The Missing Greenhouse Gas - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 81

do about nitrates because nature is doing a lot to eliminate them.” In other words, man
can learn to imitate nature's nitrogen-scrubbing processes.
Consider denitrification, for example. When water with a heavy nitrate load flows
through groundwater that has lots of carbon and little oxygen, the bacteria turn it into
harmless nitrogen gas. By enhancing this natural process, people can greatly reduce the
problem of too much nitrogen.
An accident around the Black Sea offers a mixed lesson on the revivification of
dead zones. After the dissolution of the Eastern Bloc, Black Sea nations with centrally
planned economies could no longer afford to use manufactured fertilizers. (And they
don't use the nitrogen-heavy feed for their animals that American farmers do.) Within
seven years, the nitrogen load flowing into the Black Sea had dissipated and most of the
dead zones disappeared; now the depleted fisheries are reviving. Which has been ex-
cellent for environmental health but devastating to local farmers and regional econom-
ies. Some argue that if the amount of fertilizer applied to the Mississippi River Basin
was dramatically cut, it would help to reduce the Gulf's dead zone, but at the cost of
US farmers' export of grain, a major crop. This is just one example of how complex the
politics of dead zone cleanup can be—a situation that will almost certainly be exacer-
bated as the effects of the BP oil spill are felt in the Gulf, while the human population
continues to grow, and demand for food—and clean water—intensifies.