine fisheries such as prawns, barramundi and <a href="https://tinyurl.com/2haudz3t">mud crabs</a>.</p>
<p>The rivers also have <a href="https://indigenousknowledge.unimelb.edu.au/curriculum/resources/indigenous-voices-in-water">cultural significance</a> for Aboriginal people and represent a valuable resource, providing food and supporting livelihoods. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of an endangered largetooth sawfish in shallow water" src="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556411/original/file-20231029-27-eror37.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">Endangered largetooth sawfish are sensitive to changes in river flows.</span>
<span class="attribution"><span class="source">Rich Pillans/CSIRO</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/an-el-nino-hit-this-banana-prawn-fishery-hard-heres-what-we-can-learn-from-their-experience-139852">An El Niño hit this banana prawn fishery hard. Here’s what we can learn from their experience</a>
</strong>
</em>
</p>
<hr>
<h2>Using modelling to connect rivers, estuaries and oceans</h2>
<p>We coupled CSIRO’s sophisticated <a href="https://www.csiro.au/en/showcase/nawra">river models</a> with our <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-2979.2012.00488.x">specially tailored ecosystem models</a> to represent how altering river flows may influence the downstream ecology and fishery yields. </p>
<p>We used catch data from fisheries to analyse how past natural changes in flow influenced catch rates. This was combined with extensive previous research on the biology and ecology of each species to model the dynamics of catchment-to-coast systems. We were particularly interested in the natural life cycles of fish and crustaceans in our unique northern wet-dry tropical rivers and estuaries. We then simulated multiple water resource development scenarios to assess and compare various impacts and ways to reduce them. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two column charts showing risk to key populations and fisheries in the Gulf of Carpentaria from changes in freshwater flows." src="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=562&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=562&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=562&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=707&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=707&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547140/original/file-20230908-15-efu6e7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=707&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">We quantified risk to key populations and fisheries in the Gulf of Carpentaria from changes in freshwater flows due to various hypothetical water resource developments (WRD).</span>
<span class="attribution"><span class="source">Plagányi et al. (2023) Nature Sustainability</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>For <a href="https://tinyurl.com/2haudz3t">mud crabs, we linked river flow</a> and other climate drivers to their life cycle and were able to show how past changes in flow could explain the past variation in crab catch, particularly for rivers in which flow was seasonally variable. We could then use this model to predict how crab catch and abundance might change in the future, depending on how much water is removed from rivers and the method of removal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial image of an estuary feeding into the Gulf of Carpentaria" src="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546574/original/file-20230906-27-vx8vj3.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">Rivers connect land, estuaries and the sea. Large estuaries feed into the Gulf of Carpentaria.</span>
<span class="attribution"><span class="source">Queensland Department of Agriculture and Fisheries</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/as-industry-lines-up-to-take-water-from-a-wild-top-end-river-trees-tell-the-story-of-a-much-drier-past-177221">As industry lines up to take water from a wild Top End river, trees tell the story of a much drier past</a>
</strong>
</em>
</p>
<hr>
<h2>Integrated management from catchment to coast</h2>
<p>Our research shows freshwater flows to the sea are crucial for environmentally and economically important species. Any plan to dam or extract freshwater from Australia’s last wild rivers should account for these effects.</p>
<p>Coupling scientific knowledge about marine and freshwater ecosystems with catchment development will improve infrastructure planning and flow management.</p>
<p>This is vital on a dry continent already <a href="https://theconversation.com/extreme-weather-caused-by-climate-change-has-damaged-45-of-australias-coastal-habitat-120671">challenged by climate change</a>. Every drop counts.</p>
<p><em>The authors wish to acknowledge Annie Jarrett, Chief Executive Officer of NPF Industry Pty Ltd, which represents Northern Prawn Fishery operators, for her contribution to the research.</em></p><img src="https://counter.theconversation.com/content/212690/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Éva Plagányi acknowledges Annie Jarrett, Chief Executive Officer of NPF Industry Pty Ltd, which represents Northern Prawn Fishery operators, for her contribution to the research.
Éva works for CSIRO and receives research funding from several sources, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).
2018-079 Ecological modelling of the impacts of water development in the Gulf of Carpentaria with particular reference to impacts on the NPF was supported by funding from the Fisheries Research and Development Corporation on behalf of the Australian Government</span></em></p><p class="fine-print"><em><span>Laura Blamey works for CSIRO, which receives research funding from several source, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).</span></em></p><p class="fine-print"><em><span>Michele Burford works for the Australian Rivers Institute, Griffith University and receives funding from several sources, including the National Environmental Science Program (NESP).</span></em></p><p class="fine-print"><em><span>Robert Kenyon works CSIRO, an organisation that receives research funding from several sources, including the Fisheries Research and Development Corporation (FRDC) and the Australian Fisheries Management Authority (AFMA).</span></em></p>Any plan to dam or extract water from some of Australia’s last wild rivers must carefully consider the consequences. Prawn, mud crab and barramundi fisheries could suffer in the Gulf of Carpentaria.Éva Plagányi, Senior Principal Research Scientist, CSIROLaura Blamey, Senior Research Scientist, CSIROMichele Burford, Professor - Australian Rivers Institute, and Dean - Research Infrastructure, Griffith UniversityRobert Kenyon, Marine Ecologist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2159772023-10-26T22:16:17Z2023-10-26T22:16:17ZDiscover 6 fascinating animals that live at the bottom of the St. Lawrence River<figure><img src="https://images.theconversation.com/files/554598/original/file-20231016-24-cndzzv.jpg?ixlib=rb-1.1.0&rect=7%2C3%2C2537%2C1912&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Not only do corals inhabit the cold waters of the St. Lawrence, but the species that holds the title of largest marine invertebrate on the planet is present at the entrance to the Gulf.</span> <span class="attribution"><span class="source">(Fisheries and Oceans Canada)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>In the vast St. Lawrence River, an impressive variety of animals live on the seabed. This group of organisms is called benthos. </p>
<p>These organisms live either buried in the sediment (infaunas) or on the surface of the seabed (epibenthos). Benthic invertebrates have no backbone, are not very mobile and are generally small. </p>
<p>And they are far from being rare. As far back as 1988 <a href="https://books.google.ca/books?hl=fr&lr=&id=CoDHrKyVgscC">researchers</a> listed over 1,855 species of benthic invertebrates living in the estuary and gulf of the St. Lawrence River. These represent 84 per cent of all invertebrate species in the St. Lawrence waters. </p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
<hr>
<p>Needless to say, many new species have been identified since then, and our knowledge about them continues to grow.</p>
<p>As specialists in benthic ecology, we invite you to discover the benthos through six special features that are certain to pique your curiosity.</p>
<h2>Luminous worms</h2>
<p>Like earthworms in our gardens, marine worms inhabit the ocean floor. They come in all shapes and sizes, and some are even covered in scales. But their originality doesn’t stop there. Some of these worms are actually capable of <a href="https://doi.org/10.11646/ZOOSYMPOSIA.2.1.26">bioluminescence</a>. The production of light in the form of luminous flashes has three general functions: defensive (to escape predators), offensive (in support of predation) and communicative (for reproduction). </p>
<p>In the St. Lawrence River, the only scale worms with this ability are of the <em>Harmothoe</em> genus, of which there are five species. These species can be found on both clay and rocky bottoms in both coastal and deep-water areas.</p>
<h2>Are corals cold?</h2>
<p>For many, oceans bring to mind vacations, heat, diving and coral reefs. But does coral only grow in warm waters? Absolutely not. Some <a href="https://www.dfo-mpo.gc.ca/oceans/ceccsr-cerceef/corals-coraux-eng.html">20 species</a> live in the salty waters of the St. Lawrence ecosystems and this number <a href="https://research.library.mun.ca/12107/1/thesis.pdf">triples</a> if we include the East Coast of Canada. </p>
<p>But what is coral? Corals are actually marine <a href="https://oceanservice.noaa.gov/facts/coral.html">polyps</a>, cylindrical animals with a mouth surrounded by a ring of tentacles, that secrete a molecule called calcium carbonate to form a skeleton. </p>
<p>There are two types: soft corals, with an internal skeleton that reinforces the structure of the <a href="https://oceanservice.noaa.gov/facts/coral.html">colony</a> (a collection of cloned individuals) while ensuring its elasticity, and hard corals, where each polyp secretes a cup-shaped external skeleton, creating their characteristic rigidity. </p>
<p>Not only do corals inhabit the cold waters of the St. Lawrence, but the species that holds the title of largest marine invertebrate on the planet is present at the entrance to the Gulf, notably on the rocky slopes of the Scotian Shelf. This is the <a href="https://www.dfo-mpo.gc.ca/oceans/publications/cs-ce/index-eng.html"><em>Paragorgia arborea</em></a>, some colonies of which can reach six metres in height.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="corals on the seabed" src="https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554072/original/file-20231016-27-sgbiot.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">Some colonies of Paragorgia arborea can reach six metres in height.</span>
<span class="attribution"><span class="source">(Fisheries and Oceans Canada)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>Starfish: dreaded gourmets</h2>
<p>Starfish are so colourful and pretty you can find them in souvenir stores, but don’t be fooled by their appearance. They are actually <a href="https://www.thecanadianencyclopedia.ca/en/article/starfish">fearsome predators</a>, and understanding how they feed will likely change the way you see them. </p>
<p>Faced with the two greediest species in the St. Lawrence (<em>Asterias rubens</em> and <em>Leptasterias polaris</em>), mussels normally have nothing to fear. But thanks to dozens of ambulacral feet — little suckers on their underside — starfish can easily open mussels. As soon as the mussel shows a sign of weakness, the starfish is able to extract its own stomach from its body and insert it into the mussel, where on contact with the flesh, it begins digesting it. In this rather unusual situation the meal can last around 10 hours. Afterwards, the starfish swallows its stomach again and starts hunting for new prey.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="starfish" src="https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=643&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=643&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=643&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=808&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=808&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554073/original/file-20231016-27-9kcy6a.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=808&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Starfish are formidable predators.</span>
<span class="attribution"><span class="source">(Cindy Grant)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>You said centenarian?</h2>
<p>Present in the Gulf of St. Lawrence, particularly in the Magdalen Islands, the Northern quahog (<em>Arctica islandica</em>) is the world’s longest-living animal. It is a <a href="https://www.dfo-mpo.gc.ca/shellfish-mollusques/identification-eng.htm">bivalve mollusc</a> protected by a calcareous shell with two valves, like that of a mussel or oyster. The Northern quahog can easily live up to 200 years, but the oldest specimen, recorded in Iceland, <a href="https://www.nationalgeographic.com/animals/article/131116-oldest-clam-dead-ming-science-ocean-507">was 507 years old</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="bivalve mollusc" src="https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=533&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=533&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=533&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=670&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=670&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554074/original/file-20231016-27-vxm7uh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=670&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 Northern quahog is the world’s longest-living animal.</span>
<span class="attribution"><span class="source">(Lisa Treau De Coeli)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>Other bivalves are known to live long lives. The age of these molluscs can be determined by the growth rings on their shells, rather like trees, but the technique here is called sclerochronology. It is even possible to <a href="https://www.frontiersin.org/articles/10.3389/fmars.2019.00483/full">read the history of the climate</a> on the shells of several bivalves and use this information to predict future conditions.</p>
<h2>Worms, medicine and the Olympics</h2>
<p>Arenicolous worms (<em>Arenicola marina</em>) can be identified by the typical shape of their burrows (a mound of small wiggles), which can be seen at low tide on the St. Lawrence coast.</p>
<p>Although seemingly trivial, these marine worms could enable major advances in medicine thanks to their <a href="https://pubmed.ncbi.nlm.nih.gov/34210070/">hemoglobin</a>, which is capable of transporting up to 50 times more oxygen than that of humans. This particular property enables the worms to store oxygen from seawater at high tide and use this reserve at low tide. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8304559/">In medicine</a>, the hemoglobin of the arenicolous worm could be used to improve organ preservation during transplants, to make oxygenating dressings or to develop a blood substitute for emergency transfusions. </p>
