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By Tyne Eckmyn, Publishing Associate: Researcher and Writer at Save the Water™ | April 02, 2026
Edited by April Day, Publishing Associate Consultant at Save the Water™
Approximately 66% of the Earth's surface is covered by deep oceans. Deep oceans are oceans over 200m deep. In deep oceans, humans have only ever visually seen less than 0.001%. That is an area about the size of Long Island. Thanks to a recent deep-sea research mission off the coast of Argentina, this number just got a little bit bigger. As a result, our understanding of biodiversity and deep coral reefs on this planet got a little bit better.
“[Deep]-water coral reefs [are estimated] to cover about twice as much area as shallow water coral reefs (such as the Great Barrier Reef)”, according to Erik Cordes. He is a deep-sea expert at Temple University in Philadelphia.
Deep ocean reef’s depth makes them hard to access. Humans need this information to explore unique and remote ecosystems. Then, humans can establish baselines to understand future human impacts.
To do this, researchers at Temple University collaborated with the University of Buenos Aires and the Argentine Museum of Natural Sciences. The G20 Coral Research and Development Accelerator Platform funded the collaboration. These researchers went on a deep-sea voyage along the coast of Argentina, equipped with a state-of-the-art underwater robot: the ROV SubBastian.
While sailing along the entire length of the Argentine continental shelf, the research team found multiple reef complexes. The most notable reef was a 0.4 square kilometre complex of the rare deep ocean reef species, Bathelia candida. This represents the largest Bathelia candida reef yet discovered. This finding expands its known range by 600 km south.
In addition, the team observed the following:
A whale skeleton on the seafloor at almost 4000 meters below sea level
A species of giant jellyfish that can grow as large as a school bus
28 suspected new species, such as worms, sea snails, and corals
The team also aimed to understand and to develop techniques for deep ocean reef restoration. While techniques for shallow water coral reef restoration and other marine ecosystems have been widely developed, those for deep ocean restoration have not.
Deep ocean ecosystems face several threats, including:
plastic waste, which was observed by the research team.
Bottom trawling, a fishing practice in which large weighted nets are dragged along the seafloor
To help during the voyage, the research team made and deployed artificial coral skeletons. The team made these artificial coral habitats from crushed coral and cement, which simulate natural corals. Reefs can take thousands of years to form naturally. As a result, artificial coral skeletons can help ecosystems to develop faster, by standing in for the slower, natural processes.
Save the Water™ is a 501 (c)(3) non-profit organization with a mission to conduct research to identify and remove harmful contaminants in water and to raise public awareness about water contamination and its health impacts.
