tag:theconversation.com,2011:/us/topics/diving-19383/articles
Diving – The Conversation
2023-11-20T06:46:09Z
tag:theconversation.com,2011:article/218116
2023-11-20T06:46:09Z
2023-11-20T06:46:09Z
What is a sonar pulse and how can it injure humans under water?
<p>Over the weekend, the Australian government revealed that last Tuesday its navy divers had sustained “minor injuries”, likely due to sonar pulses from a Chinese navy vessel.</p>
<p>The divers had been clearing fishing nets from the propellers of HMAS Toowoomba while in international waters off the coast of Japan. According to <a href="https://www.minister.defence.gov.au/media-releases/2023-11-18/unsafe-and-unprofessional-interaction-pla-n">a statement from deputy prime minister Richard Marles</a>, despite HMAS Toowoomba communicating with internationally recognised signals, the Chinese vessel approached the Australian ship and turned on its sonar, forcing the Australian divers to exit the water.</p>
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<a href="https://theconversation.com/view-from-the-hill-albanese-should-come-clean-about-what-he-did-or-didnt-say-to-xi-jinping-about-sonar-incident-218115">View from The Hill: Albanese should come clean about what he did or didn't say to Xi Jinping about sonar incident</a>
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<p>The incident prompted a response from the Australian government, who labelled the incident “unsafe and unprofessional”. But what exactly is a sonar pulse, and what kinds of injuries can sonar cause to divers?</p>
<h2>What is sonar?</h2>
<p>Light doesn’t travel well under water – even in clear waters, you can see perhaps some tens of metres. Sound, however, <a href="https://doi.org/10.1007/978-3-030-97540-1_6">travels very well</a> and far under water. This is because water is much denser than air, and so <a href="https://doi.org/10.1007/978-3-030-97540-1_4">can respond faster</a> and better to <a href="https://oceanexplorer.noaa.gov/explorations/sound01/background/acoustics/acoustics.html">acoustic pressure waves</a> – sound waves.</p>
<p>Because of these properties, ships use sonar to navigate through the ocean and to “see” under water. The word “sonar” stands for sound navigation and ranging.</p>
<p>Sonar equipment sends out short acoustic (sound) pulses or pings, and then analyses the echoes. Depending on the timing, amplitude, phase and direction of the echoes the equipment receives, you can tell what’s under water – the seafloor, canyon walls, coral, fishes, and of course ships and submarines.</p>
<p>Most vessels – from small, private boats to large commercial tankers – use sonar. However, compared to your off-the-shelf sonar used for finding fish, navy sonars are stronger.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A screen labelled 'echo sounder' with a heat map" src="https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560313/original/file-20231120-18-pkot7g.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>
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<span class="caption">An echo sounder on a boat uses sound waves to help gauge the depth of the water.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/view-echo-sounder-on-board-marine-1017607606">mark_vyz/Shutterstock</a></span>
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<h2>What are the effects of sonar on divers?</h2>
<p>This is a difficult topic to study, because you don’t want to deliberately expose humans to harmful levels of sound. There are, however, anecdotes from <a href="https://doi.org/10.1121/1.3280165">various navies</a> and accidental exposures. There have <a href="http://resource.npl.co.uk/docs/science_technology/acoustics/clubs_groups/13oct05_seminar/parvin_subacoustech.pdf">also been studies</a> on what humans can hear under water, with or without neoprene suits, hoods, or helmets. </p>
<p>We don’t hear well under water – no surprise, since we’ve evolved to live on land. Having said that, <a href="https://apps.dtic.mil/sti/tr/pdf/ADA407482.pdf">you would hear</a> a sonar sound under water (a mid-to-high pitch noise) and would know you’ve been exposed.</p>
<p>When it comes to <a href="https://pubmed.ncbi.nlm.nih.gov/11732884/">naval sonars</a>, human divers have rated the sound as “unpleasant to severe” at levels of roughly 150dB re 1 µPa (decibel relative to a reference pressure of one micropascal, <a href="https://dosits.org/decision-makers/units-page-for-regulators/">the standard reference for underwater sound</a>). This would be perhaps, very roughly, 10km away from a military sonar. Note that we can’t compare sound exposure under water to what we’d receive through the air, because there are too many physical differences between the two.</p>
<p>Human tolerance limits are roughly 180dB re 1 µPa, which would be around 500m from military sonar. At such levels, humans might experience dizziness, disorientation, <a href="https://www.researchgate.net/profile/Jonathan-Clark-10/publication/12672627_Noise-induced_neurologic_disturbances_in_divers_exposed_to_intense_water-borne_sound_Two_case_reports/links/578e8b7108ae9754b7e9f1c8/Noise-induced-neurologic-disturbances-in-divers-exposed-to-intense-water-borne-sound-Two-case-reports.pdf">temporary memory and concentration impacts</a>, or temporary <a href="https://doi.org/10.1007/s00405-009-1039-z">hearing loss</a>. We don’t have information on what levels the Australian divers were exposed to, but their injuries were described as minor.</p>
<p>At higher received levels, closer ranges, or longer exposures, you might see more severe physiological or health impacts. In extreme cases, in particular for impulsive, sudden sound (which sonar is not), sound <a href="https://doi.org/10.1007/978-3-030-97540-1_13">can cause damage</a> to tissues and organs.</p>
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<h2>What does sonar do to marine animals?</h2>
<p>Some of the information on what noise might do to humans under water comes from <a href="https://doi.org/10.1111/1365-2664.12955">studies and observations of animals</a>.</p>
<p>While they typically don’t have outer ears (except for <a href="https://www.britannica.com/story/whats-the-difference-between-seals-and-sea-lions">sea lions</a>), marine mammals have inner ears that function similarly to ours. They can receive hearing damage from noise, <a href="https://doi.org/10.1578/AM.45.2.2019.125">just like we do</a>. This might be temporary, like the ringing ears or reduced sensitivity you might experience after a loud concert, or it can be permanent. </p>
<p>Marine mammals living in a dark ocean rely on sound and hearing to a greater extent than your average human. They use sound to navigate, hunt, communicate with each other and to find mates. Toothed whales and dolphins have evolved a biological echo sounder or biosonar, which sends out series of clicks and listens for echoes. So, interfering with their sounds or impacting their hearing <a href="https://doi.org/10.1007/978-1-4939-8574-6_10">can disrupt critical behaviours</a>.</p>
<p>Finally, sound may also impact non-mammalian fauna, such as fishes, which <a href="https://doi.org/10.1007/978-3-319-06659-2">rely on acoustics</a> rather than vision for many of their life functions.</p>
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Read more:
<a href="https://theconversation.com/loud-sounds-at-movies-and-concerts-can-cause-hearing-loss-but-there-are-ways-to-protect-your-ears-211484">Loud sounds at movies and concerts can cause hearing loss, but there are ways to protect your ears</a>
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<img src="https://counter.theconversation.com/content/218116/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christine Erbe receives funding from offshore oil and gas companies, the US Office of Naval Research, and the Western Australian Marine Science Institution. </span></em></p>
Australian navy divers have suffered minor injuries from a sonar pulse by a Chinese navy vessel. Here’s what that means and how underwater sound can hurt divers.
Christine Erbe, Director, Centre for Marine Science & Technology, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/208100
2023-06-20T07:07:21Z
2023-06-20T07:07:21Z
Missing Titanic sub: what are submersibles, how do they communicate, and what may have gone wrong?
