Anthropogenic Impacts on Nitrogen Isotopes of Ice-Core Nitrate

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Science  05 Jun 2009:
Vol. 324, Issue 5932, pp. 1288
DOI: 10.1126/science.1170510

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A strong, unambiguous negative trend is found in the nitrogen isotopic composition (δ15N) of nitrate over the industrial period, on the basis of a 100-meter ice core from Summit, Greenland. This record indicates that ice-core nitrate reflects changes in nitrogen oxide (NOx) source emissions and that anthropogenic emissions of NOx have resulted in a 12 per mil decline in δ15N of atmospheric nitrate from preindustrial values to present. Variations in the isotopic composition of nitrate may affect the interpretation of other records of environmental change that are affected by atmospheric nitrate.

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