Tidal marshes are important ecosystems in the San Francisco-Bay Delta. They remove carbon from the atmosphere, build up soils that buffer our communities from sea level rise, mitigate excessive nutrients (like nitrogen), and provide critical habitat and food resources for a diversity of species. It is difficult to predict how tidal marshes change naturally over time versus as a response to climate change, restoration and water quality changes. This project provides the first ever multi-year dataset of the complete carbon budget of a tidal marsh. This dataset will be used to predict seasonal and annual carbon budgets in tidal marshes over a range of salinities. The model will assess the sustainability of existing and potential restored tidal wetland benefits over the next 100 years using remote sensing data. The model will be an open-source tool designed for use by wetland managers and decision makers in the Bay-Delta region. This project supports ongoing initiatives to restore tidal wetlands in the Delta and our ability to manage them in a changing world.
This project aims to improve understanding of atmospheric and hydrologic carbon fluxes in a restored tidal salt marsh in the South San Francisco Bay. I will use soil chambers to measure how much carbon dioxide and methane is taken in and emitted from the marsh. The project will also examine how spatial variability in marsh surface cover impact these exchanges. Shahan will use the data collected in this study to create a biogeochemical model that estimates the carbon budgets of wetlands in the Bay-Delta. A complete carbon budget will illuminate relationships between carbon fluxes and environmental variables. This information can support more informed management of wetlands, as well as allow researchers and decision makers to more effectively plan wetland restoration to be effective in managing carbon fluxes in the face of possible impacts due to climate change.
AmeriFlux is a network of PI-managed sites measuring ecosystem CO2, water, and energy fluxes in North, Central and South America. AmeriFlux is now one of the DOE Office of Biological and Environmental Research (BER) best-known and most highly regarded brands in climate and ecological research. AmeriFlux datasets, and the understanding derived from them, provide crucial linkages between terrestrial ecosystem processes and climate-relevant responses at landscape, regional, and continental scales. Scientific Questions What are the magnitudes of carbon storage and the exchanges of energy, CO2 and water vapor in terrestrial systems? What is the spatial and temporal variability? How is this variability influenced by vegetation type, phenology, changes in land use, management, and disturbance history, and what is the relative effect of these factors? What is the causal link between climate and the exchanges of energy, CO2 and water vapor for major vegetation types, and how does seasonal and inter-annual climate variability and anomalies influence fluxes? What is the spatial and temporal variation of boundary layer CO2 concentrations, and how does this vary with topography, climatic zone and vegetation?
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.
A team at UC Davis (Dr. Mark Lubell, Dr. Gwen Arnold, PhD Candidate Kyra Gmoser-Daskalakis) is conducting social science research on wetland restoration in the California Bay-Delta as part of a larger, interdisciplinary project on wetland restoration across multiple University of California campuses and national labs ("Coastal Wetland Restoration a Nature Based Decarbonization Multi-Benefit Climate Mitigation Solution"). First, the project is conducting social network and spatial analysis using the EcoAtlas project database to examine drivers of wetland restoration investment in the Bay-Delta from the 1980s to now. Second, case studies of individual restoration projects and interviews with 40+ restoration project partners examines barriers to the restoration implementation and perceptions and goals of multi-benefits among interested parties. Preliminary results have been shared at the State of the Estuary and Bay-Delta Science Conferences in 2024. See https://wetlands.ucsc.edu/index.html for more information.
On-going subsidence of organic soils threatens the physical structure of the Delta, its central role in the state’s water system, many diverse species that depend on it, and threatens future agricultural production. Knowledge of baseline emissions and subsidence rates is important for developing alternative land use scenarios for maximizing benefits for sequestering carbon, reducing or reversing subsidence, providing income for landowners via the carbon market, and reducing flood risk. This project will gather, process, and analyze recent data in the Delta for land-surface elevation changes, greenhouse gas fluxes measured by eddy covariance and gas chambers, soil organic matter content, depth-to-groundwater, and soil organic thickness. These data will be used to update and calibrate the SUBCALC model and refine model inputs to improve the model’s ability to simulate subsidence and CO2 emissions. Collaboration with the Jet Propulsion Laboratory and UC Berkeley will allow use of CO2 flux and InSAR data to calibrate and validate the SUBCALC model. The Delta Conservancy is another partner assisting with assessment of modeling for land-use conversion planning. TNC and Metropolitan Water District are partners to assist with use of SUBCALC for engagement of the carbon market and collaborate with the Suisun RCD to improve estimates of subsidence and CO2 emissions.
