An oligotrophic lake or water body is one which has relatively low productivity due to the low nutrient content in the lake. These lakes usually have quite clear water due to the limited growth of algae in the lake. The waters of such lakes are of high-drinking quality. Such lakes support aquatic species who require well-oxygenated, cold waters such as lake trout fish. Oligotrophic lakes are usually found in the cold regions of the world where mixing of nutrients is rare and slow due to the low temperatures of the lake waters.
Oligotrophic lakes have the following characteristics:
- Net primary production is only between 50 and 100 milligrams of carbon per square metre per day (very low),
- nutrients are in poor supply, and
- secondary production is depressed.