Amazon River new reef system

Scientists have just discovered a massive, 9,500 square-kilometer reef system at the mouth of the Amazon river. And it’s home to some truly bizarre life forms.

When we hear “reef,” we typically think colorful corals and crystal-clear tropical waters. Which is probably why nobody ever bothered to look for one at the outflow of the world’s largest river. Discharging up to 300,000 cubic meters of sediment-loaded water every second, the Amazon river generates a thick, smog-like plume that darkens the surrounding seafloor, depressing light and oxygen levels. So you can imagine the surprise of the scientists who discovered a large reef system—built mainly of sponges and algae—sitting right beneath it.

“More of these sorts of non-coral reefs have been discovered in recent years,” Fabiano Thompson, an oceanographer at the University of Brazil, told Gizmodo. “But we are not aware of this exact type of reef in other places. A special system has been formed here.”

The reef appears to be thriving below the freshwater “plume”, or outflow, of the Amazon. Compared to many other reefs, the scientists say in a paper in Science Advances on Friday, it is is relatively “impoverished”. Nevertheless, they found over 60 species of sponges, 73 species of fish, spiny lobsters, stars and much other reef life.

As reported by the Guardian, the reef, no sooner found, is said to be in grave danger. According to the paper, the Brazilian government has sold 80 blocks for oil exploration and drilling at the mouth of the Amazon and 20 of these are already producing oil – some, it is thought, right on top of the reef.

“These [exploration] blocks will soon be producing oil in close proximity to the reefs, but the environmental baseline compiled by the companies and the Brazilian government is … largely based on sparse museum specimens. Such large-scale industrial activities present a major environmental challenge,” said the study’s authors.

The Amazon is the world’s greatest river, collecting water from an area over 7m sq km.