red tide
noun
a brownish-red discoloration of marine waters caused by the presence of enormous numbers of certain microscopic flagellates, especially the dinoflagellates, that often produce a potent neurotoxin that accumulates in the tissues of shellfish, making them poisonous when eaten by humans and other vertebrates.
Origin of red tide
First recorded in 1900–05
Words nearby red tide
red stuff,
red supergiant,
red tag,
red tai,
red tape,
red tide,
red tory,
red trillium,
red underwing,
red valerian,
red water
British Dictionary definitions for red tide
red tide
noun
a discoloration of sea water caused by an explosive growth in phytoplankton density: sometimes toxic to fish life and, through accumulation in shellfish, to humans
Scientific definitions for red tide
red tide
A population explosion of certain species of dinoflagellates, a kind of protozoan found in plankton. The dinoflagellates color the water red or reddish-brown and secrete a toxin that kills fish. Red tide usually occurs in warm coastal waters.