Scientists on Friday have discovered a vibrant coral reef at the mouth of the Amazon River that stretches approximately 3,700 square miles. The finding conflicts with usual reef distribution system and according to scientists coral isn’t supposed to be able to grow there.
“We found a reef where the textbooks said there shouldn’t be one,” says study co-author Fabiano Thompson of the Federal University of Rio de Janeiro.
In 2012, Patricia Yager, oceanographer and a professor at University of Georgia, was steaming in the research ship Atlantis toward the continental shelf. She was skeptical about finding a coral reef at the mouth of the Amazon, because she knows it is thick with more runoff and sediment than any river in the world. She had heard diving in this area was like swimming through goopy, dark stew.
“I thought that everything would have just been smothered by settling mud from the river’s plume,” she says.
But, her colleague Rodrigo Moura uncovered one of the most surprising finds in modern sea research when he dredged small areas near the shelf. A vast deepwater reef system approximately 120 kilometers offshore, below the thick, dirty plume of Amazon came to light.
“We brought up the most amazing animals I’ve ever seen on an expedition like this,” says Yager.
In the Amazon plume, freshwater from the river combines with the salty water of Atlantic. It also has a large influence on the salinity, pH, light penetration and sedimentation of the tropical North Atlantic Ocean.
Corals are tiny soft-bodied animals, related to anemones and jellyfish. These tiny creatures band together to build their protective, rock-like reefs by pulling calcium and carbonate out of the ocean water.
Thompson says that the scientists have really only begun to understand what they’ve found. He adds that the scientists haven’t seen anything from the other 90%.
“We’ve only surveyed 900 kilometers,” Thompson says.
“We need to go back there 20 more times.”