Long-term increases in snow pack elevate leaf N and photosynthesis in Salix arctica: responses to a snow fence experiment in the High Arctic of NW Greenland
Long-term increases in snow pack elevate leaf N and photosynthesis in Salix arctica: responses to a snow fence experiment in the High Arctic of NW Greenland
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DOI：
10.1088/1748-9326/8/2/025023
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发表时间：
2013-06
影响因子：
6.7
通讯作者：
A. Leffler;J. Welker
中科院分区：
文献类型：
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作者：
A. Leffler;J. Welker
我们研究了冬季降水量的变化对北极高纬度地区连续冻土景观的影响。研究了格陵兰西北部10年来雪栅强化积雪后的北极杨柳（Salix arctica）的气体交换、叶片组织元素和同位素组成（N、δ 13 C、δ 15 N）以及来自树干和土壤水δ 18 O的植物水分来源。2012年夏季，对环境和+雪条件下的研究地块进行了采样。植物经历了10年的增强雪条件下有较高的叶片[N]，光合速率，更丰富的叶片δ 15 N。增强雪没有影响气孔导度或植物水分利用的深度。我们认为S.北极熊暴露于更深的积雪改变了生态地球化学循环，产生了更高的叶[N]，而不是提高水的可用性。这些数据表明北极植物对冬季条件变化的反应是复杂的。此外，我们的数据描绘了冬季和夏季条件之间的复杂联系，因为它们调节过程，如叶气体交换，可以控制水蒸气和二氧化碳之间的北极苔原和周围大气的反馈。
We examine the influence of altered winter precipitation on a High Arctic landscape with continuous permafrost. Gas exchange, leaf tissue element and isotopic composition (N, δ13C, δ15N), and plant water sources derived from stem and soil water δ18O were examined in Salix arctica (arctic willow) following a decade of snow-fence-enhanced snow pack in NW Greenland. Study plots in ambient and +snow conditions were sampled in summer 2012. Plants experiencing enhanced snow conditions for 10 years had higher leaf [N], photosynthetic rate, and more enriched leaf δ15N. Enhanced snow did not influence stomatal conductance or depth of plant water use. We attribute the higher photosynthetic rate in S. arctica exposed to deeper snow pack to altered biogeochemical cycles which yielded higher leaf [N] rather than to enhanced water availability. These data demonstrate the complexity of High Arctic plant responses to changes in winter conditions. Furthermore, our data depict the intricate linkages between winter and summer conditions as they regulate processes such as leaf gas exchange that may control water vapor and CO2 feedbacks between arctic tundra and the surrounding atmosphere.