The other day I discovered that for 15 years I have been living in a vast watershed. As a resident of Silver Spring, I’d wandered along the Sligo Creek, and seen the Great Falls of the Potomac, but never realized they were connected, or that they both fed into the Chesapeake Bay.
The Chesapeake Bay: Every time I turn on my tap to shower or have a cup of tea, I am using this watershed of creeks, streams, rivers and wetlands that flow into the bay like arteries. Credit: John Tidwell
Every time I turn on my tap to shower or have a cup of tea, I am using this watershed of creeks, streams, rivers and wetlands that flow into the bay like arteries. Famous East Coast waterways like the Susquehanna, Rappahannock, Potomac and James rivers, covering several hundred miles of Southern New York, Pennsylvania, the Virginias, Maryland and Delaware all end up in the Chesapeake Bay, linking its health directly with these states.
So it was quite a shock when I found out that last June, scientists discovered that an underwater “Dead Zone” growing for two decades in the Chesapeake Bay, had reached its largest size ever: an 80-mile plume that ran from Baltimore Harbor down to Virginia, more than a third of the entire 200-mile long watershed.1
Dead Zones are regions of coastal waters where oxygen is so low that almost nothing can live in them. Today such Dead Zones have been appearing annually in more than 400 offshore regions around the world, including the Mississippi Delta and Lake Erie.They are caused by a lethal mix of fertilizer run-off from farms, sewage dumping from cities and airborne fossil-fuel pollutants that literally rain down to the sea in precipitation.2 Dead Zones are not only bad for the bay’s 3,600 plants and animal species, but also for the people and local economies who depend on them. Some 500 million tons of seafood is harvested each year from the bay, including rockfish, striped bass and Maryland’s famous blue crabs. But since the 1990s the Chesapeake’s Dead Zone has reduced crabbing harvests by 70 percent, according to a Chesapeake Bay Foundation report.
Last year scientists at the University of Maryland’s Center for Environmental Science (UMCES) at Horn Point, discovered an even more worrisome impact of Dead Zones: they exacerbate global climate change. According to research by Dr. Lou Codispoti and his team, nitrous oxide (N2O), a bi-product of Dead Zone chemistry, rises out of the water into the atmosphere, where it intensifies the effects of greenhouse gases and helps make holes in the Earth’s ozone layer.3
The making of a dead zone
For decades scientists and governments have tried all sorts of strategies to dispel Dead Zones, some even pumping oxygen directly into the water.4 But Maryland researchers say a more feasible solution would be to let the Chesapeake’s natural ecological systems clean up the bay, as they did for tens of thousands of years.
In the late 1980s, UMCES scientist Roger Newell wrote that oysters, once abundant throughout the Chesapeake Bay, had functioned as a vast, water filtering system that kept the estuary vibrant and balanced.5 A variety of sea grass species, which once blanketed the ocean bed along the U.S. East Coast, also played a crucial role in controlling bay erosion and sequestering any excess nutrients.
Unaware of ecosystems or that oysters kept the bay healthy, humans of the 17th to the 19th centuries considered the Chesapeake’s vast oyster reefs delicious and free for the taking. For more than 200 years, overfishing and later two disease epidemics reduced the oyster population of North America’s largest estuary by more than 95 percent. Half of the Chesapeake’s wetlands and 80 percent of its aquatic grasses have also been lost because of land development and pollution. Today the bay’s health rates 28 out of a pristine 100 point scale. The story is the same for estuaries throughout the East Coast. In recent decades conservation organizations from Maine to Georgia have tried to find ways to restore native Eastern Oyster reefs to their waters, but met with mixed results. Apparently mimicking natural ecosystems that took millennia to evolve isn’t easily accomplished.
