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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Effects of extended growing season and soil warming on carbon dioxide and methane exchange of tussock tundra in Alaska
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Effects of extended growing season and soil warming on carbon dioxide and methane exchange of tussock tundra in Alaska

机译：生长期延长和土壤变暖对阿拉斯加草冻土中二氧化碳和甲烷交换的影响

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The active season of tussock tundra was extended during two growing seasons (1995 and 1996) by snow removal in early season and prevention of snow accumulation in late season to test the effects of a longer growing season on tundra carbon exchange. Three treatments were established: extended season, extended season + soil warming, and controls. Soil warming was accomplished using cold-frame, resistance heating wire installed the year prior to the initiation of treatments. Diurnal courses of CO2 exchange were measured weekly using infrared gas analysis with enclosed chamber techniques. Methane fluxes were measured two to three times a season also using enclosure methods. In 1995, snowmelt occurred unusually early, and snow removal treatments increased the season only 9-10 days. In 1996 the early season was increased approximately 24 days. As expected, thaw depth, soil temperature, and plant growth were greater earlier in the extended season and extended season + soil heating plots. Methane fluxes in both seasons were low but tended to be higher in the extended season and soil heated plots. Net ecosystem CO2 fluxes were similar among treatments early in the season, with a tendency toward more positive fluxes (system loss) for the snow removal and warmed plots, possibly due to higher belowground respiration. During midseason, fluxes were similar among the treatments. Later in the season, fluxes of extended season and warmed plots tended to be lower (less carbon loss) than controls, especially in 1995. Totaled over the season, however, the fluxes of the three treatments did not statistically differ and represented losses to the atmosphere. Measurements of dark respiration in 1996 indicate that both respiration and uptake were increased on the extended season plots, resulting in similar net fluxes to controls. [References: 35]
机译：通过在早季除雪并在后期防止积雪，在两个生长季节（1995年和1996年）延长了陆生苔原的活跃季节，以测试较长生长期对苔原碳交换的影响。建立了三种处理方法：延长季节，延长季节+土壤变暖和控制。使用处理开始前一年安装的冷框电阻加热丝完成土壤变暖。每周使用红外气体分析和密闭室技术测量二氧化碳的日变化过程。同样使用封闭方法，每个季节测量甲烷通量两次至三次。 1995年，融雪异常早地发生，除雪处理使整个季节仅增加了9-10天。在1996年，旺季增加了大约24天。正如预期的那样，在扩展季节和扩展季节+土壤加热区中，融化深度，土壤温度和植物生长都更快。在两个季节中甲烷通量均较低，但在延长季节和土壤加热区中甲烷通量往往较高。季节初期各处理之间的生态系统净二氧化碳通量相似，除雪和温暖地块的通量趋向于更正（系统损失），这可能是由于地下呼吸较高所致。在赛季中期，各处理之间的通量相似。在季节的后期，延长季节和温暖地块的通量趋向于比对照更低（更少的碳损失），尤其是在1995年。在整个季节中，三种处理的通量在统计上没有差异，代表了对土壤的损失。大气层。 1996年的暗呼吸测量表明，在延长季节的情节中，呼吸和摄取均增加，导致与对照组的净通量相似。 [参考：35]

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