Tracing the fate of atmospheric nitrate deposited onto a forest
ecosystem in eastern Asia using Δ17O 1Earth and Planetary System
Science, Faculty of Science, Hokkaido University, Sapporo, Japan
2Hokkaido Institute of Environmental Sciences, Sapporo, Japan
3Graduate School of Science and Engineering, University of
Toyama, Toyama, Japan *now at: Faculty of Earth Sciences,
Shahrood University of Technology, Shahrood, Iran Abstract. The
stable isotopic compositions of nitrate in precipitation (wet
deposition) and groundwater (spring, lake, and stream water)
were determined for the island of Rishiri, Japan, so as to use
the 17O anomalies (Δ17O) to trace the fate of atmospheric
nitrate that had deposited onto the island ecosystem, which is a
representative background forest ecosystem for eastern Asia. The
deposited nitrate had large 17O anomalies with Δ17O values
ranging from +20.8‰ to +34.5&permil (n= 32) with +26.2‰ being
the annual average. The maximum Δ17O value of +34.5‰, obtained
for precipitation on 23 to 24