However, other factors may contribute to toxic Pfiesteria outbreaks by promoting the growth of Pfiesteria populations in coastal waters. These factors include warm, brackish, poorly flushed waters and high levels of nutrients. Nutrients such as nitrogen and phosphorus are thought to encourage the growth of Pfiesteria populations by stimulating the growth of algae that Pfiesteria feeds on when in its non-toxic forms. Some evidence suggests that nutrients may also directly stimulate the growth of Pfiesteria , but more research is needed to show this conclusively. At this time, the precise role that nutrients and other factors may play in promoting toxic outbreaks of Pfiesteria is not clear, and is an area of active research.
Excess nutrients are common pollutants in coastal waters.
Chief sources of nutrient pollution in coastal areas are sewage treatment plants, septic tanks, polluted runoff from suburban landscape practices and agricultural operations, and air pollutants that settle on the land and water. State and federal agencies are working closely with local governments and academic institutions to address the problems posed by Pfiesteria . Federal agencies involved in the effort include the U.S. Environmental Protection Agency, the National Oceanic and Atmospheric Administration, the Centers for Disease Control and Prevention, the National Institute of Environmental Health Sciences, the Food and Drug Administration, the U.S. Geological Survey, and the U.S. Department of Agriculture. A few fish with lesions or even a few dead fish are not cause for alarm. If you experience health problems after being exposed to fish, water, or air at the site of a fish kill or suspected toxic Pfiesteria outbreak, contact your physician and your state or local public health agency at once.