Quantifying the effects of clear-cutting and strip-cutting on nitrate dynamics in a forested watershed using triple oxygen isotopes as tracers

Tsunogai U.; Komatsu D. D.; Ohyama T.; Suzuki A.; Nakagawa F.; Noguchi I.; Takagi K.; Nomura M.; Fukuzawa K.; Shibata H.

タイトル	en Quantifying the effects of clear-cutting and strip-cutting on nitrate dynamics in a forested watershed using triple oxygen isotopes as tracers
作成者	en Tsunogai, U. en Komatsu, D. D. en Ohyama, T. en Suzuki, A. en Nakagawa, F. en Noguchi, I. en Takagi, K. NRID 1000020322844 en Nomura, M. en Fukuzawa, K. NRID 1000010456824 en Shibata, H. NRID 1000070281798
アクセス権	open access
権利情報	http://creativecommons.org/licenses/by/3.0/ en Creative Commons Attribution 3.0 Unported
主題	NDC 653
内容注記	Abstract en Temporal variations in the stable isotopic compositions of nitrate dissolved in stream water eluted from a cool-temperate forested watershed (8 ha) were measured to quantify the biogeochemical effects of clear-cutting of trees and subsequent strip-cutting of the understory vegetation, dwarf bamboo (Sasa senanensis), with special emphasis on changes in the fate of atmospheric nitrate that had been deposited onto the watershed based on Delta O-17 values of nitrate. A significant increase in stream nitrate concentration to 15 mu mol L-1 in spring of 2004 was correlated with a significant increase in the Delta O-17 values of nitrate. Additionally, the high Delta O-17 values of +14.3 parts per thousand suggest that the direct drainage of atmospheric nitrate accounted for more than 50% of total nitrate exported from the forested watershed peaking in spring. Similar increases in both concentrations and Delta O-17 values were also found in spring of 2005. Conversely, low Delta O-17 values less than +1.5% were observed in other seasons, regardless of increases in stream nitrate concentration, indicating that the majority of nitrate exported from the forested watershed during seasons other than spring was remineralized nitrate: those retained in the forested ecosystem as either organic N or ammonium and then been converted to nitrate via microbial nitrification. When compared with the values prior to strip-cutting, the annual export of atmospheric nitrate and remineralized nitrate increased more than 16-fold and fourfold, respectively, in 2004, and more than 13-fold and fivefold, respectively, in 2005. The understory vegetation (Sasa) was particularly important to enhancing biological consumption of atmospheric nitrate.
出版者	en Copernicus Gesellschaft
日付	Issued2015-01-07
言語	eng
資源タイプ	journal article
出版タイプ	VoR
資源識別子	HDL http://hdl.handle.net/2115/57667
関連	isIdenticalTo DOI https://doi.org/10.5194/bg-11-5411-2014
収録誌情報	PISSN 1726-4170 en Biogeosciences 巻11 号19 開始ページ5411 終了ページ5424
ファイル	fulltext bg-11-5411-2014.pdf 2.05 MB (application/pdf) Issued2015-01-07
コンテンツ更新日時	2023-07-26