This project aims to characterize and quantify where detrital material (decaying plant matter) originates within wetlands, the composition of that material, and how export of detrital particles occurs. This project will combine powerful characterization tools and techniques that scale from molecules to ecosystems to assess spatial and temporal trends in particle sources, species and composition. Because restoration in the Sacramento-San Joaquin Delta will fundamentally alter particle distribution and food availability for aquatic organisms, this study will inform habitat restoration efforts and the revival of native fish populations. The tools developed and adapted for this project may inform management response during extreme conditions and climate events by helping to identify areas that may act as refugia for species.
This project focuses on nitrogen and carbon cycling within the Bay-Delta, both before and after planned 2021 upgrades to the Sacramento Regional Wastewater Treatment Plant (SRWTP). We will measure in situ benthic nitrate (NO3- ) and oxygen (O2) fluxes using a new non-invasive technique, which provides high frequency continuous data over a much larger sediment surface area than traditional methods. The SRTWP currently represents one of the largest point sources of nitrogen to the Bay-Delta, with the upgrades projected to cut nitrogen outputs from the plant by ~65%. This project will help assess the efficacy of this major management action and our results will add to biogeochemical models for the Bay-Delta.
Description The Diet and Condition study has provided information on the food habits of pelagic fishes in the estuary since 2005. We focus on the temporal and spatial differences in diet composition and feeding success of Delta Smelt, Striped Bass, Threadfin Shad, Longfin Smelt, Mississippi Silversides, and American Shad. Need Data from this project has been used to inform the Fall Low Salinity Habitat Program (FLaSH), Directed Outflow Project (DOP), and Management, Analysis and Synthesis Team reports, as well as life history models used for the conservation of fish and their habitats. Understanding what prey are utilized for food in the context of available prey, with the associated body-condition of fish, helps clarify the existence and timing of food limitation for young pelagic fish in the estuary. This work began as part of the Pelagic Organism Decline investigations and continued as a contributor to FLaSH investigations during which we in collaborated with the Fish Health Monitoring Project. Recently staff completed Longfin Smelt diet investigations as part element #296 (Longfin Smelt Investigations - in response to a litigation agreement) that will also contribute to the Longfin Smelt Conceptual Model and Synthesis effort (element #320). Finally, we will process Delta Smelt diets from investigations prompted by the Delta Smelt Resilience Strategy, and as part of the DOP. Objectives 1. What are the diets of pelagic fishes (especially Delta Smelt and Longfin Smelt) in the estuary and do they vary regionally or temporally? 2. Is there evidence of reduced feeding success spatially or temporally in the estuary? 3. Is feeding success associated with changes in relative weight or condition of fish? 4. Is there seasonal and regional overlap of diets between species (with a focus on age-0 Delta Smelt, Longfin Smelt, Striped Bass, Prickly Sculpin, Pacific Herring, and Threadfin Shad)?
The Environmental Monitoring Program (EMP) began in 1975 to conduct baseline and compliance monitoring of water quality, phytoplankton, zooplankton, and benthic invertebrates in the San Francisco Bay-Delta estuary. This monitoring program was designed to track the impact of water diversions to the State Water Project (SWP) and Central Valley Project (CVP) on the Bay-Delta. In the decades since, EMP scientists have monitored these constituents at fixed and floating stations throughout the estuary and ensured compliance with state and federal mandates such as Water Right Decision 1641 (D-1641). In the years and decades since its inception, EMP has become one of the cornerstones for scientists' and managers' understanding of the pace and pattern of change in this critical ecosystem. By sampling water quality and biological communities concurrently, EMP has created a dataset that is uniquely useful in better understanding causal connections between physical, biological, and biogeochemical processes.