<figure><img src="https://images.theconversation.com/files/532857/original/file-20230620-15-jh2y1f.jpeg?ixlib=rb-1.1.0&rect=28%2C34%2C1888%2C1043&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">OceanGate</span></span></figcaption></figure><p>An extensive <a href="https://www.bbc.com/news/world-us-canada-65953872">search and rescue operation</a> is underway to locate a commercial submersible that went missing during a dive to the Titanic shipwreck.</p>
<p>According to the US Coast Guard, contact with the submersible was lost about one hour and 45 minutes into the dive, with five people onboard. The vessel was <a href="https://www.9news.com.au/world/titanic-submersible-search-oceangate-expeditions-vessel-missing-as-us-coast-guard-launches-search/9d7352d8-6a6d-4dc1-afac-ce07dc63cea3">reported overdue</a> at 9.13pm local time on Sunday (12.13pm AEST, Monday).</p>
<p>The expedition was being run by US company OceanGate as part of an eight-day trip with guests paying US$250,000 per head to visit the wreck site. As of <a href="https://edition.cnn.com/americas/live-news/titanic-submersible-missing-search-06-19-23/h_c2b5400daf8538d8717f50c619d762ac">Monday afternoon</a> (Tuesday morning in Australia), US Coast Guard Rear Admiral John Mauger said the watercraft likely had somewhere between 70 and the full 96 hours of oxygen available to the passengers. </p>
<p>The Titanic’s wreck sits some 3,800 metres deep in the Atlantic, about 700km south of St John’s, Newfoundland. Finding an underwater vehicle the size of a small bus in this vast and remote expanse of ocean will be no small feat. Here’s what the search and rescue teams are up against. </p>
<h2>OceanGate’s Titan submersible goes missing</h2>
<p>Submersibles are manned watercraft that move in a similar fashion to submarines, but within a much more limited range. They’re often used for research and exploration purposes, including to search for shipwrecks and to document underwater environments. Unlike submarines, they usually have a viewport to allow passengers look outside, and outside cameras that provide a broader view around the submersible.</p>
<p>The missing submersible in question is an OceanGate <a href="https://oceangate.com/our-subs/titan-submersible.html">Titan</a> watercraft, which can take five people to depths of up to 4,000m. The Titan is about 22 feet (6.7m) in length, with speeds of about 3 knots (or 5.5km per hour). Although submersibles are often connected to a surface vessel by a tether, video and photos suggest the Titan was likely operating independently of the surface ship.</p>
<p>According to OceanGate’s website, the Titan is used “for site survey and inspection, research and data collection, film and media production, and deep-sea testing of hardware and software”. </p>
<p>It also has a “real-time hull health monitoring (RTM) system”. This would likely include strain gauges to monitor the health of the Titan’s carbon fibre hull. A strain gauge is a kind of sensor that can measure applied force and small deformations in material resulting from changes in pressure, tension and weight.</p>
<p>The Titan’s carbon fibre hull connects two domes made of composite titanium – a material that can withstand deep-sea pressures. At 3,800m below sea level (the depth of the Titanic) you can expect pressures about 380 times greater than the atmospheric pressure we’re used to on the surface of the earth.</p>
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<a href="https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several tube like shapes on a rectangular concrete platform underwater" src="https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=518&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=518&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532840/original/file-20230620-23-c6k9lo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=518&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Titan on the launch platform underwater, awaiting a signal to commence the dive.</span>
<span class="attribution"><a class="source" href="https://oceangate.com/gallery/gallery-titan.html#nanogallery/titangallery/0/4">OceanGate</a></span>
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<h2>Communication and rescue efforts</h2>
<p>The Titan would have had an acoustic link with its surface vessel, set up through a transponder (a device for receiving a sonar signal) on its end, and a transceiver (a device that can both transmit and receive communications) on the surface vessel. </p>
<p>This link allows for underwater acoustic positioning, as well as for short text messages to be sent back and forth to the surface vessel – but the amount of data that can be shared is limited and usually includes basic telemetry and status information. </p>
<p>The Titan is a battery-operated watercraft. Given it has lost all contact with its surface vessel, it may have suffered a power failure. Ideally, there would be an emergency backup power source (such as an independent battery) to maintain emergency and life support equipment – but it’s unclear if the missing vessel had any power backup on hand. </p>
<p>According to reports, at least two aircraft, a submarine and sonar buoys were being used to search for the vessel. The sonar buoys will be listening for underwater noise, including any emergency distress beacons that may have gone off.</p>
<p>One of the major challenges in the rescue effort will be contending with weather conditions, which will further shrink an already narrow search window.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dark blue image with a tube like shape floating in the lower third" src="https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=518&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=518&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532842/original/file-20230620-49349-cnzdk6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=518&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Titan commencing a dive to 4,000m underwater.</span>
<span class="attribution"><a class="source" href="https://oceangate.com/gallery/gallery-titan.html#nanogallery/titangallery/0/1">OceanGate</a></span>
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<h2>What might have happened?</h2>
<p>In a best case scenario, the Titan may have lost power and will have an inbuilt safety system that will help it return to the surface. For instance, it may be equipped with additional weights that can be dropped to instantly increase its buoyancy and bring it back to the surface.</p>
<p>Alternatively, the vessel may have lost power and ended up at the bottom of the ocean. This would be a more problematic outcome. </p>
<p>The worst case scenario is that it has suffered a catastrophic failure to its pressure housing. Although the Titan’s composite hull is built to withstand intense deep-sea pressures, any defect in its shape or build could compromise its integrity – in which case there’s a risk of implosion. </p>
<p>Another possibility is that there may have been a fire onboard, such as from an electrical short circuit. This could compromise the vehicle’s electronic systems which are used for navigation and control of the vessel. Fires are a disastrous event in enclosed underwater environments, and can potentially incapacitate the crew and passengers.</p>
<p>Time is of the essence. The search and rescue teams will need to find the vessel before its <a href="https://web.archive.org/web/20230331121053/https://oceangateexpeditions.com/tour/titanic-expedition/">limited supplies</a> of oxygen and water run out.</p>
<p>There’s an ongoing debate in scientific circles regarding the relative merit of manned submersibles, wherein each deployment incurs a safety risk – and the safety of the crew and passengers is paramount. </p>
<p>Currently, most underwater research and offshore industrial work is conducted using unmanned and robotic vehicles. A loss to one of these vehicles might compromise the work being done, but at least lives aren’t at stake. In light of these events, there will likely be intense discussion about the risks associated with using these systems to support deep-sea tourism.</p>
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Read more:
<a href="https://theconversation.com/indonesian-submarine-found-what-might-have-happened-to-the-kri-nanggala-in-its-final-moments-159703">Indonesian submarine found: what might have happened to the KRI Nanggala in its final moments?</a>
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<img src="https://counter.theconversation.com/content/208100/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stefan Williams works for the University of Sydney. He receives funding from the Australian Research Council, the Integrated Marine Observing System and the Trusted Autonomous Systems Defence Cooperative Research Centre for work related to the development and deployment of marine robotic systems. </span></em></p>
An expert explains some of the best and worst case scenarios facing the missing commercial watercraft.
