The article "Human Alteration of the Global Nitrogen Cycle: Sources and Consequences" by Peter M. Vitousek et al. reviews the significant impacts of human activities on the global nitrogen (N) cycle. The authors highlight that human alterations have approximately doubled the rate of N input into the terrestrial N cycle, increased concentrations of potent greenhouse gases like N₂O, and contributed to soil nutrient losses and acidification. They also discuss the increased mobility of N, which spreads its effects regionally and globally, and the environmental consequences of mobile N forms. The article further examines the effects of N on terrestrial, freshwater, and marine ecosystems, including increased organic carbon storage, accelerated loss of biological diversity, and changes in ecosystem composition and functioning. The authors emphasize the need for management practices to reduce the mobility and environmental impact of applied N, particularly in agricultural and urban areas. They also address uncertainties in understanding the N cycle, such as marine N fixation and the retention capacity of ecosystems, and suggest future prospects for slowing the rate of N input and improving efficiency in N use.The article "Human Alteration of the Global Nitrogen Cycle: Sources and Consequences" by Peter M. Vitousek et al. reviews the significant impacts of human activities on the global nitrogen (N) cycle. The authors highlight that human alterations have approximately doubled the rate of N input into the terrestrial N cycle, increased concentrations of potent greenhouse gases like N₂O, and contributed to soil nutrient losses and acidification. They also discuss the increased mobility of N, which spreads its effects regionally and globally, and the environmental consequences of mobile N forms. The article further examines the effects of N on terrestrial, freshwater, and marine ecosystems, including increased organic carbon storage, accelerated loss of biological diversity, and changes in ecosystem composition and functioning. The authors emphasize the need for management practices to reduce the mobility and environmental impact of applied N, particularly in agricultural and urban areas. They also address uncertainties in understanding the N cycle, such as marine N fixation and the retention capacity of ecosystems, and suggest future prospects for slowing the rate of N input and improving efficiency in N use.