Implications of fecal pellet size and zooplankton behaviour to estimates of pelagic-benthic carbon flux

Abstract

Numbers, volumes and carbon content of fecal pellets collected by sediment traps and bottle casts were measured with an image analysis system, from samples collected in the lower Bay of Fundy, Atlantic Canada. Analysis of sinking, resuspension and biodegradation rates indicated that small fecal pellets must be heavily grazed within the water column. Measurement of rates of coprophagy and vertical distribution of pellets without peritrophic membranes may lead to estimates of resuspension. Differences in size-frequency spectra of pellets collected in 5 h and 24 h sediment trap developments indicated that large fecal pellets which reach the benthos are produced primarily by migratory copepods and euphausids. The effects of diel vertical migration may bias estimates of pellet carbon flux made from short sediment-trap deployments.