SINK OR SWIM - ACCUMULATION OF BIOMASS AT FRONTS

The dense concentrations of biomass commonly seen at fronts are often explained by a physiological response of the organisms to the frontal environment. However, some fraction of the enhanced biomass may be explained through purely physical processes: the interaction of floating, sinking or swimming with the flows at a front. To explore this hypothesis, I present a model of steady, 2-dimensional cross-frontal circulations, which I combine with a variety of swimming behaviors. The models show how patchiness may arise at fronts through retention and accumulation zones, and the patterns which evolve given various flow and swimming characteristics. The ecological significance of the results is discussed.