Killing the Dead Zones

Killing the Dead Zones

LAST YEAR was particularly bad for the Chesapeake Bay. Among its many problems, 4.5 percent of the bay’s water had extremely low levels of oxygen saturation during the summer, creating anoxic "dead zones" that killed off valuable ecosystems. But according to a study issued recently, only 1.8 percent of the bay was anoxic this summer, encouraging the reestablishment of vital food chains. A separate evaluation released last week also highlighted a modest increase in the bay’s overall health.

What made the difference? Diligence on land may have prevented more nitrogen and phosphorus from feeding into the bay than in past years. But Beth McGee, a scientist at the private Chesapeake Bay Foundation, says human efforts should get only a small fraction of the credit. Anoxic water, a summer phenomenon, is caused by polluted runoff that flows into the bay during the spring. A dry spring, such as the one the region experienced this year, means less runoff and, therefore, fewer dead zones — even if the region is inundated later on, as it was in June. The foundation, which still gives the bay’s health a grade of D, also claims that even if all the projects to which states around the bay have committed are carried to completion, they will reduce annual pollution in the bay by only about 40 percent of their stated goal by 2010.

Still, bay states are improving their record on protecting the estuary, if too slowly, and they have time to expand their programs. Maryland encourages its farmers to plant cover crops to absorb nitrates and reduce runoff, a program paid for in part by the state’s useful Bay Restoration Fund. The Maryland Department of Agriculture has approved the subsidized planting of about 290,000 acres of cover crops for this fall — a number that should rise in future years. Virginia, which lags behind Maryland in its bay cleanup efforts, should guarantee revenue to do the same — so that farmers will be able to rely on timely support over many harvests. Both states should also expand programs that help farmers pay for other agricultural improvements, such as the construction and maintenance of riparian buffers, which are effective and natural pollution trappers.

Maryland‘s incoming attorney general, Douglas F. Gansler, ran on a platform of improving the bay by using the federal Clean Water Act to go after large agricultural polluters — even those out of state. That may also help Maryland meet its pollution reduction goals.