Brazilian Researchers Find Coral Reef at Mouth of the Amazon River

04/27/2016 - 10h35

Brazilian researchers have discovered an enormous system of coral reefs in the Atlantic Ocean at the mouth of the Amazon River. The discovery is unprecedented and contradicts the consensus that it would impossible for reefs to exist in murky waters with such high levels of sediment.

Reefs are usually found in crystalline waters, with a lot of light and low concentration of nutrients, such as those in the Caribbean and the Abrolhos Archipelago. The waters of the Amazon are precisely the opposite: dark and rich in organic material collected along the length of the river.

The Amazon is the second-longest river in the world, pouring 209,000m3 of water per second into the ocean.

The research, a partnership between scientists in eleven universities in Brazil and one in the United States, was published this month in the magazine Science Advances. It was coordinated by the professors Carlos Rezende, of the North Fluminense State University, and Fabiano Thompson of the Federal University of Rio de Janeiro.

"While a normal reef is full of fish and seaweed, what we find here are calcareous algae, sponges and chemosynthetic bacteria, which feed on minerals and do not photosynthesize," said Thompson.

Scientists have thought since 1970 that reefs are present in the region, but they could not search the area, which is up to 100 meters underwater. The team led by Thompson and Rezende made three expeditions in the last six years, using a kind of sonar to conduct mapping.

They now intend to study the composition of organisms found on the reef and describe types of sponge which have yet to be catalogued.

"We need to assess the threats to this ecosystem," said Thompson. "Currently, we have American and European companies exploring the area for oil production, which is an enormous risk to the reefs and the biodiversity of the region."

Translated by TOM GATEHOUSE

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