高寒矮嵩草草甸冬季CO_2释放特征  

CO_2 emission from an alpine Kobresia humilis meadow in winters

作　　者：吴琴[1,2] 胡启武[1,2] 曹广民[2] 李东[2] 

机构地区：[1]江西师范大学地理与环境学院,南昌330022 [2]中国科学院西北高原生物研究所,西宁810001

出　　处：《生态学报》2011年第18期5107-5112,共6页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30970520;40803022)

摘　　要：冬季碳排放在高寒草地年内碳平衡中占有重要位置。为探讨高寒草地冬季碳排放特征及温度敏感性,于2003—2005年在中国科学院海北高寒草甸生态系统研究站,利用密闭箱-气相色谱法连续观测了高寒矮嵩草草甸2个冬季的生态系统、土壤呼吸通量特征。结果表明:1)高寒矮嵩草草甸冬季生态系统呼吸、土壤呼吸均具有明显的日变化和季节变化规律,温度是其主要的控制因子,能够解释44%以上的呼吸速率变异。2)冬季生态系统呼吸与土壤呼吸速率在统计上没有显著差异,土壤呼吸占生态系统呼吸的比例高达85%以上。3)2003—2004年冬季生态系统呼吸、土壤呼吸的Q10值分别为1.53,1.38;2004—2005年冬季生态系统呼吸与土壤呼吸的Q10值为1.86,1.68,2个冬季生态系统呼吸的Q10值均高于土壤呼吸。4)未发现高寒矮嵩草草甸冷冬年份的Q10值高于暖冬年份以及冬季的Q10值高于生长季。Winter carbon（C） flux is important for annual C balance over an ecosystem level,but the field measurements are still lacking,especially in alpine grasslands which occupy approximately one third of the Tibetan Plateau area.Consequently,a determination of winter carbon flux is essential for the assessment of alpine grassland carbon budget.Previous studies showed that temperature coefficient（Q10）,an index of temperature sensitivity for respirations,increased with decreasing temperature in other ecosystem.This research therefore hypothesized that Q10 of soil and ecosystem respiration in alpine meadows would be higher in winters than in summers and higher in cold winters than in warm winters.To test the hypothesis above,ecosystem and soil CO2 fluxes were measured by a static chamber-chromatography method in an alpine Kobresia humilis meadow in two continues winters from 2003 to 2005 at Haibei Alpine Meadow Ecosystem Research Station of Chinese Academy of Sciences.The objectives of this study were to： 1） clarify the characteristics of winter soil and ecosystem CO2 fluxes and their control factors,and 2） compare temperature sensitivity of CO2 fluxes under different thermal regimes.Results showed that both ecosystem and soil respiration showed clear diurnal and seasonal patterns.Temperature mainly controlled ecosystem and soil respiration,explaining more than 44% of the respiration variance.Ecosystem respiration rates averaged 88.43 mgCO2·m-2 ·h-1（ranging from 51.63 to 206.07 mgCO2·m-2 ·h-1） in the first winter and 89.50 mgCO2·m-2 ·h-1（ranging from 35.12 to 145.17 mgCO2·m-2 ·h-1） in the second winter.By comparison,soil respiration rates varied from 47.41 to 152.94 mgCO2·m-2 ·h-1（with mean of 77.01 mgCO2·m-2 ·h-1） in the first winter and ranged from 28.21 to 107.89 mgCO2·m-2 ·h-1（with mean of 68.64 mgCO2·m-2 ·h-1） in the second winter.Because the aboveground parts were dead in winters,no significant difference was observed between ecosystem and soil respirations.Soil respirati

关 键 词：高寒草甸 生态系统呼吸 土壤呼吸 Q10 

分 类 号：S812[农业科学—草业科学]