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  • Title

    Delta Wetland Resilience and Blue Carbon

    Lead San Francisco Estuary Institute [SFEI]
    Description This project estimates 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 investigates 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 will be 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 June 14, 2024
  • 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