Are Algae Mass Murderers?

David Biello writes in Scientific American:

Algae seem harmless enough. These precursors to plants thrive throughout the world’s waters. But these single-celled plants have global consequences. We can thank them for oxygen in the atmosphere, oil in the lithosphere as well as dead zones in the oceans and now even a dead horse in France.

That’s right. The fumes from decomposing algae on a French beach killed a horse and rendered its rider unconscious this past summer. And poisonous tides caused by algal blooms make eating shellfish dicey at times as well as causing mass die-offs of fish, birds and even sea-going mammals. Plus, according to a new theory, that might just be a small taste of the plants’ killing ability.

James Castle and John Rodgers of Clemson University think that such algal blooms—triggered by warming water or an increase in nutrients — might be behind the five largest mass extinctions in Earth’s history.

Image: Algal bloom in village river taken in a small village in mountains near Chengdu, Sichuan, China in December 2005 (via Wikimedia Commons).

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