Stefan B. Williams, Professor, Australian Centre for Field Robotics, University of Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/182121
2022-05-11T05:49:32Z
2022-05-11T05:49:32Z
South Australia’s Limestone Coast was formed from the bones of dead fish. Cathedral brings the story of these caves to the stage
<figure><img src="https://images.theconversation.com/files/462377/original/file-20220511-20-ajqpqr.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C3872%2C2571&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Matt Byrne/State Theatre Company South Australia</span></span></figcaption></figure><p><em>Review: Cathedral, directed by Shannon Rush for the State Theatre Company of South Australia</em></p>
<p>Cathedral could not be more South Australian. </p>
<p>This complex and challenging one-hander is the creation of SA- born playwright Caleb Lewis and brought to life by Nathan O’Keefe, one of our state’s acting greats.</p>
<p>The unique and spectacular underwater formations along our state’s Limestone Coast form the backdrop for the story. The play’s title is taken from a beautiful but challenging dive spot southeast of Mount Gambier, a large underwater cavern known as “<a href="https://www.parks.sa.gov.au/parks/piccaninnie-ponds-conservation-park">The Cathedral</a>.”</p>
<p>Lewis’ language describing the coast and its underwater dimensions is sumptuous and arresting, plumbing the depths of geologic time. </p>
<p>O’Keefe delivers these lush lines masterfully, savouring their poetry.</p>
<p>The coast he tells us, is “haunted by a billion, billion ghosts […] We are living on their bones.”</p>
<p>Land and sea floor are formed by “the slow sleep of calcium carbonate. Patterns appear "like dishes in the sea,” with “towers rising and falling over the centuries.”</p>
<p>But always, it is “water pushing it down.”</p>
<p>And it is here, in this liquid world, where the play draws its life.</p>
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Read more:
<a href="https://theconversation.com/naracoorte-where-half-a-million-years-of-biodiversity-and-climate-history-are-trapped-in-caves-78603">Naracoorte, where half a million years of biodiversity and climate history are trapped in caves</a>
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<h2>Living with loss</h2>
<p>The opening monologue conflates this underwater world with the womb. O’Keefe, as the protagonist Clay, describes “the first sensation” as “floating, then sound,” then of a heartbeat, followed by drifting. </p>
<p>We infer from his revelation of a “brother who never left the water” he has a twin who was never born.</p>
<p>This is our first hint this play will be about water and loss, with how one lives with losses that never go away. </p>
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<a href="https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Production image" src="https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462382/original/file-20220511-24-ok0w9r.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">Nathan O'Keefe delivers a masterful performance.</span>
<span class="attribution"><span class="source">Matt Byrne/State Theatre Company South Australia</span></span>
</figcaption>
</figure>
<p>Clay’s life was marked by loss at a young age when his mother died by suicide, leaving him in the care of his grandfather. It was his crusty old “Pops” who taught him to bodysurf and develop the confidence that led him into deep water diving. </p>
<p>These acts of telling are interspersed with scenes from the past acted out as if in real time. In the first of these, Clay is trapped deep inside the cathedral while diving. He calls in a distress signal on a static-filled connection, struggling to survive on a dwindling supply of oxygen.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/free-divers-have-long-defied-science-and-we-still-dont-really-understand-how-they-go-so-deep-92690">Free divers have long defied science – and we still don't really understand how they go so deep</a>
</strong>
</em>
</p>
<hr>
<p>This realistic depiction of Clay’s struggle is sometimes problematic: there is literally no place to go when acting out states such as disorientation and panic. </p>
<p>More successful temporal shifts are the economically written passages of dialogue between Clay and the colourful offstage characters populating his life. </p>
<p>One such exchange between Clay and his Pops is built around his insistence that he saw his mother’s corpse on a dive. When Clay insists he saw her, Pops tells him he needs to leave the town, and go “anyplace but here.”</p>
<p>Clay subsequently hits the road. On the beaches of Thailand he befriends another salty character, a Scotsman named Jock. </p>
<p>This encounter leads him to a deep sea diving training course in the North Sea. Ever the straight talker, Jock reminds his trainees “down there you’re just a tadpole in the dark.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Production image" src="https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462383/original/file-20220511-24-b5pvn.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">‘Down there you’re just a tadpole in the dark.’</span>
<span class="attribution"><span class="source">Matt Byrne/State Theatre Company South Australia</span></span>
</figcaption>
</figure>
<p>The life-threatening challenges of such work are powerfully expressed, as are the more light-hearted moments of camaraderie between divers.</p>
<p>In the decompression chamber following deep dives, voices sound like divers have been sucking on helium. As Clay recalls, it’s like being in a “tin can full of tough guys that all sound like Elmo.”</p>
<p>These laugh out loud moments give the audience welcome fleeting escape from the play’s emotional demands. </p>
<h2>Strength in honesty</h2>
<p>The production’s compact, functional set (designed by Kathryn Sproul) effectively evokes the limestone walls of the southeast coast and a jetty. Also serving the production well are Andrew Howard’s sound and compositions and Mark Oakley’s precise, transformational lighting.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Production image" src="https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462380/original/file-20220511-26-5so13x.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">Kathryn Sproul’s set evokes the limestone walls of the southeast coast and a jetty.</span>
<span class="attribution"><span class="source">Matt Byrne/State Theatre Company South Australia</span></span>
</figcaption>
</figure>
<p>Lewis does a superb job of capturing the embodied experience of diving, of hovering over landscapes. He captures the feelings of awe and wonder, but equally the residual fear and terror in back of the mind of all divers – even experienced ones. </p>
<p>Facing fear and death is where the play reaches its dramatic, powerful conclusion. We have all been through the ringer these last few years, with fear and loss intruding into many of our lives. Ultimately the play’s greatest strength is its honesty. </p>
<p><em>Cathedral plays at the Space Theatre, Adelaide Festival Centre until May 21 before touring regional South Australia.</em></p><img src="https://counter.theconversation.com/content/182121/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>William Peterson 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>
Caleb Lewis’ play, named for a popular but treacherous diving cave, is a sumptuous look at the beauty – and danger – of diving.
William Peterson, Adjunct Associate Professor, Auckland University of Technology
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/92690
2018-03-16T14:26:52Z
2018-03-16T14:26:52Z
Free divers have long defied science – and we still don’t really understand how they go so deep
<figure><img src="https://images.theconversation.com/files/209739/original/file-20180309-30969-e317hq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'Under', Martina Amati.</span> <span class="attribution"><span class="source">© Martina Amati</span></span></figcaption></figure><p>Free divers swim to extreme depths underwater (the current record is 214m) without any breathing apparatus. Champions can hold their breath for extraordinary amounts of time – the record for women is nine minutes, and men 11. </p>
<p>I’m a doctor with a special interest in extreme environments, so was intrigued when I was asked to collaborate in an art project about free diving for the Wellcome Collection’s new exhibition <a href="https://wellcomecollection.org/exhibitions/WhvoAykAACgAlDoo">Somewhere in Between</a>. Scientists and those who practise free diving are in many ways utterly alien to one another. When you look at the stresses this sport places on our physiology, it initially looks almost impossible that anyone should be able to dive to such profound depths – and yet they do.</p>
<p>Unsupported, breathing only air, you could just about climb Everest without any additional support other than your protective clothing. That’s 9km or so above sea level. But when you go into the ocean actually things change much more quickly because of the rapid pressure differences.</p>
<p>If you descend only 10m into the ocean, you are subjected to another additional atmosphere of pressure: that’s twice as much pressure as you’ve been used to at the surface. And for every 10m beyond you get another atmosphere of pressure. That starts to manipulate your body, your anatomy and your physiology in quite profound ways, which actually make the endeavour of diving into the deep ocean uniquely difficult. Not only does it compress you and shrink the air-containing spaces in your body, but also it alters your physiology, alters the way the gases act within your blood stream and how they act on everything, including your nervous system.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209741/original/file-20180309-30965-vrevf1.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">Somewhere in Between installation shot.</span>
<span class="attribution"><span class="source">© Wellcome Collection</span></span>
</figcaption>
</figure>
<p>In the very early days of free-diving, physiologists were pretty convinced that people couldn’t go beyond about 30 or 40 metres. They’d drawn their graphs as scientists and they’d worked out what they saw. They worked out what they understood about the human body and the effects of pressure on it and they said: “Well, look, your lungs are going to be crushed and you’re going to be spitting blood by the time you’re at 30 or 40 metres. So there’s no way that you can do this on breath-hold diving. It just can’t be done.”</p>
<p>But of course, free divers decided to do it anyway – and they swam well past those theoretical limits. How? Martina Amati, the free diver and artist involved in the project, tried to explain the mind set that goes with this extreme sport:</p>
<blockquote>
<p>There is an element of physicality but it’s mainly mental. That’s what is incredible about free diving. It’s not about your physical ability, but about your mental skills and mental training basically. You need to let go of everything that you know and everything that makes you feel good or bad. And so it’s a very liberating process. But equally you need to stay completely aware of your body and where you are, entirely in the moment.</p>
</blockquote>
<p>At a depth of 10m we need more oxygen in our bloodstream than at 100m, because the pressure of the water all around makes the oxygen more potent. So the most tricky part of a deep dive is the last stage of the ascent, when there is the risk of a shallow water black-out as the pressure fades and the oxygen levels in our tissues suddenly drop. </p>
<p>Getting started is hard too. You are buoyant at the surface and for the first few metres of the dive. As you start to descend, the pressure of the water pushes you back towards the surface, until around 13m to 20m deep when the dynamic is reversed. Here, according to Amati: </p>
<blockquote>
<p>Your body begins to sink a little bit like a stone. We call this part the free-fall, the moment when freedivers stop moving completely, and the most beautiful part of the dive. When you eventually come back from a dive and you take your first breath, every time it feels like your first breath ever. So for me, it feels like being born again. I think of the water a little like the womb.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209740/original/file-20180309-30983-1hsf0br.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">Martina Amati swimming back to surfaced. Photograph by Daan Verhoeven.</span>
<span class="attribution"><span class="source">© Martina Amati</span></span>
</figcaption>
</figure>
<p>As a diver, what you experience is the changing chemistry of your blood stream as the increased pressure allows gases to dissolve more easily and exert their effects more readily. So the nitrogen, the larger amount of nitrogen that dissolves in your blood stream, behaves as a narcotic and actually makes you feel quite drunk and at only 30 or 40 metres. If you dive at those limits, the additional nitrogen can make you feel quite euphoric.</p>
<p>As a free diver, going deeper, you’re just squeezing those last dregs of oxygen out of your blood stream and trying to subsist on much lower levels than any human being normally ever does. And you go into this sort of strange balance between the pressures that exist at depth temporarily helping to support you while your breath-holding is threatening your life. It’s really a very, very precarious balance and it requires you to enact some very weird and very strange and not all that well understood physiological feats just to stay alive. The depth records for human free diving now are quite absurd: not tens but hundreds of metres.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1009&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1009&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1009&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1268&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1268&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209742/original/file-20180309-30983-bei9vr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1268&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’ film still.</span>
<span class="attribution"><span class="source">© Martina Amati</span></span>
</figcaption>
</figure>
<p>People have rough models of how that is achieved. It’s not a total mystery – but clearly there’s more going on than we fully understand. What I found really fascinating working on this project was that the free divers and non-scientists that participate in free diving talk about this sort of quite holistic experience of being at one with the ocean and this great feeling of well-being. To a physiologist, that’s the euphoria of oxygen starvation and hypoxia, which is not great, but for the free divers themselves this is part of the experience. It’s impossible for them to disentangle that from the diving itself.</p>
<p>There’s a grey area between life and death in which there is a chance and things can happen. In medicine we don’t explore this boundary for fun – but people who are involved in endeavours like free diving do it as a pastime.</p>
<p>And so the act of free diving, looked at by two different cultures – the free divers and the scientists – has very little real overlap. One looks on in fascinated horror and the other sort of sees it as a way of life. For me, then, this was much more than just an art-science collaboration. There was a real reason to bring those two spheres together here – each can learn an awful lot from the other.</p>
<hr>
<p><em>Martina Amati’s multi-screen installation “Under”, for which she collaborated with Kevin Fong, can be seen at <a href="https://wellcomecollection.org/exhibitions/WhvoAykAACgAlDoo">Somewhere in Between</a>, an exhibition at the Wellcome Collection, open until August 27 2018.</em></p><img src="https://counter.theconversation.com/content/92690/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Fong was a Wellcome Public Engagement Fellow from 2011-2012, and collaborated with the artist Martina Amati as part of the Wellcome Collection's latest exhibition, Somewhere in Between.</span></em></p>
Diving without oxygen tanks requires you to enact some very weird and very strange and not all that well understood physiological feats just to stay alive.
