Year Established: 2013 Start Date: 2013-03-01 End Date: 2016-02-28
Total Federal Funds: $25,433 Total Non-Federal Funds: $59,510
Principal Investigators: Rosemary Carroll
Abstract: The geologic and geochemical controls on total and dissolved Hg transport through the Carson River-Lahontan Reservoir (CRLR) system have been successfully modeled by project PIs with a linked and modified version of the US EPA RIVMOD and WASP5/MERC4. Output from the CRLR transport model serves as a boundary condition for a bioenergetics and mercury mass balance model (BMMBM) built to simulate Hg bioaccumulation in Sacramento blackfish (Orthodon microlepidotus), a filter feeding cyprinid found in Lahontan Reservoir. Previous results suggest that coupling of peak dissolved methylmercury (MeHg) loads with periods of maximum plankton growth and maximum fish consumption rates are responsible for large burdens in the planktivore. The complex mechanisms controlling mercury (Hg) transport and bioaccumulation along the CRLR system, however, make it difficult to predict system response to a changing climate. This study will use the tools developed specifically for the CRLR system to provide insight into the dominant mechanisms of Hg transport given a climate induced changing hydrograph, how significant these changes may be and how to manage change in the system to better protect aquatic health. Climate induced changes in the Carson River hydrograph will use the US Bureau of Reclamations bias-corrected and spatially down-scaled surface water projections provide 112 possible hydrographs along the Carson River. These hydrographs extend until 2099 and are based on World Climate Research Programme Coupled Model Intercomparison Project3 and a variable infiltration capacity hydrologic model. These hydrographs will drive the CRLR Hg transport model and BMMBM to assess decadal shifts in system response to changing hydrograph and significance of these shifts. Hypothetical management scenarios will then be developed based on system response, coded into RIVMOD/WASP and hydrographs rerun to test effectiveness of approach.