Year Established: 2006 Start Date: 2006-03-01 End Date: 2009-12-31
Total Federal Funds: $87,479 Total Non-Federal Funds: $174,955
Principal Investigators: Rosemary Carroll, Rosemary Carroll
Abstract: Most mercury bioaccumulation modeling efforts assume a constant loading of mercury through time and space. These are justifiable assumptions where atmospheric mercury loading is the dominant phenomenon. However, the timing of maximum growth of phytoplankton relative to that of mercury loading could matter greatly if the loading signal varies strongly over time. Therefore, accurate prediction of mercury bioaccumulation may depend upon understanding the interactions of mercury loading and phytoplankton growth at sub-annual time scales (i.e. days to weeks). It is hypothesized that the strong temporally varying signal of mercury loading to Lahontan Reservoir will cascade, albeit with expected dampening, up through the reservoir foodweb with significantly different non-linear responses depending upon the relative timing and duration of peak mercury loading and the rates of phytoplankton and zooplankton growth. The primary objective of the proposed study is to observe and model a temporally varying mercury signal in the lower food web, specifically the phytoplankton and zooplankton communities. Collected data will parameterize/drive a bioaccumulation model to simulate mercury pulse loading on uptake of several trophic levels in Lahontan Reservoir. A verified model will allow model prediction of bioaccumulation based on hypothetical flow/Hg-loading scenarios. Finally, an uncertainty analysis (Monte Carlo simulation) will provide a quantitative assessment of the expected accuracy of model predictions. This will allow a determination of significant differences between simulated scenarios.