<p>Although this worm could revolutionize medicine, it could also pose problems for anti-doping agencies and athletes. Virtually undetectable and hyper-performing, the incredible oxygenating benefits of the arenicolous worm’s hemoglobin could undoubtedly boost athletes’ performance at the next Olympics.</p>
<h2>Natural “crazy glue”</h2>
<p>Although mussels are tossed about by breaking waves all day long, they still manage to hold tight to the rocks. Their secret? The <a href="https://www.nature.com/articles/ncomms14539">byssus</a>, a collection of hair-sized fibres that are both strong and elastic. </p>
<p>The proteins that make up byssus form natural ‘crazy glue’; this liquid glue hardens rapidly, enabling the mussel to adhere with unrivalled tenacity to virtually any surface, even wet ones. </p>
<p>The unusual properties of byssus have fascinated humans since ancient times. In days gone by, these filaments of “marine silk” were used to weave luxurious garments. More recently, the particular chemical composition of the sticky proteins derived from byssal threads has inspired the creation of <a href="https://news.northwestern.edu/stories/2022/03/mussels-synthetic-glue/">underwater adhesives and surgical glues</a>.</p>
<p>In conclusion, while the epifauna of the St. Lawrence is relatively well known, knowledge of the endofauna remains sparse and patchy, even in 2023. Initiatives are underway to discover and characterize this sediment-dwelling fauna. </p>
<p>These studies will undoubtedly lead to the discovery of other exciting facts about the benthos.</p><img src="https://counter.theconversation.com/content/215977/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Philippe Archambault is scientific co-director of the ArcticNet network of centers of excellence, and a member of the Québec Océan strategic cluster, the CNRS/Université Laval International Research Laboratory, Takuvik, and co-director of the 'Ecosystem Functioning and Environmental Protection' axis at the Institut Nordique du Québec.</span></em></p><p class="fine-print"><em><span>Cindy Grant is a member of the Québec-Océan strategic group and of the Unité Mixte Internationale Takuvik.</span></em></p><p class="fine-print"><em><span>Gabrièle Deslongchamps is a member of the Québec-Océan strategic group and of the Unité Mixte Internationale Takuvik.</span></em></p><p class="fine-print"><em><span>Lisa Treau De Coeli is a member of the Québec-Océan strategic group and of the Unité Mixte Internationale Takuvik.</span></em></p>In the vast St. Lawrence River, an impressive variety of animals live on the seabed. This group of organisms is called benthos or benthic invertebrates.Philippe Archambault, Professor & CoScientific Director of ArcticNet, Université LavalCindy Grant, Professionnelle de recherche, biologie marine & écologie benthique, Université LavalGabrièle Deslongchamps, Professionnelle de recherche, Université LavalLisa Treau De Coeli, Professionnelle de recherche en écologie benthique, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2133022023-10-24T12:23:00Z2023-10-24T12:23:00ZThe Rio Grande isn’t just a border – it’s a river in crisis<figure><img src="https://images.theconversation.com/files/555415/original/file-20231023-23-wax337.jpeg?ixlib=rb-1.1.0&rect=24%2C6%2C4001%2C2257&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Rio Grande, viewed from the Zaragoza International Bridge between El Paso, Texas, and Ciudad Juarez, Mexico.</span> <span class="attribution"><span class="source">Vianey Rueda</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The Rio Grande is one of the longest rivers in North America, <a href="https://www.britannica.com/place/Rio-Grande-river-United-States-Mexico">running some 1,900 miles</a> (3,060 kilometers) from the Colorado Rockies southeast to the Gulf of Mexico. It provides fresh water for seven U.S. and Mexican states, and forms the border between Texas and Mexico, where it is known as the Río Bravo del Norte. </p>
<p>The river’s English and Spanish names mean, respectively, “large” and “rough.” But <a href="https://www2.elpasotexas.gov/misc/externally_linked/bridges/cameras.html">viewed from the Zaragoza International Bridge</a>, which connects the cities of El Paso, Texas, and Ciudad Juárez, Mexico, what was once mighty is now a dry riverbed, lined ominously with barbed wire. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the Rio Grande basin, from southwest Colorado to the Gulf of Mexico." src="https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=709&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=709&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=709&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=890&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=890&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555383/original/file-20231023-25-ddks9p.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=890&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 Rio Grande is one of the largest rivers in the southwest U.S. and northern Mexico. Because of drought and overuse, sections of the river frequently run dry.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Rio_Grande#/media/File:Riogranderivermap.png">Kmusser/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In the U.S., people often think of the Rio Grande mainly as a political border that features in negotiations over immigration, narcotics smuggling and trade. But there’s another crisis on the river that receives far less attention. The river is in decline, suffering from overuse, drought and <a href="https://theconversation.com/megadrought-along-border-strains-us-mexico-water-relations-160338">contentious water rights negotiations</a>. </p>
<p>Urban and rural border communities with poor infrastructure, <a href="https://theimmigrationcoalition.com/the-water-problem/">known in Spanish as colonias</a>, are particularly vulnerable to the water crisis. Farmers and cities in <a href="https://www.texastribune.org/2022/08/16/south-texas-water-drought/">southern Texas</a> and <a href="https://www.npr.org/2022/07/21/1112663036/extreme-drought-in-northern-mexico-has-left-millions-of-residents-without-water">northern Mexico</a> are also affected. As researchers who study <a href="https://scholar.google.com/citations?user=RJ5WJTsAAAAJ&hl=en">hydrology</a> and <a href="https://www.linkedin.com/in/vianey-rueda-a2825b127/">transboundary water management</a>, we believe managing this important resource requires closer cooperation between the U.S. and Mexico.</p>
<h2>A hidden water crisis</h2>
<p>For nearly 80 years, the U.S. and Mexico have managed and distributed water from the Colorado River and the Lower Rio Grande – from Fort Quitman, Texas, to the Gulf of Mexico – under the <a href="https://www.ibwc.gov/wp-content/uploads/2022/11/1944Treaty.pdf">1944 Water Treaty</a>, signed by presidents Franklin D. Roosevelt and Manuel Avila Camacho. The Colorado River was the <a href="https://uapress.arizona.edu/book/border-water">central focus of treaty negotiations</a> because officials believed the Colorado basin would have more economic activity and population growth, so it would need more water. In fact, however, the Rio Grande basin has also seen significant growth. </p>
<p>For the Rio Grande, the treaty allocates specific shares of water to the U.S. and Mexico from both the river’s main stem and its tributaries in Texas and Mexico. Delivery of water from six Mexican tributaries has become the source of contention. One-third of this flow is allocated to the U.S., and must total some 76 million cubic feet (2.2 million cubic meters) over each five-year period. </p>
<p>The treaty allows Mexico to roll any accrued deficits at the end of a five-year cycle over to the next cycle. Deficits can only be rolled over once, and they must be made up along with the required deliveries for the following five-year period. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ym6m2rZeXPw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Farmers as far north as Colorado rely on water from the Rio Grande for irrigation.</span></figcaption>
</figure>
<p>These five-year periods, called cycles, are numbered. Cycles 25 (1992-1997) and 26 (1997-2002) were the first time that two consecutive cycles ended in deficit. Like the Colorado River, the Rio Grande <a href="https://sgp.fas.org/crs/row/R43312.pdf">has become over-allocated</a>: The 1944 treaty promises users more water than there is in the river. The main causes are <a href="https://www.ibwc.gov/wp-content/uploads/2023/04/Exec_Rio_Grande_White_Paper_-Summary-FINAL.pdf">persistent drought</a> and increased water demand on both sides of the border. </p>
<p>Much of this demand was generated by <a href="https://upittpress.org/books/9780822960584/">the 1992 North American Free Trade Agreement</a>, which eliminated most border tariffs between Canada, the U.S. and Mexico. From 1993 through 2007, agricultural imports and exports between the U.S. and Mexico quadrupled, and there was extensive expansion of <a href="https://www.britannica.com/technology/maquiladora">maquiladoras</a> – assembly plants along the border. This growth increased water demand.</p>
<p>Ultimately, Mexico delivered more than the required amount for Cycle 27 (2002-2007), plus its incurred deficit from cycles 25 and 26, by transferring water from its reservoirs. This outcome appeased Texas users but left Mexico vulnerable. Since then, Mexico has continued to struggle to meet its treaty responsibilities and has experienced chronic water shortages.</p>
<p>In 2020, a confrontation erupted in the state of Chihuahua between the Mexican National Guard and farmers who believed delivery to Texas of water from the Rio Conchos – one of the six tributaries regulated under the 1944 treaty – <a href="https://www.nytimes.com/es/2020/10/14/espanol/america-latina/chihuahua-mexico-pago-agua.html">threatened their survival</a>. In 2022, people lined up at water distribution sites in <a href="https://www.washingtonpost.com/weather/2022/08/09/drought-mexico-water-monterrey/">the Mexican city of Monterrey</a>, where the population had doubled since 1990. As of 2023, halfway through Cycle 36, Mexico has only delivered <a href="https://ibwcsftpstg.blob.core.windows.net/wad/WeeklyReports/Current_Cycle.pdf">some 25% of its targeted amount</a>. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CyltiGPMhxz/?utm_source=ig_web_copy_link","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Border politics overshadow water shortages</h2>
<p>As climate change makes the Southwest hotter and drier, scientists predict that <a href="https://doi.org/10.1002/joc.5773">water shortages on the Rio Grande will intensify</a>. In this context, the 1944 treaty pits humanitarian needs for water in the U.S. against those in Mexico. </p>
<p>It also pits the needs of different sectors against one another. Agriculture is the <a href="https://www.bakerinstitute.org/sites/default/files/2021-11/import/mex-pub-borderwater-112921.pdf">dominant water consumer</a> in the region, followed by residential use. When there is a drought, however, the treaty prioritizes residential water use over agriculture. </p>
<p>The Rio Grande is affected by nearly the same hydroclimate conditions as the Colorado River, which flows mainly through the southwest U.S. but ends in Mexico. However, <a href="https://theconversation.com/colorado-river-states-bought-time-with-a-3-year-water-conservation-deal-now-they-need-to-think-bigger-206386">drought and water shortages</a> in the Colorado River basin receive much more public attention than the same problems on the Rio Grande. U.S. media outlets cover the Rio Grande almost exclusively when it figures in stories about immigration and river crossings, such as Texas Gov. Greg Abbott’s 2023 decision to install <a href="https://www.washingtonpost.com/world/2023/08/04/mexico-texas-buoys-rio-grande-bodies/">floating barriers</a> in the river at widely used crossing points.</p>
<p>The compact that governs use of Colorado River water has <a href="https://theconversation.com/as-climate-change-parches-the-southwest-heres-a-better-way-to-share-water-from-the-shrinking-colorado-river-168723">widely recognized flaws</a>: The agreement is 100 years old, allocates more rights to water than the river holds, and completely excludes Native American tribes. However, negotiations over the Colorado between compact states and the U.S. and Mexico are much more focused than decision-making about Rio Grande water, which has to compete with many other bilateral issues. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Dry, cracked mud with mountains in the background" src="https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555441/original/file-20231023-23-ymryd6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dry, cracked mud along the banks of the Rio Grande at Big Bend National Park in Texas, March 25, 2011. In the spring and early summer of 2022, up to 75 miles of the river went dry in the park.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/LaNina/28075c648a3c4faa9284a3312c7c0f36/photo">AP Photo/Mike Graczyk</a></span>
</figcaption>
</figure>
<h2>Adapting to the future</h2>
<p>As we see it, the 1944 water treaty is inadequate to solve the complex social, economic, hydrological and political challenges that exist today in the Rio Grande basin. We believe it needs revision to reflect modern conditions. </p>
<p>This can be done through the <a href="https://www.jstor.org/stable/40170270">minute process</a>, which permits Mexico and the U.S. to adopt legally binding amendments without having to renegotiate the entire agreement. The two countries have already used this process to update the treaty as it pertains to the Colorado River <a href="https://www.ibwc.gov/wp-content/uploads/2012/11/Minute_319.pdf">in 2012</a> and <a href="https://www.ibwc.gov/wp-content/uploads/2023/03/Min323.pdf">again in 2017</a>. </p>
<p>These steps allowed the U.S. to adjust its deliveries of Colorado River water to Mexico based on water levels in Lake Mead, the Colorado’s largest reservoir, in ways that proportionally distributed drought impacts between the two countries. In the Rio Grande basin, Mexico does not have similar flexibility. </p>
<p>The U.S. also has the ability to proportionally reduce deliveries under a <a href="https://www.ibwc.gov/wp-content/uploads/2022/11/1906Conv.pdf">separate 1906 agreement</a> that outlines water delivery from El Paso to Ciudad Juarez. In 2013, for example, <a href="http://www.cila.gob.mx/rb/asignac1906.pdf">Mexico received only 6%</a> of the water it was due under the 1906 Convention. </p>
<p>Enabling Mexico to proportionally reduce Rio Grande deliveries according to drought conditions would distribute drought and climate change impacts more fairly between both countries. As we see it, this kind of cooperation would deliver human, ecological and political benefits in a complex and contentious region.</p><img src="https://counter.theconversation.com/content/213302/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vianey Rueda received funding through CUAHSI’s Instrumentation Discovery Travel Grant, which helps researchers learn about hydrologic instrumentation. </span></em></p><p class="fine-print"><em><span>Drew Gronewold 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>When the Rio Grande figures in US news reports, it’s usually in relation to stories about immigration, drug trafficking or trade. But the river is also an important water source – and it’s shrinking.Vianey Rueda, PhD Student in Resource Ecology Management, University of MichiganDrew Gronewold, Associate Professor of Environment and Sustainability, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2113562023-10-15T23:27:42Z2023-10-15T23:27:42ZSlime after slime: why those biofilms you slip on in rivers are vitally important<figure><img src="https://images.theconversation.com/files/543180/original/file-20230817-5739-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>You might have noticed it after sliding on a rock in a Melbourne creek. Or it could have been wading through a Northern Territory waterhole. It’s slime, and our rivers are full of it. That’s a good thing. </p>
