神农架大九湖泥炭湿地非生长季CO_(2)通量特征

Characteristics and Influencing Factors of CO_(2) Flux in Non-growing Season of Dajiuhu Peat Wetland in Shennongjia

开展泥炭湿地非生长季CO_(2)通量研究,对了解泥炭湿地生态系统碳收支动态以及全球气候变化的响应模式具有重要意义。以神农架大九湖亚高山泥炭湿地为研究区,采用涡度相关法通过对研究区进行连续3年非生长季(2015年12月1日—2016年4月15日、2016年11月15日—2017年4月15日、2017年11月15日—2018年4月15日)CO_(2)通量监测,分析研究区泥炭湿地非生长季CO_(2)通量日、月变化特征及其影响因子。结果表明:(1)该泥炭湿地非生长季CO_(2)通量日变化规律均呈“U”型曲线,非生长季CO_(2)通量日变化范围分别为-0.724~4.301μmol/(m^(2)·s)(2016年)、-1.251~4.833μmol/(m^(2)·s)(2017年)、-0.980~4.982μmol/(m^(2)·s)(2018年);(2)2016—2018年研究区泥炭湿地非生长季CO_(2)通量月变化均表现为排放CO_(2),3年非生长季CO_(2)通量月累计释放量分别为28.26 g C/m^(2)、17.65 g C/m^(2)和50.73 g C/m^(2);(3)研究区泥炭湿地非生长季CO_(2)通量对降雨的响应仅在长期无降雨后,降雨量突增时CO_(2)通量释放量增加显著;(4)2016—2018年研究区泥炭湿地非生长季CO_(2)通量与10 cm层土壤温度呈极显著正相关关系,与10 cm层土壤含水率呈极显著负相关关系,与大气温度呈负相关关系,但相关性不显著。土壤温度是大九湖泥炭湿地非生长季CO_(2)通量的主要调控因子。

The study of CO_(2)flux in non-growing season of Dajiuhu peat wetland in Shennongjia is of great significance for understanding carbon budget dynamics of Dajiuhu peat wetland ecosystem and response model of global climate change.The study area is Dajiuhu subalpine peat wetland in Shennongjia.The eddy covariance method is used to monitor CO_(2)flux in the study area during the non-growing season for three consecutive years(December 1,2015—April 15,2016,November 15,2016—April 15,2017,and November 15,2017—April 15,2018).The diurnal and monthly variation characteristics and influencing factors are analyzed.The results are as follows:(1)The diurnal variation of CO_(2)flux in the non-growing season of the peat wetland ecosystem shows a u-shaped curve,and the variation range is-0.724—4.301μmol/(m^(2)·s)(2016),-1.251—4.833μmol/(m^(2)·s)(2017),and-0.980—4.982μmol/(m^(2)·s)(2018).(2)The monthly variation of non-growing season in the peat wetland in 2016—2018 is CO_(2)emission,and the cumulative release is 28.26 g C/m^(2),17.65 g C/m^(2)and 50.73 g C/m^(2),respectively.(3)The response of CO_(2)flux in the non-growing season of the peat wetland to rainfall is significant only after long-term absence of precipita-tion,and CO_(2)flux release increases significantly when precipitation suddenly increases.(4)CO_(2)flux of the peat wetland in the study area during the non-growing season in 2016-2018 has a very significant positive correlation with soil temperature of 10 cm layer,a very significant negative correlation with soil water content of 10 cm layer,and a negative correlation with T,but not significant.Soil temperature is the main re-gulator of CO_(2)flux in the non-growing season of Dajiuhu peat wetland.