GEOC 39 |
| The conversion of nitrogen oxides to HNO3 via ozone enriches tropospheric nitric acid in the 17O isotope. This enrichment, defined as Δ17O = δ17O - .52 δ18O, is a powerful tracer of atmospherically deposited HNO3. It can be used to detect and quantify the atmospheric contribution of nitrate to the total nitrate pool in soils, rivers, and lakes. Changing Δ17O signals with time can be due to new deposition inputs (increased Δ17O) or an increase in nitrification rates (decreased Δ17O). Δ17O data from biologically inactive environments (the Antarctic Dry Valleys, the Atacama Desert), to marginally active environments (Mojave Desert) to biologically active regions (Southern California, Lake Tahoe) highlight the diversity of nitrogen cycling in these unique environments. In combination with simultaneous δ18O and δ15N measurements, Δ17O techniques show great promise in elucidating watershed scale N cycling dynamics.
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The Biogeochemical Cycling of Nitrogen at Various Spatial and Temporal Scales
1:30 PM-4:40 PM, Monday, August 20, 2007 Boston Park Plaza -- St. James Rm, Oral
Sci-Mix
Division of Geochemistry |