This study is to determine and quantify the carbon contributions of the autotrophic and heterotrophic food webs to zooplankton and fish in the floodplain and tidal habitats of the Central Valley and Northeast Delta by use of stable isotopes. It is hypothesized that the relative contribution of the heterotrophic food web to zooplankton and higher-level consumers in Central Valley floodplains and Northeast Delta has previously been underestimated. Stable isotope tracers have been used extensively in aquatic food web studies and can offer detailed information on the relative utilization of carbon resources. More specifically, the goals include quantifying, spatiotemporally, the relative use of alternative carbon pathways and how differences in resource use changes zooplankton community composition. Juvenile Chinook Salmon will be used to assess the contribution of the heterotrophic food web to higher level consumers and integrate habitat conditions over a period of weeks. Additionally, zooplankton community composition will be used to assess resource availability to fish such as juvenile Chinook salmon. This study will help inform management of floodplain and freshwater tidal habitat in the Delta and guide restoration actions in these locations.
Regents of the University of California, Davis
Objectives are to:
1. Use stable isotopes as tracers to determine sources of carbon between various habitat types in primary and secondary consumers.
2. Compare resource use of zooplankton and juvenile salmon between habitats/seasons, elucidate location and/or season specific patterns.
3. Determine if community level changes in zooplankton assemblage occur with changes in resource use or availability. Quantify the most abundant zooplankton species and determine the quality of food resources for juvenile salmon (zooplankton size and motility).
4. Build ecosystem productivity models for various habitats to compare carbon sources and productivity potential for comparisons between various managements and restoration types.
Research/Planning (including Science)
Project Benefits a Disadvantaged Community (or SDAC):