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Mulholland is an Author of New Report about Climate Change and the Cheseapeake Bay

Margaret Mulholland

Old Dominion University biological oceanographer Margaret Mulholland and a dozen other scientists have reviewed the latest research on climate change and its likely impacts on the Chesapeake Bay. Their report predicts mostly negative consequences by the end of the century, but also a few that might be positive.

Populations of marine fish that favor cold water - striped bass, summer and winter flounder and black sea bass are examples - can be expected to become less abundant, or disappear altogether from the bay, the scientists say. However, warmer water fish - cobia, Spanish mackerel, black and red drum and spot - may become more abundant.

The scientists paint an overall picture of increased incidences of flooding, the submergence of estuarine wetlands, and increases in harmful algae blooms that can be toxic, disrupt ecosystems and contribute to the oxygen-diminished dead zones in the bay.

Their article, "Potential Climate-Change Impacts on the Chesapeake Bay," was featured this fall in the journal "Estuarine, Coastal and Shelf Science." Other than Mulholland, the authors include the research team leader, Raymond Najjar, of Penn State University, as well as coauthors from the University of Maryland, Cornell University, Virginia Institute of Marine Sciences, Smithsonian Environmental Research Center, and additional laboratories and government agencies.

"The goal of this paper is to review and synthesize the scientific literature on climate change impacts on the Chesapeake Bay, one of the largest and most productive estuaries in the world," the authors write. Recent government reports show that the bay's commercial fisheries are worth $172 million annually. "Although these figures are significant, they understate the value of the Chesapeake Bay and its fisheries because they do not account for the ecological and recreational services the bay provides to the food web and fisheries of the North American Atlantic Coast."

Added Mulholland in an interview, "While there have been a variety of studies assessing impacts of climate change in terrestrial and oceanic systems, impacts to estuaries have been largely ignored. These highly variable and complex regions are among the most productive ecosystems on earth."

Estuaries and coastal systems also have a long history of being impacted by human populations, she said. Efforts to restore the Chesapeake Bay, the nation's largest estuary, are being accelerated as a result of President Obama's recent executive order on Chesapeake Bay Protection and Restoration.

"To be successful, actions taken affecting this national treasure must consider climate change, as climate change will undoubtedly affect the delivery of nutrients and other pollutants into the bay," Mulholland said.

The authors elaborate on the numerous impacts to the bay that will likely occur as a result of current and projected rises in atmospheric carbon dioxide concentrations, and associated sea level rise and increased air and water temperatures. They also provide a laundry list of research that remains to be done in order better understand how this complex estuarine ecosystem works, how climate change might affect the ecosystem function, and how humans might adapt to these changes.

Among the scientists' recommendations is more social science research. "Climate change in the Chesapeake Bay region has the potential to create cultural and socio-economic impacts on a wide range of stakeholders, including commercial watermen, farmers, property owners, and municipal and county governments," according to the researchers' article. They declare that it is important that climate change be incorporated into the public planning and policy process.

Based on the scientists' review of previous research, they note that some impacts of global warming could allow a longer growing season for finfish and shellfish in the bay and provide other changes that might actually increase yields of valuable resources such as blue crabs and oysters. On the other hand, the soft clam, an important fisheries stock now, could be lost to the bay because of warming waters by the century's end. Also, the scientists report that warming waters could give new vigor to pathogens and parasites that already cause millions of dollars in losses for commercial fisheries.

This effort to synthesize research on climate change to project future scenarios for the Chesapeake Bay system was initiated through the Scientific and Technical Advisory Committee of the Chesapeake Bay Program (CBP). Mulholland became a member of this committee in 2006. She applies her expertise on nutrient enrichment and algae blooms and other aspects of biological oceanography on behalf of the CBP, which is a joint program involving the states of Virginia, Maryland, Pennsylvania, Delaware, New York and West Virginia, as well as the District of Columbia, the Chesapeake Bay Commission and the U.S. Environmental Protection Agency.

An ODU faculty member since 2000, Mulholland was granted a doctorate in biological oceanography by the University of Maryland in 1998. Her research focus involves various aspects of carbon and nitrogen cycling in aquatic systems.

This article was posted on: December 15, 2009

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