The first reefs developed about 400 million years ago, but modern reef have only existed for some 5 million years. Over time, broken bits of coral skeleton and calcium carbonate material are cemented together by a type of red coralline algae and by magnesium calcite particles found in the sea water. The reefs of Komodo National Park are an important habitat for about 1000 species of fishes, over 250 species of reef-building corals, and at least 105 species of crustaceans and 70 species of sponges. They are made up of sea grasses, which are a type of flowering plant. Sea grasses are an important shelter for many young fish and invertebrates.
Many animals eat sea grass such as turtles, dugongs, mollusks and urchins.
As their name suggests, they generally look like large blades of grass growing underwater in sand near the shore. Mangroves Mangroves are a natural physical barrier against soil erosion and they also provide a unique eco system. The aerial roots are an important breeding ground, nursery and shelter for juvenile fish and shrimp. Mangroves are a special tree that can live in salty soil or water. Part of the mangrove root is above the water so that it can take carbon dioxide from the air.