The depletion of dissolved oxygen
in water, a condition resulting from an overabundance of nutrients of human or
natural origin that stimulates the growth of algae, which in turn die and
require large amounts of oxygen as the algae decompose. It was the most
frequently cited direct cause of fishkills in the U.S. from 1980 to 1989.

Create large areas also known as ‘Dead Zones’

See Also: Dead Zone