Editors' Summary: Pfiesteria piscicida, a sometimes toxic microorganism, is responsible for the death of millions of fish in Delaware, Maryland, North Carolina, and Virginia. Although the problem of Pfiesteria-related fish kills is associated with the Mid-Atlantic region, other toxic microorganisms have threatened fish and marine wildlife throughout the world. Scientists attribute this "global epidemic" of toxic microbes to excessive nutrient loading from nonpoint sources of pollution.

Water scarcity is no longer a threat, it is a reality. Increasing populations throughout the country and the world are putting increased pressure on existing supplies of freshwater. Cities, states, and regions are scrambling to find solutions to this burgeoning problem. The impact of drought, which has been felt not only in the typically dry Southwest, but also in the humid Southeast this past summer, compounds the problem. So, what mechanisms evolve to help alleviate the problem?