Transfer of Contaminants between the Water Column and Bottom Sediments: The Role of Deposit-and Suspension-Feeding Benthic Invertebrates

摘要

The long-term goal of this research was to determine the dominant mechanisms whereby and the rates at which fine particles (<50 micronmeter) are incorporated into marine sediments. Flume and still-water experiments were conducted to quantify specific effects of deposit-feeding benthic invertebrates on the transport of fine suspended particulates from the water column to the bottom, and the retention of such particulates within the seabed. Experiments were conducted on (1) the effects of biogenic roughness (fecal mounds) on sand transport, (2) the potential effects of worm-tube arrays on fine-particle deposition, (3) fine-particle subduction by a surface deposit-feeding worm, and (4) density-dependent bioturbation by a head-down deposit-feeding worm. We also studied particle trapping by the viscous sublayer. These studies demonstrate ways in which deposit feeders can enhance fine-article deposition and retention within sandy marine sediments.