Kevin Fong, Honorary Professor in Physiology, UCL
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/88851
2018-01-08T02:47:02Z
2018-01-08T02:47:02Z
Scientist at work: I’ve dived in hundreds of underwater caves hunting for new forms of life
<figure><img src="https://images.theconversation.com/files/198218/original/file-20171207-11347-1kls1cd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Author Tom Iliffe leads scientists on a cave dive.</span> <span class="attribution"><span class="source">Jill Heinerth </span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Maybe when you picture a university professor doing research it involves test tubes and beakers, or perhaps poring over musty manuscripts in a dimly lit library, or maybe going out into the field to examine new crop-growing techniques or animal-breeding methods. All of it’s good, solid research and I commend them all.</p>
<p>Then there is what I do – cave diving. To study the biology and ecology of coastal, saltwater caves and the marine fauna that inhabit them, my cave diving partners and I head underground and underwater to explore these unique and challenging ecosystems. Often we go to places no other human has been. While the peaks of the tallest mountains can be viewed from an airplane or the depths of the sea mapped with sonar, caves can only be explored firsthand.</p>
<p>Around the globe, from Australia to the Mediterranean, from Hawaii to the Bahamas and throughout the Caribbean, I have explored more than 1,500 such underwater caves over the last 40 years. The experience can be breathtaking. When you are down 60 to 100 feet in a cave that has zero light and is 20 miles long, you never know what you are about to see as you turn the next corner.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=544&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=544&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=544&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=683&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=683&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200890/original/file-20180105-26139-u0oep3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=683&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 remipede <em>Cryptocorynetes elmorei</em> from Eleuthera, Bahamas. Remipedes are only found in deeper saltwater layers from caves on opposite sides of the Atlantic and from the Indian Ocean coast of Western Australia.</span>
<span class="attribution"><span class="source">Tom Iliffe</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>My primary focus is searching for new forms of life – mostly white, eyeless crustaceans – that are specifically adapted to this totally dark, food-poor environment. Cave diving is an essential tool in our investigations since the caves I’m interested are filled with water: typically a layer of fresh or brackish water on the surface and then saltwater at depths of 10 to 20 meters or more.</p>
<p>There’s no other way to access these unexplored areas than to strap on your scuba tanks and jump in.</p>
<h2>Scientific research as extreme sport</h2>
<p>The list of what can go wrong in a cave dive could fill your event planner.</p>
<p>Equipment or light failure, leaking scuba tanks, broken guide lines, getting lost, cave collapse, stirred up silt resulting in zero visibility, poisonous gas mixtures – you get the idea.</p>
<p>It’s fieldwork that can be a matter of life or death. I have had some close calls over the years, and sadly, have lost several good friends and researchers in cave accidents.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200888/original/file-20180105-159080-p3lh5o.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">Tom Iliffe preparing for a side mount dive at Cliff Pool, Bermuda. Rather than carrying tanks on his back as in conventional scuba, a tank is clipped off under each arm, allowing him to pass through low sections in a cave where it would otherwise be impossible to go.</span>
<span class="attribution"><span class="source">Gil Nolan</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>To put it mildly, underwater caves can be very hostile and unforgiving. One such cave – the Devil’s system in north-central Florida – has <a href="https://www.ncbi.nlm.nih.gov/pubmed/27723015">claimed at least 14 lives in the last 30 years</a>, and there are other examples elsewhere in Florida and in Mexico.</p>
<p>Most of the time, human error is to blame, when divers don’t follow the rules they should or lack essential training and experience in cave diving.</p>
<p>My family has gotten used to the idea that what I do is not always a walk in the park. They know that since I’m 69, I stress safety, being physically and mentally prepared, and that I religiously abide by the cardinal rule of cave diving – that you never ever dive alone. My colleagues and I usually go into a cave with teams of two to three divers and constantly look after each other to see if there is anything going wrong during our dives, which usually last about 90 minutes, but can be as long as three hours or more.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200892/original/file-20180105-26166-1lzfi53.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">Tom Iliffe diving with his Megalodon closed-circuit rebreather in a lava tube cave in the Canary Islands.</span>
<span class="attribution"><span class="source">Jill Heinerth</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Death-defying dives pay off in discoveries</h2>
<p>It’s not just <a href="https://doi.org/10.5852/ejt.2017.316">new species</a> we are discovering, <a href="https://doi.org/10.3897/subtbiol.21.11181">but also higher groups of animals</a> including a new class, <a href="https://doi.org/10.2307/1548221">orders</a>, <a href="https://doi.org/10.1016/j.ode.2006.07.002">families</a> and <a href="https://doi.org/10.1080/00364827.1985.10419688">genera</a>, previously unknown from any other habitat on the planet. Some of our newfound animals have <a href="https://doi.org/10.1007/s12526-009-0021-8">close relatives living in similar caves</a> on <a href="https://doi.org/10.1126/science.225.4659.309">opposite margins of the Atlantic Ocean</a> or even the far side of the Earth (such as the Bahamas versus Western Australia).</p>
<p>While most of these caves are formed in limestone, they can also include seawater-flooded lava tubes created by volcanic eruptions. Amazingly, <a href="http://www.geoparquelanzarote.org/wp-content/uploads/2016/01/Guia-interpretativa-ecosistemas-anquialinos-EN.pdf">similar types of animals inhabit both</a>.</p>
<p>In the deserts of West Texas, our team discovered and explored the <a href="http://www.admfoundation.org/projects/phantomcave2013/phantom2013.html">deepest underwater cave in the U.S.</a>, reaching a depth of 462 feet.</p>
<p>The graduate students <a href="http://www.cavebiology.com">in my lab</a> work on a diverse group of questions. They’re uncovering the nature of <a href="https://dx.doi.org/10.1038/s41467-017-01776-x">chemosynthetic processes in caves</a> – how microorganisms use energy from chemical bonds, rather than light energy as in photosynthesis, to produce organic matter – and their significance to the cave food web.</p>
<p>Other students are examining records of <a href="https://doi.org/10.1016/j.marmicro.2012.02.007">Ice Age sea level history</a> held in cave sediments, as well as the presence of tree roots penetrating into underwater caves and their importance to the overlying tropical forest. We’re finding evidence that sister species of cave animals on opposite shores of the Atlantic separated from one another about <a href="https://doi.org/10.1038/s41598-017-03107-y">110 million years ago as tectonic plate movements</a> initiated the opening of the Atlantic, as well as determining how environmental and ecological factors affect the <a href="https://www.researchgate.net/publication/248393742_Anchialine_cave_ecology">abundance and diversity of animals in saltwater caves</a>.</p>
<p>Our research has significant implications, especially concerning endangered species and environmental protection. Since many cave animals occur only in a single cave and nowhere else on Earth, pollution or destruction of caves can result in species extinctions. Unfortunately, the creation of many protected areas and nature reserves <a href="https://doi.org/10.1002/aqc.2350">failed to take cave species into account</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200891/original/file-20180105-26151-136wew2.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">The remipede <em>Godzillius robustus</em> from Abaco, Bahamas. Note the darker shaded venom-injecting fangs on the first pair of appendages.</span>
<span class="attribution"><span class="source">Tom Iliffe</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Some discoveries can be completely unanticipated. For example, when we sequenced DNA from a variety of arthropods, including crustaceans and insects, the data strongly <a href="https://doi.org/10.1093/molbev/msr270">support a sister group relationship</a> between hexapods (the insects) and remipedes, a small and enigmatic group of marine crustaceans exclusively found in underwater caves. This places the remipedes in a pivotal position to understanding the evolution of crustaceans and insects.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/200889/original/file-20180105-159080-130ipje.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">
<figcaption>
<span class="caption">The author on a cave dive.</span>
<span class="attribution"><span class="source">Jill Heinerth</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Even at this stage of my life, to me the risks attendant to my cave diving research are worth it. It’s like the Star Trek mantra come true – to boldly go where no man has gone before. The chance to discover new forms of marine life, to view never-before-seen underwater formations, vast chambers, endless tunnels and deep chasms, to swim in some of the bluest and purest water on Earth – I will take that sort of research and its challenges any day.</p>
<p>Yes, it can give new meaning to the old line about “publish or perish” in academia. But I love it, and I will tell you with all honesty, I can’t wait until my next trip.</p><img src="https://counter.theconversation.com/content/88851/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tom Iliffe 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>
Scientific fieldwork that happens underground and underwater in spectacular but dangerous caves opens a window on a largely unknown world.
