Effects of acid mine drainage on the estuarine food web, Britannia Beach, Howe Sound, British Columbia, Canada

摘要

We investigated the effects of acid mine drainage (AMD) from Britannia Creek, BC, Canada, a stream contaminated by an abandoned copper mine, on the estuarine food web. Near the mouth of Britannia Creek, sediments and the water contained high concentrations of dissolved copper and the waters were highly acidic. Relative to a reference location, rockweed (Fucus gardneri Silva) cover was reduced, phytoplankton biomass was lower, chironomid larvae were less abundant, and fewer gammarid amphipods colonized basket traps. Laboratory toxicity tests confirmed that sediments and water from the lower reaches of Britannia Creek and its estuary were highly toxic to midge larvae (Chironomus tentans Fabricius), the marine amphipod (Eohaustorius washingtonianus Thorsteinson) and also impaired fertilization of sand dollars (Dendraster excentricus Eschscholtz). Analyses of stomach contents of chum salmon fry (Oncorhynchus keta Walbaum) indicated that they preferred to feed on chironomid larvae and gammarid amphipods at Britannia Creek estuary but these two taxa were less abundant at Britannia Creek estuary relative to the reference location. AMD from Britannia Mine disrupted the structure and function of the intertidal ecosystem resulting in loss of food production for fish including chum salmon fry and other species.