冻土带
永久冻土
环境科学
生态系统
全球变暖
生长季节
碳循环
气候变化
水槽(地理)
生态系统呼吸
热岩溶
生态学
大气科学
北极的
碳汇
温室气体
土壤碳
陆地生态系统
初级生产
土壤科学
土壤水分
生物
地理
地图学
地质学
作者
Susan M. Natali,Edward A. G. Schuur,Elizabeth E. Webb,Caitlin Hicks Pries,Kathryn G. Crummer
出处
期刊:Ecology
[Wiley]
日期:2013-11-27
卷期号:95 (3): 602-608
被引量:127
摘要
A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years because cold and waterlogged conditions have protected soil organic material from microbial decomposition. As the climate warms this vast and frozen C pool is at risk of being thawed, decomposed, and released to the atmosphere as greenhouse gasses. At the same time, some C losses may be offset by warming-mediated increases in plant productivity. Plant and microbial responses to warming ultimately determine net C exchange from ecosystems, but the timing and magnitude of these responses remain uncertain. Here we show that experimental warming and permafrost (ground that remains below 0 degrees C for two or more consecutive years) degradation led to a two-fold increase in net ecosystem C uptake during the growing season. However, warming also enhanced winter respiration, which entirely offset growing-season C gains. Winter C losses may be even higher in response to actual climate warming than to our experimental manipulations, and, in that scenario, could be expected to more than double overall net C losses from tundra to the atmosphere. Our results highlight the importance of winter processes in determining whether tundra acts as a C source or sink, and demonstrate the potential magnitude of C release from the permafrost zone that might be expected in a warmer climate.
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