Climate Change Turning Antarctica Green.
Recent climate change on the Antarctic Peninsula is well documented, with warming, alongside increases in precipitation, wind strength, and melt season length, driving environmental change. However, meteorological records mostly began in the 1950s, and paleo-environmental datasets that provide a longer-term context to recent climate change are limited in number, and often from single sites and/or discontinuous in time. Here moss bank cores from a 600-km transect from Green Island (65.3°S) to Elephant Island (61.1°S) are used as paleo-climate archives sensitive to regional temperature change, moderated by water availability and surface microclimate. Mosses grow slowly, but cold temperatures minimise decomposition, facilitating multi-proxy analysis of preserved peat. Carbon isotope discrimination in cellulose indicates the favourability of conditions for photosynthesis. Testate amoebae are representative heterotrophs in peatlands, so their populations are an indicator of microbial productivity. Moss growth and mass accumulation rates represent the balance between growth and decomposition. Analysing these proxies in five cores at three sites over 150 years reveals increased biological activity over the past 50 years, in response to climate change. The researchers identified significant change points 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. Credit: Research Paper in Current Biology 18 May 2017.
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