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  • Title

    Operation Baseline Project 2C: Zooplankton, Romberg Tiburon Center, SFSU

    Lead San Francisco State University [SFSU]
    Description This project will examine responses of zooplankton (copepods) to variations in the foodweb attributable to nutrient sources. At each wetland site we will determine spatial abundance patterns and rates of reproduction, growth, and mortality. These will be integrated with information on phytoplankton and physical dynamics to determine how population dynamics responds to nutrient conditions. Stable isotopes will be used to assess nutrient source contributions to growth.
    Science topics Algae, Floating aquatic vegetation, Food webs, Nitrogen and ammonia, Open water, Other discharge contaminants, Phytoplankton, Submerged aquatic vegetation, Wastewater discharge, Water operations / exports, Wetlands, Zooplankton
    Updated December 14, 2022
  • Title

    Mechanisms underlying the flow relationship of longfin smelt: I. Movement and feeding

    Lead San Francisco State University [SFSU]
    Description The project is to apply modern analytical methods, bioacoustic detection and particle tracking models to refine understanding of the vertical and longitudinal distribution of longfin smelt (Spirinchus thaleichthys) and how they are affected by flow and food availability. Funding will be used to conduct the research to protect and maintain the estuary's threatened longfin smelt population.
    Science topics Longfin Smelt
    Updated November 17, 2022
  • Title

    Climate change impacts to San Francisco Bay-Delta wetlands: Links to pelagic food webs and predictive responses based on landscape modeling

    Lead San Francisco State University [SFSU]
    Description The purpose of this project is to 1) evaluate the potential impacts of climate change on SF Bay-Delta tidal wetlands, 2) improve our understanding of the linkage between these wetlands and the pelagic food web, especially fish populations, and 3) use this information to make predictions about potential effects of climate change on Bay-Delta fish populations.
    Science topics Pelagic fish, Wetlands
    Updated April 29, 2022
  • Title

    Comparison of Nutrient Sources and Phytoplankton Growth and Species Composition in Two Rivers: Their Roles in Determining Productivity and Food Web Conditions in Suisun Bay and the Delta

    Lead San Francisco State University [SFSU]
    Description
    Science topics Phytoplankton, Pelagic fish, Nitrogen and ammonia
    Updated April 29, 2022
  • Title

    Habitat Values of Native SAV [Submerged Aquatic Vegetation] in the Low Salinity Zone of San Francisco Estuary

    Lead San Francisco State University [SFSU]
    Description We will investigate the importance of native submerged aquatic vegetation (SAV) in providing food web support for native fish species in the low salinity zone of the San Francisco Bay-Delta. These SAV beds, composed primarily of Stuckenia pectinata (sago pondweed), are an extensive feature along many of the islands in Suisun Bay and the west Delta, yet almost nothing is known of their seasonal or interannual patterns, their invertebrate communities, or how their physical structure or food resources influence use by native fishes. We hypothesize that the position of these beds in the shallow subtidal zone along the islands increases habitat options adjacent to wetlands and channels for numerous fish species, including species of concern such as delta smelt and chinook salmon. The objectives of this project are to: 1) characterize patterns in habitat structure, community composition, and productivity of SAV beds in four locations in Suisun Bay and the western Delta over a three year period (with comparisons to non-native Egeria densa beds), 2) document the epifaunal invertebrate community composition and abundance in the Stuckenia beds, 3) assess fish use of these beds through seining and acoustic monitoring of hatchery-tagged fish, 4) utilize stable isotope analyses to evaluate food web relationships within and among the beds, and 5) begin preliminary evaluation of the potential to restore native SAV to subsided lands in this region.
    Science topics Chinook Salmon, Green sturgeon, White Sturgeon, Sacramento Splittail, Delta Smelt, Steelhead Trout
    Updated April 29, 2022
  • Title

    Foodweb Support for the Threatened Delta Smelt and Other Estuarine Fishes in Suisun Bay and the Western Sacramento-San Joaquin Delta

    Lead San Francisco State University [SFSU]
    Description The purpose of the project is to increase understanding of the foodweb supporting delta smelt and other estuarine species. This research is important because: 1) it could lead to increased foodweb support for the threatened delta smelt and 2) identify potential mechanisms underlying relationships of abundance or survival of some fish to freshwater flow.
    Science topics Delta Smelt
    Updated April 29, 2022
  • Title

