Aschenbroich A., Marchand Cyril, Molnar N., Deborde Jonathan, Hubas C., Rybarczyk H., Meziane T. (2015). Spatio-temporal variations in the composition of organic matter in surface sediments of a mangrove receiving shrimp farm effluents (New Caledonia). Science of the Total Environment, 512, p. 296-307. ISSN 0048-9697.
Titre du document
Spatio-temporal variations in the composition of organic matter in surface sediments of a mangrove receiving shrimp farm effluents (New Caledonia)
Aschenbroich A., Marchand Cyril, Molnar N., Deborde Jonathan, Hubas C., Rybarczyk H., Meziane T.
Source
Science of the Total Environment, 2015,
512, p. 296-307 ISSN 0048-9697
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.
Plan de classement
Ecologie, systèmes aquatiques [036]
;
Ressources halieutiques [040]
;
Etudes, transformation, conservation du milieu naturel [082]
