Tracing atmospheric nitrate deposition in a complex semiarid ecosystem using Δ¹⁷O

Abstract

The isotopic composition of nitrate collected from aerosols, fog, and precipitation was measured and found to have a large ¹⁷O anomaly with Δ¹⁷O values ranging from 20‰ to 30‰ (Δ¹⁷O δ¹⁷O - 0.52(δ¹⁸O)). This ¹⁷O anomaly was used to trace atmospheric deposition of nitrate to a semiarid ecosystem in southern California. We demonstrate that the Δ¹⁷O signal is a conserved tracer of atmospheric nitrate deposition and is a more robust indicator of N deposition relative to standard δ¹⁸O 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.

Citation

Michalski, Greg; Meixner, Thomas; Fenn, Mark E.; Hernandez, Larry; Sirulnik, Abby; Allen, Edith; Thiemens, Mark. 2004. Tracing atmospheric nitrate deposition in a complex semiarid ecosystem using Δ¹⁷O. Environmental Science and Technology 38(7):2175-2181