Science activity

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.