Rising plant-mediated methane emissions from arctic wetlands
Rising plant-mediated methane emissions from arctic wetlands
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DOI：
10.1111/gcb.13469
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发表时间：
2017-03-01
影响因子：
11.6
通讯作者：
Lougheed, Vanessa L.
中科院分区：
文献类型：
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作者：
Andresen, Christian G.;Lara, Mark J.;Lougheed, Vanessa L.
植物介导的CH4通量是陆地-大气CH4排放的重要途径，但在北极苔原湿地，特别是在气候变化的长期影响下，对跨越空间和时间尺度的大小、时间和环境控制仍然知之甚少。在生长高峰期，对阿拉斯加北极海滨平原的主要水生新兴植物苔草和黄花草的CH4通量进行了现场测量，以评估CH4通量的大小和物种特有的控制。植物生物量是黄曲霉CH4通量的较强预测因子，而水深和融化深度是水体CH4通量的共同预测因子。我们使用了1971年至1972年阿拉斯加州巴罗附近历史悠久的国际生物计划(IBP)研究地点的植物和环境数据，并在2010-2013年重新采样，以量化植物生物量和融化深度的变化，并使用这些数据估计特定物种的CH4通量的十年尺度变化。从过去40年冻土带池塘中观察到的植物生物量和融化深度的增加估计，CH4通量增加了60%。尽管只覆盖了大约5%的景观，但我们估计，水生的水生水生扁藻和黄曲霉占巴罗半岛区域CH4通量总量的三分之二。在过去40年中，区域内观察到的植物生物量的增加和活动层的增厚不仅对能量和水平衡产生了重大影响，而且显著改变了该区域的陆地-大气CH4排放，潜在地对气候变暖起到了积极的反馈作用。
Plant-mediated CH4 flux is an important pathway for land-atmosphere CH4 emissions, but the magnitude, timing, and environmental controls, spanning scales of space and time, remain poorly understood in arctic tundra wetlands, particularly under the long-term effects of climate change. CH4 fluxes were measured in situ during peak growing season for the dominant aquatic emergent plants in the Alaskan arctic coastal plain, Carex aquatilis and Arctophila fulva, to assess the magnitude and species- specific controls on CH4 flux. Plant biomass was a strong predictor of A. fulva CH4 flux while water depth and thaw depth were copredictors for C. aquatilis CH4 flux. We used plant and environmental data from 1971 to 1972 from the historic International Biological Program (IBP) research site near Barrow, Alaska, which we resampled in 2010-2013, to quantify changes in plant biomass and thaw depth, and used these to estimate species-specific decadal-scale changes in CH4 fluxes. A similar to 60% increase in CH4 flux was estimated from the observed plant biomass and thaw depth increases in tundra ponds over the past 40 years. Despite covering only similar to 5% of the landscape, we estimate that aquatic C. aquatilis and A. fulva account for two-thirds of the total regional CH4 flux of the Barrow Peninsula. The regionally observed increases in plant biomass and active layer thickening over the past 40 years not only have major implications for energy and water balance, but also have significantly altered land-atmosphere CH4 emissions for this region, potentially acting as a positive feedback to climate warming.