[Coral-List] Posting relevant to algae coral discussions
KimF at spc.int
Thu Oct 12 00:02:16 EDT 2006
Posting on the Marine & Coastal Community Network list that may be of interest to current discussions
Invading Algae's Sweet Touch Spells Death for Coral (International)
Corals may be vulnerable to the same processes that cause tooth decay in humans. Healthy coral lives symbiotically with single-celled algae, but fleshy macroalgae spreading over reefs, usually as a result of pollution, can spell trouble.
Now Jennifer Smith of the University of California, Santa Barbara, has shown that sugars released by the algae diffuse into the coral and fertilise bacteria, making them pathogenic. "Algae can indirectly cause coral mortality by enhancing microbial activity," she says.
Smith and her colleagues took coral and algae from reefs off the Line Islands in the south Pacific and placed them in adjacent chambers separated by a 0.02-micrometre filter. This prevented the passage of microbes and viruses but allowed the diffusion of dissolved sugars. All the coral died. When the experiment was repeated, this time with the addition of ampicillin, a broad-spectrum antibiotic, all the coral survived. Smith presented the results at the International Society of Reef Studies in Bremen, Germany, last month.
"The work highlights another potential mechanism by which macroalgal-dominated reefs could persist and reduce the likelihood of switching back to a coral-dominated state," says Peter Mumby of the University of Exeter, UK.
Dr Kim Friedman
Senior Reef Fisheries Scientist (Invertebrates)
Secretariat of the Pacific Community (SPC)
Secrétariat de la Communauté du Pacifique (CPS)
BP D5 - 98848 NOUMEA CEDEX
Phone: +687 265 474
Fax: +687 26 38 18
E-mail : kimf at spc.int <mailto:kimf at spc.int>
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