Deep-sea scientists in Uruguay may have discovered over 30 new species among flourishing reefs of cold-water corals.
The researchers came across the deep-sea reefs while exploring the waters off Uruguay using the remotely operated vehicle (ROV) SuBastian during Schmidt Ocean Institute’s 100th ocean research expedition. They were excited to find surprisingly large and healthy ecosystems.
“We always expect to find the unexpected, but the diversity and complexity of what we found exceeded all our expectations,” says the expedition’s chief scientist, Dr. Alvar Carranza of the Universidad de la República and the Centro Universitario Regional del Este.
The reefs they discovered were built by a slow-growing, cold-water stony coral called Desmophyllum pertusum, which is considered vulnerable to extinction globally. One of the largest is located 300 metres deep in the ocean’s twilight (mesopelagic) zone. This enormous reef spanned 0.5 square miles – that’s almost three times the size ofVatican City.
Among the reefs, they recorded hundreds of species that have never been seen off the coast of Uruguay before – including crystal squids, dumbo octopuses and tripod fish – and they also believe they may have discovered over 30 new species of sponges, snails, crustaceans and more.
A possible new species of bamboo coral was documented at a depth of 2,415 metres at the base of the Cabo Polonio submarine canyon. Credit: ROV SuBastian / Schmidt Ocean Institute
As well as the new species, they also came across sharks, groupers, and lots of other species of fish. One astonishing find was a sea snail called an ovulid munching on gorgonian soft coral. In the tropics, it’s not unusual to see this type of snail feeding on gorgonians but it’s so uncommon in colder waters that Carranza compares it to spotting a giraffe in Antarctica.
They also found communities that you wouldn’t expect to see living close to one another: worms called Lamellibrachia victori were growing right next to reef mounds. These worms live on cold seeps where they feed on chemical energy from the seabed (on these seeps, chemicals such as methane spew from the seafloor) while corals snack on tiny food particles floating past in the water.
“We’ve seen glimpses of this relationship in the Gulf of Mexico, but I have not seen a more perfect visual example of the association,” says Dr. Erik Cordes, a deep-sea coral and seep expert at Temple University. “The reefs they discovered are incredible.”
The research team explored the shipwreck of the ROU Uruguay, collecting data on the cannon-class destroyer that now serves as a reef habitat. Credit: ROV SuBastian / Schmidt Ocean Institute
During the expedition, the team also studied a World War II cannon-class destroyer called the Uruguay, which was given to Uruguay by the United States in 1952. It was used by the country in patrols and training exercises for many years until it was scuttled (sank on purpose) in 1995. Since then, it has embedded itself into the marine environment and turned into an artificial reef, providing a home for many ocean animals.
No-one has ever explored this wreck before but the expedition team spent a full day collecting data so they can learn how it has transformed and broken down over time and whether there are any contaminants present that could harm marine life.
These fascinating discoveries will help inform the management of Uruguay’s marine habitats, hopefully preserving these vulnerable ecosystems for future generations.
A deep-sea nudibranch (a type of sea slug) in the Bathydoris genus documented on the seafloor at 3,125 metres on an abyssal plain at the foot and east of the Río de la Plata Canyon off the coast of Uruguay. Credit: ROV SuBastian / Schmidt Ocean InstituteThis deep-sea lizardfish from the family Bathysauridae was observed at 3,125 metres. Credit: ROV SuBastian / Schmidt Ocean InstituteBlackbelly rosefish (Helicolenus dactylopterus) were documented among soft mushroom corals (Heteropolypus sp) at 246 metres. Credit: ROV SuBastian / Schmidt Ocean InstituteA variety of corals, including slow-growing, cold-water stony and soft mushroom corals, were documented at 246 metres deep, during a dive that took place at the head of the Montevideo Canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteAn isopod from the family Antarcturidae perches at the top of a coral branch — as a filter feeder, it must wait for particles to drift within reach to eat. This image was documented at 2,415 metres. Credit: ROV SuBastian / Schmidt Ocean InstituteR/V Falkor (too) pictured in Uruguay. Credit: Alex Ingle / Schmidt Ocean InstituteYellowtail amberjack (Seriola lalandi) swim over Desmophyllum pertusum, a slow-growing, cold-water stony coral, at a depth of 201 metres. This dive took place on the outer edge of the continental platform near the head of the José Ignacio submarine canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteSquid in the genus Gonatus at depth of 1,462 metres. Credit: ROV SuBastian / Schmidt Ocean InstituteAn ovulid sea snail feeds on gorgonian soft coral, an uncommon sight in these cooler waters. Chief Scientist Dr. Alvar Carranza described the observation, made via ROV SuBastian, as akin to finding a giraffe in Antarctica. Credit: ROV SuBastian / Schmidt Ocean InstituteA lithodid crab with barnacles growing on its shell, documented at a depth of 1,779 metres. The dive took place in the middle portion of the Montevideo Canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteThe bright blue-green eye of a monkfish (Lophiidae) documented at 297 metres during an ROV dive at the head of the Montevideo Canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteAn octopus moves around deep-sea corals at 1,612 metres during a dive near the historic HMS Challenger's oceanographic station 320, where the country's first coral samples were collected almost 150 years ago. Credit: ROV SuBastian / Schmidt Ocean InstituteAn octopus, deep-sea sponge and anemones on an outcrop with various corals at 1,619 metres deep. Credit: ROV SuBastian / Schmidt Ocean InstituteScientist Leticia Burone from the Universidad de la República of Uruguay and researchers watch footage of the seafloor streamed live in the Control Room on R/V Falkor (too); images and data are transmitted via the Schmidt Ocean Institute’s Remotely Operated Vehicle (ROV) SuBastian. Credit: Alex Ingle / Schmidt Ocean InstituteA deep-sea catshark (Scyliorhinus haeckelii) documented at 198 metres on the outer edge of the continental shelf, near the head of the La Paloma submarine canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteChief Scientist Alvar Carranza from the Universidad de la República in Uruguay, along with members of the science team, narrates streaming deep-sea footage for audiences watching in Uruguay and around the world. Credit: Alex Ingle / Schmidt Ocean InstituteThe ship was donated by the US to Uruguay in 1952 and sunk in 1995 as a naval exercise. Credit: ROV SuBastian / Schmidt Ocean InstituteA deep-sea skate documented at 2,439 metres at the base of the Cabo Polonio submarine canyon. Credit: ROV SuBastian / Schmidt Ocean InstituteBrittle stars and coral at a depth of 278 metres. Credit: ROV SuBastian / Schmidt Ocean Institute
Top image: deep-sea octopus in Montevideo Canyon, Uruguay
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Melissa Hobson, doing business as The Ocean Writer Ltd., is a marine science and conservation writer based in Hastings. She has written about the ocean for outlets including BBC Wildlife, BBC Countryfile, National Geographic, New Scientist and the Guardian. Visit Melissa’s website at melissahobson.co.uk or follow her on LinkedIn.
