Predatory dinoflagellate

Predatory dinoflagellates are predatory heterotrophic or mixotrophic alveolates that derive some or most of their nutrients from digesting other organisms. About one half of dinoflagellates lack photosynthetic pigments and specialize in consuming other eukaryotic cells, and even photosynthetic forms are often predatory.

Organisms that derive their nutrition in this manner include Oxyrrhis marina, which feeds phagocytically on phytoplankton,Polykrikos kofoidii, which feeds on several species of red-tide and/or toxic dinoflagellates,Ceratium furca, which is primarily photosynthetic but also capable of ingesting other protists such as ciliates,Cochlodinium polykrikoides, which feeds on phytoplankton,Gambierdiscus toxicus, which feeds on algae and produces a toxin that causes ciguatera fish poisoning when ingested, and Pfiesteria and related species such as Luciella masanensis, which feed on diverse prey including fish skin and human blood cells. Predatory dinoflagellates can kill their prey by releasing toxins or phagocytize small prey directly.

Some predatory algae have evolved extreme survival strategies. For example, Oxyrrhis marina can turn cannibalistic on its own species when no suitable non-self prey is available, and Pfiesteria and related species have been discovered to kill and feed on fish, and since have been (mistakenly) referred to as carnivorous "algae" by the media.

The media has applied the term carnivorous or predatory algae mainly to Pfiesteria piscicida, Pfiesteria shumwayae and other Pfiesteria-like dinoflagellates implicated in harmful algal blooms and fish kills.Pfiesteria as an "ambush predator" utilizes a "hit and run" feeding strategy by releasing a toxin that paralyzes the respiratory systems of susceptible fish, such as menhaden, thus causing death by suffocation. It then consumes the tissue sloughed off its dead prey.Pfiesteria piscicida (Latin: fish killer) has been blamed for killing more than one billion fish in the Neuse and Pamlico river estuaries in North Carolina and causing skin lesions in humans in the 1990s. It has been described as "skinning fish alive to feed on their flesh" or chemically sensing fish and producing lethal toxins to kill their prey and feed off the decaying remains. Its deadly nature has led to Pfiesteria being referred to as "killer algae" and has earned the organism the reputation as the "T. rex of the dinoflagellate world" or "the Cell from Hell."

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