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Breakthrough Discovery Deepens Our Understanding of Why Algae Form Blooms

A new discovery by a National Centers for Coastal Ocean Science researcher and NOAA-funded scientists in California and Scotland provides new insight into why marine algae form blooms.

It has long been known that bloom-forming microalgae influence climate and harm ecosystems and man are closely associated with certain bacterial species, but the reasons why were unknown.  The scientists discovered that the bacteria and algae have evolved a mutually beneficial arrangement in which the bacteria promote the growth of the algae by releasing a chemical that increases the biological uptake of the critical nutrient iron, while the algae release organic molecules that support bacterial growth.

They further found that dense cell blooms at the sea surface accentuate these two beneficial effects.  The new insight will help scientists and environmental managers develop more realistic bloom formation models, which will enable better bloom prediction and mitigation strategies.

Bloom-forming microscopic plants (microalgae) support world fisheries and help regulate climate; but toxic species can also cause harm.  Robust predictive ecosystem models for the formation of beneficial and harmful blooms require a fundamental knowledge of the biological and chemical processes that promote bloom formation.


Amin, Shady A., David H. Green, Mark C. Hart, Frithjof C. Küpper, William G. Sunda, and Carl J. Carrano.  2009.  Photolysis of iron-siderophore chelates promotes bacterial-algal mutualismProceedings of the National Academy of Sciences of the United States of America 106(40): 17,071-17,076.

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Shorter web link for sharing: http://coastalscience.noaa.gov/news/?p=5927

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