Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation. As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N2O) mole fractions have increased from a pre-industrial value of ~270 nmol/mol to ~319 nmol/mol in 2005. Human activities account for over one-third of N2O emissions, most of which are due to the agricultural sector. This article is intended to give a brief review of the history of anthropogenic N inputs, and reported impacts of nitrogen inputs on selected terrestrial and aquatic ecosystems.
Read more about Human Impact On The Nitrogen Cycle: History of Anthropogenic Nitrogen Inputs, Impacts of Anthropogenic Inputs On The Nitrogen Cycle, Integration
Famous quotes containing the words human, impact and/or cycle:
“Promises are the uniquely human way of ordering the future, making it predictable and reliable to the extent that this is humanly possible.”
—Hannah Arendt (1906–1975)
“Too many existing classrooms for young children have this overriding goal: To get the children ready for first grade. This goal is unworthy. It is hurtful. This goal has had the most distorting impact on five-year-olds. It causes kindergartens to be merely the handmaidens of first grade.... Kindergarten teachers cannot look at their own children and plan for their present needs as five-year-olds.”
—James L. Hymes, Jr. (20th century)
“The Buddha, the Godhead, resides quite as comfortably in the circuits of a digital computer or the gears of a cycle transmission as he does at the top of a mountain or in the petals of a flower.”
—Robert M. Pirsig (b. 1928)