Nutrients - Elements or compounds essential for growth of organisms. Oligotrophic - A condition of lakes characterized by low concentrations of nutrients and algae and resulting good water transparency. An oligotrophic lake has less nutrients than a mesotrophic or eutrophic lake. Pathogens - Microorganisms that can cause disease in other organisms or humans, animals, and plants. Pathogens include bacteria, viruses, fungi, or parasites found in sewage, in runoff from farms or city streets, and in water used for swimming.
Pathogens can be present in municipal, industrial, and nonpoint source discharges.
Pelagic Zone - Deep, open water area of a lake away from the edge of the littoral zone towards the center of the lake. A pH less than 7 is considered acidic and above 7 is basic. Phosphorus - One of the elements essential as a nutrient for the growth of organisms. In western Washington lakes, it is usually the algae nutrient in shortest supply relative to the needs of the algae. Phosphorus occurs naturally in soils, as well as in organic material.