Temporal changes in the biochemical composition of particulate organic matter sedimentation in the Bay of Banyuls-sur-Mer

Abstract Gross sedimentation rates (GSRs) were monitored together with meteorological data and the main biochemical characteristics of the collected material (i.e. organic content, C, N, total proteins, carbohydrates, lipids and available proteins) over a three year cycle at a shallow station (18 m) of the Bay of Banyuls, France. GSRs were between 0.26 (l 1/04/ 92) and 317.75 gDW m −2 d −1 (18/02/94). They followed an annual cycle with low and relatively constant values during spring and summer and high, variable values during fall and winter. During the study GSRs correlated poorly (state of the sea, precipitation) or even non-significantly (wind speed) with the main meteorological parameters. GSRs correlated negatively with the organic content of the material collected within the sediment traps suggesting the importance of resuspension in controlling GSRs. This hypothesis is consistent with the fact that, among all the measured biochemical parameters, available proteins (i.e. enzymatically hydrolizable proteins) are the most negatively correlated with GSRs. Available proteins showed important temporal changes that are only partly described by changes in carbon and nitrogen contents. These results are discussed in relation to the conceptualisation and the modelling of benthic trophic networks. The major objectives of our research group within the framework of the second phase of the French “Programme National d'Oceanographie Cotiere” are briefly discussed.