red tide

A proliferation of a marine plankton toxic and often fatal to fish, perhaps stimulated by the addition of nutrients. A tide can be red, green, or brown, depending on the coloration of the plankton. A proliferation or bloom of a certain type of plankton with red to orange coloration, that often causes massive fish kills. Though they are a natural phenomenon, blooms are believed to be stimulated by phosphorus and other nutrients discharged into waterways by man. Sea water which is covered or discoloured by the sudden growth of algal bloom or by a great increase in single-celled organisms, dinoflagellates. Red tides are often fatal to many forms of marine life and, in some cases, can result in human deaths because the dinoflagellates are eaten by clams and mussels which concentrate the paralysing toxins which they produce.