“Restoration of habitat is a new discipline,” explains Dr. Ray Grizzle, an expert in estuary biology at the University of New Hampshire, “We need to really understand … the natural system and its ability to respond to what we do.”6
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Listen to the full interview with Dr. Ray Grizzle:
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Scientists like Grizzle are also working to re-establish oyster beds with specially bred, disease-resistant oysters. Since 1994 scores of oyster sanctuary projects, some as large as 36,000 acres, were created throughout the bay, and are off-limits to harvesting.7 Adult oysters can filter about 50 gallons of seawater per day, and once they clear the water, Grizzle says new sea grass plantings can take root and help prevent wave erosion. Marsh grasses on the bay’s banks can also help remove nitrogen from groundwater, so bottom–dwelling oysters can have more oxygen-rich water.8
Unaware of ecosystems or that oysters kept the bay healthy, humans of the 17th to the 19th centuries considered the Chesapeake’s vast oyster reefs delicious and free for the taking.
If the Eastern oysters can be restored to their original numbers, Grizzle says, they wouldn’t be harvested. These oysters would provide what conservation scientists call “Ecosystem Services”, like cleaning the bay water, while those found in restaurants would be from farms, just as they are today. Grizzle says restoring the bay will take serious financial and political commitment, which isn’t easy to find in current economic hard times.
“This is not a one to two year project and then you walk away,” he says, “We need five to ten year commitments. You can’t do this piecemeal.”9
But the politics of conservation is neither simple, nor easy. 2011 has been a contentious year for Chesapeake Bay funding, with political battles, largely along party lines, pitting powerful agriculture lobbies against bay supporters like President Obama. Last year Mr. Obama’s Chesapeake Bay Executive Order got federal agencies to draft a $491 million action plan to restore the Bay,10 and by December the EPA had created a ‘Pollution Diet’ strategy to reduce agricultural run-off nationwide by 40 percent.11
But House Republicans and agriculture industry lobbyists were equally convinced such actions would be too expensive and restrictive for businesses. During the first half of 2011, they mounted scores of lawsuits and bills to halt the Chesapeake Bay effort and called for drastic cuts to the EPA’s funding in 2012’s national budget. While a deal was reached by August 2 in the House of Representatives, including a proposed $14.7 million increase to the EPA’s Chesapeake Bay Program,12 no one knows if gains will survive this September in the Senate. Which leaves the future of the Chesapeake Bay in a strange limbo, caught between warring political parties. The irony is, most scientists working on the bay maintain that the science and strategies to restore it are ready. All they need is the support and funding.
“The bay is probably the most studied, data-rich estuary in the world, explains Ann P. Swanson, Executive Director of the Chesapeake Bay Commission, which is supported by Maryland, Virginia and Pennsylvania state governments. “So if there is any place that we would know what to do, it is here.”13
Footnotes:
1Darryl Fears, Alarming ‘dead zone’ grows in the Chesapeake,” Washington Post, July 20, 2011.
2Julia Whitty, Dead zones fuel global warming,” Mother Jones, Mar. 11, 2010.
3Julia Whitty, Dead zones fuel global warming,” Mother Jones, Mar. 11, 2010.
4Kari Lydersen,The Washington Post, Scientists warn of persistent ‘Dead Zones’ in Bay, elsewhere, Feb. 17, 2009.
5Merrill Leffler, Oyster reefs: Key to restoring Bay grasses?, Maryland Marine Notes, Jan.-Feb., 2001.
6Interview with Ray Grizzle by J. Tidwell, July 2011.
7Darryl Fears, Maryland’s plan to boost Chesapeake Bay oysters will require a lot of hanky-panky,” Washington Post, May 26, 2011.
8Merrill Leffler, Oyster reefs: Key to restoring Bay grasses?, Maryland Marine Notes, Jan.-Feb., 2001.
9Interview with Ray Grizzle by J. Tidwell, July 2011.
10Interview with Ann P. Swanson by J. Tidwell, August 2011.
11RootsWire: EPA Chesapeake Restoration Adviser confident about pollution diet in court Aug. 3, 2011.
12EPA Budget Proposal 2012.
13Interview with Ann P. Swanson by J. Tidwell, August 2011.