Coral reefs are often referred to as the "rainforests of the sea" because, like rainforests on land, they are highly diverse ecosystems that support a wide variety of plant and animal species. Coral reefs are home to about 25% of all marine species, despite covering less than 1% of the ocean floor. Just like rainforests, coral reefs are also a crucial source of biodiversity and provide important ecosystem services, such as protecting coastlines from erosion and supporting fisheries.