<p>Wherever there are hard surfaces like snags and rocks in our rivers, you’ll find slime. Or, as ecologists call it, <a href="https://en.wikipedia.org/wiki/Biofilm">biofilm</a>. Biofilms consist of communities of microorganisms that include algae, cyanobacteria, bacteria, fungi and protozoa. Together, they’re fixed in a matrix of natural polymers made by bacteria and other tiny creatures. It’s this matrix which gives the slippery, slimy texture we encounter when swimming in rivers. </p>
<p>Biofilms play an important role in our freshwater ecosystems. They underpin healthy rivers by forming the base of freshwater <a href="https://flow-mer.org.au/basin-theme-food-webs-water-quality/">food webs</a>. </p>
<p>Our <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.4680">new research</a> explores how these common but unsung communities change over time. We found that biofilms are most nutritious when new – less than six weeks old. After that, their food value declines. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="biofilm and algae from river" src="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.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">This is what a 73-day-old biofilm looks like after being pulled from a lowland river.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why are biofilms important?</h2>
<p>Without slime, rivers would lack a fundamental source of food for animals. That sounds like a big statement, but <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1442-8903.2001.00069.x">it’s true</a>. </p>
<p>Algae take energy from the sun and convert it into new biomass through <a href="https://education.nationalgeographic.org/resource/photosynthesis/">photosynthesis</a>. Bacteria and fungi break down organic debris, from dead leaves to dead fish, and recycle the nutrients. Tiny invertebrate grazers such as <a href="https://en.wikipedia.org/wiki/Zooplankton">zooplankton</a> and <a href="https://www.mdfrc.org.au/bugguide/">macroinvertebrates</a> feed on biofilms. In turn, they become food for larger predators such as fish, platypus and turtles. </p>
<p>Not all biofilms offer the same quality of food. And different communities of biofilm grow under different physical conditions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-on-earth-was-nothing-but-slime-for-a-boring-billion-years-23358">Life on Earth was nothing but slime for a 'boring billion' years
</a>
</strong>
</em>
</p>
<hr>
<p>When the water level goes up in a river, rocks and dead trees at the surface are submerged and biofilms colonise this new habitat. It happens very quickly. Bacteria arrive first, followed by algae in the next few weeks. </p>
<p>Biofilms undergo natural changes in community composition over time, influenced by physical disturbance (such as scouring when water flow is high, or sedimentation from low flows) or chemical changes, such as additional nutrients from runoff. </p>
<p>These disturbances often lead to periods of collapse and recolonisation by new organisms. Biofilms are thought to become a poorer source of food for animals as they get older. That’s because older biofilm communities become dominated by <a href="https://en.wikipedia.org/wiki/Cyanobacteria">cyanobacteria</a> and <a href="https://en.wikipedia.org/wiki/Spirogyra">filamentous algae</a>, which aren’t as nutritious as a food for animals.</p>
<h2>So what makes good slime?</h2>
<p>For the discerning invertebrate, the best biofilm is one containing lots of algae – especially <a href="https://en.wikipedia.org/wiki/Diatom">diatoms</a> and green algae. These are rich sources of <a href="https://onlinelibrary.wiley.com/doi/10.1111/brv.13017">omega 3 fatty acids</a>, molecules essential for animal growth and reproduction. (That’s why the food supplement industry likes to sell us products rich in omega 3s). </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="mayfly nymphs" src="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mayfly nymphs, such as this <em>Offadens</em> spp. (Baetidae) scrape algae and fine detritus from submerged rocks, wood and macrophytes in rivers.</span>
<span class="attribution"><span class="source">Chris Davey</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Having high quality food is one thing. But the food also needs to be easy to get. In the study of food webs, we often use a theory called <a href="https://encyclopedia2.thefreedictionary.com/ecological+energetics">ecological energetics</a>. Put simply, this suggests the success of an animal population is limited by how hard it is for individuals to obtain sufficient <a href="https://onlinelibrary.wiley.com/doi/10.1111/fwb.13895">food for growth</a> and reproduction. </p>
<p>You might have long-chain omega 3 fatty acids present, but buried under a pile of less edible microorganisms and detritus. The effort may simply not be worth the reward. </p>
<p>To date, we have a poor understanding of when biofilms hit their peak food value for animals. That’s what we set out to find. </p>
<h2>What did we find?</h2>
<p>Many of our rivers are regulated by dams and weirs. That means we can alter water levels to cover rocks and snags with water and trigger growth of new biofilms. </p>
<p>If we know how long it takes for biofilms to reach optimum quality, we can manage water levels to improve food value and benefit both biofilm grazers and the fish that eat them. </p>
<p>In our study, we sank wooden redgum blocks 20 centimetres under the surface of three rivers. Then we sampled the biofilm for 73 days, taking DNA to assess how the proportions of algae, cyanobacteria and fungi varied over time. </p>
<p>We developed a novel approach to assess food value, accounting for both quality of fatty acid profiles and their availability in space.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.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">
<figcaption>
<span class="caption">Redgum blocks give biofilm communities something to grow on.</span>
</figcaption>
</figure>
<p>What did we find? Food value for animals peaked between 24 and 43 days after the blocks were submerged.</p>
<p>After 43 days, the food value of biofilms declined. Filamentous algae and cyanobacteria numbers increased as the biofilms aged, while green algae and diatoms abundance decreased. The amount of slimy-feeling natural polymers also increased over time, making our once-delicious biofilms even less nutritious.</p>
<p>So what does this mean? Water agencies are increasingly using environmental flows to support freshwater fish and animal populations. A widely used application for environmental water is to raise water levels in rivers and weirs to inundate new hard surfaces to grow new biofilms.</p>
<p>Now we know that after six weeks the food value of biofilms for animals declines – and that can help managers find the best ways of using environmental water to produce a biofilm bonanza for invertebrates and everything that eats them.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/unlocking-the-secrets-of-bacterial-biofilms-to-use-against-them-59148">Unlocking the secrets of bacterial biofilms – to use against them</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211356/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul McInerney receives funding from the Murray Darling Basin Authority and the Commonwealth Environmental Water Office. </span></em></p>Slime gets a bad name in popular culture, but it’s food for invertebrates who become food for many other creatures.Paul McInerney, Senior Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2146202023-10-11T12:30:46Z2023-10-11T12:30:46ZWhat is seawater intrusion? A hydrogeologist explains the shifting balance between fresh and salt water at the coast<figure><img src="https://images.theconversation.com/files/552819/original/file-20231009-22-uvy78h.jpg?ixlib=rb-1.1.0&rect=18%2C12%2C4031%2C2683&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In 2022, California built an emergency drought barrier across the West False River near Oakley to protect against saltwater intrusion. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/FreshwaterLosingBattleAgainstOcean/0b33666dca68482bb6d393fcf1d0ebdb/photo">AP Photo/Terry Chea</a></span></figcaption></figure><p>Seawater intrusion is the movement of saline water from the ocean or estuaries into freshwater systems. The seawater that has <a href="https://www.whitehouse.gov/briefing-room/presidential-actions/2023/09/27/president-joseph-r-biden-jr-approves-louisiana-emergency-declaration-4/">crept up the Mississippi River</a> in the summer and early fall of 2023 is a reminder that coastal communities teeter in a fragile land-sea balance. </p>
<p>Fresh water is essential for drinking, irrigation and healthy ecosystems. When seawater moves inland, the salt it contains can wreak havoc on farmlands, ecosystems, lives and livelihoods. </p>
<p>I am a <a href="https://scholar.google.com/scholar?hl=en&as_sdt=0,8&q=holly+michael&oq=holly">coastal hydrogeologist</a> and have studied water across the land-sea interface for 25 years. I think of seawater intrusion as being like a seesaw: The place where fresh water and salt water meet is the balance point between forces from land and forces from the sea. </p>
<p>A push from the land side, such as heavy rainfall or high river flows, moves the balance point seaward. A push from the sea side – whether it’s sea-level rise, storm surge or high tides – moves the balance point landward. Droughts or heavy use of fresh water can also cause seawater to move inland. As climate change and population growth stress freshwater supplies, one result will be <a href="https://www.epa.gov/climateimpacts/climate-change-impacts-freshwater-resources">more seawater intrusion</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic of a coastal aquifer." src="https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552820/original/file-20231009-17-7xa2ak.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">Under natural conditions, fresh water flows underground toward the ocean and keeps seawater from moving into coastal aquifers. Pumping too much groundwater from the aquifer lowers water levels and can draw seawater inland.</span>
<span class="attribution"><a class="source" href="https://ca.water.usgs.gov/sustainable-groundwater-management/seawater-intrusion-california.html">USGS</a></span>
</figcaption>
</figure>
<h2>When the ocean moves upriver</h2>
<p>The current seawater intrusion in the lower Mississippi River is due primarily to <a href="https://www.washingtonpost.com/climate-environment/2023/09/29/saltwater-intrusion-louisiana-drinking-water/">drought in the Midwest</a>, which has reduced the river’s volume. Both the magnitude of reduction in river flow and the length of time that the river is low influence how far upriver the salt water moves. As of Oct. 2, 2023, the saltwater “wedge” in the Mississippi had moved <a href="https://www.mvn.usace.army.mil/Missions/Engineering/Stage-and-Hydrologic-Data/SaltwaterWedge/SaltwaterWedgeNow/">nearly 70 miles upstream</a> from the river’s mouth.</p>
<p>This <a href="https://theconversation.com/record-low-water-levels-on-the-mississippi-river-in-2022-show-how-climate-change-is-altering-large-rivers-193920">isn’t the first time</a> that low water on the river has allowed seawater to move inland. But as climate change raises sea levels and causes more severe weather anomalies, intrusion will become more common and will inch farther upstream. </p>
<p>And the problem isn’t unique to the Mississippi. In Delaware, seawater is <a href="https://doi.org/10.1111/gwat.13274">traveling farther up small tidal streams</a> during storms and the highest tides, flooding farmland and killing crops. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/t9papp-5QCo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Researchers in Maryland explain how seawater intrusion threatens coastal agriculture.</span></figcaption>
</figure>
<p>In the Sundarbans of India and Bangladesh – one of the largest coastal mangrove forests in the world – seawater is intruding into the mouth of the Ganges River. The main causes there are upstream dams and water diversions from the river for irrigation and navigability, plus encroachment due to sea-level rise. Seawater intrusion could <a href="https://doi.org/10.1007/s00027-006-0868-8">threaten many types of plants and animals</a> in this <a href="https://whc.unesco.org/en/list/798/">UNESCO World Heritage Site</a>, which is home to countless rare and endangered species. </p>
<h2>Invading underground</h2>
<p>Another interface between fresh water and salt water at the coast is less obvious because <a href="https://www.usgs.gov/mission-areas/water-resources/science/saltwater-intrusion">it’s underground</a>. Many coastal communities draw their freshwater supply from groundwater – clean water that moves through pore spaces between grains of sand and soil. </p>
<p>Groundwater doesn’t just stop at the coastline: Under the ocean floor, the groundwater is salty, and somewhere between land and the ocean, there is an underground meeting point. It typically is landward of the coastline because salt water is denser than fresh water, so it has a greater force and naturally pushes in. But just as with a river, <a href="https://www.usgs.gov/mission-areas/water-resources/science/saltwater-intrusion">that interface moves</a> when groundwater levels drop on land or water levels rise offshore. </p>
<p>In <a href="https://data.cnra.ca.gov/dataset/ca-gw-basin-boundary-descriptions">groundwater basins</a> of central and southern California, <a href="https://theconversation.com/drilling-deeper-wells-is-a-band-aid-solution-to-us-groundwater-woes-121219">widespread pumping</a> has caused groundwater levels to drop hundreds of feet in some areas. This is tipping the seesaw and causing groundwater from the sea to move far inland. Accessible groundwater has supported irrigated agriculture in these areas, but now the double hazard of reduced groundwater availability and seawater intrusion <a href="https://www.climatehubs.usda.gov/hubs/california/topic/climate-vulnerabilities-california-specialty-crops">threatens crops like strawberries and lettuce</a>.</p>
<p>Seawater intrusion into groundwater is happening all over the world, but perhaps the most threatened places are communities on <a href="https://www.nature.com/articles/nclimate3128">low-lying islands</a>. Fresh groundwater is often the sole source of water for drinking and irrigation on small islands, and it exists in a thin lens that floats on top of saline groundwater. </p>
<p>The lens can shrink in response to droughts, pumping and sea-level rise. It can also become salty from floodwater infiltration during storms or high tides. </p>