Tom Iliffe, Professor of Marine Biology, Texas A&M University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/86287
2017-11-02T11:41:18Z
2017-11-02T11:41:18Z
Weightlifters and divers offer a lesson for business in risk and reward
<figure><img src="https://images.theconversation.com/files/192441/original/file-20171030-18738-1kuoqsx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/singapore2010/4637741587/in/photolist-4UqHhi-CzCXpQ-SxRKUV-wVYsfe-pZS2KG-cKtfeb-84PCZR-7TdEN7-r1pRE-7MxAtY-4wr6Fu-cJKDe1-5AbG93-uYimY-cJKG3y-cJKE85-cJKHmq-5Cr2mm-r1rcx-62wB4F-8tncpo-5A7qSZ-cJKF8y-9UqCv3-aAVKD-S4vTqa-b8ET1-r1ppc-3QKBCo-SdMPz3-5AbJi5-r1qvL-B4tmhv-6QdWqD-7FS9CT-Kx9W4E-4yFeQK-Ax3uz5-LkGGSW-sFx3kv-fUT4sR-cJKFxQ-cJKDLU-cJKCUb-bmKibc-a4xYMP-6LDb18-6Aq7Nd-5wifUN-5dBW6o">Singapore 2010 Youth Olympics/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>What do elite weightlifting and diving competitions have in common with top-level money management or pharmaceutical development?</p>
<p>In all of these diverse fields, there is an element of “tournament”. The rewards are fixed in advance, concentrated at the top, and based on relative rather than absolute performance. Whether you’re a world-class sprinter or an investment wizard, all that really matters is your performance compared to that of your rivals. That might be other runners leaning at the tape or other investors also trying to beat the market.</p>
<p>Classic <a href="https://ideas.repec.org/a/ucp/jpolec/v89y1981i5p841-64.html">economic analysis</a> <a href="https://ideas.repec.org/a/ucp/jpolec/v91y1983i3p349-64.html">says that</a> the <a href="https://www.jstor.org/stable/3003535?seq=1#page_scan_tab_contents">larger the incentive</a>, the more effort competitors put in: people will train harder for the Olympics than a regional track meet, and money managers will pull out all the stops if they scent the next trade of the century.</p>
<p>But in real life, effort doesn’t always translate into performance – and one reason is the “choke factor”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/192444/original/file-20171030-18704-r3ap66.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">When the pressure’s on.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/businessman-afraid-huge-shadow-hand-holding-720553729?src=hPInBZnNFQwvAkZz4zVokg-1-84">ra2studio/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Taking risks</h2>
<p>In practice, competitors often do not only choose their level of effort; they also have to decide between more or less risky strategies. For example, a pharmaceutical firm that is lagging behind in a patent race may start exploring more risky projects, and a money manager with below-market returns might start investing in riskier assets.</p>
<p>So, colleagues and I looked at top-level weightlifting and diving competitions, including the Olympics, to examine athletes’ choices about effort and risk-taking in a tournament setting, with an eye on whether we could draw any lessons which applied to business.</p>
<p>In weightlifting, athletes have to announce in advance the amount they intend to lift. That means it is possible to observe not only whether a lift is successful, but also how risky their strategy is: the heavier the weight, the greater the chance of failure. We also observed the interplay between mid-tournament ranking and success in lifting a given weight.</p>
<p>What was surprising was that the probability of a successful lift increases the further an athlete is down the rankings. In other words, an athlete has a lower probability of successfully lifting a given weight if they are ranked first than if they are ranked eleventh, suggesting that athletes may perform badly under pressure, even though motivation and effort may be high.</p>
<p>Now, weightlifters can save themselves in competitions like this, lifting rarely to save energy, and that can cause the rankings to ebb and flow. The study – which looked at round-by-round results from competitions between 1990-2006 – was designed to discover what the result would be be if the same athlete was lifting the same weight from different ranking positions. </p>
<p>The result is consistent with anecdotal evidence of a “choke factor” – or choking under pressure – on which there has been plenty of talk-radio comment from disappointed sports fans, but little empirical evidence.</p>
<h2>Diving in</h2>
<p>A follow-up study on diving competitions focused on a sport with a very different set of skills (agility versus physical strength), but again we found consistent evidence that professional divers underperform when close to the top of the interim ranking, despite strong motivation to succeed. Divers can pick trickier dives as they go through the competition and seek to climb the rankings. Our findings were that a diver was more likely to score highly on a particular dive if they were poorly ranked, than if they were protecting a high ranking. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/192445/original/file-20171030-18693-rtcxvm.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">In sync.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/russia-moscow-april-29-2015-athletes-294527276?src=SqGwIrx-cmqiIidAQ3L4rQ-1-43">Mitrofanov Alexander/Shutterstock</a></span>
</figcaption>
</figure>
<p>And in both disciplines, the finding was that athletes tend to underperform when competition is more intense and the tournament more prestigious. When the pressure builds, the coach of one national team said, performance suffers:</p>
<blockquote>
<p>Of course, it is well known that athletes in training they would lift these kilos. But then in the game, they choke. </p>
</blockquote>
<p>So what does this mean for money management or other high-stakes business environments?</p>
<p>Overall, our findings suggest that tournament-like incentives – single achievable targets such as a promotion or a bonuses – can change workers’ behaviour and could be a powerful tool in the hands of capable managers. Managers may use this knowledge to induce risk-averse workers to innovate, experiment and ultimately take risky, but profitable, strategies.</p>
<p>On the other hand, our results show that tournaments can be too successful in encouraging risk-taking, leading to excessive risk and lower average performance. This may be ideal in sport, where gunning for ultimate glory makes sense and where suspense and extraordinary performances are what the spectators want. It may, however, not be so desirable within companies. If profitability is affected more by consistent and average performance than by the rare exceptional performance of a few individuals, then tournament-like incentives may encourage needless risk and reduce overall company performance.</p>
<p>What’s more, raising the stakes or the rewards promised to employees may actually hurt their performance overall, and particularly at the top. The idea of “choking under pressure” seems to be an important psychological phenomenon, even for experienced professionals competing at the very top of their game.</p><img src="https://counter.theconversation.com/content/86287/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christos Genakos 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 choke factor is visible in tournament-style athletics competitions, and should teach managers about incentives.
