南极半岛紫外辐射(UVR)变化的湖泊沉积记录及生态效应

项目名称： 南极半岛紫外辐射(UVR)变化的湖泊沉积记录及生态效应

项目编号： No.40876096

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 化学工业

项目作者： 刘晓东

作者单位： 中国科学技术大学

项目金额： 50万元

中文摘要： 以南极富含藻类植物残体和海鸟粪的湖泊沉积剖面作为环境记录的载体，运用多学科交叉的研究方法，分析了沉积物中紫外辐射屏蔽色素Scytonemin及其衍生物和其它色素含量变化，并结合营养元素、同位素等常规生物地球化学指标，恢复出了南极地区紫外辐射（UVR）、太阳光强度变化以及湖泊初级生产力演化的历史记录，探讨了影响它们变化的主要因素；利用色素沉积记录恢复出了湖泊沉积序列中不同藻类种属的丰度与组合的变化关系，分析了南极湖泊生态系统对UVR变化和企鹅粪输入的响应过程；利用新技术手段和方法重建了南极企鹅数量变化，并探讨了南极气候变化对企鹅生态的可能影响。在此基础上，通过对比研究了较长时间尺度的南北极湖泊生产力变化记录，发现极地湖泊生态对气候变化的响应具有一致性。另外，对于偏远地区湖泊沉积物中的污染记录开展了研究，发现全球变暖所导致的湖泊生产力增加以及企鹅的生物传输都会影响污染物的分布。上述研究将有利于我们全面了解历史时期南极紫外辐射的变化，以及湖泊生态系统对紫外辐射增强的响应，从而为在全球变暖的背景下客观评估紫外辐射增强对南极生态系统的可能影响提供科学资料，促进UV气候学和生态地质学的发展。

中文关键词： 南极；紫外辐射；历史记录；湖泊沉积；生态效应

英文摘要： In this project, we have used preglacial lake sedimentary profiles containing algal and penguin guano remnants in the Antarctic region as environmental carriers, and analysed ultraviolet(UV) radiation-screening pigment Scytonemin and its derivatives produced from algae and bacteria, as well as other sedimentary pigments such as carotenoids, chlorophylls and derivatives based on multi-disciplinary approaches. Combined with some conventional biogeochemical paramenters including nutrient elements, isotopic geochemistry etc., we have reconstructed some eco-environmental records including the changes of historical ultraviolet radiation (UVR) level, the intensity of sun's rays (the sum of UVR and PAR, Photosynthetically Active Radiation) and the evolution of historical primary productivity in the studied lakes, and then discussed their main influencing factors. In addition, based on the sedimentary pigment records, we have reconstructed the variable processes of different lake algae species abundance and component in the sedimentary sequences, and analyzed the possible response models of lacustrine ecosystem to the UVR change and the penguin guano input from a holistic point of view. Furthermore, new technical and geochemical approaches have been used to reconstruct the historical change of Antarctic penguin population,and the possible influence of Antarctic climatic change on the penguin ecology was discussed in this project. On that basis, the comparative researches between the long-term records of lake primary production in the Antarctic and Arctic regions showed that the response of polar lake ecosystem to the climatic change was consistent. In addition, the study on the pollution records in the lacustrine sediments from the remote regions revealed that the increased lake primary production related to global warming and the penguin bio-vector could cause significant influence on the distribution of contaminants. The above study results can provide an opporunity for us to fully understand the change history of Antarctic UVR level, and the possible response of lake ecosystem to increased UVR level. Accordingly, our research results can offer scientific data to evaluate objectively the possible effects of presently increased UVR level on the Antarctic ecosystem under the background of global warming, and further promote subject advances of UV climatology and eco-geology.

英文关键词： Antarctica; UV radiation; Historical records; Lacustrine sediment; Ecological effect