Scientists for the first time have identified and mapped the chemical structure of molecules used by certain species of marine seaweed to kill or inhibit the growth of reef-building coral. Chemicals found on the surfaces of several species of seaweed have been shown to harm coral, suggesting that competition with these macroalgae could be a factor in the worldwide decline and lack of recovery of coral reefs.
Seaweed growth on coral reefs is normally controlled by plant-eating fish, but in many parts of the world, overfishing has dramatically reduced populations of these consumers allowing the seaweed to dominate. Understanding these harmful chemicals and the seaweeds that produce them, however, could lead to development of new management techniques aimed at protecting fish that consume the most harmful seaweed. Protecting these herbivores could help reduce the pressure on coral, potentially allowing recovery of some endangered reefs.
Research on the coral-harming chemicals will be reported October 17th in the online Early Edition of the journal Proceedings of the National Academy of Sciences (PNAS). The research has been supported by the National Science Foundation, the National Institutes of Health and the Teasley Endowment at the Georgia Institute of Technology.
"We were able to isolate some of the key molecules responsible for the harmful interactions between seaweed and coral," said Douglas Rasher, a graduate student in the School of Biology at Georgia Tech. "These molecules are active at very low concentrations, suggesting that they need only to be expressed on the surfaces of the seaweed in minute concentrations to have damaging effects when they are in contact with the coral."
A May 2010 PNAS study published by Rasher and School of Biology professor Mark Hay showed for the first time that chemicals on the surfaces of seaweed could harm coral. To assess the scope of the coral-seaweed interaction, the res
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Georgia Institute of Technology Research News