Largest known deep sea coral reef mapped off US Atlantic coast

Largest known deep-sea coral reef mapped off US Atlantic coast – The Guardian

Scientists have mapped the largest known deep-sea coral reef, which stretches hundreds of kilometers off the Atlantic coast of the United States.

While researchers have known there were corals off the Atlantic since the 1960s, the size of the reef remained a mystery until new underwater mapping technologies made it possible to create 3D images of the seafloor.

The largest deep-sea coral reef known to date “was right under our noses, waiting to be discovered,” said Derek Sowers, an oceanographer with the nonprofit Ocean Exploration Trust.

Sowers and other scientists, including several from the federal National Oceanic and Atmospheric Administration, recently published maps of the reef in the journal Geomatics.

The reef stretches about 310 miles (500 km) from Florida to South Carolina, reaching 68 miles (110 km) wide in some places. The total area is almost three times the size of Yellowstone National Park.

“It's eye-opening — the scale is breathtaking,” said Stuart Sandin, a marine biologist at the Scripps Institution of Oceanography who was not involved in the study.

The reef was found at depths between 200 and 1,000 meters, where sunlight does not penetrate. Unlike tropical coral reefs, where photosynthesis is important for growth, corals this far down must filter food particles from the water to generate energy.

Deep coral reefs provide habitat for sharks, swordfish, starfish, octopuses, shrimp and many other fish species, the scientists said.

Tropical reefs are better known to scientists, snorkelers and divers because they are more accessible. The world's largest tropical coral reef system, the Great Barrier Reef in Australia, stretches for approximately 1,430 miles (2,300 km).

Sowers said it is possible that larger deep-sea reefs will be discovered in the future because only about 25% of the world's seafloor has been mapped at high resolution.

Maps of the seabed are created using high-resolution sonar devices carried on ships. Deep-sea reefs cover a larger portion of the ocean floor than tropical reefs.

Both types of habitats are vulnerable to climate change and disruption from oil and gas drilling, said Erik Cordes, a marine biologist at Temple University and co-author of the new study.

The Associated Press contributed reporting