Scientists discovered a 1,000-km-long coral reef at the mouth of the Amazon

Whoa. Just whoa.

An international team of researchers has discovered a 1,000-km (600-mile) long coral reef sitting at the murky, muddy mouth of the Amazon river.

The incredible discovery proves that no matter how well we think we've mapped the surface of our planet, there are still secrets left for us to discover. In this case, a huge, flourishing sponge and coral reef that appears to stretch from the southern tip of French Guiana all the way to the state of Maranhão in Brazil. 

The announcement also comes at a time when we're running incredibly low on hope for coral reefs everywhere - just this week scientists admitted that 93 percent of the Great Barrier Reef has now been bleached, and large portions might not recover. So the discovery of a new reef is welcome news. But how the hell did it go so long without anyone spotting it?

The reef was able to remain hidden so well because the mouth of the Amazon is, to be frank, a little bit of a mess. Out of all the water that flows from Earth's rivers into Earth's oceans every day, roughly one-fifth of that water pours out here, at the mouth of the Amazon.

With that, come nutrients, waste, and organic matter collected along the river's 6,992 km (4,344 mile) winding journey through the rainforests and farmlands of South America. And by the time it reaches the water, it bring a whole lot of mud and triggers plenty of algae blooms, both of which cloud the water of the flume.

The paper in question, from almost 40 years ago, described species of reef fishes and sponges being dredged up from the mouth of the Amazon - and these species were unique to the tropical flora and fauna you'd find in the islands of the Caribbean.

But since then, no one had really given it much thought - after all, given our general understanding of coral reefs, would you expect to find any under here?

Yager wasn't even there to look for the reefs. She was using the RV Atlantis to look into how Amazonian plume was affecting carbon dioxide absorption in the ocean. But to get approval to study the mouth of the Amazon she needed to get some Brazilian oceanographers involved, and one of those, Rodrigo Moura, asked for her help looking for the reef while they were there.

The discovery makes the reef the most northernmost known in Brazil, Meyer reports.