Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4RJ, UK.
Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4RJ, UK.
Curr Biol. 2017 Jun 5;27(11):1616-1622.e2. doi: 10.1016/j.cub.2017.04.034. Epub 2017 May 18.
Recent climate change on the Antarctic Peninsula is well documented [1-5], with warming, alongside increases in precipitation, wind strength, and melt season length [1, 6, 7], driving environmental change [8, 9]. However, meteorological records mostly began in the 1950s, and paleoenvironmental datasets that provide a longer-term context to recent climate change are limited in number and often from single sites [7] and/or discontinuous in time [10, 11]. Here we use moss bank cores from a 600-km transect from Green Island (65.3°S) to Elephant Island (61.1°S) as paleoclimate archives sensitive to regional temperature change, moderated by water availability and surface microclimate [12, 13]. Mosses grow slowly, but cold temperatures minimize decomposition, facilitating multi-proxy analysis of preserved peat [14]. Carbon isotope discrimination (ΔC) in cellulose indicates the favorability of conditions for photosynthesis [15]. Testate amoebae are representative heterotrophs in peatlands [16-18], so their populations are an indicator of microbial productivity [14]. Moss growth and mass accumulation rates represent the balance between growth and decomposition [19]. Analyzing these proxies in five cores at three sites over 150 years reveals increased biological activity over the past ca. 50 years, in response to climate change. We identified significant changepoints in all sites and proxies, suggesting fundamental and widespread changes in the terrestrial biosphere. The regional sensitivity of moss growth to past temperature rises suggests that terrestrial ecosystems will alter rapidly under future warming, leading to major changes in the biology and landscape of this iconic region-an Antarctic greening to parallel well-established observations in the Arctic [20].
近年来，南极半岛的气候变化有大量记录[1-5]，变暖的同时降水增加、风力增强、融冰季节延长[1、6、7]，导致环境发生变化[8、9]。然而，气象记录大多始于 20 世纪 50 年代，提供近期气候变化长期背景的古环境数据集数量有限，而且往往来自单一地点[7]，或者时间上不连续[10、11]。在这里，我们使用来自从格林岛（南纬 65.3°）到象岛（南纬 61.1°）的 600 公里横剖面的苔藓库芯作为对区域温度变化敏感的古气候档案，这些变化受水可用性和地表小气候的调节[12、13]。苔藓生长缓慢，但低温会最大限度地减少分解，有利于对保存下来的泥炭进行多指标分析[14]。纤维素中的碳同位素分馏（ΔC）表明光合作用条件有利[15]。在苔藓地中，有孔虫是代表性的异养生物[16-18]，因此它们的种群是微生物生产力的指标[14]。苔藓生长和质量积累速率代表生长和分解之间的平衡[19]。在三个地点的五个核心中分析这些指标，揭示了过去 50 年来生物活动的增加，这是对气候变化的响应。我们在所有地点和指标中都发现了显著的变点，表明陆地生物圈发生了根本性和广泛的变化。苔藓生长对过去气温上升的区域敏感性表明，陆地生态系统将在未来变暖下迅速发生变化，导致这个标志性地区的生物和景观发生重大变化——与北极已经确立的观测结果相呼应，出现南极变绿[20]。
