Response of Terrestrial Ecosystems along the Antarctic Peninsula to a Changing Climate

在过去的50年里，南极半岛西海岸记录的气温和紫外线-B辐射(UVB)的显著上升代表了一场深刻的气候变化，可以说比地球上任何其他地区在过去半个世纪经历的都要大。除了这些有据可查的变化外，半岛沿线的年降水量和冬季积雪深度似乎也在增加。气候的这些快速变化为研究气候变化对陆地生态系统的影响提供了一个独特的机会。在过去关于气候变暖和UVB对半岛陆地维管植物性能影响的工作的基础上，该项目将研究气候变化如何改变维管植物为主的群落中的养分(碳和氮)库以及植物、凋落物和土壤之间的循环，总体目标是预测对植物初级生产力的长期影响。将采用两种相辅相成的方法：对植物群落气候的试验性操纵，以及沿着代表长期气候梯度的环境横断面检查植物群落的模式。在第一种方法中，将通过控制温度、水的可获得性和维管植物微观世界在三个生长季节的紫外线暴露来检验系统对气候变化的短期反应。科学家们将评估这些操作如何影响植物生长和初级生产力、二氧化碳通量、凋落物质量和分解、C和N的池和周转率，以及土壤微生物和节肢动物群落的结构。这些现实的环境操作将允许准确评估未来不同变暖情景的影响，以及太阳UVB的影响。在第二种方法中，将通过测量代表长期温度制度梯度的样带上植物、凋落物和土壤中的碳和氮池来评估对气候变暖的长期反应。在沿这些梯度发现的模式的背景下分析短期变暖操作的结果，将使开发较长时间尺度上的变暖影响的概念模型成为可能。该项目的更广泛影响包括：(1)招聘和培训代表不足的本科生。(2)向公众公布调查结果。(3)通过提高我们对气候变化如何影响植物生产力和生态系统碳储存的理解，为整个社会做出贡献。这些影响是社会关注的问题，因为它们涉及农作物生产，以及生态系统对气候变化的反应是否会减缓或促进温室气体的持续积累。

The striking increases in air temperatures and ultraviolet-B radiation (UVB) documented along the west coast of the Antarctic Peninsula over the past 50 years represent a profound climatic change, arguably larger than experienced by any other region on earth over the last half century. Along with these well-documented changes, annual precipitation and the depth of winter snow pack also appear to be increasing along the Peninsula. These rapid changes in climate provide a unique opportunity to examine the effects of climate change on terrestrial ecosystems. Building on past work that focused on the impacts of warming and UVB on the performance of terrestrial vascular plants on the Peninsula, this project will examine how climate change alters nutrient (carbon and nitrogen) pools and cycling among plants, litter and soils in vascular-plant dominated communities, with the overall goal of predicting long-term effects on plant primary productivity. Two complementary approaches will be employed: experimental manipulation of the climate of plant communities and examining patterns in plant communities along environmental transects that represent long-term climatic gradients. In the first approach, shorter-term system responses to climate change will be examined by manipulating temperature, water availability, and UVB exposure of vascular-plant microcosms over three growing seasons. Scientists will assess how these manipulations influence plant growth and primary productivity, carbon dioxide fluxes, litter quality and decomposition, pools and turnover rates of C and N, and the structure of soil microbial and arthropod communities. These realistic environmental manipulations will allow for an accurate assessment of the effects of different future warming scenarios, as well as the effects of solar UVB. In the second approach, longer-term responses to warming will be evaluated by measuring pools of carbon and nitrogen in plants, litter and soils in plant communities along transects that represent gradients of long-term temperature regime. Analyzing the results from short-term warming manipulations in the context of patterns found along these gradients will make it possible to develop a conceptual model of warming impacts over longer time scales. The broader impacts of this project include: (1) Recruiting and training underrepresented, undergraduate students. (2) The dissemination of findings to the general public. (3) Contributing to society at large by improving our understanding of how climate change impacts plant productivity and ecosystem carbon storage. These impacts are societal concerns because they relate to crop production, as well as whether ecosystem responses to climate change will mitigate or promote continued buildups of greenhouse gases.