A microbe that has been linked to massive fish kills in Maryland, Delaware and North Carolina. Some scientists believe pfiesteria’s growth is fostered by nutrients such as nitrogen and phosphorus from air pollution, cities, suburbs, sewage plants and farms. Both nitrogen and phosphorus are concentrated in chicken manure, which is spread liberally on farmland as fertilizer in watersheds adjoining the affected rivers. While there is no proven direct connection, the farm community is involved in efforts to identify the causal linkages and remedy the problem.