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MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS
Citation:
GRANEK, E., J. E. COMPTON, AND D. L. PHILLIPS. MANGROVE-DERIVED NUTRIENTS AND CORAL REEFS. Presented at Western Society of Naturalists, Redmond, WA, November 09 - 12, 2006.
Description:
Understanding the consequences of the declining global cover of mangroves due to anthropogenic disturbance necessitates consideration of how mangrove-derived nutrients contribute to threatened coral reef systems. We sampled potential sources of organic matter and a suite of sessile reef invertebrate consumers from six sites in Bocas del Toro, Panama in the Caribbean Sea for stable isotope analysis using δ34S or δ13C. Using IsoSource mixing models we determined the range of potential contributions to consumers from the various organic matter sources in the system. Mangrove organic matter contributed substantially to most filter feeders ranging across sites from 11-53% for sponges, 18-44% for file clams, and 29-51% for feather duster worms. Mangroves contributed 7-31% of the organic matter of corals depending on species. To examine how mangrove contribution varied with distance from mangrove source we conducted a transplant experiment. Results indicated that the mangrove contribution to invertebrate species declined with increasing distance from shore. These results provide the first evidence that mangrove inputs of organic matter to sessile invertebrate species are substantial and offer an indication of the magnitude of incorporation. Thus, removal of mangroves from tropical shores can potentially generate a deficit in the organic inputs to reef organisms, with as yet unknown ecological consequences for the integrity and persistence of reefs. Understanding the consequences of the declining global cover of mangroves due to anthropogenic disturbance necessitates consideration of how mangrove-derived nutrients contribute to threatened coral reef systems. We sampled potential sources of organic matter and a suite of sessile reef invertebrate consumers from six sites in Bocas del Toro, Panama in the Caribbean Sea for stable isotope analysis using δ34S or δ13C. Using IsoSource mixing models we determined the range of potential contributions to consumers from the various organic matter sources in the system. Mangrove organic matter contributed substantially to most filter feeders ranging across sites from 11-53% for sponges, 18-44% for file clams, and 29-51% for feather duster worms. Mangroves contributed 7-31% of the organic matter of corals depending on species. To examine how mangrove contribution varied with distance from mangrove source we conducted a transplant experiment. Results indicated that the mangrove contribution to invertebrate species declined with increasing distance from shore. These results provide the first evidence that mangrove inputs of organic matter to sessile invertebrate species are substantial and offer an indication of the magnitude of incorporation. Thus, removal of mangroves from tropical shores can potentially generate a deficit in the organic inputs to reef organisms, with as yet unknown ecological consequences for the integrity and persistence of reefs.