同位素2026，Vol.39Issue(3)：210-216,7.DOI:10.7538/tws.2025.youxian.081
土壤微生物呼吸CO2气体浓度及其碳稳定同位素值原位检测研究
Study on an In Situ Detection Method for CO2 Concentration and Carbon Stable Isotope Values from Soil Microbial Respiration
摘要
Abstract
Stable isotope technique has been used to attribute carbon dioxide(CO2)emissions to different processes,and over the past two decades their use has come to the forefront as a promising tool for CO2 source partitioning.Accurate quantification of carbon dioxide(CO2)(and other greenhouse gases)as a result of the activities of soil microorganisms is important for understanding soil respiration process and predicting carbon exchange between soil and atmosphere.Recently,laser-based analyzers have become commercially available for simultaneously measurements of the concentrations and the isotopic composition of CO2,using cavity-enhanced absorption spectroscopy for the analysis of ambient air samples.However,despite this innovation for the possibility of in situ field measurements,their use raises unique demanding for an on-line gas sampling and displacement auxiliary.In order to realize the continuous measurement of soil microbial respiration,this study aimed to establish an online analytical method suitable for continuous in situ monitoring of CO2 concentration and its δ13C value from soil microbial respiration gases.Based on CRDS technology,a self-developed multi-channel online gas exchange and sample introduction device was integrated with a carbon stable isotope analyzer(G2201-i)to construct an automated continuous monitoring system.Tests using a series of standard gases demonstrated that the system achieved high accuracy and precision in measuring CO2 concentration and δ13C values.The measured values were consistent with reference values,with a coefficient of variation for concentration measurements less than 0.1%and δ13C measurements below 0.5‰,meeting practical testing requirements.The application of this system to in situ soil microbial respiration studies yielded results consistent with those obtained by traditional gas chromatography-isotope ratio mass spectrometry(GC-IRMS)(correlation coefficients R2 were 0.999 and 0.997,and slopes were 0.998 and 0.995,respectively),validating the reliability of the method.The established method enables synchronous,high-precision,and automated in situ measurement of CO2 and its isotopic composition from soil microbial respiration.It exhibits excellent timeliness and stability,providing a key technical solution for in-depth investigation into soil organic carbon transformation processes and microbial driving mechanisms.This method holds significant application value for the precise quantification of carbon fluxes in terrestrial ecosystems.关键词
光腔衰荡光谱技术/土壤有机碳/微生物呼吸/多通道/在线检测Key words
cavity ring-down spectroscopy/soil organic carbon/microbial respiration/multi-channel/on-line detection分类
能源科技引用本文复制引用
袁红朝,钟欢,王久荣,贺珍,张丽萍,耿梅梅,许丽卫,陈闻,李春勇,彭灿,唐思宇..土壤微生物呼吸CO2气体浓度及其碳稳定同位素值原位检测研究[J].同位素,2026,39(3):210-216,7.基金项目
国家自然科学基金项目(42177330) （42177330）
中国科学院仪器功能开发项目 （）
中国科学院技术支撑人才项目资助 （）
