Mesoscale eddy diffusion, particle sinking, and the interpretation of sediment trap data

A Lagrangian analysis of a particle sinking through a random mesoscale eddy field is used to evaluate the effects of horizontal diffusion and particle sinking rates on paniculate fluxes sampled by an idealized sediment trap. The analysis indicates that the spatial region where collected particles are formed ( L x ) is dependent upon the mean sinking rate of the collected particles and the mesoscale eddy advective field above the trap. This weighted spatial averaging creates difficulties in the interpretation of sediment trap data as fluxes of rapidly sinking particles (>200 m d −1 ) represent local processes ( L x 200 km) for a trap deployed at 1000 m. Several examples of the potential effects that this spatial averaging may have upon the ecological interpretation of the sediment trap collected particle fluxes are presented.