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.
Sacramento-San Joaquin Delta (Delta) ecosystems are suffering a collapse in pelagic ecosystems due in part to a decline in energy flow from detrital material (dead phytoplankton, aquatic and terrestrial vascular plants, and minerals), resulting in population declines in threatened and endangered native fish species. Declining primary productivity, decreasing sedimentary inputs to the Delta, impacts of climate change, and the shift in nutrients due to the EchoWater Resource Recovery Facility (EchoWater Facility) upgrade completed in 2023 together evoke a dire need to characterize rapidly changing algal and detrital particle sources and cycling within the Delta to inform management solutions that could improve the food web and better support native fish. To fill this knowledge gap, the researchers assessed the spatial distribution and availability of detrital particles to pelagic aquatic food webs within the Delta by modernizing and developing in-situ light sensors and integrating physical and chemical measurements. They also conducted lab experiments to characterize particle sources and quality by using biomarkers and genetic material to identify species present in the detritus.