<p>In the Marshall Islands, for example, a combination of sea-level rise and wave-driven flooding is predicted to make many islands <a href="http://dx.doi.org/10.1126/sciadv.aap9741">uninhabitable by the end of the century</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman pours water from a box into her dog's dish" src="https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552822/original/file-20231009-17-622g49.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">Kelli Marinovich fills her dog’s bowl with boxed water at her home in Buras, La., on Oct. 4, 2023. With salt water moving up the Mississippi River, thousands of Plaquemines Parish residents have been living on bottled water and dealing with saltwater intrusion for more than three months.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/kelli-marinovich-fills-her-dogs-bowl-with-boxed-water-at-news-photo/1712281174">Kathleen Flynn/Washington Post via Getty Images</a></span>
</figcaption>
</figure>
<h2>Shifting the balance</h2>
<p>As salt water continues to encroach on freshwater systems, there will be consequences. Drinking water that contains even 2% seawater can <a href="https://www.cnn.com/2023/10/05/health/louisiana-salt-levels-drinking-water-health/index.html">increase blood pressure and stress kidneys</a>. If salt water gets into supply lines, it can <a href="https://doi.org/10.1016/j.jenvman.2022.115153">corrode pipes</a> and produce <a href="https://doi.org/10.1016/j.desal.2014.04.021">toxic disinfection by-products</a> in water treatment plants. </p>
<p>Seawater intrusion reduces the life span of roads, bridges and other infrastructure. It has been implicated as a contributor to the <a href="https://www.nbcnews.com/news/us-news/surfside-condo-collapse-salt-groundwater-rcna16473">Champlain Towers South condominium collapse</a> in Surfside, Florida, in 2021. Seawater intrusion changes ecosystems, creating <a href="https://doi.org/10.1073/pnas.2314607120">ghost forests</a> as trees die and marshes move inland.</p>
<p><a href="https://doi.org/10.1002/2017WR020851">Smart management</a> can tip the seesaw back toward the sea. Limiting surface water extraction and groundwater pumping, or injecting treated wastewater into vulnerable aquifers, can increase the force pushing against intruding salt water. </p>
<p>Constructing <a href="https://oceanservice.noaa.gov/facts/shoreline-armoring.html">seawalls</a> or maintaining <a href="https://coastalscience.noaa.gov/news/understanding-processes-driving-sand-dune-erosion-and-creation-on-an-atlantic-seashore/">healthy dune systems</a> also can help hold seawater at bay, though these approaches protect only against saltwater flooding and infiltration at the surface, not underground. Pumping out saline groundwater or installing underground barriers can keep deeper salt water from moving inland. </p>
<p>Being proactive is best, because once groundwater is contaminated, it’s hard to remove the salt. If salt water does penetrate inland, communities can manage water quality by constructing <a href="https://www.usgs.gov/special-topics/water-science-school/science/desalination">desalination plants</a> and switching to salt-tolerant crops. </p>
<p>Another option is to let nature take its course. Allowing marshes to migrate inland can <a href="https://doi.org/10.1002/2016GL068507">compensate for losses at the coastline</a> as sea level rises. This preserves critical habitats, enhances flood protection and stores carbon at rates <a href="https://oceanservice.noaa.gov/ecosystems/coastal-blue-carbon/">far exceeding most terrestrial ecosystems</a> – dialing back the acceleration of climate change.</p><img src="https://counter.theconversation.com/content/214620/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Holly Michael receives funding from the US National Science Foundation, the US Geological Survey, and the US National Park Service.</span></em></p>Saltwater intrusion is bad for human health, ecosystems, crops and infrastructure. Here’s how seawater can move inland, and why climate change is making this phenomenon more frequent and severe.Holly Michael, Director, Delaware Environmental Institute, and Professor of Earth Sciences and Civil and Environmental Engineering, University of DelawareLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2146192023-10-04T16:40:14Z2023-10-04T16:40:14ZUnderstanding the dynamics of snow cover in forests can help us predict flood risks<figure><img src="https://images.theconversation.com/files/551050/original/file-20230926-17-3adew2.jpg?ixlib=rb-1.1.0&rect=23%2C5%2C3914%2C2964&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A better understanding of the interactions between snow cover and forest will help improve hydrological models and thus ensure public protection against flooding.</span> <span class="attribution"><span class="source">(Benjamin Bouchard)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>For more than six months a year, Quebec’s boreal forest is covered in a thick blanket of snow. While this is essential for the balance of our ecosystems, for the people living downstream from forested watersheds the snow can be like a sword of Damocles hanging over their heads. </p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
<hr>
<p>The major floods of spring 2023 in the Charlevoix region show why the snow cover poses a risk. </p>
<p>Last winter, the Rivière du Gouffre watershed, of which <a href="https://charlevoixmontmorency.ca/l-obv-cm/territoire/">nearly 75 per cent is covered by forests</a>, accumulated a large amount of snow. The melting of this snow cover combined with an extremely intense rainfall event helped push the river out of its bed, causing <a href="https://www.cbc.ca/news/canada/montreal/flood-baie-saint-paul-residents-cleaning-1.6829490">unprecedented flooding in Baie-Saint-Paul</a>.</p>
<p>As part of my PhD at Université Laval, in collaboration with <a href="https://sentinellenord.ulaval.ca/en/home">Sentinel North</a>, I am looking at the impact of snow cover properties on watershed hydrology in the boreal forest.</p>
<h2>Rain as an energy carrier</h2>
<p>As we saw in the spring of 2023, rain events combined with snow cover can lead to a sudden rise in river water levels. One reason for this is that rainwater transfers heat to the snow. </p>
<p>A heat exchange occurs between rain and snow when their temperatures differ. The snow warms up, and the rain cools down. Once the snow has reached a temperature of 0°C, any additional heat from the rain causes melting.</p>
<p>So, a snow cover of near 0 C, common in spring, and heavy rainfall at high temperatures, together create conditions where both meltwater and rainwater contribute to a higher flow of water. This increases the likelihood of flooding. However, this will only happen if the water produced can flow easily through the snow cover. </p>
<p>On the other hand, a cold snow cover combined with low-temperature rainfall can lead to rainwater freezing in the snow. This water will then remain trapped in the snow and won’t present a flooding risk. </p>
<p>After all, heat exchange goes both ways!</p>
<h2>The snow cover, a complexly structured environment</h2>
<p>The snow cover is a porous medium that does not have uniform physical properties. Rather, it is a stack of snow layers that represent the history of the winter’s meteorological events. Rainwater must percolate through all the snow layers to reach the ground, and eventually, the watercourse.</p>
<p>Some layers, such as fine-grained layers and layers of ice, limit the flow of water through the snow. In contrast, coarse-grained layers, which have larger pores, facilitate the flow of water. As a result, they enable rainwater and meltwater to reach the ground quickly.</p>
<h2>The role of the forest</h2>
<p>The structure of the snow cover influences the risk of flooding. But what effect do forests have on snow structure? </p>
<p>By intercepting part of the precipitation in its solid form (snow), trees limit the accumulation of snow on the ground. That, in turn, contributes to the <a href="https://doi.org/10.1029/JC088iC09p05475">growth of snow grains and pores on the ground</a> through upward water vapour flux. In addition, the discharge of snow intercepted by trees in solid or liquid form <a href="https://doi.org/10.1016/j.foreco.2019.01.052">increases the heterogeneity of the snow cover</a>. These processes promote rapid water flow in the snow cover that forms beneath the trees.</p>
<h2>The same everywhere?</h2>
<p>Forest cover is far from uniform in the boreal forest. It’s more akin to sparse vegetation with treeless zones known as gaps. In these gaps, the structure of the snow cover is very different from that under the trees.</p>
<p>The greater accumulation of snow in the gaps favours the compaction of snow layers and the formation of fine grains. In addition, daily cycles of surface refreezing lead to the formation of low-permeability ice layers. </p>
<p>The snow cover in the gaps is, therefore, less favourable to the percolation of water to the ground <a href="https://doi.org/10.1002/hyp.14681">than that found under the trees</a>.</p>
<p>But does this mean that the presence of gaps reduces the risk of flooding? Not quite.</p>
<h2>Snow melts faster in gaps</h2>
<p>The structure of the snow cover is just one of the factors that influences flooding. Ground that is frozen, which limits infiltration, as well as rapid snowmelt also increase the risk of flooding. </p>
<p>In Québec’s boreal forests, although the ground does not freeze in the gaps between trees due to the insulating nature of the snow cover, the <a href="https://doi.org/10.5194/hess-2023-191">melt rate is much higher</a> because solar radiation is stronger than it is under the trees, particularly in spring. </p>
<p>Although more snow would accumulate in the gaps, it takes less time to melt and reaches the watercourse more quickly than the snow under the trees. That increases waterflow and, as a consequence, the risk of flooding.</p>
<p>The combination of thicker snow cover in the gaps and more permeable snow layers under the trees contributed to the Rivière du Gouffre flooding Baie-Saint-Paul during the extreme rainfall of spring 2023.</p>
<p>Rainfall events like this <a href="https://www.ouranos.ca/en/precipitations-projected-changes">will continue to increase in frequency as global temperatures warm</a>. However, increased knowledge of the interactions between snow cover and forest will help improve hydrological models and ensure better public protection against flooding.</p><img src="https://counter.theconversation.com/content/214619/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Benjamin Bouchard has received funding from the Fonds de recherche Nature et technologie du Québec (FRQNT), the Natural Sciences and Engineering Research Council of Canada (NSERC) and Sentinel North. </span></em></p><p class="fine-print"><em><span>Daniel Nadeau has received funding from Environment and Climate Change Canada, as well as from the Natural Sciences and Engineering Research Council of Canada.</span></em></p><p class="fine-print"><em><span>Florent Domine has received funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>A better understanding of the interactions between the boreal forest and snow will make it possible to improve hydrological models and ensure optimal management of the resource.Benjamin Bouchard, Étudiant-chercheur au doctorat en génie des eaux, Université LavalDaniel Nadeau, Professeur titulaire en hydrologie des régions froides, Université LavalFlorent Domine, Professeur, chimie, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2117682023-10-04T03:56:59Z2023-10-04T03:56:59ZBradfield’s pipedream: irrigating Australia’s deserts won’t increase rainfall, new modelling shows<figure><img src="https://images.theconversation.com/files/549959/original/file-20230925-19-sjqj2w.jpg?ixlib=rb-1.1.0&rect=24%2C8%2C5467%2C3647&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/long-awaited-rain-storm-one-drop-1541576591">Shutterstock</a></span></figcaption></figure><p>For generations, Australians have been fascinated with the idea of turning our inland deserts green with lush vegetation. </p>
<p><a href="https://www.smh.com.au/politics/queensland/leaders-tout-bradfield-scheme-options-in-queensland-election-fight-20191101-p536o2.html">Both sides</a> of politics have supported proposals to irrigate the country’s centre by turning northern rivers inland. Proponents have argued water lost to evaporation would rise through the atmosphere and fall back as rain, spreading the benefits throughout the desert. But this claim has hardly ever been tested.</p>
<p>Our <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023GL103913">recently published research</a> shows irrigating Australia’s deserts would not increase rainfall, contrary to a century of claims otherwise. </p>
<p>This provides a new argument against irrigating Australia’s deserts, in addition to critiques on economic and environmental grounds.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4oquAtVWIYs?wmode=transparent&start=69" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the Bradfield Scheme? Featuring Griffith University’s Professor Fran Sheldon.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-bradfield-rerouting-rivers-to-recapture-a-pioneering-spirit-127010">'New Bradfield': rerouting rivers to recapture a pioneering spirit</a>
</strong>
</em>
</p>
<hr>
<h2>The Bradfield scheme</h2>
<p>Proposals to irrigate the country’s centre by diverting water inland date back to at least the 1930s. The person most widely credited with the idea is John Bradfield, the civil engineer who designed the Sydney Harbour Bridge. He <a href="https://trove.nla.gov.au/newspaper/article/97050378">proposed a series of dams and tunnels</a> that would transport water from northern Queensland to Kati Thanda-Lake Eyre.</p>
<p>Variants of the original scheme have been proposed <a href="https://www.brisbanetimes.com.au/politics/queensland/a-turning-point-lnp-vows-to-irrigate-drought-addled-western-qld-20201018-p5665l.html">as recently as 2020</a>. The Queensland Liberal National Party campaigned on a policy to build a Bradfield-like scheme in the last state election. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Vz-vk80JQMQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An aerial view of the Queensland LNP’s ‘new Bradfield scheme’ (Liberal National Party of Queensland, October 2020)</span></figcaption>
</figure>
<p>Despite our fascination with it, the Bradfield scheme has well-documented problems. It is not cost-effective and would likely be a disaster for the environment. These findings have been confirmed repeatedly by <a href="https://trove.nla.gov.au/newspaper/article/97099323">multiple</a> <a href="https://www.csiro.au/en/research/natural-environment/water/water-resource-assessment/the-bradfield-scheme-assessment">reviews</a>, as recently as <a href="https://www.rdmw.qld.gov.au/water/consultations-initiatives/bradfield-regional-assessment-development-panel">2022</a>.</p>
<p>Yet the idea resurfaces <a href="https://theconversation.com/new-bradfield-rerouting-rivers-to-recapture-a-pioneering-spirit-127010">over and over again</a> and the debate around it remains active and ongoing. </p>
<p>Crossbencher Bob Katter, the federal member for Kennedy in Queensland, is a prominent supporter of the scheme. He <a href="https://www.abc.net.au/news/2022-12-09/queensland-government-abandons-bradfield-scheme-after-report/101751678">rejected the critical findings</a> of a <a href="https://www.csiro.au/en/research/natural-environment/water/water-resource-assessment/the-bradfield-scheme-assessment">recent CSIRO review</a> that found the scheme and others like it were not economically viable. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-cant-we-just-build-a-pipe-to-move-water-to-areas-in-drought-123454">Curious Kids: why can't we just build a pipe to move water to areas in drought?</a>
