Experimental estimation of assimilation rates of meiofauna feeding on 14C-labelled benthic diatoms

Abstract

Knowledge of the trophic position of meiofauna in marine sediments is still contradictory primarily due to the scarcity of experimental data. The present study analyses diatom-feeders among the meiofauna. The assimilation rate of carbon by meiofauna was determined through a grazing experiment using in situ collected diatoms pre-labelled with 14C. The assimilation rates of diatom carbon were estimated for the bulk meiofaunal community (0.84ng C.ind−1.h−1), for the bulk harpacticoid copepods (1.92ng C.ind.−1h−1) and for two dominant nematode species (Metachromadora remanei 1.26ng C ind−1h−1, Daptonema oxycerca 1.35ngC.ind. −1h−1). Experimental results were extrapolated to compute the consumption of meiofauna in situ that would attain up to 12% of primary benthic production in the Brouage mudflat (Marennes-Oléron Bay, southwest Atlantic coast).