Scientist at Work: I’ve Dived in Hundreds of Underwater Caves Hunting for New Forms of Life
By Tom Iliffe
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.
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.
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.
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.
The remipede Cryptocorynetes elmorei 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.Tom Iliffe, CC BY-ND
There's no other way to access these unexplored areas than to strap on your scuba tanks and jump in.
Scientific Research as Extreme Sport
The list of what can go wrong in a cave dive could fill your event planner.
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.
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.
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. Gil Nolan, CC BY-ND
To put it mildly, underwater caves can be very hostile and unforgiving. One such cave—the Devil's system in north-central Florida—has claimed at least 14 lives in the last 30 years, and there are other examples elsewhere in Florida and in Mexico.
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.
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.
Tom Iliffe diving with his Megalodon closed-circuit rebreather in a lava tube cave in the Canary Islands. Jill Heinerth, CC BY-ND
Death-Defying Dives Pay Off in Discoveries
It's not just new species we are discovering, but also higher groups of animals including a new class, orders, families and genera, previously unknown from any other habitat on the planet. Some of our newfound animals have close relatives living in similar caves on opposite margins of the Atlantic Ocean or even the far side of the Earth (such as the Bahamas versus Western Australia).
While most of these caves are formed in limestone, they can also include seawater-flooded lava tubes created by volcanic eruptions. Amazingly, similar types of animals inhabit both.
In the deserts of West Texas, our team discovered and explored the deepest underwater cave in the U.S., reaching a depth of 462 feet.
The graduate students in my lab work on a diverse group of questions. They're uncovering the nature of chemosynthetic processes in caves—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.
Other students are examining records of Ice Age sea level history 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 110 million years ago as tectonic plate movements initiated the opening of the Atlantic, as well as determining how environmental and ecological factors affect the abundance and diversity of animals in saltwater caves.
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 failed to take cave species into account.
The remipede Godzillius robustus from Abaco, Bahamas. Note the darker shaded venom-injecting fangs on the first pair of appendages. Tom Iliffe, CC BY-ND
Some discoveries can be completely unanticipated. For example, when we sequenced DNA from a variety of arthropods, including crustaceans and insects, the data strongly support a sister group relationship 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.
The author on a cave dive. Jill Heinerth, CC BY-ND
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.
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.
Reposted with permission from our media associate The Conversation.
By Dana M Bergstrom, Euan Ritchie, Lesley Hughes and Michael Depledge
In 1992, 1,700 scientists warned that human beings and the natural world were "on a collision course." Seventeen years later, scientists described planetary boundaries within which humans and other life could have a "safe space to operate." These are environmental thresholds, such as the amount of carbon dioxide in the atmosphere and changes in land use.
The Good and Bad News<p><span>Ecosystems consist of living and non-living components, and their interactions. They work like a super-complex engine: when some components are removed or stop working, knock-on consequences can lead to system failure.</span></p><p>Our study is based on measured data and observations, not modeling or predictions for the future. Encouragingly, not all ecosystems we examined have collapsed across their entire range. We still have, for instance, some intact reefs on the Great Barrier Reef, especially in deeper waters. And northern Australia has some of the most intact and least-modified stretches of savanna woodlands on Earth.</p><p><span>Still, collapses are happening, including in regions critical for growing food. This includes the </span><a href="https://www.mdba.gov.au/importance-murray-darling-basin/where-basin" target="_blank" rel="noopener noreferrer">Murray-Darling Basin</a><span>, which covers around 14% of Australia's landmass. Its rivers and other freshwater systems support more than </span><a href="https://www.abs.gov.au/ausstats/[email protected]/latestproducts/94F2007584736094CA2574A50014B1B6?opendocument" target="_blank" rel="noopener noreferrer">30% of Australia's food</a><span> production.