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Highly sensitive analysis of geochemical cycles of nitrous oxide and methane through isotope tracers

通过同位素示踪剂对一氧化二氮和甲烷的地球化学循环进行高灵敏度分析

基本信息

批准号：
08454164
负责人：
YOSHIDA Naohiro
金额：
$ 4.99万
依托单位：
Institute for Hydrospheric-Atmospheric Sciences, Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454164/
关键词：
Nitrous oxide Methane Nitrogen isotope ratio Oxygen isotope ratio Carbon isotope ratio Hydrogen isotope ratio Ocean Atmoshere 湖沼

项目摘要

(1) Molecules of low concentration but relatively large amount from atmosphere or atmospheric equilibrated water samples have been analyzed on an mass spectrometer equipped with dual inlet systems, and those of high concentration and small amount, from soil gass for example, have been analyzed on a gas chromatograph/combusion/isotope ratio mass spectrometer. In addition to these system, highly sensitive analytical system has been constructed to determine the isotope ratios of molecules of low concentration and very small amount in the present study.Carbon isotope ratios in methane dissolved in the sea surface waters and molecular fractions of dissolved organic matters, and the methane production process originated from methylamine are analyzed. Nitrous oxide and methane have been determined for their concentration and isotope ratios and their behavior are analyzed. Source materials of nitrous oxide including organic nitrogen and inorganic nitrogen containing molecules especially nitrate have been determined for its nitrogen and oxygen isotope ratios so that source and sink process of nitrous oxide has been assessed.Tunable diode laser absorption spectrometer has been calibrated with gas chromatograph systems. Continuous measurement system has been constructed for concentration and flux determinations, and field observation has been started.

(1)用双进气质谱计分析大气或大气平衡水样中低浓度但相对较多的分子，用气相色谱/燃烧/同位素比质谱仪分析高浓度和少量的土壤气体分子。此外，本研究还构建了高灵敏度的分析系统来测定低浓度和极少量分子的同位素比值，分析了海水中溶解的甲烷和溶解有机物的分子分数的碳同位素比值，以及甲胺产生甲烷的过程。测定了一氧化二氮和甲烷的浓度和同位素比值，并对其行为进行了分析。测定了氧化亚氮的氮氧同位素比值，确定了氧化亚氮的来源物质，包括有机氮和无机氮分子，特别是硝酸盐，从而确定了氧化亚氮的源和汇过程。用气相色谱系统对可调谐半导体激光吸收光谱仪进行了标定。建立了浓度和通量的连续测量系统，并开始了现场观测。