Aschenbroich A. auteur aut IRD Marchand Cyril auteur aut IRD Molnar N. auteur aut IRD Deborde Jonathan auteur aut IRD Hubas C. auteur aut IRD Rybarczyk H. auteur aut IRD Meziane T. auteur aut IRD text journalArticle eng text/pdf born digital access In order to investigate spatio-temporal variations in the composition and origin of the benthic organic matter (OM) at the sediment surface in mangrove receiving shrimp farm effluents, fatty acid (FA) biomarkers, natural stable isotopes (delta C-13 and delta N-15), C:N ratios and chlorophyll-a (chl-a) concentrations were determined during the active and the non-active period of the farm. Fatty acid compositions in surface sediments within the mangrove forest indicated that organic matter inputs varied along the year as a result of farm activity. Effluents were the source of fresh particulate organic matter for the mangrove, as evidenced by the unsaturated fatty acid (UFA) distribution. The anthropogenic MUFA 18:1 omega 9 was not only accumulated at the sediment surface in some parts of the mangrove, but was also exported to the seafront. Direct release of bacteria and enhanced in situ production of fungi, as revealed by specific FM, stimulated mangrove litter decomposition under effluent runoff condition. Also, microalgae released from ponds contributed to maintain high benthic chl-a concentrations in mangrove sediments in winter and to a shift in microphytobenthic community assemblage. Primary production was high whether the farm released effluent or not which questioned the temporary effect of shrimp farm effluent on benthic microalgae dynamic. This study outlined that mangrove benthic organic matter was qualitatively and quantitatively affected by shrimp farm effluent release and that responses to environmental condition changes likely depended on mangrove stand characteristics. specialized Mangrove Organic matter Shrimp farming Fatty acids Chlorophyll-a Stable isotopes NOUVELLE CALEDONIE 082 036 040 512 296-307 2015 0048-9697 https://www.documentation.ird.fr/hor/fdi:010064069 10.1016/j.scitotenv.2014.12.082 0048-9697 [F B010064069] https://www.documentation.ird.fr/hor/fdi:010064069 https://www.documentation.ird.fr/intranet/publi/2015/04/010064069.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2015-05-04 2017-08-23 fdi:010064069 fre