Standing in front of a wall-mounted screen in a NOAA operations support center, watching a remotely operated camera glide through complete darkness hundreds of meters below the ocean’s surface, and realizing that you’re looking at a habitat that has existed for centuries without anyone ever seeing it, is a subtly unsettling experience. For years, NOAA’s deep-sea coral researchers have had to deal with this reality: a vast, mostly invisible world that keeps coming to light in unexpected ways.
It’s hard to understand the numbers by themselves. In just two years, from 2018 to 2019, NOAA and its research partners identified the largest deep-sea coral reef system ever found along the U.S. Southeast coast, mapped about 55,000 square miles of seafloor that had never been surveyed in meaningful resolution, and described 21 previously unknown coral species.
| Category | Details |
|---|---|
| Organization | National Oceanic and Atmospheric Administration (NOAA) |
| Program Name | Deep Sea Coral Research and Technology Program |
| Founded | NOAA established 1970; Deep Sea Coral Program authorized 2000 |
| Headquarters | Silver Spring, Maryland, USA |
| Primary Research Vessel | NOAA Ship Okeanos Explorer |
| New Species Described (2018–2019) | 21 new deep-sea coral species |
| Seafloor Mapped | 55,000 square miles of previously poorly understood seafloor |
| Notable Discovery | Most expansive deep-sea coral reef area known off the U.S. Southeast coast |
| Coral Lifespan | Up to 100 years (Desmophyllum cristagalli) |
| Annual Growth Rate | Approximately 1 millimeter per year |
| Key Management Bodies Informed | Pacific, New England, and Gulf of Mexico Fishery Management Councils |
| Report Published | Report to Congress, April 2021 |
In particular, that final point merits some attention. An entire reef system of that size was sitting there, unexplored, despite the United States having one of the world’s most comprehensive ocean monitoring programs for decades. It’s possible that we’ve been measuring the ocean in the same way that someone measures a house by simply going through the hallways.
The fact that deep-sea corals survive at all is what makes them truly unique and scientifically indispensable. Deep-sea corals do not receive sunlight, in contrast to the corals that most people picture when they think of the Great Barrier Reef. The metabolic heavy lifting is not carried out by photosynthetic algae that reside within them.
Rather, they live on the slow, continuous drift of dead microscopic organisms that fall from the surface, which scientists sometimes refer to as marine snow. Only a small portion of that material is left by the time it reaches the deep ocean floor. And species like Desmophyllum cristagalli, which grow only a millimeter annually, are able to survive for up to a century from that limited supply. That is patience on a level that is difficult for the human mind to fully comprehend, not just survival.
These corals are extremely valuable as historical records because of their slow growth. As they develop, their skeletons serve as long-term environmental journals, recording chemical signatures from the surrounding water. By reading them, scientists can gain a thorough understanding of ocean chemistry, temperature, and circulation patterns spanning decades or more. It’s the type of data that can’t be created after the fact, and once a coral colony is destroyed by trawling or sediment disturbance, it can’t be recovered.
It seems that American fisheries management has been gradually but more urgently coming to terms with this reality. In recent years, NOAA’s coral data has been used by the Pacific, New England, and Gulf of Mexico Fishery Management Councils to develop new fishing regulations that selectively reopen less vulnerable zones while introducing protections for large seafloor areas. It’s still unclear if those protections are progressing fast enough to be significant. In ways that don’t wait for regulatory calendars, the health of the ocean has been declining.
In the end, NOAA’s deep-sea coral research is telling us more than just that there are more species than previously thought. It indicates that there are significant gaps in our mental model of the ocean, which is based on surface surveys, satellite imagery, and a few decades of selective sampling. Most of the planet’s surface is covered by the deep sea. The majority of it is still not mapped at a useful resolution. A version of Earth’s history that cannot be replicated in a lab is being recorded by ancient coral colonies that are growing one millimeter at a time somewhere in that darkness. It’s difficult not to feel like we’re just starting to realize how much we stand to lose.
