The Coral Reef

Coral reefs are fragile, living ecosystems increasingly being threatened and damaged by pollution, disease and habitat destruction. EPA has several activities involving the protection of coral reefs. Further education of the coral reef biological indicators is important to bring additional awareness to these very unique ecosystems.

Coral reefs are among the world's richest ecosystems, second only to tropical rain forests in plant and animal diversity. However, they are extremely sensitive environments that have special temperature, salinity, light, oxygen, and nutrient requirements. If environmental conditions fall outside the acceptable range of these requirements, the health and dynamics of a coral reef community can be severely disrupted. That's why coral communities are sensitive indicators of water quality and the ecological health of the coastal watershed.

Corals themselves are tiny animals which belong to the group cnidaria (the "c" is silent). Other cnidarians include hydras, jellyfish, and sea anemones. Corals are sessile animals, meaning they are not mobile but stay fixed in one place. They feed by reaching out with tentacles to catch prey such as small fish and planktonic animals. Coral reefs provide habitats for a large variety of organisms. These organisms rely on corals as a source of food and shelter. Besides the corals themselves and their symbiotic algae, other creatures that call coral reefs home include various sponges; molluscs such as sea slugs, nudibranchs, oysters, and clams; crustaceans like crabs and shrimp; many kinds of sea worms; echinoderms like star fish and sea urchins; other cnidarians such as jellyfish and sea anemones; various types of fungi; sea turtles; and many species of fish.