Wetland and Marshland

Wetland and Marshland

During the Validation Phase, MRCSP worked with researchers from the University of Maryland to investigate the potential of reclaimed wetland and marshland for carbon sequestration. 

Wetlands and marshlands have great potential for carbon sequestration because they have high levels of net primary productivity and low decomposition rates, meaning that a large volume of organic matter is accumulated annually. It is believed that carbon can accumulate at rates up to 5,700 kilograms of carbon per hectare (~5,100 pounds of carbon per acre) per year in wetlands. The continual accretion from organic matter (i.e., the buildup of land from waterborne sediments) means that there is potential for long-term continual carbon sequestration.
Yet, as seen in the photos below, 8,000 acres or 12 square miles have been lost, at a rate of 150-400 acres per year. Reasons for loss include sea level rise, subsidence (or sinking), erosion, salt water intrusion, and plant-eating invasive species.
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    1938

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    2005

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Marshes Can Be Restored

Using clean dredged material from the Chesapeake Bay channel, the U.S. Army Corps of Engineers is engaged in a project to help restore the wetlands at the Blackwater Refuge. Volunteers plant marsh grasses, including Olney’s 3-square (Schoenoplectus americanus), salt marsh bulrush (Schoenoplectus robustus), and smooth cordgrass (Spartina alterniflora), on the clean dredge, quickly restoring the marsh.
The Value of the Research

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.

Project Snapshots

Representatives from participating organizations visited the research site in November, 2006. They included representatives from the U.S. Fish and Wildlife Service, the DOE, and members of the university research team and the MRCSP. Click here to view photographs of their visit; a presentation on the Wildlife Refuge by Dixie Birch, U.S. Fish and Wildlife Service; and a presentation of the terrestrial sequestration research by Dr. Brian Needelman, University of Maryland.
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