Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica
Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica
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DOI：
10.1038/s41559-017-0253-0
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发表时间：
2017-09-01
影响因子：
16.8
通讯作者：
Wall, Diana H.
中科院分区：
文献类型：
--
作者：
Gooseff, Michael N.;Barrett, John E.;Wall, Diana H.
极地地区放大的气候变化正在显著改变区域生态系统，但很少有记录这些反应的长期记录。麦克默多干谷(MDV)寒冷的沙漠生态系统是南极洲最大的无冰区，由土壤、冰川、融水溪流和永久冰盖的湖泊组成。数十年的记录表明，MDV对不同寻常的南半球夏季和随之而来的气候变化表现出独特的生态系统反应。一个十年一遇的夏季降温阶段于2002年结束，冰川剧烈融化(“洪涝年”)--水资源供应的阶段性变化引发了生态系统的明显变化。在2002年前，生态系统表现出同步行为：河流流量下降，湖泊水位下降，湖泊冰盖增厚，湖泊和溪流初级生产力减少，土壤次生生产力减少。自2002年以来，夏季气温和太阳通量相对一致，导致湖泊水位上升，湖泊冰变薄，河流流量上升。生物反应各不相同；一种溪流蓝藻垫型立即增加产量，而另一种溪席蓝藻类型、土壤无脊椎动物和湖泊初级生产力在2002年后几年内不同步反应。这种生态系统对气候异常的反应表明，生物群落对重大扰动的反应是不同的，并通过物理生态系统性质的变化来调节生物对气候变化的反应。
Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt ('flood year')-a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties.