Dinoflagellates

 Dinoflagellates

These organisms are mostly marine and photosynthetic.

They appear yellow, green, brown, blue or red depending

on the main pigments present in their cells. The cell wall

has stiff cellulose plates on the outer surface. Most of

them have two flagella; one lies longitudinally and the

other transversely in a furrow between the wall plates.

Very often, red dinoflagellates (Example: Gonyaulax)

undergo such rapid multiplication that they make the

sea appear red (red tides). Toxins released by such large

numbers may even kill other marine animals such as

fishes.