Emission and oxidation of CH4 and N2O in forest catchment and effect of hydrological process

森林流域CH4和N2O的排放、氧化及水文过程的影响

• 批准号: 15580124
• 负责人: SUGIMOTO Atsuko
• 金额: $ 2.37万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15580124/
• 关键词: carbon dioxide; methane; forest catchment; hydrology; anoxic environment; denitrification; 酸化還元環境; 一酸化二窒素(N_2O); メタン(CH_4)

To elucidate the mechanisms of N_2O and CH_4 gas exchange in the forested catchment, the field experiments have been conducted at the Kiryu Experimental Watershed located in the southern Shiga prefecture, focusing on the hydrologic controls on biogeochemical processes for N_2O and CH_4 dynamics. Gas emitting rate and concentration in soil gas and dissolved gas concentration in soil and ground waters were measured both for CH_4 and N_2O at the stream side wetland and riparian zones in the headwater (zero-order) catchment. In addition to those observations, the stable isotope ratio of carbon in CH_4 was measured. The results provides following findings.1.Continuous absorption was observed at the relatively dry soil in the Japanese cypress forest all through the year, while emission was constantly observed at the streamside wetland. Especially in the summer, the emission rate from the wetland was remarkably higher than the absorption rate at the slope side in the Japanese cypress stands.2.CH_4 production and emission in the wetland was essentially controlled by soil temperature and groundwater level. Absorption was mainly controlled by the soil moisture content of surface horizon.3.Seasonal variation in the d13C of CH_4 synchronized with that of dissolved CH_4 concentration in groundwater, suggesting that the major origin of CH_4 was the CO_2 produced by the decomposition of the organic matters mainly supplied by litter fall.4.N_2O was mainly produced in the rim of the groundwater zone where the DOC was supply sufficiently from the slope side soils. The N_2O was considered to be produced through denitrification due to saturated condition in reduced environment below the groundwater level. In the deepest horizon in the groundwater zone, N_2O concentration was lower than that of ambient N_2O concentration, suggesting conversion of N_2O to N_2.

为了阐明森林流域内N_2O和CH_4气体交换的机制，在位于滋贺县南部的桐生实验流域进行了野外实验，重点研究了N_2O和CH_4动态的生物地球化学过程的水文控制。在源头（零级）流域的溪边湿地和河岸带测量了CH_4和N_2O的气体排放速率和土壤气体浓度以及土壤和地下水中的溶解气体浓度。除了这些观察之外，还测量了 CH_4 中碳的稳定同位素比率。研究结果如下： 1.日本扁柏林土壤相对干燥，全年持续吸收，而河边湿地持续排放。特别是在夏季,日本柏林湿地的排放速率明显高于坡侧的吸收速率。2.湿地CH_4的产生和排放主要受土壤温度和地下水位的控制。吸收主要受地表土壤含水量控制。3.CH_4 d13C的季节变化与地下水中溶解CH_4浓度同步变化,表明CH_4的主要来源是由凋落物供给的有机物分解产生的CO_2。4.N_2O主要产生于DOC供给的地下水区边缘 充分地从斜坡一侧的土壤中取出。 N_2O被认为是由于地下水位以下的还原环境中的饱和条件而通过反硝化作用产生的。在地下水位最深层，N_2O浓度低于环境N_2O浓度，表明N_2O转化为N_2。

项目成果

Tracing sources of nitrate in snowmelt runoff using a high‐resolution isotopic technique

• DOI: 10.1029/2004gl020908
• 发表时间: 2004-11
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: N. Ohte;S. Sebestyen;J. Shanley;D. Doctor;C. Kendall;S. Wankel;E. Boyer

Episodic increases in nitrate concentrations in streamwater due to the partial dieback of a pine forest in Japan : Runoff generation processes control seasonality

由于日本松林的部分枯死，溪流中硝酸盐浓度间歇性增加：径流产生过程控制季节性

• 发表时间: 2003
• 期刊: Hydrological Processes 17
• 作者: Ohte;N.
• 通讯作者: N.

温帯森林流域におけるメタンフラックスの時空間変動.

温带森林流域甲烷通量的时空变化。

• 发表时间: 2005
• 期刊: 水文・水資源学会誌 18(3),
• 作者: Osaka;K.;Ohte;N.;Koba;K.;Katsuyama;M.;Nakajima T.;伊藤雅之
• 通讯作者: 伊藤雅之

Hydrological control of the streamwater NO3-concentration in a weathered granitic headwater catchment.

风化花岗岩源头流域溪流NO3浓度的水文控制。

• 发表时间: 2004
• 期刊: Journal of Japanese Forestry Society (in Japanese with English summary) 86(1)
• 作者: Katsuyama;M.
• 通讯作者: M.

Interactive responses of dissolved sulfate and nitrate to disturbance associated with pine wilt disease in a temperate forest.

溶解的硫酸盐和硝酸盐对温带森林松枯病相关干扰的相互作用反应。

• 发表时间: 2003
• 期刊: Soil Science and Plant Nutrition 49
• 作者: Kim;S.
• 通讯作者: S.