algae

A group of plants living in the water, including all seaweeds, and ranging in size from microscopic cells to fronds many meters long. A group of unicellular algae, the Cyanobacter, growing on dams, ponds and lakes can cause severe mortalities in animals drinking the water. See also algal, microcystis, prototheca. Artificial culture of algae as a source of livestock feed is being tried in some arid countries.