    Resolving Contradictions in Foodweb Support for Native Pelagic Fishes

    Lead San Francisco State University [SFSU]
    Description Much research in the Delta has focused on foodweb dynamics, stimulated by evidence that low productivity of plankton is linked to declines in several fish species including the endangered delta smelt. Pseudodiaptomus forbesi is the most abundant copepod (small crustaceans) in the Delta in summer. It is an important food source for many fishes and makes up about half of the food of delta smelt. This study focuses on the feeding, reproduction, and growth of copepods as essential foodweb support for fishes. This work investigates four diverse habitats including two open-water channels and two shallow habitats. The researchers will measure copepods´ feeding rates on microscopic plants and animals, and relate feeding to their rates of growth and reproduction. Computer models will be used to estimate their movement and death rates. These results will show the sources of nutrition used for growth and reproduction of these key organisms. Results will inform how food webs respond to large scale changes in the Delta ecosystem, for example, restoration and the Sacramento wastewater treatment plant upgrade.
    Science topics None specified
    Updated April 29, 2022
  • Title

    The Role of Microcystis Blooms in the Delta Foodweb: A Functional Approach

    Lead San Francisco State University [SFSU]
    Description We propose a collaborative investigation of blooms of the toxic, cyanobacteria Microcystis in the San Francisco Estuary Delta including how blooms develop, identification of toxic species and strains, controls on toxin production, and foodweb effects. The research will address Delta Science Program Priority Research Topic 2 and Research Topic 5 in the CALFED-funded analysis of ammonium issues in the Estuary. The appearance of Microcystis in the Delta was coincident with the POD, suggesting a link. The spatial and temporal scales of Microcystis blooms was identified with their environmental covariates but a mechanistic analysis of the conditions that distinguish bloom periods and locations, which are critical for ecosystem modeling and management, are still lacking. Our objectives are to determine: 1- the biotic and abiotic factors controlling Microcystis bloom formation and toxin production;2- how Microcystis strains and microbial associations influence toxicity;3- the role of Microcystis in the Delta pelagic food web and its effect on the POD through zooplankton grazing. Our 3-year work plan comprises 2 years of laboratory and field work (contrasting bloom and non bloom locations). Experiments will be conducted to determine mechanisms driving observed in situ patterns. We will synthesize the results and clarify the environmental-bloom-food web effects in a useable format for management efforts aimed towards water supply, fisheries and recreational use of the Delta.
    Science topics Harmful algal blooms HAB
    Updated April 29, 2022
  • Title

    Modeling the Delta Smelt Population of the San Francisco Estuary

    Lead San Francisco State University [SFSU]
    Description The purpose of this project is to develop an individual-based particle-tracking model examining population behavior of Delta smelt under different scenarios.
    Science topics Delta Smelt
    Updated April 29, 2022
  • Title

    Revealing the invisible contributors to the diets of larval longfin smelt and striped bass in the San Francisco Estuary.

    Lead San Francisco State University [SFSU]
    Description To better understand why the longfn smelt is threatened, the project compared the diet of larval longfn smelt to a thriving fsh with overlapping natal habitat and of similar size and morphology— the Pacifc herring. Using new genetic analysis methods, the project aimed to elucidate species composition of fsh diets in greater detail than has been done before and to measure diferences in composition and frequency of prey across habitats. In particular, the project aimed to identify prey items that were not previously seen using traditional diet analysis methods and assess whether any prey are indicative of natal habitats
    Science topics Fish, Longfin Smelt
    Updated February 26, 2024
  • Title

    Understanding Social-Environmental Interactions in Suisun-Delta Tidal Marsh Restoration

    Lead San Francisco State University [SFSU]
    Description

    Assessing the success of tidal marsh restoration is a top priority for coastal managers across the US. Estuarine habitat restoration has been prioritized due to the importance of the ecosystem functions (Callaway et al. 2012) and services (Costanza et al. 2014) they provide and the threats to them by climate driven sea-level rise (hereafter SLR; Craft et al. 2009, Donnelly & Bertness 2001, Schile et al. 2014) and other stressors (Mariotti & Fagharazzi 2013). Given the importance of management for estuarine habitats to survive SLR (Kirwan & Megonigal 2013) and the importance of public responses to approve and fund restoration projects, it is critical to understand how to broadly assess the success of restoration from the perspectives of both ecological performance and public perceptions. However, the San Francisco Estuary (SF Estuary), stretching from the Lower San Francisco Bay through Suisun Marsh to the Sacramento-San Joaquin Delta, encapsulates diverse social and environmental dynamics (Moyle et al. 2014) and varying perceptions by sociodemographic group (Rudnick et al 2022). Our project is focused on the Suisun Marsh and Delta and seeks to understand these complexities by integrating social, environmental, and management perspectives.

     

    Science topics Habitat restoration
    Updated July 16, 2025