The Blackwater National Wildlife Refuge is a wetland of international importance, named in the International Convention on Wetlands (Ramsar Convention). It is one of six priority wetland areas noted in the North American Waterfowl Management Plan. The Nature Conservancy calls it one of the “Last Great Places.” Others have labeled it as the “Everglades of the North.”
The MRCSP team examined three tidal marsh cells -- one newly created 5-acre cell, created with dredge material in 2003; one older cell, created in 1983; and a third that was a natural marsh cell. Researchers established approximately 50 field plots per cell and conducted annual soil analyses, including organic carbon content, bulk density, active carbon (particulate, chemically labile), nutrients, pH, and other selected samples, such as particle size, sulfides, and metals.
These tests were used to determine the rate of carbon sequestration and the total amount of carbon that can be sequestered in restored versus natural marshes. While rates may start slowly, it is anticipated that total amounts sequestered in restored marshes could match or exceed natural marshes. Research will also identify the best management practices to maximize carbon sequestration by maximizing net primary productivity and minimizing decomposition rates. This project will help to develop a sampling protocol for validation that can be used elsewhere.
Finally, the research shed light not just on carbon sequestration potential in marshes and wetlands, but also helped scientists better understand marsh sustainability and soil properties, including the effects of different grasses, nutrients and sediment inputs and retention, as well as the biogeochemistry of a marsh, including effects from eutrophication (lack of oxygen) and acidification.