温度对克氏针茅草原生态系统生长季碳通量的影响

草地生态系统碳通量的驱动机制研究是碳循环研究的重要方面。利用涡度相关技术观测了克氏针茅草原生态系统的净生态系统碳交换(NEE)、生态系统初级生产力(GEP)、生态系统呼吸(Reco)的变化,探讨了2010年生长季内温度对该系统NEE、GEP和Reco的影响。结果表明,2010年生长季内,克氏针茅草原日尺度上NEE和GEP只出现了1个明显的吸收峰,Reco则呈现倒"U"型变化规律。克氏针茅草原空气温度与NEE、GEP和Reco呈极显著相关关系,气温日较差对该系统碳通量的影响程度较小;土壤温度与NEE、GEP和Reco之间也呈极显著相关关系,土壤温度的增加会同时提高克氏针茅草原生态系统的固碳能力、初级生产力及呼吸作用。空气温度和土壤温度都是影响克氏针茅草原生态系统碳收支的重要驱动因子。

The Impact of Temperature on Carbon Flux Over Stipa krylovii Ecosystem During the Growing Season

The driving mechanism of grassland ecosystem carbon fluxes is the important research aspect on carbon cycle.To gain insight into temperature effects on the net ecosystem carbon exchange(NEE),the gross ecosystem productivity(GEP),and the ecosystem respiration(Reco),NEE,GEP and Reco of the Stipa krylovii ecosystem were measured by the eddy covariance technique in the 2010 growing season.The results showed that both NEE and GEP had only one peak on the daily-scale level in the 2010 growing season.The Reco had an inverted Ushaped variation pattern.The maximal carbon emission of the Stipa krylovii ecosystem occurred in the late July of 2010.GEP had the highly significant positive correlation with NEE and the highly significant negative correlation with Reco.There were the highly significant correlation between air temperatures and NEE,GEP,Reco,indicating the rise of air temperature would improve both carbon fixation ability and carbon emission ability of the Stipa krylovii ecosystem.Air temperature had higher influence on respiration than on carbon fixation function of the Stipa krylovii ecosystem.The diurnal change of temperature had a significant positive correlation with Reco,while on the whole,the diurnal change of temperature had little influence on carbon fluxes of Stipa krylovii ecosystem in the 2010 growing season.Meanwhile,there were the highly significant correlation between soil temperatures and NEE,GEP,Reco,meaning the rise of soil temperature would improve carbon fixation ability,gross ecosystem productivity,and respiration function.Soil temperature had higher influence on respiration than on carbon fixation function of Stipa krylovii ecosystem.Air temperature and soil temperature were important driving factors which impact the carbon budget of the Stipa krylovii ecosystem.