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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Continuous estimates of CO2 efflux from arctic and boreal soils during the snow-covered season in Alaska
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Continuous estimates of CO2 efflux from arctic and boreal soils during the snow-covered season in Alaska

机译：连续估算阿拉斯加积雪季节北极和北方土壤的二氧化碳排放

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Soils in arctic and boreal ecosystems hold large stocks of soil carbon (C), which may be sensitive to changes in climate. Recent studies suggest that winter CO2 efflux from the subnivean environment may be an important component of annual C budgets in arctic and boreal ecosystems. The present study was designed to examine the seasonal patterns and magnitudes of winter CO2 efflux from arctic tussock tundra near Toolik Lake, Alaska, and upland boreal forest in Anchorage, Alaska. The seasonal pattern of winter CO2 efflux differed strongly between the two sites. Tussock tundra showed a prolonged period with very low flux rates between late December and mid-April. In contrast, rates of CO2 efflux were relatively high, but variable, throughout the winter at the boreal site. Estimates of C efflux for the snow-covered season were within the range of previous studies in tussock tundra (24 g C m(-2)) and upland boreal forest (75 g C m(-2)). A simple exponential model, using shallow soil temperatures, explained much of the variation in CO2 efflux from tussock tundra. In contrast, air temperature was an important secondary control on winter CO2 efflux from the boreal forest, suggesting that trees became active during prolonged winter thaws. Results of the study imply that warmer winters may increase rates of C efflux from high-latitude ecosystems. Changes in the depth or duration of snow cover will, however, modulate the relationship between air and soil temperatures and could amplify or dampen the effects of climate warming.
机译：北极和北方生态系统中的土壤拥有大量的土壤碳（C），这可能对气候变化敏感。最近的研究表明，来自亚次大陆环境的冬季二氧化碳排放可能是北极和北方生态系统年度碳预算的重要组成部分。本研究旨在检查阿拉斯加Toolik湖附近的北极丛苔原和阿拉斯加安克雷奇的高寒北方森林的冬季CO2排放的季节模式和强度。在两个地点之间，冬季CO2流出的季节模式差异很大。在12月下旬至4月中旬之间，Tussock苔原表现出延长的时期，且通量率非常低。相反，整个冬季，寒带地区的二氧化碳外排率相对较高，但变化很大。在积雪冻的苔原（24 g C m（-2））和山地北方森林（75 g C m（-2））中，积雪季节的C外排的估计值在先前的研究范围内。一个简单的指数模型，使用了浅层土壤温度，解释了从陆生苔原产生的二氧化碳排放量的大部分变化。相比之下，气温是控制北方森林冬季二氧化碳排放的重要次要控制因素，表明树木在长时间的冬季解冻过程中变得活跃。研究结果表明，冬季变暖可能会增加高纬度生态系统的碳外流率。然而，积雪深度或持续时间的变化将调节空气与土壤温度之间的关系，并可能放大或减弱气候变暖的影响。

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