Particle transport processes in a small marine bay

Abstract

Particle transport in Elliott Bay, a 20 km2 embayment in Puget Sound, Washington, was studied in an integrated program employing shipboard CTD/transmissometer observations, moored sediment traps, and moored transmissometer/current meter observations. Surface and bottom high/turbidity layers are present throughout the bay during both summer and winter seasons. Particles added to the surface layer by river input and phytoplankton production are rapidly advected out of the bay and provide only a minor contribution to the local sedimentation rate. The benthic nepheloid layer is maintained not by local resuspension but by particles advected into Elliott Bay with turbid deep water from the adjoining Main Basin of Puget Sound. A severalfold drop in mean current speed as Main Basin water enters Elliott Bay results in increased particle fallout within the benthic nepheloid layer, a high sedimentation rate, and the embayment functioning as a sink for particles from throughout Puget Sound.