Nonpoint source water pollution regulations in the United States The primary nutrients found in water due to nonpoint source pollution are nitrogen and phosphorus from fertilizers. An influx of these nutrients can lead to eutrophication within the water. This is when there is an excess of nutrients in water, thus leading to an explosion in the growth of algae. The algae can cover the lake and block sunlight from reaching the organisms below, typically killing them. NPS water pollution is regulated at the federal, state, and local level. Yet, the pollution persists and remains a significant problem. There are a number of reasons why current regulations have failed to
Plant defense against herbivory change their defenses in response to changes in nutrients. For example, if plants are grown in low-nitrogen conditions, then these plants will implement a defensive strategy composed of constitutive carbon-based defenses. If nutrient levels subsequently increase, by for example the addition of fertilizers, these carbon-based defenses will decrease. The growth rate hypothesis, also known as the "resource availability hypothesis", states that defense strategies are determined by the inherent growth rate of the plant, which is in turn determined by the resources available to the plant. A major assumption is that available resources are the limiting factor in determining the maximum