Forecasting Responses of Coastal Lands to Sea-level Rise

Since 1938, approximately 8,000 acres of marshland have been lost in Maryland’s Blackwater National Wildlife, which is a sanctuary for the Bald eagle, the Delmarva Fox Squirrel and the Peregrine Falcon.

December 4, 2012

From Louisiana to Maryland, from Delaware to New Jersey, the world’s most valuable ecosystem- coastal marshes, are threatened by sea level rise. An experienced team of faculty and graduate students from the Department of Environmental Science and Technology (ENST) are studying Chesapeake Bay coastal marshes along the Nanticoke River and at Blackwater Wildlife Refuge.


According to the National Oceanic Atmospheric Administration, since 1938, approximately 8,000 acres of marshland have been lost in Maryland’s Blackwater National Wildlife Refuge alone, vanishing at a rate of nearly 130 acres per year.

Dr. Andrew Baldwin, associate professor and wetland ecologist, explains that “the causes of the degradation include vegetation death and collapse of the root zone, increased rate of decomposition, drawdown of the water table, and decreasing sediment loads.” As a result, vertical accretion, the building up of a marsh, has not been as fast as the rate of sea level rise. 



Photos (left to right): Dr. Andrew Baldwin, Jenna Clark, Leah Beckett, Dr. Brian Needelman, Weisley Bickford, George Geatz, Jenny Allen. 

To understand the responses of tidal freshwater marshes to sea level rise, Dr. Baldwin and ENST graduate students Jenny Allen, Jenna Clark and Leah Beckett have been examining short and long-term rates of accretion and elevation changes since 2007. The team installed surface elevation tables and marker horizon plots along 20 miles of the salinity gradient in the Nanticoke River in Maryland and Delaware. “The preliminary findings indicate elevation decreases along the gradient, with the highest rates of elevation loss in brackish marshes despite high rates of accretion,” says Dr. Baldwin.

In a similar study, Dr. Brian Needelman, associate professor and soil scientist, is investigating ways of optimizing organic matter accretion through improved design and management of tidal marshes. “Organic matter accretion is critical because marshes must raise their elevation in order to keep pace with sea-level rise,” explains Dr. Needelman. “We are going to lose many of our coastal marshes in this century due to sea-level rise, but by maximizing accretion rates we can slow this loss and allow marshes to migrate inland.” Dr. Needelman and ENST graduate students Wesley Bickford and George Geatz conducted a field study at Blackwater and learned that prescribed burns will ultimatly stimulate increased plant growth through removal of the canopy. Their findings indicate that while these marshes will be lost to rising sea levels, the beneficial effect of canopy removal through burns may impede their pace of loss.