Trace metals in marine copepods: a field test of a bioaccumulation model coupled to laboratory uptake kinetics data

A first order bioenergetic-based kinetic model has been developed to describe metal accumulation in marine copepods. To field-test predictions of the kinetic model regarding metal concentrations in marine zooplankton, we analyzed Cd, Zn, Ag, Co, and Se in water, phytoplankton, and zooplankton samples collected off the coast of Monaco. Mean concentrations in copepods were 1.3 nmol g^-1 for Ag, 22.2 nmol g^-1 for Cd, 9.5 nmol g^-1 for Co, 16.0 nmol g^-1 for Se, and 2570 nmol g^-1 for Zn; mean dissolved metal concentrations were 10.5 pM Ag, 72.3 pM Cd, 260 pM Co, and 4270 pM Zn. For each metal, model-predicted concentrations in zooplankton using kinetic parameters for influx rates from the dissolved phase, assimilation from ingested phytoplankton, and efflux rates measured in laboratory experiments generally matched field measurements, although discrepancies were noted, especially for Cd where a 4-fold difference between predicted and measured concentrations was observed. Overall, it appears that it is possible to account for the major processes governing metal accumulation from food and water in marine copepod populations.