Multiple environmental stressors such as trace metal contaminants, increased ultraviolet (UV) radiation, and climate warming are having synergistic effects on aquatic ecosystems. Abiotic effects propagate through all levels of ecosystem organization, providing opportunities to develop the integrative models needed to assess and predict important interactive effects of multiple stressors. For example, when invertebrates bioaccumulate metals above thresholds beyond which some species cannot regulate metal intake, it leads to impaired growth, reproduction, and survival that alter the structure of invertebrate communities in ways that should be predictable. I propose to develop models that couple the geochemistry of natural waters as altered by UV exposure with the biological uptake of metals and the resulting structure of invertebrate communities. Current regulatory policy for metals generally ignores most natural variation and the synergistic impacts of multiple stressors (e.g., seasonal and temporal fluctuations in metal concentrations coupled with UV exposure). Based on an extensive, regional data set, my models will link atmospheric, climatic, and geochemical effects on the spatial dispersion of invertebrate diversity throughout several watersheds, and will have important implications for both regulatory policy and ecological theory. collapse