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Titel |
Tracing the fate of atmospheric nitrate deposited onto a forest ecosystem in Eastern Asia using Δ¹⁷O |
VerfasserIn |
U. Tsunogai, D. D. Komatsu, S. Daita, G. A. Kazemi, F. Nakagawa, I. Noguchi, J. Zhang |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 4 ; Nr. 10, no. 4 (2010-02-16), S.1809-1820 |
Datensatznummer |
250008117
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Publikation (Nr.) |
copernicus.org/acp-10-1809-2010.pdf |
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Zusammenfassung |
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‰
(n = 32) with +26.2‰ being
the annual average. The maximum Δ17O value of +34.5‰, obtained for
precipitation on the 23rd to 24th of February 2007, was an
extraordinarily large value among values for all samples of precipitation in
Rishiri. Most nitrate in the sample might have been produced via NO3
radical in a highly polluted air mass that had been supplied from megacities
on the eastern coast of the Asian continent. On the other hand, nitrate in
groundwater had small Δ17O values ranging from +0.9‰ to 3.2‰ (n = 19),
which corresponds to an mixing ratio of atmospheric nitrate to total nitrate
of (7.4±2.6)%. Comparing the inflow and outflow of atmospheric
nitrate in groundwater within the island, we estimated that the direct
drainage accounts for (8.8±4.6)% of atmospheric nitrate that has
deposited on the island and that the residual portion has undergone
biological processing before being exported from the forest ecosystem. |
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