Coral reefs are fascinating ecosystems. Some support more than 7,000 species of fish, plants, turtles, birds, and mammals. About 25% of the whole ocean’s fish rely on coral reefs. Coral reefs allow animals to find food, find shelter, and birth and take care of their young. Without coral reefs, many species would die out.
There are two different kinds of coral. Shallow water reefs, and deep water coral. Shallow water coral is what makes up coral reefs. They rely on a photosynthetic algae called zooxanthellae. The algae produces carbohydrates that coral uses as food and oxygen. The algae also helps the coral remove waste. In return, the coral provides shelter. This is called mutualism, a type of symbiosis. Deep water coral, on the other hand, lives in very deep and cold water, where there is no zooxanthellae. Instead, deep water coral gets its food from plankton and organic matter.
Coral reefs benefit many animals, but did you know that coral benefits us too? Coral reefs provide barriers against storms and erosion. They’re also a source of food and medicine, since so much fish and ocean wildlife live there. Over half a billion people rely on coral reefs for food, money, or shelter against storms. Coral reefs also provide tourism activities like fishing, diving, and snorkeling, which brings in hundreds of millions of dollars. Altogether the money coral reefs make is around tens of billions of U.S dollars per year. These ecosystems are important to indigenous people all over the world.
Sadly, coral reefs are in great danger. There are diseases, predators, and storms that kill coral reefs. But a lot of the damage on the coral comes from people. Things like pollution, excessive fishing, sedimentation, and global warming are causing more and more coral reefs to die, which puts so many other species of underwater animals in danger of dying too! The coral bleaches, or turns white, from the stress of the threats. But, if the conditions improve soon, the coral can recover from the bleaching. If people can control the damage that we do on the coral reefs, we can still save them.