Twenty-Eight New Species Found in Argentina’s Deep Sea, Including the World’s Largest Cold-Water Coral Reef
Discarded fishing gear, such as this net filmed at 619 meters, is called ghost gear; ghost gear is a hazard for wildlife and navigation.
CREDIT: ROV SuBastian / Schmidt Ocean Institute (L-R) Biology student Lucía Alzaga (University of Buenos Aires UBA), and geology PhD candidate Luana Yazmin Acosta (CONICET-UBA), and undergrad student Gino Zamborlini (University of Buenos Aires UBA) examine a push core containing sediment samples on the aft deck of R/V Falkor (too). CREDIT: Misha Vallejo Prut / Schmidt Ocean Institute(L-R) Chief Scientist Dr. María Emilia Bravo ( IGeBA – CONICET – UBA) and Biology Student Lisandro Scarrone (University of Buenos Aires, UBA) work on a biological sample in the main lab on board R/V Falkor (too).
CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteDeep-sea jellyfish prefer the darker depths, where their red hue helps keep them hidden (red is harder to see in the deep) and helps disguise bioluminescent prey in their bellies. ROV pilots filmed this Periphylla at 2,070 meters while exploring the Colorado-Rawson submarine canyon. CREDIT: ROV SuBastian / Schmidt Ocean Institute A squat lobster takes shelter in a coral mound at 1,070 meters depth along the Argentine Continental Slope. Coral mounds are accumulations of calcified coral structures that build up over thousands of years, and they provide safe harbor, access to food, and spawning grounds for many deep-sea animals. CREDIT: ROV SuBastian / Schmidt Ocean Institute Scientists observed a sea spider (Colossendeis sp.) eating a sea cucumber (Scotoplanes sp.) during an ROV dive at 884 meters in the Colorado-Rawson submarine canyon. These marine arthropods of the class Pycnogonida use a long mouthpart, called a proboscis, which they insert into soft animals in order to suck out their internal fluids. CREDIT: ROV SuBastian / Schmidt Ocean Institute ROV pilots filmed the remains of a deceased whale that had dropped to the seafloor, called a whalefall, at about 3,890 meters deep during a dive on the Salado-Colorado Kilometer scarp in the Argentine Basin. Whale falls offer up thousands of years of nourishment to a place accustomed to scarcity. From large scavengers to invisible microbes and bone-eating Osedax worms, there is something for all creatures that happen upon a whale fall. Once organic matter has been consumed, the succession stage is named reef phase and it is mostly used by the animals as a hard-substrate, as in the case of this whale carcass which presumably has spent decades in the seafloor. CREDIT: ROV SuBastian / Schmidt Ocean Institute Expedition Chief Scientist Dr. María Emilia Bravo, a researcher at IGeBA – CONICET – UBA, directs an ROV SuBastian dive from the mission control room on the Research Vessel Falkor (too). CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteDuring one ROV SuBastian dive, the science team observed this seafloor feature with “horseshoe mound” geomorphology at 614 meters, where rocky outcrops formed by methane seepage alternate with soft sediments and clam beds of Archivesica sp. and Calyptogena sp. at depths. In Argentine waters, the biodiversity and environmental context of these chemosynthetic ecosystems remain poorly understood. CREDIT: ROV SuBastian / Schmidt Ocean Institute Deep-sea corals are slow-growing and long-lived. They are often classified as Vulnerable Marine Ecosystems, or VMEs, because they support high biodiversity and are threatened by human activities such as bottom trawling. In this image, red and pink basket stars (Gorgonocephalus chilensis) perch on top of white hard corals (primarily Bathelia candida and Solenosmilia sp.). The sea stars and corals actively feed by capturing particles and small organisms from the water. CREDIT: ROV SuBastian / Schmidt Ocean Institute Pilots recover a VHS tape using ROV SuBastian’s manipulator arm at about 2,640 meters. The science team found the relic while exploring a wall of the Colorado-Rawson submarine canyon offshore of Argentina. The scientists were amazed by the good state of preservation of the plastic, and they will investigate if these plastics are being consumed by the associated fauna. CREDIT: ROV SuBastian / Schmidt Ocean Institute ROV pilots zoomed in on this basket star (Gorgonochephalus chilensis), a suborder of brittle stars, at 1,050 meters depth offshore of Argentina. CREDIT: ROV SuBastian / Schmidt Ocean Institute ROV pilots filmed this tripod fish (belonging to the Family Ipnopidae) at 2,700 meters on an escarpment in the Argentine Basin. CREDIT: ROV SuBastian / Schmidt Ocean Institute Paragorgia arborea, commonly known as bubblegum coral, grows at a rate of approximately one centimeter per year. As these colonies exceed 1 m in height, it indicates that they are likely hundreds of years old. Filmed by ROV pilots at 500 m depth on the southern flank of the Malvinas Trench, the corals formed an extensive coral garden. CREDIT: ROV SuBastian / Schmidt Ocean Institute Rocky surfaces offer a hard surface for sessile, or immobile, animals like corals and sponges to cling to. ROV pilots filmed this seafloor community at 931 meters. CREDIT: ROV SuBastian / Schmidt Ocean Institute Juvenile fish (Centrolophus sp.) swim around the bell of a Stygiomedusa gigantea, commonly known as the giant phantom jelly, which ROV pilots filmed at 250 meters. Their bell can grow up to 1 m (3.3 ft) in diameter, and their four arms can reach up to 10 m (33 ft) long. They do not have any stinging tentacles, but use their arms to catch prey, including plankton and small fish. CREDIT: ROV SuBastian / Schmidt Ocean Institute Research Vessel Falkor (too) with its ROV SuBastian deployed in the South Atlantic Ocean during the “Life In Extremes – Cold Seeps Of Argentina” expedition. CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteScientists observed this snailfish swimming near a nephteid soft coral which is growing on top of a coral mound located at 1,075 meters deep. Coral mounds are accumulations of calcified coral structures that build up over thousands of years, and they offer essential habitat for many other deep-sea animals. CREDIT: ROV