Direct and Indirect Effects of Diesel Fuel on Microphytobenthos and Meiofauna in Saltmarsh Sediments

摘要

Results provide several insights into the influence of diesel contaminants on benthic food webs. Benthic microalgae constitute the base of this food web. The consistency of results from 1994 and 1995 experiments indicates the robustness of our observations of reduced copepod grazing and enhanced algal biomass in the presence of high levels of diesel contamination. While the broad responses of the two communities were similar, differences in the response of the meiofaunal communities are consistent with the hypothesis that the MS community is more sensitive to contaminants. Microalgal biomass in sediments is controlled primarily by meiofaunal grazing pressure. Mortality to meiofaunal grazers releases algae from grazing pressure. The algae grow until they become N-limited. Enhanced ammonium production in diesel contaminated sediments then allows algal blooms to develop further.