Michalski Greg, Meixner Thomas, Fenn Mark, Hernandez Larry, Sirulnik Abby, Allen Edith, Thiemens Mark
University of California, San Diego, La Jolla, California 92095-0356, USA.
Environ Sci Technol. 2004 Apr 1;38(7):2175-81. doi: 10.1021/es034980+.
The isotopic composition of nitrate collected from aerosols, fog, and precipitation was measured and found to have a large 17O anomaly with delta17O values ranging from 20 percent per thousand to 30% percent per thousand (delta17O = delta17O - 0.52(delta18O)). This 17O anomaly was used to trace atmospheric deposition of nitrate to a semiarid ecosystem in southern California. We demonstrate that the delta17O signal is a conserved tracer of atmospheric nitrate deposition and is a more robust indicator of N deposition relative to standard delta18O techniques. The data indicate that a substantial portion of nitrate found in the local soil, stream, and groundwater is of atmospheric origin and does not undergo biologic processing before being exported from the system.
