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
Jethro Tull (agriculturist) the plant." Again, he declares elsewhere, "That which nourishes and augments a plant is the true food of it. Every plant is earth, and the growth and true increase of a plant is the addition of more earth." And in his chapter on the "Pasture of Plants", Tull told his readers with great gravity that "this pasturage is the inner or internal superficies of the earth; or, which is the same thing, it is the superficies of the pores, cavities, or interstices of the divided parts of the earth, which are of two sorts, natural and artificial. The mouths or