SuBastian / Schmidt Ocean InstituteThese reef-forming corals (Bathelia candida and Solenosmilia sp.) cover hundreds of meters of a submarine canyon wall on the Patagonian Continental Margin, at depths of approximately 1,044 m. They serve as biodiversity refugia in the deep sea and are highly sensitive to environmental impacts from human activities. CREDIT: ROV SuBastian / Schmidt Ocean InstituteStudent Siara Mitchell (Scripps Institution of Oceanography) makes photographs of a biological sample in the main lab on R/V Falkor (too). CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteScientists observed this squat lobster in a bed of chemosynthetic clam shells of the genus Archivesica sp. and Calyptogena sp. at 619 meters while exploring chemosynthetic habitat patches associated with a methane-derived carbonate mound. In Argentine waters, the biodiversity and environmental context of these chemosynthetic ecosystems remain poorly understood. CREDIT: ROV SuBastian / Schmidt Ocean Institute(L-R) Fabrizio Scarabino (Universidad de la República – Udelar), Dr. Juliana Giménez (CONICET-UBA), and Dr. Leonel Pacheco (CONICET) look at biological samples in the main lab on board R/V Falkor (too). CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteR/V Falkor (too) crew recover ROV SuBastian following operations in the South Atlantic Ocean. Each ROV dive produces about a billion bytes of video data, along with sensor data and samples for further study. CREDIT: Misha Vallejo Prut / Schmidt Ocean InstituteROV pilots filmed this glass squid at 1,725 meters while exploring the Colorado-Rawson submarine canyon off the coast of Argentina. CREDIT: ROV SuBastian / Schmidt Ocean Institute With their three-dimensional structure, deep-sea corals provide shelter, nursery grounds, spawning areas, and feeding habitats for many other species, such as this charismatic octopus. ROV pilots collected this footage at 1,010 meters along the Argentine Continental Slope. CREDIT: ROV SuBastian / Schmidt Ocean Institute
The Argentine deep sea just shattered expectations. An expedition led by Dr. María Emilia Bravo of the University of Buenos Aires, aboard the Schmidt Ocean Institute’s research vessel Falkor (too), has documented 28 suspected new species along the country’s continental shelf, from Buenos Aires in the north to waters offshore from Tierra del Fuego in the south. The findings, announced in early February 2026, include sea snails, urchins, anemones, worms, and corals, many of them living within a cold-water reef so vast it rivals the footprint of Vatican City.
That reef, formed by the stony coral Bathelia candida, spans at least 0.4 square kilometers and represents the largest known colony of its kind anywhere in the global ocean. The team also found Bathelia growing roughly 600 kilometers further south than its previously documented range, extending to 43.5° latitude. Classified as a Vulnerable Marine Ecosystem indicator species, Bathelia candida provides three-dimensional structure that shelters fish, crustaceans, and octopuses. Its slow growth rate means that the reef likely took centuries, perhaps millennia, to reach its current size.
The expedition’s original mission was to locate cold seeps: deep-sea environments where methane and other chemicals released from the seafloor fuel microbial communities, which in turn sustain clams, mussels, and tube worms. Researchers found one active seep covering roughly one square kilometer, twice the size of the Bathelia reef itself. But the surrounding biodiversity caught the team off guard.
“We were not expecting to see this level of biodiversity in the Argentine deep sea, and are so excited to see it teeming with life,” Bravo said in a statement from the Schmidt Ocean Institute. “We opened a window into our country’s biodiversity only to find there are so many more windows left to be opened.”
Among the expedition’s more cinematic discoveries: a rare giant phantom jellyfish (Stygiomedusa gigantea), filmed at 250 meters depth by the institute’s remotely operated vehicle, ROV SuBastian. The species can grow a bell up to one meter in diameter and trail four ribbon-like arms stretching as long as 10 meters. It catches prey not with stinging tentacles, which it lacks entirely, but by enveloping small fish and plankton in those arms.
The team also documented Argentina’s first known deep-water whale fall at approximately 3,890 meters below the surface. Whale falls occur when the carcass of a deceased whale sinks to the seafloor, creating a temporary ecosystem that can sustain scavengers, bone-eating Osedax worms, microbes, and eventually reef-building organisms for decades or longer. Footage showed sharks, crabs, and other marine life congregating around the remains.
Not everything the expedition found belonged to the natural world. ROV surveys also recorded garbage bags, fishing nets, and a “near-pristine” VHS tape on the deep seafloor, a stark reminder of how far plastic pollution has traveled.
“With every expedition to the deep sea, we find the ocean is full of life, as much as we see on land, and perhaps more because the ocean contains 98 percent of the living space on this planet,” said Schmidt Ocean Institute executive director Jyotika Virmani.
More than 80% of the world’s ocean floor remains unmapped and unexplored. Expeditions like this one underscore a persistent tension in ocean governance: the ecosystems most vulnerable to deep-sea mining, bottom trawling, and climate disruption are often the ones we understand the least. Argentina’s deep-sea biodiversity, it turns out, was hiding in plain sight. The question now is whether the political will exists to protect it before industrial pressures catch up.
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Schmidt Ocean Institute was established in 2009 by Eric and Wendy Schmidt to catalyze the discoveries needed to understand our ocean, sustain life, and ensure the health of our planet through the pursuit of impactful scientific research and intelligent observation, technological advancement, open sharing of information, and public engagement, all at the highest levels of international excellence. For more information, visit www.schmidtocean.org.