</strong>
</em>
</p>
<hr>
<h2>Would it increase rainfall?</h2>
<p>Would the Bradfield scheme increase rainfall in central Australia? Given all the debate about the scheme, this question has received surprisingly <a href="https://nla.gov.au/nla.obj-964034842/view?partId=nla.obj-964065417">little</a> <a href="https://www.cmar.csiro.au/e-print/internal/mcgregor_x2004a.pdf">attention</a>.</p>
<p>Bradfield argued the added irrigation water would effectively <a href="https://trove.nla.gov.au/newspaper/article/97050378">double or triple the region’s rainfall</a>:</p>
<blockquote>
<p>This irrigation water would augment the average rainfall of the district from 10 to 20 inches per annum […] Sceptics and croakers say the water will evaporate or seep away […] [but] it will not go far.</p>
</blockquote>
<p>To test Bradfield’s claim, we turned to climate models. In a collaboration between scientists at the University of Melbourne, Harvard University, National Taiwan University and the Australian Bureau of Meteorology, we simulated two worlds: one with a Bradfield-like scheme and one without it. </p>
<p>In our model of the Bradfield-like scheme, we permanently filled the region around Kati Thanda-Lake Eyre with water. That differs a bit from Bradfield’s original scheme but captures the basic idea. If anything, it is more extreme than Bradfield’s scheme. If Bradfield is right, we would expect our scheme’s effects on rainfall to be even larger.</p>
<p>Our simulations showed no significant increase in rainfall. This may sound surprising but can be explained with basic physical arguments.</p>
<h2>Why no rain?</h2>
<p>Rain forms when moist air rises. As it rises, temperatures drop, water condenses from vapour to liquid and clouds form. </p>
<p>Hot air rises, so high temperatures near the surface can promote rainfall. But in our simulations, irrigating the surface led to evaporative cooling of the air. The colder air did not rise as much, and rainfall was suppressed.</p>
<p>Where does all that extra water go? In our simulations, the water evaporated and was blown all over the Australian continent by wind. The additional water ended up being spread thinly over a large area. When it did eventually rain out, the effect on local rainfall was tiny.</p>
<p>Climate models aren’t perfect and have known weaknesses in simulating rainfall. But the basic explanation for the small change in rainfall can be understood without appealing to climate models. </p>
<p>Could irrigating a larger region, or a different part of the country, change the results? Maybe, and we are looking into it. But the Bradfield scheme is already <a href="https://www.rdmw.qld.gov.au/water/consultations-initiatives/bradfield-regional-assessment-development-panel">not cost effective</a>. Making the scheme larger or moving it away from natural flow paths would only make this problem worse.</p>
<p>Previous reviews of the Bradfield scheme have mainly focused on the economics of the scheme. Australian economist <a href="https://www.rdmw.qld.gov.au/water/consultations-initiatives/bradfield-regional-assessment-development-panel">Ross Garnaut’s report</a> in December 2022 is the most recent to find the scheme is economically unviable. </p>
<p>Our study provides a new argument against the Bradfield scheme, separate to economic arguments.</p>
<p>The idea of transforming our dry continent is seductive. But our study shows no plausible engineering scheme would be capable of making it rain enough to do so. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-cant-drought-proof-australia-and-trying-is-a-fools-errand-124504">We can’t drought-proof Australia, and trying is a fool's errand</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211768/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kaighin McColl receives funding from the National Science Foundation, NASA, the Sloan Foundation, the Sahara Project, and Harvard University. </span></em></p><p class="fine-print"><em><span>Dongryeol Ryu 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>New research shows turning northern rivers inland to irrigate Australia’s dry interior would not increase rainfall. This is another argument against the Bradfield scheme.Kaighin McColl, Assistant Professor of Earth and Planetary Sciences and Environmental Science and Engineering, Harvard UniversityDongryeol Ryu, Professor, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126512023-10-03T12:10:37Z2023-10-03T12:10:37ZEven platypuses aren’t safe from bushfires – a new DNA study tracks their disappearance<p>When the Black Summer bushfires swept across eastern Australia in 2019–20, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.13473">thousands of animal species lived</a> in the path of these megafires. </p>
<p>You’d be forgiven for thinking water-dwelling animals like platypuses were spared. Surely animals living in rivers and streams would be safe?</p>
<p>But our new research, published today in <a href="https://doi.org/10.1016/j.biocon.2023.110219">Biological Conservation</a>, reveals platypuses are disappearing from waterways after fire.</p>
<p>We took water samples from streams and rivers across south-eastern Australia to test for platypus DNA. We found platypuses were less likely to be found in burnt catchment areas, six months after fire. But the species returned after 18 months. We hope our findings will support conservation actions in the event of future bushfires.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-platypus-can-glow-green-and-hunt-prey-with-electricity-but-it-cant-climb-dams-to-find-a-mate-193707">A platypus can glow green and hunt prey with electricity – but it can't climb dams to find a mate</a>
</strong>
</em>
</p>
<hr>
<h2>An evolutionary masterpiece</h2>
<p>Platypuses are much loved and unique to Australia. As monotremes, they lay eggs. They’re one of only five species of mammals that does – the other four are echidnas. </p>
<p>They have webbed feet for swimming. And they have <a href="https://www.britannica.com/science/electroreception">electroreceptors</a> in their bills to help them find food in rivers and streams.</p>
<p>But they can be hard to find. It’s difficult to determine whether there’s a platypus living in a particular waterway. </p>
<p>Monitoring allows us to detect changes in populations or communities. There may be gradual changes over time, or rapid responses to a big disturbance, such as a fire. Quick, efficient methods are vital for surveying species that occupy large areas.</p>
<h2>DNA detective work</h2>
<p>Platypuses are found in waterways throughout the east coast of Australia, from Cooktown in northern Queensland to Tasmania. </p>
<p>Little is known about how platypuses and other aquatic or semi-aquatic animals respond to fire. Ideally we would have good data on species before and after a fire, to draw comparisons. But that is rare. </p>
<p>Other research shows aquatic invertebrates (animals with no backbones) and fish can be harmed by bushfire, especially when rain follows fire. </p>
<p>Bushfires burn and kill the vegetation that stabilises the soil around rivers or streams. When rain follows fire, a lot of ash, soil and other debris can be washed into waterways. The water chemistry might change or there might be big increases in sediment, which makes the river or stream inhospitable for invertebrates and fish. </p>
<p>As platypuses feed on aquatic invertebrates such as yabbies, these flow on effects of fire could also impact them. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A grey mud-covered platypus on the bank of a creek with foliage and sticks next to it" src="https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=792&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=792&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=792&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=995&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=995&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551317/original/file-20231002-15-55pavu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=995&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Platypus feed on invertebrates, which find debris- and sediment-filled waterways inhospitable.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Just as people leave traces behind as they move through the environment (such as fingerprints, hair and skin cells), so do animals. These traces contain genetic material that can be analysed to identify the likely source. </p>
<p>We used this “environmental DNA” to detect where platypuses were present across the study area. </p>
<p>We sampled 118 rivers and creeks across Victoria, New South Wales and the Australian Capital Territory a year before the Black Summer fires, for a project on platypus distribution. This was fortuitous, because it provided a baseline for us to determine the effects of the unprecedented fires. </p>
<p>We took more environmental DNA samples from the same 118 sites at six months after the megafires, and also 12–18 months post-fire, giving us three data points for the same rivers and creeks. </p>
<p>The sampling sites were spread across burnt and unburnt areas, giving us unaffected (control) sites to use as a comparison. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-at-work-we-use-environmental-dna-to-monitor-how-human-activities-affect-life-in-rivers-and-streams-164529">Scientists at work: We use environmental DNA to monitor how human activities affect life in rivers and streams</a>
</strong>
</em>
</p>
<hr>
<h2>What we found</h2>
<p>Six months after the megafires, platypuses were less likely to be living at sites that experienced fire. But the difference between burnt and unburnt sites was negligible after 18 months. </p>
<p>The combination of severe fire and rainfall minimised the chance of finding platypuses living at a site. </p>
<p>Watersheds are areas of land that drain rainwater into local streams and creeks. We used the watershed of each site to calculate the area over which rain would drain to a site. </p>
<p>We also looked at what proportion of the watershed was burnt at high severity, as we thought this would increase the chance of destabilised soils and ash being washed into the waterways. We classified high severity fire as fire which removed all of the leaves from trees and burnt grasslands or pasture. </p>
<p>From our work, we predicted that sites where the watershed had at least 25% of its area burnt at high severity, and also experienced high rainfall, had a less than 10% chance of platypuses occupying those sites.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black ground with thin dead black trees, the aftermath of a fire" src="https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551318/original/file-20231002-23-nafgj6.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">The ash and debris from bushfires can get washed into nearby waterways, affecting the water chemistry and wildlife habitat.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Understanding change</h2>
<p>Climate change is predicted to lead to more <a href="https://www.nature.com/articles/s41467-021-27225-4">frequent</a>, <a href="https://onlinelibrary.wiley.com/doi/10.1111/geb.13514">severe and extensive bushfires</a> in south-eastern Australia, as well as to more <a href="https://nespclimate.com.au/wp-content/uploads/2018/12/ESCC-NESP-Southern-Australia-6pp-WEB.pdf">extreme rainfall events</a>. </p>
<p>Our work adds to our understanding of how just one species could be harmed by the climate crisis. </p>
<p>We need these types of systematic surveys to provide baselines and monitor how populations and communities are changing. Monitoring will also help us respond more efficiently to major disturbances like the Black Summer bushfires, where, for many species, there wasn’t enough data to inform the initial emergency conservation response. </p>
<p><em>We would like to acknowledge Josh Griffiths, Reid Tingley and Luke Collins for their invaluable contribution to this work and Jaana Dielenberg for early discussions about this article.</em></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/worried-about-heat-and-fire-this-summer-heres-how-to-prepare-212443">Worried about heat and fire this summer? Here's how to prepare</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/212651/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emily McColl-Gausden receives funding from San Diego Zoo Wildlife Alliance, The University of Melbourne and the Ecological Society of Australia. </span></em></p><p class="fine-print"><em><span>Andrew Weeks is a Director at EnviroDNA, a company that offers eDNA based services to industry. He receives funding from San Diego Zoo Wildlife Alliance and the Australian Research Council.</span></em></p>We sampled 118 rivers and creeks before and after the Black Summer bushfires, searching for platypus DNA. Here’s what we found.Emily McColl-Gausden, Research fellow, The University of MelbourneAndrew Weeks, Associate Senior Research Scientist, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2127912023-09-25T02:02:34Z2023-09-25T02:02:34ZSeals, swimmers, bat carers – exploring the world of the pale brown, oft-maligned Yarra River<figure><img src="https://images.theconversation.com/files/549214/original/file-20230920-26-jfkcdl.jpg?ixlib=rb-1.1.0&rect=19%2C417%2C3235%2C2784&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Kummeleon/Shutterstock</span></span></figcaption></figure><p>Author Harry Saddler’s <a href="https://affirmpress.com.au/browse/book/Harry-Saddler-Clear-Flowing-Yarra-9781922848116/">book on Melbourne’s Yarra River</a> is an engaging account of his years exploring its native species and human communities. He acknowledges the river’s First Nations name of Birrarung, writing with a boyish enthusiasm. At times I felt his emotion jumping out of the pages, almost channelling David Attenborough’s passion for species and the environment.</p>
<hr>
<p><em>Review: A Clear Flowing Yarra – Harry Saddler (Affirm Press)</em></p>
<hr>
<p>The book’s major focus is on Saddler’s obvious fascination with native animals. He delights in telling us about his adventures finding them on, in, and near to the Yarra. It sometimes reads like a police drama as be describes “staking out” the habitat of an elusive species. Night after night, Saddler keeps going back to potential hideouts. At one point he watches eleven sugar gliders emerge from a hollow in a river red gum, only metres from townhouses. </p>
<p>Saddler had me hooked with his description of first encounter with a Yarra platypus: </p>
<blockquote>
<p>We gawped and we gaped in mind-bent wonderment as a dark-brown platypus bobbed up to the surface of the pale brown Yarra and then dived again, disappearing instantly in the turbid water.</p>
</blockquote>
<p>One of this book’s themes is Melburnians don’t really think much about the Yarra River. And not just the locals. I’m ashamed to remember hearing unflattering jokes about the Yarra in my childhood in Sydney. They involved the muddy appearance of the river, that looked like it flowed “upside down”. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-law-finally-gives-voice-to-the-yarra-rivers-traditional-owners-83307">New law finally gives voice to the Yarra River's traditional owners</a>
</strong>
</em>
</p>
<hr>
