Types of phytoplankton - Dinoflagellates

-Unicellular and some form chains. -Have 2 flagella. Some are autotrophic, 50% are heterotrophs and eat phytoplankton/zooplankton. Some are mixotrophic. -Separate into: Thecate (cellulose) and Naked (without). Have 2 taxonomic groups: Desmophycae (flagella arise from anterior, Cell wall has two valves that separate during division) and Dinophycae (The majority, most are thecate, posterior flagella and form a girdle). -Form blooms named "red-tides": they may contain neurotoxins (saxitoxin), shellfish filtrate the toxin and it can cause paralysis to us.