Dead Seas: Nutrient Pollution in Coastal Waters

by Doug Daigle

The English poet William Blake claimed we could see the world in a grain of sand. Substitute a bit of sediment from the floor of the Gulf of Mexico off Louisiana, and observe how right he was. The record of chemical change recorded in the sediment, and in dead, bottom-dwelling creatures like crabs, brittlestars and seaworms around it, points to a world far different than the one Blake knew. Every summer, following spring flows on the Mississippi, the Gulf experiences a massive die off or "dead zone," the result of nutrient pollution.

Human modification of the global carbon cycle (through the burning of fossil fuels) has garnered the lion's share of public attention due to the implications of climate change, yet human changes to the global nitrogen cycle have been just as profound.

From 1960 to 1990, human activities ranging from sewage pumping to use of synthetic fertilizers and pesticides to tailpipe emissions from cars and trucks more than doubled the amount of nitrogen in the global system, and increased the flow of nitrogen to U.S. coastal waters by four to eight times.

During the same period, the flow of another nutrient, phosphorous, into the oceans increased by a factor of three. South Florida's politically powerful sugar industry (federally subsidized since the U.S. embargo of Cuba was established) is just one example of a major user of phosphorous fertilizer in an ecosystem (including the Everglades and coral reefs) that historically has thrived in a low-nutrient environment.

The most pervasive result of this change has been the spread of eutrophication, or the loading of nutrients and organic matter, in coastal ecosystems. Scientists have cited this "over-enrichment" of coastal waters by nutrients, in particular nitrogen, as the most widespread and measurable effect of pollution in U.S. coastal waters. Two-thirds of estuaries and bays in the United States are showing symptoms of eutrophication, which can including hypoxia (low oxygen), toxic algal blooms (that can kill fish and sicken people), and the loss of habitats such as corals and sea-grass beds.

The annual "dead zone" that forms off Louisiana's coast is one of the largest manifestations of this trend. In 2002, the Gulf hypoxic zone reached a new record size of over 8,000 square miles, an area larger than the state of New Jersey. Yet hypoxia is also a long-standing problem in the Chesapeake Bay and Long Island Sound, and has had a dramatic increase off North Carolina's coast in recent years (a growth paralleled by that of massive corporate hog farms -- and their waste lagoons -- in the state's floodplains). The low oxygen levels that constitute hypoxia can decimate benthic (bottom-dwelling) life forms, disrupt marine food chains and impact fisheries.

One of the most extensive scientific assessments carried out to address one of the largest problems, "The Integrated Assessment of Hypoxia in the Northern Gulf of Mexico," was published in 2000. It involved a team of 47 leading scientists to produce six reports that examined environmental, economic and social dimensions of the "dead zone" problem. In the same year, the National Research Council published its own evaluation of coastal eutrophication, predicting that the trend will increase with population growth.

These and other studies report that:

• The activities that lead to nutrient loading, such as chemical-intensive agriculture, fossil fuel combustion, urban runoff and wastewater, have been clearly identified.
• While there have been significant reductions in point source (end of the pipe) discharges over the past 30 years thanks to the Clean Water Act, pollution from non-point sources (such as agricultural and urban runoff) has increased.
• Alterations in the landscape, such as loss of wetlands and salt marshes due to coastal sprawl, and "channelization" of streams and rivers by the Army Corps of Engineers and others, have worked to remove the buffering capacity of natural systems to filter and absorb nutrients from the water.
• The combination of these trends means that addressing coastal eutrophication in a significant way will mean dealing with watersheds far inland, sometimes hundreds or even thousands of miles upstream from beaches and shores.

These challenges figure prominently in two of the largest U.S. watersheds, the Chesapeake Bay and the Mississippi River Basin. Sewage and atmospheric deposition of nitrogen have more of an impact in the relatively enclosed Chesapeake system, where rapid urbanization combines with agro-industrial poultry production by contract farmers for Tyson, Perdue and other corporations to amplify the effects of nutrient loading in the watershed. In the Mississippi River, by contrast, most of the nitrogen enters the river north of its confluence with the Ohio, from sub-basins of the U.S. agricultural heartland. The Mississippi watershed drains 52 percent of U.S. farms that over the last half century have become increasingly dependent on chemical inputs. These chemicals both deplete the soil and follow streams' and rivers' spring flood into the Gulf of Mexico.

Yet the actions and policies that can reverse these trends are relatively clear in theory and practice. Eutrophication in coastal waters can be reduced, although the recovery time of ecosystems and species may be long, depending on the degree of damage.

On a global scale, the Black Sea offers an interesting case study. The collapse of the Soviet economy resulted in a drastic reduction in production of fertilizer in countries bordering the Black Sea. The subsequent reduction in runoff led to a significant reduction in the Black Sea's polluted areas.

Although those economic conditions are not likely to be replicated in the United States, it does demonstrate the ability of coastal and marine systems to recover from environmental abuses. There are also success stories in the United States that have resulted from implementing far-sighted legal and policy options. Reductions in discharges have raised oxygen levels in the Delaware River estuary near Philadelphia and in New York harbor, while partial recovery of seagrass beds following reductions in nutrient pollution has been observed in Sarasota, Tampa and Chesapeake Bays.

At the same time, success cannot be assumed. Larger watersheds pose larger challenges. The process that led in 2000 to a consensus of federal agencies and states along the mainstem Mississippi River on an "Action Plan for Reducing, Controlling, and Mitigating Hypoxia in the Northern Gulf of Mexico" was long and at times combative, as upstream states came to terms with the effects of their economies on waters far away. Yet the fate of the Action Plan also illustrates another dimension of the challenge: mustering political will.

The hypoxia issue was addressed at the highest levels of government during the Clinton administration, which ended as implementation was set to begin. Three years after its completion, the Action Plan is still largely unfunded under the Bush Administration, and implementation is running at least two years behind schedule. Fiscal policy at the federal level has denied states the assistance they need, and has impeded coordinated action throughout the basin. While many career people within the Environmental Protection Agency and the National Oceanic and Atmospheric Administration continue to advocate for full federal participation in the recovery plan, the administration's attitude seems one of, at best, benign neglect.

Even where significant policies have been implemented on a national scale, such as the conservation and nutrient management programs in the Farm Bill, funding has been uncertain, and other trends such as urbanization of watersheds could counteract agricultural reductions of nutrient runoff.

The National Research Council report on coastal eutrophication recommended that reducing nutrient pollution should be a national priority, and called for a nationwide strategy to achieve that goal.

The outlines of a national initiative also have to start at a fundamental level, with the funding of an adequate monitoring system to assess the health of ecosystems and of programs to improve water quality. But some in the U.S. Congress are pushing hard to gut the budget of the U.S. Geological Survey, the primary monitoring agency.

Many estuaries do have defenders, however, with interagency programs, citizen-activist groups and the general public acting to improve water quality, reduce habitat loss and direct public and private resources to restore the health of coastal systems. One coalition of activists, Restore America's Estuaries, steered passage of the federal Estuary Restoration Act (ERA) of 2000, and created a "National Strategy to Restore Coastal and Estuarine Habitat" that complements the various government studies and action plans of recent years. While the Estuary Act calls for $275 million in restoration funding, only about $1 million has been allocated to date.

Funding and expanding programs to address nutrient pollution is essential if healthy living watersheds, coasts and seas are to be restored.

To do that, however, requires broadening political constituencies of support -- a reasonable goal, since all people depend on watersheds.

Doug Daigle is the Lower River Program Director for the Mississippi River Basin Alliance, a non-profit organization representing 150 groups along the length of the river dedicated to the protection and restoration of the health of the river system and the communities who depend on it.