(1) Delta Science Fellowship postdoctoral research project

Funding agencies: The Delta Science Stewardship Council and California Sea Grant

Project link

Fellow and principal investigators:

  • Denise Colombano (UC Berkeley)
  • Albert Ruhi (UC Berkeley)
  • Stephanie Carlson (UC Berkeley)

Community mentor:

  • James Hobbs (California Department of Fish and Wildlife)

Project description:

Estuaries are transition zones that physically and ecologically link marine and freshwater ecosystems. In river-dominated estuaries, such as the San Francisco Estuary, oceanic influences propagate landward while terrestrial influences propagate seaward. Importantly, the relative magnitude of these opposing influences vary as a function of seasonal and interannual variation in hydroclimate. Over the last decade, numerous studies have quantified the effects of such physical drivers on water quality and primary and secondary productivity along the estuarine gradient. Different long-term datasets exist that would allow us to better understand past and predict future responses of fishes to such hydroclimatic fluctuations. However, such exercises are challenging because there is variation in sampling methodology, species targeted, sampling effort, etc.

Our project seeks to synthesize long-term datasets to answer the following questions: How does community stability and juvenile recruitment vary along the estuarine gradient? How do fishes respond to physical habitat types (e.g., depth, shoreline type) along the estuarine gradient? How will fishes respond to future climate regimes, sea level rise, and freshwater flows along the estuarine gradient?

Time frame:

Funded from June 2020 to May 2022.


(2) Proposition 1 Watershed Restoration Grant & Delta Water Quality and Ecosystem Restoration Grant

Funding agency: California Department of Fish and Wildlife

Principal investigators:

  • Albert Ruhi (UC Berkeley)
  • Stephanie Carlson (UC Berkeley)

Postdoctoral researchers:

  • Denise Colombano (UC Berkeley)
  • Robert Fournier (UC Berkeley)

Advisors:

  • James Hobbs (California Department of Fish and Wildlife)
  • Noah Knowles (US Geological Survey)
  • Lisa Lucas (US Geological Survey)

Project description:

Can climate change disrupt estuarine food webs by desynchronizing their components? Evidence suggests that climate-driven mismatches between fish and their prey are likely— but how, when, and where mismatches will occur in the SF Bay-Delta remains unclear. Here we advance our understanding of climate change impacts on pelagic food web dynamics (i.e., phytoplankton-zooplankton-fish) by examining the effects of hydroclimatic fluctuations on species phenology (e.g., spawning, migration, productivity), both within and between trophic levels. Using Multivariate Autoregressive State Space (MARSS) models, we compare how trophic levels respond to shifts in hydroclimate (e.g., early spring onset), and identify what may cause trophic mismatches (e.g., prey without predators or ‘trophic dead-ends’; predators –longfin smelt, striped bass, Pacific herring– without prey or ‘food limitation’). We also evaluate future climate change scenarios and identify areas that are at particularly high risk of a phenological mismatch.

Time frame:

Funded from Nov 2021 to Dec 2024.