Story highlights A 600 mile-long coral reef was found at the mouth of the Amazon River

Many of the reef's fish are carnivorous

(CNN) The Amazon River, known for its array of wildlife from pink dolphins to flesh-eating piranhas, has revealed a new treasure -- a massive coral reef that stretches for some 600 miles, scientists say.

A team of scientists from Brazil and the United States discovered the reef in the muddy waters at the mouth of the Amazon, according to a report published in the journal Science on Friday.

The reef system spans 3,600-square miles along the ocean floor, stretching from French Guiana to Brazil's Maranhao state along the edge of South America's continental shelf.

The finding is surprising because large rivers normally create gaps in reef distribution due to unfavorable conditions such as salinity, pH and light penetration. However, this coral reef system seems to be healthy, according to the report.

American and Brazilian researchers collected this sponge sample as well.

The carbonate structure, which functions as a waterway passage for fish and other marine life, is home to a big colony of sponges and other creatures that thrive in low-light waters. The study recorded 73 reef fish species, many of them carnivorous.

Read More