Dinoflagellate, << `dih` nuh FLAJ uh layt or `dy` noh FLAJ uh layt, >> is a kind of single-celled living thing found in oceans and freshwater lakes and ponds. Scientists classify dinoflagellates in a group of living things called protists. Some dinoflagellates function as plants. They need only sunlight and certain nutrients for growth. Other kinds live more as animals do, and consume bacteria and other tiny organisms (living things). Still other kinds change back and forth between plantlike and animallike ways of life.
Typical dinoflagellates have two flagella (long, hairlike projections) that enable them to swim. Many possess thick cell walls that look like plates of armor. Some can even produce a chemical light called bioluminescence.
Dinoflagellates change form during their life cycle. Most go through an active, swimming stage of life and a more stationary stage. In the stationary period, some dinoflagellates develop into thick-walled, seedlike forms called cysts. Scientists believe that cysts settle at the bottom of oceans and lakes, enabling dinoflagellates to survive when water conditions are unfavorable for growth.
Dinoflagellates make up part of plankton, the mass of tiny organisms that drift with the water. Plankton provides food for much sea life. However, a few dinoflagellates produce powerful poisons that kill fish. When dinoflagellates become abundant, they may discolor the water, causing red tides. Red tides can harm marine life if they contain poisonous dinoflagellate species, or if the dinoflagellates remove all oxygen from the water. Harmful red tides often occur in coastal waters.
