大九湖泥炭湿地生态系统碳水通量及水分利用效率研究

Studies on Carbon-water Flux and Water Use Efficiency in Dajiuhu Peat Wetland Ecosystem

为研究大九湖泥炭湿地生态系统碳水通量及水分利用效率(WUE)的变化特征,于2015年12月至2017年11月采用涡度相关观测系统对大九湖泥炭湿地生态系统CO_2通量、H_2O通量和环境因子进行了监测。结果表明:①大九湖泥炭湿地生态系统各季节的CO_2通量和H_2O通量整体均呈现单峰型曲线,其中夏季碳水通量的变化幅度最大,冬季碳水通量的变化幅度最小;②大九湖泥炭湿地生态系统CO_2通量与H_2O通量在0.01的检验水平上显著相关,且两者的比值存在一定的函数关系,其中三次拟合效果最优,拟合优度R^2为0.38;③大九湖泥炭湿地生态系统WUE的变化范围为0.06～13.95g C/kg H_2O,其日均值为3.26g C/kg H_2O,各季节湿地生态系统WUE的变化幅度表现为夏季>冬天>秋季>春季;④大九湖泥炭湿地生态系统WUE与蒸散量(ET)的拟合关系中,夏季和冬季的拟合效果较好,随着ET的增加,湿地生态系统WUE不断减小;⑤大九湖泥炭湿地生态系统WUE与气温(T_a)的拟合关系中,夏季拟合效果较好,随着T_a的升高,湿地生态系统WUE不断减小;⑥大九湖泥炭湿地生态系统WUE与土壤温度(T_s)的拟合关系中,秋季拟合效果较好,随着T_s的升高,湿地生态系统WUE增加。该研究结果可为大九湖泥炭湿地生态系统变化趋势的预测及功能调控提供理论支持,也可为正确评价湿地生态系统碳水耦合、水分利用效率提供科学依据。

In order to study carbon-water flux and Water Use Efficiency(WUE),this paper uses eddy covariance technology to observe CO2 flux,H2O flux and environmental factors from December 2015 to November 2017 in Dajiuhu peat wetland.The results show that①In Dajiuhu peat wetland,seasonal CO2 flux and H2O flux are all represented as a unimodal type curve.The change rule of summer is most evident and it is not obvious in winter;②There is a significant correlation between CO2 flux and H2O flux and functional relationship existed among them.The cubic fitting equation was optimal,with the fitting result of about 0.38;③The daily variation range of WUE in two years is 0.06~13.95 g C/kg H2O,with a daily mean value of 3.26 g C/kg H 2O.The range in every season is summer >winter >autumn >spring;④The functional relationship between WUE and evapotranspiration(ET)is a quadratic fitting equation.The fitting results in summer and winter are better.With the increasing of evapotranspiration(ET),WUE decreases;⑤The functional relationship between WUE and temperature(Ta)is a quadratic fitting equation.The fitting result in summer is better.With the rise of temperature(Ta),water use efficiency(WUE)decreases;⑥The functional relationship between WUE and soil temperature(ts)is a quadratic fitting equation.The fitting result in autumn is better.With the rise of soil temperature(ts),water use efficiency(WUE)increases.