Mercury bioaccumulation in mountain lakes varies widely due to strong environmental gradients, and there are complex, hierarchical factors that affect mercury transport and loading, methylmercury production, and food web biomagnification.
Researchers sought to assess how catchment tree cover, lake benthic primary production, and fish diet were associated with mercury concentrations in mountain lake fish. Mean fish mercury concentrations varied threefold between lakes, with nearshore tree cover and fish diet accounting for the most variation. Tree cover was likely positively correlated to fish mercury due to its contributions to local deposition and its effect on lake biogeochemistry. Fish with benthic diets tended to have higher mercury concentrations, illustrating that food web processes are an important consideration when investigating drivers of contaminant bioaccumulation. Results suggest that both landscape and ecological factors are determinants of fish mercury bioaccumulation, and thus variables at multiple scales should be considered when managing mountain lake food webs for mercury exposure risk.
Chiapella, A.M., Eagles-Smith, C.A., Strecker, A.L., 2020, From forests to fish: Mercury in mountain lake food webs influenced by factors at multiple scales: Limnology and Oceanography, https://doi.org/10.1002/lno.11659