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Proc Natl Acad Sci U S A. 2009 Jan 6;106(1):203-8. doi: 10.1073/pnas.0810193105. Epub 2008 Dec 31.

On the fate of anthropogenic nitrogen.

Author information

1
Cary Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545, USA. schlesingerw@ecostudies.org

Abstract

This article provides a synthesis of literature values to trace the fate of 150 Tg/yr anthropogenic nitrogen applied by humans to the Earth's land surface. Approximately 9 TgN/yr may be accumulating in the terrestrial biosphere in pools with residence times of ten to several hundred years. Enhanced fluvial transport of nitrogen in rivers and percolation to groundwater accounts for approximately 35 and 15 TgN/yr, respectively. Greater denitrification in terrestrial soils and wetlands may account for the loss of approximately 17 TgN/yr from the land surface, calculated by a compilation of data on the fraction of N(2)O emitted to the atmosphere and the current global rise of this gas in the atmosphere. A recent estimate of atmospheric transport of reactive nitrogen from land to sea (NO(x) and NH(x)) accounts for 48 TgN/yr. The total of these enhanced sinks, 124 TgN/yr, is less than the human-enhanced inputs to the land surface, indicating areas of needed additional attention to global nitrogen biogeochemistry. Policy makers should focus on increasing nitrogen-use efficiency in fertilization, reducing transport of reactive N to rivers and groundwater, and maximizing denitrification to its N(2) endproduct.

PMID:
19118195
PMCID:
PMC2613040
DOI:
10.1073/pnas.0810193105
[Indexed for MEDLINE]
Free PMC Article

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