Describing additional fluxes to deep sediment traps and water-column decay in a coastal environment

Sediment traps were moored at three stations in Sechelt Inlet, a fjord in southern British Columbia, Canada, for five one-month deployment periods from late January to late June, 1991. On each mooring were traps at three depths; total and constituent fluxes often increased with depth. We present the flux data and describe an analytical model that is based on a set of simultaneous equations for which two unknowns are the decay rate of material representatively caught by two vertically' separated sediment traps and the composition of material causing observed increases in flux with depth. The unknowns are solved in a least-squares sense and the results indicate that 60-71% of organic carbon, 57-62% of nitrogen and 41-48% of biogenic silica were lost from the particulate phase over a 200 m depth interval during the study. The results also suggest that material contributing additional fluxes to deep traps was compositionally similar to material settling from traps above.