<p>Once the Yarra was world famous for swimming: a long distance (three-mile) swim was held there for nearly 50 years up to 1964. It was once the largest <a href="https://theconversation.com/watered-down-what-happened-to-australias-river-swimming-tradition-69728">open water swimming competition</a> in the world. Perhaps this book might help address the Yarra River’s image problem. And remind people of its many values, from its rich biodiversity to providing <a href="https://www.melbournewater.com.au/water-and-environment/water-management/water-storage-reservoirs">5 million people with much of their water supply</a>. </p>
<p>It might surprise many the Yarra River is still popular for swimming. Saddler tells us of his amazement when on a hot March day near Warrandyte in 2017: </p>
<blockquote>
<p>As if in a dream, I found there a remarkable sight: hundreds of people swimming and bathing in a wide sparkling stream.</p>
</blockquote>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A river at sunset." src="https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549213/original/file-20230920-21-tsb23b.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">The Yarra in Warrandyte at sunset.</span>
<span class="attribution"><span class="source">Nils Versemann/Shutterstock</span></span>
</figcaption>
</figure>
<p>Just a word of warning though. As with many rivers affected by urbanisation and other human activities, water quality in the Yarra can be poor and hazardous to human health. As tennis player Jim Courier discovered, when he dived in the river after celebrating his 1993 men’s singles victory in the Australian Open and picked up <a href="https://jtsportingreviews.com/2022/01/26/30-years-ago-today-jim-courier-jumped-in-the-yarra-river/">a stomach bug</a>. </p>
<p>As I read, I could not help myself. I looked up the latest water quality advice for swimming provided by the <a href="https://www.epa.vic.gov.au/for-community/summer-water-quality/yarra-watch">Victorian EPA</a>. At the time of writing, they showed the river at Warrandyte had “good” water quality. This offered the only suitable swimming location on the river. The other three sites (Kew, Healesville and Yarra Junction) were all rated as “poor”. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-tale-of-2-rivers-is-it-safer-to-swim-in-the-yarra-in-victoria-or-the-nepean-in-nsw-130791">A tale of 2 rivers: is it safer to swim in the Yarra in Victoria, or the Nepean in NSW?</a>
</strong>
</em>
</p>
<hr>
<h2>Contrasting layers</h2>
<p>This book is written in contrasting layers. Chapters alternate between exploring different native species found in the Yarra, and exploring how people interact with the river. </p>
<p>Native species that get their own chapter include the Powerful Owl, <a href="https://en.wikipedia.org/wiki/Brush-tailed_phascogale">Brush-Tailed Phascogale</a>, Short-finned Eel, Swamp Wallaby, Snakes, Rakali (the native water rat), Azure Kingfisher and Grey-Headed Flying Foxes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four flying foxes." src="https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549252/original/file-20230920-29-o73xlb.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">Flying foxes get their own chapter.</span>
<span class="attribution"><span class="source">Craig Dingle/Shutterstock</span></span>
</figcaption>
</figure>
<p>The Flying Fox chapter reveals a Yarra species, also commonly called fruit bats, that seems to attract very strong emotions. We are introduced to people caring for their welfare, such as Megan from “Friends of Bats and Bushcare”. She points out how vulnerable they are to stress in very hot weather, with sprinklers installed in the Yarra bat colony to help keep them cool during heat waves.</p>
<p>On the opposing side we are told about the removal of a colony that had settled along the Yarra in the Royal Botanic Gardens – dispersed using noise, smoke and lights. It also gets political. The book mentions an unnamed former politician who tried to have a colony of bats in his electorate removed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/not-in-my-backyard-how-to-live-alongside-flying-foxes-in-urban-australia-59893">Not in my backyard? How to live alongside flying-foxes in urban Australia</a>
</strong>
</em>
</p>
<hr>
<p>Saddler describes how:</p>
<blockquote>
<p>The biggest and most beautiful tiger snake I’ve ever seen was sliding out of the Plenty River onto broad, sunny rocks where that tributary joined the Yarra.</p>
</blockquote>
<p>In case the reader still has any doubt about his feelings towards snakes, he states: “Snakes are great. I’ll tolerate no snake badmouthing here”.</p>
<p>For me, a major appeal is that along with celebrating the remarkable biodiversity of the river, Saddler explores the many groups and individuals who care about it: cleaning up litter, clearing the banks of invasive weeds. Dedicated people such as Daniella, who has lived near the river for 20 years. She has regularly picked up rubbish to help keep the river and its banks clean. </p>
<p>As I read, I wondered if Saddler would have written this book if a native Melburnian. He moved to Melbourne from Canberra about 20 years ago, where he lived far from the ocean. He grew up comfortable in fresh water: swimming in Lake Burley-Griffin and ACT rivers such as the Cotter, Molonglo and Murrumbidgee. </p>
<p>His book reads like an adventurous exploration of an unknown world. At least to him. And also, perhaps, millions of Melburnians. There is something about the excitement of exploring around the next bend of the river. Documenting unfamiliar landscapes, and discovering the home and habits of another species.</p>
<p>Apart from the playtpus, my other favorite species described by Saddler is Salvatore the Australian Fur Seal, who gets his own chapter. Salvatore became an unlikely star attraction living in the river during a very dark time for Melbourne, in 2021 during one of its tough COVID lockdowns. For thousands of people, capturing a sight of this unusual visitor provided a thrill. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/-iVs7GRrEPc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Harry describes the thousands of teasing photos and videos of Salvatore on the internet. I felt his frustration growing as he cycled up and down the river, meeting crowds of people elated after an encounter with the famous seal. But he kept missing out. Until finally, one day, near the Gipps Street bridge, on the main Yarra trail, his patience was rewarded. </p>
<blockquote>
<p>He dived, and sometimes disappeared for what seemed like minutes before resurfacing further upstream, or further downstream; in these moments people on canoes would occasionally paddle by and I shouted out warning to them: be careful, there was a seal here just a minute ago and he’s <em>massive</em>. </p>
</blockquote>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=918&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=918&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=918&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1154&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1154&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549022/original/file-20230919-21-e1jtyk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1154&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"><span class="source">Affirm Press</span></span>
</figcaption>
</figure>
<p>Perhaps another edition of this book might have pictures. And I really would have loved a map or two. Still, it reminds me of the importance of providing safe access for communities to engage with waterways, perhaps helped by walking or cycling paths, parks and public transport. Even in highly modified urban settings we might be able to observe native species mostly hidden from the public gaze. </p>
<p>This book, while a love letter to the Yarra/Birrarung, might also remind those readers not in Melbourne a similar unexplored river or natural landscape likely exists right under their noses.</p><img src="https://counter.theconversation.com/content/212791/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian A Wright receives funding from industry, as well as Commonwealth, NSW and local governments. He formerly worked for Sydney Water Corporation.</span></em></p>A new book delves into the species that live in, on and near Melbourne’s Yarra: from the millions of humans who rely on it for water to creatures such as owls, wallabies and flying foxes.Ian A. Wright, Associate Professor in Environmental Science, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132972023-09-14T15:02:42Z2023-09-14T15:02:42ZAs climate change warms rivers, they are running out of breath – and so could the plants and animals they harbor<figure><img src="https://images.theconversation.com/files/547729/original/file-20230912-15-x93l4l.jpg?ixlib=rb-1.1.0&rect=22%2C7%2C5069%2C3382&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Potomac River spills over Great Falls west of Washington, D.C..</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/great-falls-of-the-potomac-river-virginia-maryland-at-great-news-photo/1449185440">Marli Miller/UCG/Universal Images Group via Getty Images</a></span></figcaption></figure><p>As climate change warms rivers, they are losing dissolved oxygen from their water. This process, which is called <a href="https://www.iucn.org/resources/issues-brief/ocean-deoxygenation">deoxygenation</a>, was already known to be occurring in large bodies of water, like oceans and lakes. A study that colleagues and I just published in <a href="https://www.nature.com/articles/s41558-023-01793-3">Nature Climate Change</a> shows that it is happening in rivers as well. </p>
<p>We documented this change using a type of artificial intelligence called a deep learning model – specifically, a <a href="https://www.geeksforgeeks.org/deep-learning-introduction-to-long-short-term-memory/">long short-term memory model</a> – to predict water temperature and oxygen levels. The data that we fed the model included past records of water temperature and oxygen concentrations in rivers, along with past weather data and the features of adjoining land – for example, whether it held cities, farms or forests. </p>
<p>The original water temperatures and oxygen data, however, were measured sparsely and often in different periods and with different frequency. This made it challenging before our study to compare across rivers and in different periods.</p>
<p>Using all of this information from 580 rivers in the U.S. and 216 rivers in central Europe, our AI program reconstructed day-to-day temperatures and oxygen levels in those rivers from 1981 to 2019. We also used future climate projections to predict future water temperature and oxygen levels. This enabled us to consistently compare past and future river water temperatures and oxygen levels across hundreds of rivers, which would not have been possible without using AI. </p>
<p>On average, we found, rivers were warming by 0.29 degrees Fahrenheit (0.16 degrees Celsius) per decade in the U.S. and 0.49 F (0.27 C) per decade in central Europe. Deoxygenation rates reached as high as 1% to 1.5% loss per decade. These rates are faster than deoxygenation rates occurring in oceans, and slower than those in lakes and coastal regions. </p>
<p>Urban rivers are warming up most rapidly, while rivers in agricultural areas are losing oxygen most rapidly. This could be partly due to <a href="https://theconversation.com/to-reduce-harmful-algal-blooms-and-dead-zones-the-us-needs-a-national-strategy-for-regulating-farm-pollution-186286">nutrient pollution</a>, which combines with warmer waters to fuel large blooms of algae. When the algae die and decompose, this process depletes dissolved oxygen in the water.</p>
<h2>Why it matters</h2>
<p>Oxygen is crucial for plants, animals, fish and aquatic insects that live in rivers. These organisms <a href="https://www.usgs.gov/special-topics/water-science-school/science/dissolved-oxygen-and-water">breathe dissolved oxygen from river water</a>. If oxygen levels drop too low, river species will suffocate. </p>
<p>While scientists know that oceans and lakes have been losing oxygen in a warming climate, we have mainly thought that rivers were safe from this problem. Rivers are shallow, and fast-moving water can absorb oxygen directly from the air <a href="https://www.usgs.gov/special-topics/water-science-school/science/dissolved-oxygen-and-water">more rapidly</a> than standing water. Rivers also harbor plants that make oxygen.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/c5JZKUssy9c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Chelsea Miller of the Maryland Department of Natural Resources explains why dissolved oxygen is important in aquatic environments and shows how researchers test for it.</span></figcaption>
</figure>
<p>The health of rivers affects everything in and around them, from aquatic life to humans who rely on the rivers for water, food, transportation and recreation. Warming rivers with low oxygen could suffer fish die-offs and degraded water quality. Fisheries, tourism and even property values along rivers could decline, affecting livelihoods and economies.</p>
<p>As the air warms in a changing climate, rivers will also become warmer. As a liquid’s temperature increases, <a href="https://doi.org/10.1038/s44221-023-00038-z">its capacity to hold gases declines</a>. This means that climate change will further reduce dissolved oxygen in river water. </p>
<p>At extreme levels, this process can create <a href="https://oceanservice.noaa.gov/facts/deadzone.html">dead zones</a> where fish and other species cannot survive. Dead zones already form in coastal areas, such as the <a href="https://www.noaa.gov/news-release/noaa-and-partners-announce-below-average-dead-zone-measured-in-gulf-of-mexico">Gulf of Mexico</a> and <a href="https://ohioseagrant.osu.edu/research/issues/habs">Lake Erie</a>. We found that some rivers, especially in warmer areas like Florida, may face more low-oxygen days in the future. </p>
<p>Low oxygen in rivers also can promote chemical and biological reactions that lead to the <a href="https://pubs.usgs.gov/circ/circ1133/heavy-metals.html">release of toxic metals from river sediments</a> and increased emissions of greenhouse gases, such as <a href="https://doi.org/10.1038/s41558-019-0665-8">nitrous oxide</a> and <a href="https://doi.org/10.1038/s41586-023-06344-6">methane</a>. </p>
<h2>What’s next</h2>
<p>Most of our data on dissolved oxygen was collected during the day, when plants in rivers are actively making oxygen through photosynthesis, powered by sunlight. This means that our findings may underestimate the low-oxygen problem. At night, when plants aren’t producing oxygen, dissolved oxygen levels could be lower.</p>
<p>I see this research as a wake-up call for more study of how climate change is <a href="https://doi.org/10.1029/2021EF002603">affecting river water quality worldwide</a>. Better monitoring and more analysis can make the full scope of river deoxygenation clearer. Ultimately, I hope more research will lead to policy changes that promote responsible land use and water management and better stewardship of rivers, our planet’s veins.</p>
<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><img src="https://counter.theconversation.com/content/213297/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Li Li has received funding from the US National Science Foundation and the US Department of Energy. She 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 her academic appointment.
