Cold Season Respiration across a Low Arctic Landscape: the Influence of Vegetation Type, Snow Depth, and Interannual Climatic Variation
Cold Season Respiration across a Low Arctic Landscape: the Influence of Vegetation Type, Snow Depth, and Interannual Climatic Variation
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DOI：
10.1657/1938-4246-44.4.446
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发表时间：
2012-11-01
影响因子：
2
通讯作者：
Grogan, Paul
中科院分区：
文献类型：
--
作者：
Grogan, Paul
冷季呼吸作用可能显著影响北极陆地生态系统的年净碳平衡。在加拿大低北极地区，研究了植被类型、实验性积雪加深和年际气候变化对冷季CO2总排放量的影响，该地区包括干燥石南、高桦树林下、桦树丘和湿莎草生态系统，不同植被类型的总排放量为34 - 126 g CO2-Cm（-2），高大的桦树林下的呼吸至少是桦树丘的两倍，是干燥的石南或潮湿的莎草的四倍。这种变化并不与土壤温度差异单独，而是由于生态系统之间的相互作用，雪深，植被冠层覆盖，土壤温度和水分，以及植物生物量和凋落物的差异。从桦树丘网站的呼吸是2006/2007年（一年的相对温暖的秋天和冬末土壤温度阶段）的两倍高，相比2004/2005年，并增强了雪栅栏治疗只有在后一年。总之，这些数据表明，冷季CO2释放苔原植被类型之间的差异很大，并强烈表明，这些流出可以显着抵消生长季节的碳收益，导致在某些年份的年度净碳损失。
Cold season respiration may significantly affect arctic terrestrial ecosystem annual net carbon balances. Here, the influences of vegetation type, experimentally deepened snow, and interannual climatic variation on total cold season CO2 efflux were investigated in a Canadian low arctic site containing dry heath, tall birch understory, birch hummock, and wet sedge ecosystems.Total efflux ranged from 34 to 126 g CO2-C m(-2) among the vegetation types, with the tall birch understory respiring at least twice that of the birch hummock and four times that of either the dry heath or wet sedge. This variation did not correlate with soil temperature differences alone, but instead was attributed to ecosystem-specific interactions between snow depth, vegetation canopy cover, soil temperature, and moisture, as well as differences in plant biomass and litter production. Respiration from the birch hummock site was twice as high in 2006/2007 (the year of relatively warm fall and late winter soil temperature phases) as compared to 2004/2005, and was enhanced by the snow fence treatment only in the latter year. Together, these data demonstrate that cold season CO2 release differs substantially among tundra vegetation types, and strongly suggest that these effluxes can significantly offset growing season carbon gains, resulting in annual net carbon losses in some years.