Christos Genakos, Senior Lecturer in Economics, Cambridge Judge Business School
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/63818
2016-08-11T07:19:53Z
2016-08-11T07:19:53Z
Going for … green? Why Rio’s swimming pools are changing colour
<p>On Monday, the diving pool at the Rio Olympics was fine. By Tuesday, it had <a href="http://www.smh.com.au/sport/olympics/rio-2016/diving-pool-turns-green-for-synchronised-final-at-rio-olympics-20160809-gqov5i.html">turned green</a>. Now, the water polo pool is <a href="http://www.smh.com.au/sport/olympics/rio-2016/olympics-swimming/australians-left-with-stinging-eyes-after-another-%20rio-olympics-pool-turns-green-20160810-gqpqgr.html">showing a distinctly green tone</a>. </p>
<p>Authorities were <a href="http://www.smh.com.au/sport/olympics/rio-2016/diving-pool-turns-green-for-synchronised-final-at-rio-olympics-20160809-gqov5i.html">quick to deny</a> that the green pool posed a risk to divers’ health, but that actually depends on why the water changed colour.</p>
<p>The possible culprits are: a sudden algae bloom; a change in pool alkalinity; or a chemical reaction in the water. How do these cause a change in the water colour?</p>
<h2>Blooming algae</h2>
<p>Algal blooms, caused by a sudden proliferation of microscopic algae or cyanobacteria, are found in ponds, rivers and seas the world over. But they are certainly not expected in Olympic swimming pools. </p>
<p>Phenomena such as “<a href="http://www.smh.com.au/environment/water-issues/red-beaches-glow-blue-after-dark-20121129-2ahu9.html">red tides</a>” and their beautiful night-time bioluminescence occur when conditions are perfect for rapid algae growth. </p>
<p>There’s no single triggering factor for this growth, but large amounts of rain (which cause nutrients to be flushed into the water), followed by sunny and warm weather as well as calm waters, are thought to be contributing environmental factors.</p>
<p>Olympic officials <a href="http://www.espn.com/olympics/swimming/story/_/id/17258143/2016-summer-olympics-green-pool-olympic-organizers-loss-explain-why">have suggested</a> that the remarkable change in pool colour could be a result of the sudden growth of an algal species. While small amounts of algae are present in swimming pools, they are not detectable by the human eye and the chemicals used to treat the water usually keep them at bay. </p>
<p>Warm weather conditions compounded by low winds may have contributed to an algae outbreak, but it seems more likely that a chemical imbalance or broken filter system is the underlying cause of the change in colour. </p>
<h2>A not-so-basic explanation</h2>
<p>Some news sources have reported that a “<a href="http://www.reuters.com/article/us-olympics-rio-diving-pool-idUSKCN10L1XN">decrease in alkalinity</a>” is responsible for the fluctuations in the colour of the diving and water polo pools. One of the tanks connected to the pool is said to have run out of one of the chemicals used to moderate the pH of the water.</p>
<p>An <a href="https://www.betterhealth.vic.gov.au/health/healthyliving/swimming-pools-water-quality">ideal pH for a swimming pool</a> is slightly alkaline (just over pH 7) to match the pH of our eyes and mucus membranes and hence avoid irritation. </p>
<p>The chemicals responsible for maintaining a safe pH also influence the multitude of chemical reactions occurring in the swimming pool. </p>
<p>Chlorine, for example, is the most widely known disinfectant used in swimming pools. But chlorine’s ability to kill pathogens is reduced when the pH of the pool is altered.</p>
<p>A reduction in alkalinity could have triggered the suspected algal bloom.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?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">Rio’s water polo pool also turned green.</span>
<span class="attribution"><span class="source">Reuters/Kai Pfaffenbach</span></span>
</figcaption>
</figure>
<h2>Chemical relay reaction</h2>
<p>A cocktail of chemicals is necessary to keep pools, which are basically large bodies of stagnant water, safe for swimming and, in particular, to kill harmful bacteria or parasites such as <em>E. Coli</em> and <em>Giardia lamblia</em>. </p>
<p>Chemicals such as chlorine aren’t just reactive to pathogens, though. They also react with chemicals introduced to the water by the swimmers. Olympian perspiration, <a href="http://www.telegraph.co.uk/sport/olympics/swimming/9457088/Michael-Phelps-admits-we-do-pee-in-the-pool.html">urine</a> and sun tan lotion can all react with the chemicals added to the water to produce byproducts. </p>
<p>The addition of extra chlorine to the chameleon-like water polo pool has been blamed for the <a href="http://www.smh.com.au/sport/olympics/rio-2016/olympics-swimming/australians-left-with-stinging-eyes-after-another-rio-olympics-pool-turns-green-20160810-gqpqgr.html">stinging eyes</a> of the Australian water polo players. But one of the aforementioned byproducts may actually be responsible. </p>
<p>Urine contains a lot of a nitrogen-rich molecule called urea, which reacts with chlorine to form an irritant called trichloramine. Even the characteristic smell of a swimming pool is not actually chlorine but rather a collection of similar byproducts. </p>
<h2>Gold, silver or copper?</h2>
<p>The presence of metal ions can also lead to changes of colour in aqueous environments such as swimming pools. Some have suggested that copper or other metals from water pipes could be responsible for the dramatic green of the diving pool. </p>
<p>The simplest complex that copper forms with water is a blue solution, hexaaquacopper (II), where a copper ion is completely surrounded by six molecules of water. If the water is displaced by other molecules, such as chloride, colour changes can result. </p>
<p>Different metals form different coloured solutions depending on their oxidation state and the nature of the molecules coordinated to the metal. Some combinations result in green solutions. But none of the analyses from the Rio pools have mentioned metal complexes so far. </p>
<h2>No need to adjust your sets</h2>
<p>Both Brazilian experts and <a href="http://www.fina.org/">FINA</a> have checked the water quality and determined that it poses no risk to athletes. Olympic officials will be hoping the colour of the pool changes back to blue and that the focus returns to the feats of those in the water rather than the water itself.</p><img src="https://counter.theconversation.com/content/63818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Motion 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 possible culprits are: a sudden algae bloom; a change in pool alkalinity; or a chemical reaction in the water. How do these cause a change in the colour of the water?
Alice Motion, Postdoctoral Research Associate and Teaching Fellow in Chemistry, University of Sydney
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/52504
2016-01-18T04:04:15Z
2016-01-18T04:04:15Z
How scuba diving is warding off threats to its future
<figure><img src="https://images.theconversation.com/files/108038/original/image-20160113-10444-173vnqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scuba diving must be done in a sustainable manner to preserve the industry.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Scuba diving is an important tourism market, generating a <a href="http://coralreef.noaa.gov/aboutcorals/values/tourismrecreation/">billion-dollar industry</a> worldwide. African countries are highly recommended for divers; 20% of the best dives in the world are located on the <a href="http://www.scubatravel.co.uk/topdiveslong.html">continent</a>.</p>
<p>Some of the most popular destinations include: </p>
<ul>
<li><p>the warm tropical waters of the Red Sea, which is home to <a href="http://www.scubatravel.co.uk/redsea/wreckdive.html#Thistlegorm">Thistlegorm</a>, and <a href="http://www.scubatravel.co.uk/redsea/sharmdive.html">Shark and Yolanda Reef</a> in Sharm El Sheikh;</p></li>
<li><p>the high latitude reefs of <a href="http://www.divewild.com/en/mozambique-scuba-diving/ponta-do-ouro">southern Mozambique</a>; and</p></li>
<li><p>the cold waters of <a href="http://www.divestyle.co.za/index.php?option=com_content&view=article&id=372:-the-top-5-dive-sites-in-south-africa&catid=8:local-travel&Itemid=20">South Africa</a> that host great white sharks, old mines, <a href="http://www.southafrica.net/za/it/articles/entry/article-miracle-waters-north-west">lakes</a>, and <a href="http://www.kznwildlife.com/marine-protected-area-kzn.html">marine parks</a>.</p></li>
</ul>
