三江平原小叶章湿地碳排放对雪被变化的短期响应

为了解三江平原小叶章湿地碳排放对雪被变化的响应,利用黑龙江省科学院自然与生态研究所三江平原湿地生态定位研究站内试验平台,采用静态箱-气相色谱法,分别对剔除雪被处理(0 cm)和添加雪被处理(50 cm)以及对照(20 cm)小叶章湿地进行了温室气体排放通量观测,并同步观测相关环境因子。结果表明:不同处理土壤温度、含水量及碳排放量均在覆雪期较低,并随时间呈逐渐升高趋势。随着时间推移和雪被厚度增加,土壤温度不断上升,处理间差异逐渐缩小;剔除雪被处理的土壤含水量始终低于对照和添加雪被处理;在融雪期和后融雪期,对照和添加雪被处理比剔除雪被处理更能促进土壤CO₂排放;各时期土壤累积CH₄排放量在不同处理间无显著性差异。土壤温度与累积CO₂和CH₄排放量均呈显著相关关系,随土壤温度的升高,土壤累积CO₂排放量持续增加,土壤累积CH₄排放量呈先减少后迅速增加趋势;土壤含水量与累积CO₂和CH₄排放量也呈显著相关关系,随土壤含水量的增加,土壤累积CO₂排放量逐渐增多,达到一定值后趋于平缓,土壤累积CH₄排放量则持续显著增加。

Short-term response of carbon emission to snow cover change in Calamagrostis angustifolia wetlands of Sanjiang Plain,Northeast China

To understand the response of Calamagrostis angustifolia wetland of the Sanjiang Plain to changes in snow cover, we examined the greenhouse gases emission flux of the removed snow treatment (0 cm, RS), the added snow treatment (50 cm, AS) and the control (20 cm, CK) of a C. angustifolia wetland, and their relations with environmental factors with the method of the static chamber-gas chromatography. The results showed that soil temperature, soil water content, and carbon emissions were lowest during the snow-covering period under all treatments, and gradually increased with time. With the increases of time and snow thickness, soil temperature was rised and the difference of three treatments gradually was decreased. Soil water content of RS was always lower than that of CK and AS. AS and CK could promote soil CO₂ emission compared with RS during and after snowmelt. The soil cumulative CH₄ emissions differed little among the treatments. There was significant correlation between soil temperature and cumulative CO₂ and CH₄ emissions. With the increases of soil temperature, soil cumulative CO₂ emission continued to increase and soil cumulative CH₄ emission decreased firstly and then increased rapidly. Soil water content was significantly correlated with cumulative CO₂ and CH₄ emissions. As the soil moisture increased, the cumulative soil CO₂ emission gradually increased, reaching a certain threshold and then flattening, while soil cumulative CH₄ emission continuously increased.