The Sherman Island site is a 38-ha peatland pasture, west of the Delta, that is owned by the state and managed by the California Department of Water Resources. The site is degraded and heavily grazed with ~100 cattle in the area that circumscribes the main field and fetch. The island has been drained and farmed since the late 1800s. The soils of the Delta overlay deep peat that was sequestered over the Holocene period as sea-level rose and flooding of archaic wetlands prevented decomposition of roots and stems. Hence, the upper 10 m of peatland has been lost to decomposition, compaction, and subsidence. Today a mineral soil overlays a peat layer, which coincides with the general depth of the water table. This site was discontinued in 2015 as the land was converted into a restored wetland. A new site was established in 2016 nearby, US_Sne

The research approach of the University of California, Berkeley Biometeorology Laboratory involves the coordinated use of experimental measurements and theoretical models to understand the physical, biological, and chemical processes that control trace gas fluxes between the biosphere and atmosphere and to quantify their temporal and spatial variations. By developing and testing methane efflux models within a peatland pasture, new methane emission algorithms can later be implemented in coupled climate-carbon cycle models. The research objectives of the Mayberry Wetland, Sherman Island, and Twitchell Island sites are as follows: 1) Describe differences in the fluxes of CO2, CH4, H2O, and energy between different land uses; 2) Understand the mechanisms controlling these fluxes; 3) Use ecosystem modeling to understand controls on these mechanisms under different environmental scenarios. These three sites were selected to capture a wide range of inundated conditions within the Sacramento-San Joaquin River Delta. The research focuses on the eddy covariance technique to measure CH4, CO2, H2O, and energy fluxes and works to combine measurements of both net fluxes and partitioned fluxes in order to achieve a mechanistic understanding of the ecological controls on current and future carbon flux in the Delta.