Impacts of nitrogen pollution on terrestrial ecosystems in the United States
Nitrogen (N) has historically been the nutrient that most often limits plant growth in the United States. However, human activity since the Industrial Revolution has resulted in increased emission and hence deposition of N.1 Initial increases in N deposition can act as a fertilizer for some plant species, increasing growth, which may be beneficial for some systems, but over time or as deposition continues to increase, added N often has detrimental effects. Since N is a scarce resource, it is typically cycled from one organism or pool to another with minimal losses from the ecosystem.