The agricultural history of human-nitrogen interactions as recorded in ice core δ15N-NO3−
Article first published online: 25 APR 2013
©2013. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 40, Issue 8, pages 1642–1646, 28 April 2013
How to Cite
2013), The agricultural history of human-nitrogen interactions as recorded in ice core δ15N-NO3−, Geophys. Res. Lett., 40, 1642–1646, doi:10.1002/grl.50209., and (
- Issue published online: 17 MAY 2013
- Article first published online: 25 APR 2013
- Accepted manuscript online: 4 FEB 2013 12:16PM EST
- Manuscript Accepted: 30 JAN 2013
- Manuscript Revised: 28 JAN 2013
- Manuscript Received: 13 NOV 2012
- ice core;
 The advent and industrialization of the Haber Bosch process in the early twentieth century ushered in a new era of reactive nitrogen distributions on Earth. Since the appearance of the first commercial scale Haber Bosch fertilizer plants, fertilizer application rates have greatly increased in the U.S. While the contributions of fertilizer runoff to eutrophication and anoxic dead zones in coastal regions have been well-documented, the potential influences of increased fertilizer applications on air quality and precipitation chemistry are poorly constrained. Here we combine a 255-year record of precipitation nitrate isotopes preserved in a Greenland ice core, historical reconstructions of fertilizer application rates, and field characterization of the isotopic composition of nitrogen oxides produced biogenically in soils, to provide new constraints on the contributions of biogenic emissions to North American NOx inventories. Our results indicate that increases in twentieth century commercial fertilizer use led to large increases in soil NO, a byproduct released during nitrification and denitrification reactions. These large shifts in soil NO production are evidenced by sharp declines in ice core δ15N-NO3− values. Further, these results suggest that biogenic NOx emissions are underestimated by two to four fold in the U.S. NOx emission inventories used to construct global reactive nitrogen budgets. These results demonstrate that nitrate isotopes in ice cores, coupled with newly constrained δ15N-NOx values for NOx emission sources, provide a novel means for estimating contemporary and historic contributions from individual NOx emission sources to deposition.