</span></em></p>When water warms, it holds less oxygen, and this can harm aquatic life and degrade water quality. A new study finds that climate change is driving oxygen loss in hundreds of US and European rivers.Li Li (李黎), Professor of Civil and Environmental Engineering, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2126272023-09-14T13:36:49Z2023-09-14T13:36:49ZKenya: Ongata Rongai boom town destroyed two vital rivers – new study flags a major health risk<p>Over the past 10 years, Ongata Rongai, a satellite town on the edge of Kenya’s capital, Nairobi, has experienced uncontrolled development and exponential population growth. Because of its appealing location close to the city, it’s <a href="http://www.citypopulation.de/en/kenya/riftvalley/kajiado/3414__ongata_rongai/">jumped from</a> just under 40,000 residents in 2009 to a population of over 172,000 in 2019. The most recent <a href="http://www.citypopulation.de/en/kenya/riftvalley/kajiado/3414__ongata_rongai/">census data</a> showed a high annual population growth rate of 16%. </p>
<p>The rapid increase in population, and accompanying development of residential buildings, has led to huge pressure on the environment, including its waterways.</p>
<p>There are two main rivers flowing through Ongata Rongai: the Mbagathi River and the Kandisi-Kiserian River. These rivers are important historically and, to an extent, today. People fish in them, use them to wash their clothes and collect water from them to use at home. Children and adults swim and bathe in them. Pastoralists water their livestock here and graze animals along the riverbanks. They were also the place where neighbouring clans would meet or where the Agikuyu community would come to pray at the towering <em>mugumo</em> (fig) trees. Indigenous plants growing on the riverbanks were harvested to make medicines. </p>
<p>I carried out <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2023.1164881/full">a study</a> which examined how Rongai’s growth has affected the riparian (river) environment and surrounding communities. </p>
<p>What I found was a severely degraded riparian environment and frustrated residents. Ongata Rongai is not special. It can be seen as a microcosm of a wider issue: that of rapid urban development at the expense of the environment. </p>
<p>Environments like this are <a href="https://pubmed.ncbi.nlm.nih.gov/30778691/">common</a> wherever urban populations are growing faster than resources and plans can keep up. The municipality has a responsibility to act on what’s known about the health of its land, people and animals.</p>
<h2>Drivers of pollution</h2>
<p>I carried out my study using archival materials, interviews and focus group discussions. </p>
<p>Ongata Rongai was, until fairly recently, a savannah with few or no permanent structures. It is now a densely populated urban area, no longer peripheral to but a part of the Nairobi metropolitan area. </p>
<p>This rapid development has happened without services keeping pace, including mains sewerage, solid waste disposal, piped safe water, or any sewage treatment plant. The main problem of the rivers today, cited by everyone I spoke to, was that of sewage. Untreated sewage is pumped into or flows into the rivers daily, primarily from low-cost and poorly constructed apartment buildings belonging to wealthy business people.</p>
<p>Another cause of degradation is people’s disconnection from the environment. Interviewees discussed how the proliferation of Christianity had a disconnecting effect, and traditional knowledge was forgotten. Few people retain knowledge about plants. And if the environment holds no meaning, people don’t see the consequences of throwing trash into the river.</p>
<h2>Impacts of the pollution</h2>
<p>The pollution makes the rivers almost unusable and hazardous. But there’s a lack of alternatives. </p>
<p>People use the river water for farming, laundry, bathing and other purposes, out of necessity or convenience. Climate change has reduced rainfall and created unpredictability, forcing livestock herders to depend on the polluted rivers – which are sometimes just trickles. </p>
<p>The poor state of the rivers and their surrounding environment leads to health challenges for both people and animals. Livestock often refuse to drink the river water. Children playing and swimming in it get ill and crops wither and die. </p>
<p>People are very aware of water safety and are wary of using river water. As one farmer in Rongai told me:</p>
<blockquote>
<p>The problem with this river is, it is filthy. You see, if you use it to water your vegetables in your garden, even you are eating that filth. If you harvest these vegetables right now, you go and cook them, you are eating that filth. And it’s not even just us, it’s the animals too who have to drink that water. So those who are pouring the raw sewage into the river, can they just think about it and stop?</p>
</blockquote>
<p>Another farmer told me:</p>
<blockquote>
<p>These days if you wash in the river you find your skin dries up … as if you have an illness … and if you keep washing there, you’ll get typhoid.</p>
</blockquote>
<h2>What happens now?</h2>
<p>There was extreme frustration with structural-level actors including local government and agencies. The residents I spoke to lamented corrupt government bodies and the lack of enforcement of existing environmental regulations. They felt hopeless as individuals without functioning institutions for environmental protection. </p>
<p>The situation is a typical example of how the health of people, animals and the environment is connected. Wildlife, livestock and a surge in human population have come together, putting pressure on a fragile ecosystem and environment. Without healthy rivers, there will be a dangerous knock-on effect on human and animal health. </p>
<p>The Rongai Rivers are one example of the rapid destruction of urban rivers globally. There’s been much <a href="https://scienceafrica.co.ke/2023/02/24/kenya-new-commission-to-spearhead-cleanliness-of-nairobi-rivers-launched/">talk</a> of regenerating riparian and green spaces in Nairobi and in other African cities. But the time for talking is over. People and governments must act to save these vital spaces.</p><img src="https://counter.theconversation.com/content/212627/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Olivia Howland 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>Rongai’s rapid development has happened without services keeping pace, and the rivers have paid the price.Olivia Howland, Research Fellow in Social Science and Geography, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124922023-09-13T10:55:07Z2023-09-13T10:55:07ZAddis Ababa faces growing climate change risks like heat, drought and floods, study warns<figure><img src="https://images.theconversation.com/files/545484/original/file-20230830-19-8bq04m.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C5000%2C3315&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">About 70% of people in Addis Ababa live in informal settlements that are vulnerable to climate change. Amanuel Sileshi/AFP/</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/muslim-devotees-gather-at-meskel-square-to-break-their-fast-news-photo/1240330823?adppopup=true">Getty Images</a></span></figcaption></figure><p>Addis Ababa, Ethiopia’s capital city, will likely face increased heatwaves, droughts and severe flooding over the next 67 years. These changes will pose risks to public health and infrastructure. They’ll also be felt most acutely by the city’s most vulnerable residents: those living in informal settlements. </p>
<p>Addis Ababa is one of the fastest-growing cities in Africa, and its current metropolitan population of about 5.4 million is projected to reach close to <a href="https://worldpopulationreview.com/world-cities/addis-ababa-population">9 million</a> by 2035.</p>
<p>This increase in the city’s population will be absorbed by informal settlements, the prime destination for most migrants. And informal settlements are characterised by poor or non-existent infrastructure, and face the twin challenges of worsening climate change and poor urban environmental policy.</p>
<p>To investigate the city’s vulnerability to climate change, researchers at <a href="https://www.climatepolicylab.org/">Tufts University</a> and the <a href="https://www.woodwellclimate.org/">Woodwell Climate Research Center</a> analysed flood risk and temperature data for different time periods, projecting from the past to the future.</p>
<p>We predicted that the city’s extreme daily maximum temperatures would increase by about <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">1.7°C over the period 2040-2060</a>, compared with 2000–2020. An increase of 1.7°C would result in a <a href="https://iopscience.iop.org/article/10.1088/1748-9326/aab827">rise</a> in the frequency, duration, and intensity of heatwaves. In addition, higher temperatures contribute to increased water vapour and transpiration. This will <a href="https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_LongerReport.pdf#page=16">threaten</a> health, ecosystems, infrastructure, livelihoods, and food supplies.</p>
<p>Certain southern neighbourhoods, such as <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">Akaki-Kaliti, Bole and Nifas Silk-Lafto</a>, have experienced notably higher temperatures, especially during the warm season from March to May. And, looking to the future, temperature projections for <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">Nifas Silk-Lafto suggest an average temperature increase to 26.21°C between 2040 and 2060, and further increase to 27.78°C from 2070 to 2090</a> and <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">27.78°C from 2070 to 2090</a>. </p>
<p>For the warm-season months of March, April, and May, a temperature increase of 1.8°C is projected. This suggests that the peak temperature for the hottest day of the year will rise by an average of 1.8°C compared to recent data. From 2000 to 2020 the average temperature in the Nifas Silk-Lafto sub-city was 24.70°C. </p>
<p>Increases in temperatures of this magnitude will lead to public health challenges such as increased malaria risks, disproportionately affecting vulnerable groups like the elderly, children, and women.</p>
<h2>More droughts</h2>
<p>Over the past two decades, Addis Ababa has endured an average of three months of extreme drought yearly. Using the <a href="https://www.droughtmanagement.info/palmer-drought-severity-index-pdsi/">Palmer Drought Severity Index</a> to assess temperature and precipitation data in a geographical area, our analysis suggests that extreme drought events will become more frequent between 2040 and 2060. The city is expected to experience an additional 1.6 months of extreme drought annually, a 53% increase compared with 2000-2020. </p>
<p>This rising frequency of droughts, along with the city’s growing population, is intensifying water insecurity. Groundwater reserves for drought emergencies are already being <a href="https://onlinelibrary.wiley.com/doi/10.1002/tqem.21512">depleted</a>. </p>
<p>These droughts will affect health, hydroelectric energy production and urban agriculture. </p>
<h2>Flooding</h2>
<p>Too much rainfall, particularly if it occurs within a short period of time in an urban area, leads to flooding. Flooding poses a significant environmental risk to Addis Ababa, especially because the city has developed around three primary rivers. </p>
<p>Climate change will increase water-related challenges by affecting the flow of rivers and the replenishment of groundwater. </p>
<p>Currently, <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">67%</a> of the population in Addis lives in flood prone areas. The parts of the city that are most at risk include central Addis, which has the greatest density of impervious surfaces like tarmac and concrete. These contribute to flood risk because water can’t seep into the ground.</p>
<p>Other <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">parts of the city that are at risk</a> include the southern half – where the slope is relatively flatter, so water doesn’t flow away – and the Nifas Silk-Lafto region, where considerable development has taken place in the floodplain. </p>
<p>Several factors will add to the flooding challenge. The city has <a href="https://www.sciencedirect.com/science/article/pii/S2214581819301843">inadequate sewerage infrastructure</a> and <a href="https://onlinelibrary.wiley.com/doi/10.1111/jfr3.12629">weak drainage systems</a> which are often obstructed by solid waste. </p>
<h2>The impact</h2>
<p>The effects on the city’s residents will be substantial. </p>
<p>Health is just one example. </p>
<p>Our data show that average temperatures in the city will make year-round <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2003489#:%7E:text=This%20model%20suggests%20a%20temperature,climate%20change%20on%20malaria%20transmission">malaria transmission</a> a risk. There will have to be sustained policy measures to deal with the risk.</p>
<p>Older adults and pregnant women are particularly vulnerable to the health impacts of climate change. The elderly are more <a href="https://www.ohchr.org/en/climate-change/impact-climate-change-rights-older-persons">sensitive</a> to heat and pollution due to existing health conditions, limited mobility, and compromised immune systems. Pregnant women face <a href="https://www.sciencedirect.com/science/article/pii/S0015028222003831">risks</a> from thermal variations and mosquito-borne illnesses like malaria and Zika. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-will-cause-more-african-children-to-die-from-hot-weather-188609">Climate change will cause more African children to die from hot weather</a>
</strong>
</em>
</p>
<hr>