</span></p><p><span></span><span>The effects of floods, fires, heatwaves and storms do not stop at farm gates; they're felt equally in agricultural areas and natural ecosystems. We shouldn't forget how towns ran out of </span><a href="https://www.mdba.gov.au/issues-murray-darling-basin/drought#effects" target="_blank" rel="noopener noreferrer">drinking water</a><span> during the recent drought.</span></p><p><span></span><span>Drinking water is also at risk when ecosystems collapse in our water catchments. In Victoria, for example, the degradation of giant </span><a href="https://theconversation.com/logging-must-stop-in-melbournes-biggest-water-supply-catchment-106922" target="_blank" rel="noopener noreferrer">Mountain Ash forests</a><span> greatly reduces the amount of water flowing through the Thompson catchment, threatening nearly five million people's drinking water in Melbourne.</span></p><p>This is a dire <em data-redactor-tag="em">wake-up</em> call — not just a <em data-redactor-tag="em">warning</em>. Put bluntly, current changes across the continent, and their potential outcomes, pose an existential threat to our survival, and other life we share environments with.</p><p><span>In investigating patterns of collapse, we found most ecosystems experience multiple, concurrent pressures from both global climate change and regional human impacts (such as land clearing). Pressures are often </span><a href="https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2664.13427" target="_blank" rel="noopener noreferrer">additive and extreme</a><span>.</span></p><p>Take the last 11 years in Western Australia as an example.</p><p>In the summer of 2010 and 2011, a <a href="https://theconversation.com/marine-heatwaves-are-getting-hotter-lasting-longer-and-doing-more-damage-95637" target="_blank" rel="noopener noreferrer">heatwave</a> spanning more than 300,000 square kilometers ravaged both marine and land ecosystems. The extreme heat devastated forests and woodlands, kelp forests, seagrass meadows and coral reefs. This catastrophe was followed by two cyclones.</p><p>A record-breaking, marine heatwave in late 2019 dealt a further blow. And another marine heatwave is predicted for <a href="https://www.theguardian.com/environment/2020/dec/24/wa-coastline-facing-marine-heatwave-in-early-2021-csiro-predicts" target="_blank" rel="noopener noreferrer">this April</a>.</p>
What to Do About It?<p><span>Our brains trust comprises 38 experts from 21 universities, CSIRO and the federal Department of Agriculture Water and Environment. Beyond quantifying and reporting more doom and gloom, we asked the question: what can be done?</span></p><p>We devised a simple but tractable scheme called the 3As:</p><ul><li>Awareness of what is important</li><li>Anticipation of what is coming down the line</li><li>Action to stop the pressures or deal with impacts.</li></ul><p>In our paper, we identify positive actions to help protect or restore ecosystems. Many are already happening. In some cases, ecosystems might be better left to recover by themselves, such as coral after a cyclone.</p><p>In other cases, active human intervention will be required – for example, placing artificial nesting boxes for Carnaby's black cockatoos in areas where old trees have been <a href="https://www.environment.gov.au/biodiversity/threatened/publications/factsheet-carnabys-black-cockatoo-calyptorhynchus-latirostris" target="_blank" rel="noopener noreferrer">removed</a>.</p><p><span>"Future-ready" actions are also vital. This includes reinstating </span><a href="https://www.abc.net.au/gardening/factsheets/a-burning-question-fire/12395700" target="_blank" rel="noopener noreferrer">cultural burning practices</a><span>, which have </span><a href="https://theconversation.com/australia-you-have-unfinished-business-its-time-to-let-our-fire-people-care-for-this-land-135196" target="_blank" rel="noopener noreferrer">multiple values and benefits for Aboriginal communities</a><span> and can help minimize the risk and strength of bushfires.</span></p><p>It might also include replanting banks along the Murray River with species better suited to <a href="https://www.abc.net.au/gardening/factsheets/my-garden-path---matt-hansen/12322978" target="_blank" rel="noopener noreferrer">warmer conditions</a>.</p><p>Some actions may be small and localized, but have substantial positive benefits.