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Predator-Sensing Algae

May 1, 2015

Unicellular plankton turn toxic when they sniff nearby predators.


red tide at midnight Mike Flickr CC BY-SA 2.0

Red tide at night. (Mike/Flickr/Creative Commons License BY-SA 2.0)


A trigger for toxic red tides. I’m Bob Hi rshon and this is Science Update.

Single-celled marine algae called dinoflagellates are usually harmless. But occasionally, some species produce deadly toxins in a phenomenon known as red tide, killing fish and rendering shellfish too toxic to eat. In the Proceedings of the National Academy of Sciences, University of Gothenburg marine biologist Erik Selandar and his colleagues report that in the lab, the algae produce the toxins when they detect chemicals secreted by copepods, tiny creatures that graze on the algae.

ERIK SELANDER (University of Gothenburg):

It’s been debated why these small algal cells produce toxins and this is a strong argument that they do it to protect themselves against grazers.


Dinoflagellates are ubiquitous in oceans worldwide. Selander and his team are trying to better understand them and their effects on the marine ecosystem. I’m Bob Hirshon, for AAAS, the science society.