WWR led a collaborative research team to develop and test Best Management Practices for operating diked, seasonally managed wetlands in Suisun Marsh to reduce their generation and discharge of low dissolved oxygen (DO) waters and elevated methyl mercury (MeHg) concentrations.
Low DO events have been documented periodically in the smaller perimeter tidal sloughs in Suisun Marsh mainly in fall months when the diked marshes begin their fall flood-up cycles. Conditions leading to low DO events also support the biogeochemical processes that transform mercury ubiquitous in soils into the toxic methyl mercury form.
This two-year field study utilized two diked marshes for management modifications and intensive field sampling that included continuous measurements of water depth, temperature, conductivity, DO, pH and chlorophyll, grab soil and water samples for MeHg and organic carbon, meteorological data, wetland topography and vegetation, and a laboratory experiment for MeHg-vegetation relationships. Collaborators included Bachand and Associates, Suisun Resource Conservation District, U.S. Geological Survey, California Department of Water Resources, U.C. Davis, and the Moss Landing Marine Laboratory.