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  • Title

    Delta Wetland Resilience and Blue Carbon

    Lead San Francisco Estuary Institute [SFEI]
    Description This project estimatee carbon storage for the past, present and future Delta, as well as GHG fluxes and elevation change based on chosen restoration and rice farming scenarios in the future Delta using the Delta Landscape Scenario Planning Tool. The project also investigated how well the current organic matter parameterizations and inorganic sediment parameterization in the Marsh Equilibrium Model (MEM) represent Delta marsh accretion processes. Knowledge of marsh accretion and migration was used to develop a spatial conceptual model of marsh resilience in the Delta.
    Science topics Carbon, Greenhouse gas GHG, Resilience, Sea level rise, Subsidence, Wetlands
    Updated October 24, 2025
  • Title

    Carbon Biogeochemical Cycling in Tidal Wetlands: Exploring Lateral Carbon Exchange and Sequestration Potential

    Lead University of California - Berkeley [UC Berkeley]
    Description Tidal wetlands, at the interface of land and ocean, play a critical role in carbon biogeochemical cycling and have the potential to provide major feedback to the Earth system through greenhouse gas exchange and long-term carbon sequestration. However, the efficiency of carbon sequestration in tidal systems relies on both vertical carbon exchange with the atmosphere and lateral tidal exchange with adjacent water bodies. Unfortunately, the importance of hydrologic carbon fluxes has been largely overlooked, leaving a crucial aspect of coastal wetland net carbon balance unaddressed. We employed an integrated approach to quantify vertical and lateral carbon exchange and studied their dynamics, combining eddy covariance flux measurements with on-site water quality and tidal discharge measurements, as well as manual 24h surface water samplings. Our measurements were conducted in a recently restored tidal freshwater marsh in the Sacramento-San Joaquin Delta, CA, that stands out in global networks like FLUXNET and Ameriflux owing to its impressive net ecosystem exchange of -850 g C m-2 yr-1. Using wavelet decomposition, we examined the variability of carbon exchange (CO2 and CH4) across different timescales. Through information theory and mutual information analysis, we assessed the factors influencing both vertical and lateral exchanges. Our preliminary findings suggest that variability in carbon exchange is largest at the diel scale, with plant gross primary productivity and tidal fluctuations in depth having the most significant interactions with CO2 and CH4 fluxes, respectively. Furthermore, our tidal cycle samplings revealed that dissolved inorganic carbon dominates the fraction of lateral carbon loss, accounting for approximately 80% of the export. Remarkably, similarities existed between the values for net lateral carbon export and ecosystem respiration, signifying that the dissolved, terrestrial-to-ocean carbon flux could represent one of the primary fates of the fixed carbon in this tidal ecosystem. These large dissolved inorganic carbon fluxes and their chemical speciation, are important to consider when estimating the climate mitigation potential of restored tidal wetlands.
    Science topics Carbon, Carbon storage, Greenhouse gas GHG
    Updated January 30, 2024
  • Title

    Fish and Fish Habitat Monitoring - Wetland Regional Monitoring Program.

    Lead University of California - Davis [UC Davis]
    Description

    The Wetland Regional Monitoring Program (WRMP) Fish and Fish Habitat Monitoring project is a collaborative effort to track biological responses to tidal wetland restoration in the San Francisco Estuary. Monthly sampling is conducted across a network of benchmark, reference, and project restoration sites in the South Bay and North Bay, with the goal of evaluating how wetland restoration influences fish assemblages, habitat use, and ecological condition.

    The study uses primarily otter trawls to monitor fish and macroinvertebrate communities. Standardized field methods align with those used in long-term monitoring programs to ensure comparability and data integration across regions. Environmental data, including water temperature, salinity, and dissolved oxygen, are collected in tandem with biological sampling to assess habitat quality and seasonal dynamics.

    The program addresses WRMP Guiding Question #4: How do policies, programs, and projects to protect and restore tidal marshes affect the distribution, abundance, and health of fish and wildlife? The data support adaptive management, regulatory compliance, and science-based restoration planning by identifying key habitats, tracking restoration performance, and detecting regional patterns in species composition and abundance over time.
    Science topics Backwater, Benthic, Benthos, Biosentinels, Bivalve, Corbicula and Potamocorbula, Crustaceans, Dissolved oxygen, Dredging, Drought, Endangered species, Environmental drivers, Estuaries, Fish, Flows, Habitat, Habitat restoration, Intertidal and transition zones, Invasive and non native species, Invertebrates, Jellyfish, Longfin Smelt, Marsh wildlife, Mollusks, Monitoring methods and techniques, Mudflats, Mysis, Other species, Pelagic fish, pH, Resilience, Restoration, Restoration planning, Sacramento Splittail, Salinity, Sloughs, Steelhead Trout, Striped bass, Sturgeon, Tidal wetlands, Tides, Turbidity, Wastewater discharge, Water, Water temperature, Wetland mapping, Wetlands, White Sturgeon
    Updated May 28, 2025
  • Title

    Ecosystem Engineering Impacts of Water Primrose in the Delta

    Lead University of California - Merced [UC Merced]
    Description

    Water primrose (Ludwigia spp.) is a highly invasive, non-native floating macrophyte in the Delta. In recent years, water primrose has extended its niche into marsh habitat, causing extensive mortality of marsh macrophytes including tules and cattails. The goal of this project is to determine whether the growth strategy of water primrose, its allelopathic properties, or factors related to plant community structure are the cause of marsh loss following water primrose invasion in the Delta. Part of this study will identify and map the marshes most vulnerable to loss and quantify the spatial trajectory of marsh loss during the past 15 years. The ultimate benefit will be an improved understanding of the water primrose invasion processes in the Delta, which can be used to prioritize herbicide treatment of this highly invasive plant in marshes most vulnerable to invasion and with the highest habitat value.

    Objectives:

    1. Determine which water primrose functional traits are the likely cause of marsh loss in the Delta.
    2. Determine the effect(s) of community structure on water primrose invasion success and occurrence of marsh loss.
    3. Quantify the amount and spatial trajectory of marsh loss due to primrose invasion from 2004 - 2019.
    4. Identify and map the marshes that are most vulnerable to loss due to water primrose invasion in the Delta.
    5. Disseminate findings to relevant state agencies and additional stakeholders to ensure habitat restoration success and sustainability, and to focus resources on controlling water primrose in marshes most vulnerable to loss and of highest habitat value.

     
    Science topics Aquatic vegetation, Emergent macrophytes, Environmental drivers, Floating aquatic vegetation, Habitat, Habitat restoration, Intertidal and transition zones, Invasive and non native species, Landscape change, Landscape metrics, Remote sensing, Residence time, Resilience, Restoration, SAV and FAV, Submerged aquatic vegetation, Tidal wetlands, Wetlands
    Updated December 11, 2025