Cultural eutrophication activity. Polar regions have less human activity and subsequently less cultural eutrophication. One response to added amounts of nutrients in the aquatic ecosystem is the rapid growth of microscopic algae, also known as an algal bloom. In freshwater systems, the formation of floating algal blooms are commonly nitrogen-fixing cyanobacteria (blue-green algae). This outcome is favoured when nitrogen inputs are reduced and phosphorus inputs are increased. Large amounts of algae reduce the amount of dissolved oxygen available in the water for other organisms, which increases fish mortality rates. These areas affected by algal blooms are known as dead zones, and are
Liebig's law of the minimum Liebig's law of the minimum Liebig's law of the minimum, often simply called Liebig's law or the law of the minimum, is a principle developed in agricultural science by Carl Sprengel (1828) and later popularized by Justus von Liebig. It states that growth is dictated not by total resources available, but by the scarcest resource (limiting factor). The law has also been applied to biological populations and ecosystem models for factors such as sunlight or mineral nutrients. This concept was originally applied to plant or crop growth, where it was found that increasing the amount of plentiful nutrients did not