</p><p>For example, billions of migrating Bogong moths, the main summer food for critically endangered mountain pygmy possums, have not arrived in their typical numbers in Australian alpine regions in recent years. This was further exacerbated by the <a href="https://theconversation.com/six-million-hectares-of-threatened-species-habitat-up-in-smoke-129438" target="_blank" rel="noopener noreferrer">2019-20</a> fires. Brilliantly, <a href="https://www.zoo.org.au/" target="_blank" rel="noopener noreferrer">Zoos Victoria</a> anticipated this pressure and developed supplementary food — <a href="https://theconversation.com/looks-like-an-anzac-biscuit-tastes-like-a-protein-bar-bogong-bikkies-help-mountain-pygmy-possums-after-fire-131045" target="_blank" rel="noopener noreferrer">Bogong bikkies</a>.</p><p><span>Other more challenging, global or large-scale actions must address the </span><a href="https://www.youtube.com/watch?v=iICpI9H0GkU&t=34s" target="_blank" rel="noopener noreferrer">root cause of environmental threats</a><span>, such as </span><a href="https://www.nature.com/articles/s41559-018-0504-8" target="_blank" rel="noopener noreferrer">human population growth and per-capita consumption</a><span> of environmental resources.</span><br></p><p>We must rapidly reduce greenhouse gas emissions to net-zero, remove or suppress invasive species such as <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/mam.12080" target="_blank" rel="noopener noreferrer">feral cats</a> and <a href="https://theconversation.com/the-buffel-kerfuffle-how-one-species-quietly-destroys-native-wildlife-and-cultural-sites-in-arid-australia-149456" target="_blank" rel="noopener noreferrer">buffel grass</a>, and stop widespread <a href="https://theconversation.com/to-reduce-fire-risk-and-meet-climate-targets-over-300-scientists-call-for-stronger-land-clearing-laws-113172" target="_blank" rel="noopener noreferrer">land clearing</a> and other forms of habitat destruction.</p>
Our Lives Depend On It<p>The multiple ecosystem collapses we have documented in Australia are a harbinger for <a href="https://www.iucn.org/news/protected-areas/202102/natures-future-our-future-world-speaks" target="_blank">environments globally</a>.</p><p>The simplicity of the 3As is to show people <em>can</em> do something positive, either at the local level of a landcare group, or at the level of government departments and conservation agencies.</p><p>Our lives and those of our <a href="https://theconversation.com/children-are-our-future-and-the-planets-heres-how-you-can-teach-them-to-take-care-of-it-113759" target="_blank">children</a>, as well as our <a href="https://theconversation.com/taking-care-of-business-the-private-sector-is-waking-up-to-natures-value-153786" target="_blank" rel="noopener noreferrer">economies</a>, societies and <a href="https://theconversation.com/to-address-the-ecological-crisis-aboriginal-peoples-must-be-restored-as-custodians-of-country-108594" target="_blank" rel="noopener noreferrer">cultures</a>, depend on it.</p><p>We simply cannot afford any further delay.</p><p><em><a rel="noopener noreferrer" href="https://theconversation.com/profiles/dana-m-bergstrom-1008495" target="_blank" style="">Dana M Bergstrom</a> is a principal research scientist at the University of Wollongong. <a rel="noopener noreferrer" href="https://theconversation.com/profiles/euan-ritchie-735" target="_blank" style="">Euan Ritchie</a> is a professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences at Deakin University. <a rel="noopener noreferrer" href="https://theconversation.com/profiles/lesley-hughes-5823" target="_blank">Lesley Hughes</a> is a professor at the Department of Biological Sciences at Macquarie University. <a rel="noopener noreferrer" href="https://theconversation.com/profiles/michael-depledge-114659" target="_blank">Michael Depledge</a> is a professor and chair, Environment and Human Health, at the University of Exeter. </em></p><p><em>Disclosure statements: Dana Bergstrom works for the Australian Antarctic Division and is a Visiting Fellow at the University of Wollongong. Her research including fieldwork on Macquarie Island and in Antarctica was supported by the Australian Antarctic Division.</em></p><p><em>Euan Ritchie receives funding from the Australian Research Council, The Australia and Pacific Science Foundation, Australian Geographic, Parks Victoria, Department of Environment, Land, Water and Planning, and the Bushfire and Natural Hazards CRC. Euan Ritchie is a Director (Media Working Group) of the Ecological Society of Australia, and a member of the Australian Mammal Society.</em></p><p><em>Lesley Hughes receives funding from the Australian Research Council. She is a Councillor with the Climate Council of Australia, a member of the Wentworth Group of Concerned Scientists and a Director of WWF-Australia.</em></p><p><em>Michael Depledge 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.</em></p><p><em>Reposted with permission from <a href="https://theconversation.com/existential-threat-to-our-survival-see-the-19-australian-ecosystems-already-collapsing-154077" target="_blank" style="">The Conversation</a>. </em></p>
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