A team of scientists has discovered a huge coral reef in the Amazon River. The team from universities in the USA and Brazil was on an expedition to learn more about plumes when it made the discovery. Plumes are the areas near where a river meets the sea and the river's freshwater mixes with the ocean's saltwater. The reef system covers an area of 5,800 square kilometres, stretching from the coast of French Guiana to the Brazilian rainforest. The finding is surprising because reefs are rarely found in rivers as the water is usually too muddy and does not contain enough salt.
The scientists explored just 10 per cent of the reef. There were many sponges, creatures and other marine life that had adapted to life in the dark water. They also found 73 species of reef fish, many of them carnivorous. A researcher said: "We brought up the most amazing and colorful animals I have ever seen." Not all news about the reef is good. The area has been marked for oil exploration. The researcher warned that: "From ocean acidification and ocean warming to plans for offshore oil exploration…the whole system is at risk from human impacts."