<p>Scuba diving has grown in popularity over the past two decades. This is evident from the rapid growth in the number of <a href="https://www.padi.com/scuba-diving/">certifications</a> issued worldwide. The number has grown to 23 million at a pace of about one million every year.</p>
<p>But the industry is not without its fair share of challenges. Some of these, such as environmental degradation and the effects of climate change, are threatening the industry.</p>
<h2>Challenges</h2>
<p>The global <a href="http://www.theguardian.com/business/2015/nov/14/global-economy-slowing-down-recession-or-protectionism">economic downturn</a> has led to people cutting down on unnecessary expenses such as <a href="http://www.backpackingscubadiver.com/scuba-diving-expensive/">costly</a> leisure activities. This has had negative consequences for tourism destinations, scuba diving charters and diving schools. </p>
<p>Sociopolitical instability also affects diving. For example, political challenges in Egypt have affected the diving <a href="http://www.telegraph.co.uk/travel/travelnews/8317053/Egypt-crisis-the-charms-of-an-empty-Sharm.html">numbers</a>. </p>
<p><a href="http://news.bbc.co.uk/2/hi/asia-pacific/4375815.stm">Natural disasters</a> and <a href="http://www.reuters.com/article/environment-tourism-environment-dc-idUSL0188388420071001">climate change</a> are also affecting diving destinations. Increasing water temperatures and coral <a href="http://news.nationalgeographic.com/news/2006/05/warming-coral.html">bleaching</a> events have <a href="http://travel.cnn.com/bangkok/visit/closure-18-dive-sites-413619/">deterred</a> divers from visiting affected destinations. </p>
<p>Divers and diving operations have a <a href="http://www.reefresilience.org/coral-reefs/stressors/local-stressors/coral-reefs-tourism-and-recreational-impacts/">negative impact</a> on the environment, causing <a href="https://www.divein.com/articles/a-scuba-divers-impact-on-a-coral-reef/">direct damage</a> as well as indirect damage through <a href="http://www.scubadiving.com/photos/clean-water-happy-reefs">pollution</a> and <a href="http://ocean.nationalgeographic.com/ocean/critical-issues-marine-habitat-destruction/">development</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/108041/original/image-20160113-10444-tbmi5i.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">Pollution is one of the problems affecting scuba diving.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The industry has also been hit hard by <a href="http://www.news24.com/SciTech/News/Diving-ban-WWF-has-its-say-20071206">poaching</a> and <a href="http://overfishing.org/">overfishing</a>. Several sites have been <a href="http://www.iol.co.za/news/south-africa/poachers-why-attack-law-bidding-divers-1.381856?ot=inmsa.ArticlePrintPageLayout.ot">closed</a> and permit systems introduced, <a href="http://www.iol.co.za/news/south-africa/poachers-why-attack-law-bidding-divers-1.381856?ot=inmsa.ArticlePrintPageLayout.ot">frustrating</a> some operators.</p>
<h2>Solutions</h2>
<p>A number of initiatives have been taken locally and globally to address some of these issues. The scuba diving industry, scientists and decision-makers are all trying to work on solutions. </p>
<p>To manage the tough economic environment, the industry has begun to take steps to attract <a href="http://www.elitedivingagency.com/articles/6-types-divers-group/">different markets.</a> There are also initiatives to cater for different types of divers. This improves competitiveness. Divers are also being advised on how to travel in a tough <a href="http://www.travelworldnews.com/newsoffers/news_upload/Industry_20Events_2edb.scuba.pdf">economy</a>.</p>
<p>The diving industry has organised <a href="http://bobsummit.com/">summits</a> to address the issue of climate change and its consequences. Topics most commonly covered are eco-compatible business practices, how <a href="http://www.responsibletravelreport.com/sti-news/news/2241-scuba-dive-industry-addresses-global-warming-and-climate-friendly-diving">awareness</a> can be raised among divers about carbon emissions and the promotion of <a href="http://greenfins.net/">sustainable</a> resources.</p>
<p>Problems like overfishing, trawling, poaching, and pollution from boat traffic have been addressed with the establishment of <a href="http://www.mmmpa.eu/">Marine Protected Areas</a>. These are designed to pose restrictions and regulations on the industry.</p>
<p>And there are more initiatives to promote scientific research, to generate revenue for conservation, and to promote and control non-consumptive use of the marine resources including scuba diving. African governments have successfully established some of the largest and oldest <a href="http://isimangaliso.com/">networks</a> of marine and terrestrial protected areas for these purposes. </p>
<p>Some locations affected by natural disasters, as in Thailand, have managed to <a href="http://www.asiadivesite.com/news/thailand-250406.php">re-establish</a> themselves and <a href="http://www.miss-scuba.com/thailand.html">continue</a> their operations.</p>
<p>Proper scuba diver conduct is being promoted through marine conservation, environmental awareness and education initiatives and by involving scuba divers in conservation. One of the most popular is <a href="http://www.projectaware.org/">Project AWARE.</a> This is a global underwater conservation movement of scuba divers who tackle problems including marine litter and shark culling through education and participatory events. </p>
<p>There are numerous other initiatives and projects worldwide to educate, promote research and highlight the importance of sustainability. <a href="http://www.ghostfishing.org/">Ghost Fishing</a>, <a href="http://www.earthdive.com/">earthdive</a> and <a href="http://greenfins.net/">Green Fins</a> are all involved in such activities.</p>
<h2>What’s happening in Africa</h2>
<p>Divers and researchers in collaboration with the protected <a href="http://www.divestyle.co.za/index.php?option=com_content&view=article&id=410:mpas-in-sa-how-divers-can-help-&catid=912:news&Itemid=125">areas</a> and organisations are all actively engaged in initiatives and collaborations to promote research, education and sustainability. </p>
<p>Examples include projects like:</p>
<ul>
<li><p>the <a href="http://www.sst.org.za/">Sustainable Seas Trust</a>;</p></li>
<li><p>the <a href="http://www.marinemegafauna.org">Marine Megafauna Foundation</a>;</p></li>
<li><p>the <a href="http://www.sharkconservancy.org/">South African Shark Conservancy</a>;</p></li>
<li><p><a href="http://www.jacarandachildren.co.za/diveforlife.html">Dive for Life</a>;</p></li>
<li><p><a href="http://www.iucn-medmis.org/?c=About/show">MedMIS</a>; and </p></li>
<li><p><a href="http://www.greenbubbles.eu/?lang=en">Green Bubbles RISE</a>. </p></li>
</ul>
<p>In a backdrop of global change, the scuba diving industry seems to be strong enough to fight to stay alive. But this fight cannot be won until the value and potential of the industry is truly acknowledged. Enhancing the scuba diving industry can have a number of beneficial effects, direct and indirect, for the areas that support it. </p>
<p>This is particularly important for developing countries, where local communities may be not well integrated in the scuba diving system for various reasons. The scuba diving industry is capable of mobilising initiatives, actively engaging in conservation, education and poverty alleviation, managing diving destinations through entrepreneurship, and carrying out scientific research.</p>
<p>Perhaps this potential is due to the passion and dedication of many divers for the underwater environment. This urges them to fight for its survival and protection, and thus for the survival of their business. Whether selfish or not, this is reason alone to value scuba diving as one of the most powerful tools in educating society about the importance of our aquatic world.</p><img src="https://counter.theconversation.com/content/52504/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Serena Lucrezi works at TREES, North-West University (NWU), South Africa. She receives funding from TREES-NWU; the the National Research Foundation; and Green Bubbles RISE. Green Bubbles RISE has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 643712. This article reflects only the author's view. The European Research Agency is not responsible for any use that may be made of the information it contains.</span></em></p>
Africa has a number of excellent scuba diving sites, but these must be maintained sustainably to keep attracting different divers.