<p>Many urban residents will be prone to increasing floods. Already <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">10%</a> of the city’s newly developed areas are within a 100-year floodplain, threatening lives and infrastructures.</p>
<p>People living in informal settlements are particularly at risk – that’s about <a href="https://unhabitat.org/ethiopia-addis-ababa-urban-profile">70%</a> of Addis Ababa’s residents. These settlements crop up in limited and unused spaces, such as riverbanks. They are at a higher <a href="https://gsdrc.org/topic-guides/urban-governance/key-policy-challenges/informal-settlements/">risk</a> of flood impact, and the risk is growing.</p>
<p>Our data shows that currently the percentage difference in vulnerability between formal and informal settlements is <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">0.6%</a>. The figure illustrates the extent to which buildings within formal and informal settlements would be affected by flooding events. It is expected to rise to <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">1.3% by 2050 and 1.6% by 2080</a>. </p>
<h2>Policy recommendations</h2>
<p>There’s an urgent need for policies that can rise to these challenges. We suggest:</p>
<ul>
<li><p>the government should establish a climate adaptation and resilience office, to integrate <a href="https://www.c2es.org/document/what-is-climate-resilience-and-why-does-it-matter/">climate resilience</a> into <a href="https://theconversation.com/cape-towns-climate-strategy-isnt-perfect-but-every-african-city-should-have-one-149287">urban planning</a></p></li>
<li><p>an independent body should then assess policies in practice</p></li>
<li><p>a water management strategy to ensure equitable access and sustainable <a href="https://waterfdn.org/sustainable-water-management-swm-profile/#:%7E:text=Sustainable%20water%20management%20means%20using,those%20needs%20in%20the%20future.">use of water</a></p></li>
<li><p>the city should invest in <a href="https://environment.ec.europa.eu/topics/nature-and-biodiversity/green-infrastructure_en">green infrastructure</a> </p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/global-climate-finance-leaves-out-cities-fixing-it-is-critical-to-battling-climate-change-194375">Global climate finance leaves out cities: fixing it is critical to battling climate change</a>
</strong>
</em>
</p>
<hr>
<ul>
<li><p>upgrading infrastructure and improving waste management</p></li>
<li><p>public awareness campaigns and <a href="https://www.unesco.org/en/climate-change/education#:%7E:text=Education%20is%20crucial%20to%20promote,act%20as%20agents%20of%20change.">school</a> education on climate change impacts</p></li>
<li><p>developing mechanisms for effective <a href="https://coastadapt.com.au/how-to-pages/collaboration-and-partnerships-climate-change-adaptation">collaboration</a> among government departments, non-governmental organisations and international agencies.</p></li>
</ul><img src="https://counter.theconversation.com/content/212492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abay Yimere 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>Climate change is putting pressure on Ethiopia’s largest city, Addis Ababa, and exposing people to disease and natural disasters.Abay Yimere, Postdoctoral Scholar in International Environment and Resource Policy, The Fletcher School, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2129242023-09-06T12:26:36Z2023-09-06T12:26:36ZInvasive species cause billions of dollars in damage worldwide: 4 essential reads<p>Invasive species – including plants, animals and fish – cause heavy damage to crops, wildlife and human health worldwide. Some prey on native species; other out-compete them for space and food or spread disease. A new United Nations report estimates the losses generated by invasives at <a href="https://zenodo.org/record/8314303">more than US$423 billion yearly</a> and shows that these damages have at least quadrupled in every decade since 1970.</p>
<p>Humans regularly move animals, plants and other living species from their home areas to new locations, either accidentally or on purpose. For example, they may import plants from faraway locations to <a href="https://theconversation.com/invasive-grasses-are-fueling-wildfires-across-the-us-126574">raise as crops</a> or bring in a nonnative animal to <a href="https://theconversation.com/everyone-agreed-cane-toads-would-be-a-winner-for-australia-19881">prey on a local pest</a>. Other invasives <a href="https://theconversation.com/the-invasive-emerald-ash-borer-has-destroyed-millions-of-trees-scientists-aim-to-control-it-with-tiny-parasitic-wasps-158403">hitch rides in cargo</a> or <a href="https://theconversation.com/ballast-water-management-is-reducing-the-flow-of-invasive-species-into-the-great-lakes-190880">ships’ ballast water</a>.</p>
<p>When a species that is not native to a particular area becomes established there, reproducing quickly and causing harm, it has become invasive. These recent articles from The Conversation describe how several invasive species are causing economic and ecological harm across the U.S. They also explain steps that people can take to avoid contributing to this urgent global problem.</p>
<h2>1. The best intentions: Callery pear trees</h2>
<p>Many invasive species were introduced to new locations because people thought they would be useful. One example that’s widely visible across the U.S. Northeast, Midwest and South is the Callery pear (<em>Pyrus calleryana</em>), a flowering tree that botanists brought to the U.S. from Asia more than 100 years ago. </p>
<p>Horticulturists loved the Callery pear for landscaping and wanted to produce trees that all grew and bloomed in the same way. As University of Dayton plant ecologist <a href="https://scholar.google.com/citations?user=uRA-SZ0AAAAJ&hl=en&oi=sra">Ryan W. McEwan</a> explained, they created identical clones from cuttings of trees with the desired characteristics – a process called grafting. Unlike some trees, a Callery pear can’t fertilize its flowers with its own pollen, so plant experts thought it wouldn’t spread.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/1i8hL2mhCpM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Missouri state foresters explain why Callery pear trees became so popular and the problems they cause.</span></figcaption>
</figure>
<p>However, “as horticulturalists tinkered with Callery pears to produce new versions, they made the individuals different enough to <a href="https://theconversation.com/once-the-callery-pear-tree-was-landscapers-favorite-now-states-are-banning-this-invasive-species-and-urging-homeowners-to-cut-it-down-198724">escape the fertilization barrier</a>,” McEwan wrote. As wind and birds spread the trees’ seeds, wild populations of the trees became established and started crowding out native species. </p>
<p>Today, Callery pear trees are such scourges that several states have banned them. Others are paying residents to cut them down and replace them with native plants. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/once-the-callery-pear-tree-was-landscapers-favorite-now-states-are-banning-this-invasive-species-and-urging-homeowners-to-cut-it-down-198724">Once the Callery pear tree was landscapers' favorite – now states are banning this invasive species and urging homeowners to cut it down</a>
</strong>
</em>
</p>
<hr>
<h2>2. Tiny organisms, big impacts: Zebra and quagga mussels</h2>
<p>Invasive species don’t have to be large to cause outsized damage. Zebra and quagga mussels – shellfish the size of a fingernail – invaded the Great Lakes in the 1980s, clogging water intake pipes and out-competing native mollusks for food. Now they’re spreading west via rivers, lakes and bays, threatening waters all the way to the Pacific coast and Alaska.</p>
<p>As Rochester Institute of Technology environmental historian <a href="https://www.researchgate.net/scientific-contributions/Christine-Keiner-2071802254">Christine Keiner</a> wrote, it took several decades for the U.S. and Canada to regulate ships’ management of their ballast water tanks, which was the route by which the mussels were introduced to North America. </p>
<p>“Now, however, other human activities are increasingly contributing to harmful freshwater introductions – and with shipping regulated, the main culprits are <a href="https://theconversation.com/the-westward-spread-of-zebra-and-quagga-mussels-shows-how-tiny-invaders-can-cause-big-problems-185286">thousands of private boaters and anglers</a>,” Keller wrote. Limiting the destructive impacts of invasive species “requires scientific, technological and historical knowledge, political will and skill to persuade the public that everyone is part of the solution.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Infographic showing locations on a motorboat to check for invasive mussels." src="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546519/original/file-20230905-29-ibkd25.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many states require boaters to clean and dry their boats after use to avoid spreading zebra and quagga mussels.</span>
<span class="attribution"><a class="source" href="https://neinvasives.com/stop-aquatic-hitchhikers">Nebraska Invasive Species Program</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-westward-spread-of-zebra-and-quagga-mussels-shows-how-tiny-invaders-can-cause-big-problems-185286">The westward spread of zebra and quagga mussels shows how tiny invaders can cause big problems</a>
</strong>
</em>
</p>
<hr>
<h2>3. Threatening entire ecosystems: Lionfish</h2>
<p>When an invasive species is especially successful at spreading and reproducing, it can threaten the health of entire ecosystems. Consider the Pacific red lionfish (<em>Pterois volitans</em>), which has spread throughout the Caribbean and now is <a href="https://theconversation.com/invasive-lionfish-have-spread-south-from-the-caribbean-to-brazil-threatening-ecosystems-and-livelihoods-199229">moving south along Brazil’s coast</a>. </p>
<p>Lionfish thrive in many ocean habitats, from coastal mangrove forests to deepwater reefs, and they prey on numerous smaller fish species. In the Caribbean, they have reduced the number of small juvenile fish on reefs by up to 80% within as little as five weeks. </p>
<p>“Scientists and environmental managers widely agree that the lionfish invasion in Brazil is a potential ecological disaster,” warned Brazilian marine ecologist <a href="https://scholar.google.com.au/citations?user=_ArEYYMAAAAJ&hl=en">Osmar J. Luiz</a> of Charles Darwin University. “Brazil’s northeast coast, with its rich artisanal fishing activity, stands on the front line of this invasive threat.”</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1692994189099700515"}"></div></p>
<p>Although the Brazilian government was slow to address the lionfish threat, Luiz asserted that “with strategic, swift action and international collaboration, it can mitigate the impacts of this invasive species and safeguard its marine ecosystems.” That will require many techniques, from recruiting coastal residents to monitor for the invaders to tracking lionfish subpopulations using DNA analysis. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invasive-lionfish-have-spread-south-from-the-caribbean-to-brazil-threatening-ecosystems-and-livelihoods-199229">Invasive lionfish have spread south from the Caribbean to Brazil, threatening ecosystems and livelihoods</a>
</strong>
</em>
</p>
<hr>
<h2>4. The value of acting locally</h2>
<p>Public awareness is critical for stemming the spread of many invasive plants and animals. That can involve actions as simple as cleaning your shoes and socks after a hike. </p>
<p>“Certain species of nonnative invasive plants produce seeds <a href="https://theconversation.com/those-seeds-clinging-to-your-hiking-socks-may-be-from-invasive-plants-heres-how-to-avoid-spreading-them-to-new-locations-195697">designed to attach to unsuspecting animals or people</a>. Once affixed, these sticky seeds can be carried long distances before they fall off in new environments,” explains Boise State University ecology Ph.D. candidate <a href="https://scholar.google.com/citations?user=nmAblPEAAAAJ&hl=en&oi=ao">Megan Dolman</a>. </p>
<p>Research shows that recreational trails promote the introduction of invasive plant species into natural and protected areas, including national parks and scenic trails.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CkgNbwptsgc/?utm_source=ig_web_copy_link\u0026igshid=MzRlODBiNWFlZA==","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>In her research, Dolman found that few Appalachian Trail hikers were aware of the risk of carrying invasive plant seeds on their shoes or socks, so they typically did not take steps such as cleaning their gear before and after hiking. By knowing about invasive species in their areas and ways to manage them, people can help protect special places and keep invasive species from spreading.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/those-seeds-clinging-to-your-hiking-socks-may-be-from-invasive-plants-heres-how-to-avoid-spreading-them-to-new-locations-195697">Those seeds clinging to your hiking socks may be from invasive plants – here's how to avoid spreading them to new locations</a>
</strong>
</em>
</p>
<hr>
<p><em>Editor’s note: This story is a roundup of articles from The Conversation’s archives.</em></p><img src="https://counter.theconversation.com/content/212924/count.gif" alt="The Conversation" width="1" height="1" />
According to a new UN report, invasive species do more than US$423 billion in damage worldwide every year. Four articles explore examples, from mollusks to poisonous fish.Jennifer Weeks, Senior Environment + Cities Editor, The ConversationLicensed as Creative Commons – attribution, no derivatives.