神农架大九湖泥炭湿地二氧化碳和甲烷排放化学计量比研究

Stoichiometry Ratio of CO2 and CH4 Emissions in Dajiuhu Peat Wetland of Shennongjia

湿地碳释放产物之间关系的研究对了解湿地生态系统碳固定和温室气体排放机理具有重要意义。运用涡度相关技术连续原位观测,对湖北省神农架林区大九湖亚高山泥炭湿地二氧化碳(CO2)和甲烷(CH4)的排放特征、CO2与CH4排放化学计量比(CO2∶CH4比值)的动态变化及其与环境因子的相关性进行了分析。结果表明:①大九湖泥炭湿地CH4和CO2通量均表现出较明显的月和季节变化规律,从CO2与CH4排放的相关性拟合结果来看,各季节CH4与CO2排放的月平均关系表现为线性拟合或一元二次拟合效果最佳,而其日平均关系则表现为一元二次拟合效果较好;②泥炭湿地CO2∶CH4比值从2017年3月到2018年1月呈"U"型曲线,1月达到最大值后下降,且全年CO2:CH4比值日平均与CO2呈极显著正相关关系;③除地面以下20cm处土壤含水量(SWC20)月平均外,CO2∶CH4日/月平均变化与环境因子均呈极显著相关关系,其中CO2∶CH4比值与环境温度、土壤温度呈极显著负相关关系,而CO2∶CH4比值与土壤含水量呈极显著正相关关系。

The study of the relationship between wetland carbon release products is of great significance to understanding the mechanism of carbon fixation and greenhouse gas emission in wetland ecosystem.This paper applies continuous in-situ observation of eddy covariance technique to analyzing the dynamic changes of the stoichiometry of carbon dioxide (CO2) and methane (CH4) emissions (CO2∶CH4) of Dajiuhu subalpine peat wetland in Shennongjia Forestry Administration District of Hubei Province,as well as the correlation between CO2∶CH4 and environmental factors.The results are as follows:①Both CH4 and CO2 fluxes in peat wetland show significant monthly and seasonal changes;from the fitting relation of CO2 and CH4 emission fluxes,the monthly average relation is best linear fitting or quadratic fitting while the daily average relationship shows the best quadratic fitting with one variable;②CO2∶CH4 in peat wetland is "U" from March 2017 to January 2018.CO2∶CH4 fell after peaking in January,and it is positively correlated with carbon dioxide;③Except for the monthly average of the soil water content 20cm below the ground ( SWC 20 ),the daily/monthly average of CO2∶CH4 is significantly correlated with environmental factors.The environmental temperature and soil temperature are much correlated with CO2∶CH4,while the soil moisture content is positively correlated with CO2∶CH4.