Serena Lucrezi, Post-doctoral researcher in Tourism Research in Economic Environs and Society, North-West University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/45769
2015-08-19T22:52:50Z
2015-08-19T22:52:50Z
Diving for treasure to help protect the world’s great reefs
<figure><img src="https://images.theconversation.com/files/92240/original/image-20150818-12433-gsg605.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Diving in Indonesia's Raja Ampat Marine Park to see these clownfish will cost you more than before – but for good reason.</span> <span class="attribution"><span class="source">Boris Bialek/Flickr</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><em>Amid growing demand for seafood, gas and other resources drawn from the world’s oceans, and growing stresses from climate change, we examine some of the challenges and solutions for developing “<a href="https://theconversation.com/marine-science-challenges-for-a-growing-blue-economy-22845">the blue economy</a>” in smarter, more sustainable ways.</em></p>
<p>Diving the warm, crystal clear waters of Indonesia’s Raja Ampat Marine Park is an experience for the lucky few. Its coral reefs attract a huge variety of marine life, including turtles, manta rays and countless species of tropical fish – including the now iconic <a href="https://theconversation.com/can-you-surf-the-east-australian-current-finding-nemo-style-27392">clownfish</a>. </p>
<p>If you’ve gone diving there recently, or are planning a holiday, you may have noticed that the <a href="http://www.stayrajaampat.com/ultimate-raja-ampat-guide/information/raja-ampat-marine-park-entry-permit-tag/">marine park fees</a> have gone up sharply in past 12 months – as they have in many other parts of Indonesia, Malaysia and Thailand. </p>
<p>But you might actually be happy to discover why.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92060/original/image-20150817-5124-175quzu.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"></span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fishywang/8089350851/in/photolist-djQ3bp-wYx2P-djtYdD-djtY1x-djPFcM-djPHcV-djPLEY-djtZsj-djQaZs-dju226-djPJFz-djPJ5m-djQbXg-djPJ1F-djPHuF-djPKie-djQc5n-djtZNu-djtYXt-djtZyC-djPLK6-djtYbS-djtY5q-djtYug-djPMCB-djPN9N-9fzrNo-djPH2B-dju1zF-dju19N-djPGFX-djtZ9s-djPG52-djtYEU-djPKCP-djPG3h-djQ4VC-djQ483-djQ4gN-djtXRB-djtY72-djPMbB-djPLcj-djPMyd-djPF3g-djQccg-djPJHG-djPGsb-djQb3F-djQ52R">Yuxuan Wang/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>The cost of caring for coral reefs</h2>
<p>The dive industry has long been criticised as contributing to declines in coral reef health around the world. Coral reefs globally are under increasing pressure from the cumulative impacts of fishing, shipping, and coastal development, as well as longer-term impacts due to climate change. And unless it’s managed, increased diving and snorkelling tourism can become just another environmental strain. </p>
<p>That’s not in anyone’s interests. Failure to adequately manage activities within reef areas is likely to lead to their degradation, which will make them less attractive to divers and other tourists in the long-term.</p>
<p>But taking better care of our reefs comes at a cost. It requires monitoring and surveillance, as well as ensuring users (such as divers) and beneficiaries (such as local businesses) of the reefs are aware of their impacts and understand how to avoid them.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92059/original/image-20150817-5103-hgs7oo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scuba diving off the Thai coast.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/39891373@N07/4396008774/in/photolist-7GsGfJ-kfP4kw-9Mo17Z-7oX85r-dfHViW-pxFWA7-4Y2Cdx-6sMHrd-BQ3GG-8ZWtFV-6yG7gN-6FN3b1-4t975p-nsLysS-puZp4q-5jRBPX-2AvaVi-6FN6SA-6FHZvR-ktvPUi-7GiCsg-6FHRRr-5x6nua-t67a7-6cWscJ-5jRB7z-6FNoSS-5jVT2L-5jVSyW-3pJihP-cbtV2S-7GMGr7-6FJoHi-5jVThh-6FHPYB-6FN7HL-9eKkPB-4XTma7-4tapEP-6FJ12e-6FJ2LM-6FMZsd-6FNaXA-6FHNYB-6FMYEA-6FHUbX-6FMUL9-6FNbEU-6FHPgP-6FJ5Y6">Ilse Reijs and Jan-Noud Hutten/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Across Indonesia, Malaysia and Thailand, dive tourism directly dependent on the health of coral reefs brings in around <a href="https://research.jcu.edu.au/tropwater/publications/Pascoeetal2014Estimatingthepotentialimpactofentryfeesformarineparks.pdf">US$1.5 billion a year</a> to local communities. Most of this is in remote areas, where alternative sources of income are limited.</p>
<p>Those three countries have set up a number of marine parks to protect their reefs. And about 70% of those parks have long had dive fees in place.</p>
<p>But the fees have typically been very low, while government contributions were also relatively constrained – which is why <a href="http://www.sciencedirect.com/science/article/pii/S0964569106000263">a 2006 study</a> found that only about one in seven marine reserves in south east Asia had adequate financial resources.</p>
<p>That’s where learning from the Australian experience, together with modelling work from an international team of researchers, has helped provide a practical solution.</p>
<h2>How tourists help pay to preserve the Great Barrier Reef</h2>
<p>The Great Barrier Reef Marine Park is one of Australia’s great tourism international drawcards – for divers in particular – injecting an estimated <a href="http://www.environment.gov.au/system/files/resources/a3ef2e3f-37fc-4c6f-ab1b-3b54ffc3f449/files/gbr-economic-contribution.pdf">AUS$5 billion</a> into the economy and generating around 64,000 full-time equivalent jobs. </p>
<p>But right from the early days of establishing the Great Barrier Reef Marine Park, Australia had to grapple with how to pay for crucial conservation work.</p>
<p>That’s why divers and other visitors to the Great Barrier Reef Marine Park each pay an environmental management charge of AU$6 a day. That contributes around 20% of the AU$40 million annual management costs.</p>
<p><a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1467-8489.2011.00548.x/full">Modelling</a> to test what impact this charge has on visitor numbers suggests that it is very small, and the gains in terms of financial resources for management far exceed any potential losses to local businesses – which, after all, also depend on the reef for their continued survival.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92225/original/image-20150818-12383-1xjlq13.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">Smile for the camera – diving the Great Barrier Reef.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/tangledcontrolpads/721614540/in/photolist-26LsS1-6FSQz7-3zZxbQ-EH77z-32QErn-8vUSvi-bvB1y5-8ScCWb-eVhE3G-dAUnsD-bJvMAg-bJvMup-EH4St-EH6KS-bJvMha-8CnRME-p1i9p-eVhJAh-EH53p-eVhKKG-jGPps-5xfjuU-pGfFyj-fBf3NB-3THpvA-9g5ku4-p1p9CV-5xjnm5-65JL5j-98TVRh-biQJKR-aiP9ph-98QN8X-5xf2ZK-5xf7z8-aiPdjQ-2YyGv-9g5kbK-aiLo74-6zuUni-6zuU2e-6zyZM9-8GGCjR-6iXykY-6iTkTH-4rBZxn-4rG2NL-4rG5Rw-4rBWEV-4rBZu6">Brian Costelloe/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Testing a model solution</h2>
<p>But until a few years ago, the idea of charging higher fees was opposed by many tourism and related businesses in south east Asian diving communities, concerned that it might cause tourist numbers and earnings fall.</p>
<p>In 2013, a group of international researchers supported by the <a href="http://www.apn-gcr.org/">Asia-Pacific Network for Global Change Research</a> worked with managers, resort owners and dive operators in Indonesia, Malaysia and Thailand to develop options for improved reef management in the region. </p>
<p>This included modelling what might happen if you increased dive fees to pay for reef conservation. <a href="https://research.jcu.edu.au/tropwater/publications/Pascoeetal2014Estimatingthepotentialimpactofentryfeesformarineparks.pdf">That study</a> predicted that even if the conservation fees were more than doubled, it was unlikely to deter many divers, who care about the places they go diving in.</p>
<p>It also predicted that the revenue raised for reef protection would far exceed the loss in tourism expenditure in local communities, and help ensure that the communities as well as the reefs would survive into the future.</p>
<h2>What higher diving fees are funding</h2>
<p>Since then, as any keen divers reading this might already have seen, user fees in many of their marine parks have been introduced or increased. For example, at the Raja Ampat Marine Park in Indonesia, fees for foreign visitors have doubled in 2015 to 1,000,000 Indonesian Rupiah (about AU$100) for an annual permit.</p>
<p>More modest fee increases (and fee levels) have also been seen in most Thai and Malaysian marine parks this year, with most now charging international visitors between AU$10 and AU$20 a day for access.</p>
<p>So what are you paying for? Among other things, divers are helping by paying more for rangers’ wages and for patrols to keep out illegal fishing, mining and poachers, as well as conservation and reef rehabilitation projects in the parks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92239/original/image-20150818-12454-eisgoq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A turtle emerges from a hidey-hole in a coral off Indonesia’s coast.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/bbialek905/16401330827/in/album-72157648404315244/">Boris Bialek/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>But when you consider how much it costs to go on a diving holiday, being asked to pay the equivalent of a light meal is not too much to ask. Indeed, from the modelling study, most visitors gain substantially much more than this in terms of benefits from diving on these coral reefs, and could potentially contribute greater amounts to protect them for future generations. </p>
<p>By digging a little deeper, divers can do more than just go on holiday: they can contribute to longer-term conservation of some of the most extraordinary places on Earth.</p><img src="https://counter.theconversation.com/content/45769/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sean Pascoe receives funding from the Fisheries Research and Development Corporation and the Asia Pacific Network for Global Change Research. He was part of the international research team who did the 2013 study.</span></em></p><p class="fine-print"><em><span>Natalie Stoeckl receives funding from the (Australian) National Environmental Research Program, the (Australian) National Environmental Science Program, The Australian Marine Mammal Centre and the Australian Marine Conservation Society. She is on the Reef 2050 Plan Independent Expert Panel. This article reflects her personal views, not those of the panel.</span></em></p>
Diving in many parts of Indonesia, Thailand and Malaysia now costs a little more than it used to – but you might be happy to discover why.
Sean Pascoe, Fisheries Economist, Oceans and Atmosphere Flagship, CSIRO
Natalie Stoeckl, Professor, James Cook University
Licensed as Creative Commons – attribution, no derivatives.