Threatened species of Echinodermata

The 5,700 species of echinodermata are marine invertebrates common in temperate or tropical zones. They play a very important role in marine ecology by changing the shore-line, removing decaying organic matter, regulating the production of mollusks, and producing microscopic larvae which constitute an important food element for slightly larger plankton organisms. It is not known how many of these species are endangered by different forms of marine pollution.