高山湖泊吉仁错枝角类古生态变化及其对气候环境的响应

发布时间：2018-11-05 20:52

【摘要】：高山湖泊吉仁错位于川西高原树线以上,受现代冰川融水补给影响.通过吉仁错沉积钻孔~(210)Pb/~(137)Cs定年和沉积枝角类和多环境代用指标分析,结合主成分分析和冗余分析等方法,高分辨率重建了近200 a来吉仁错枝角类组合和环境变化的过程.结果表明,尽管过去200 a来吉仁错枝角类组合一直以沿岸种为主,但仍经历了3个明显的变化阶段.1850 AD后,枝角类组合中Alonella nana、Chydorus sphaericus和Pleuroxus sp.的增加、以及Alona rustica和Alona guttata丰度的下降指示了水温和水体pH值的上升.1900 AD后枝角类通量的增高并不同步于组合的变化,指示了湖泊营养开始增加,这种不一致的变化分别代表了大气氮沉降和区域气候变暖的影响结果.多指标综合分析得出,过去150 a来,气候变暖和大气污染沉降通过直接和间接作用(流域冰川融水过程和植被土壤过程),较深刻地影响了湖泊物理过程(水温升高和无冰期加长)、营养过程(氮、磷营养升高)和酸碱平衡过程(碱性增强),改变了湖泊生物的生长季节,并通过促进藻类发育,最终引起了湖泊枝角类群落组合的变化和生物量的增加.1945 AD前后吉仁错枝角类与藻类群落结构和湖泊环境的同步变化,响应于持续增温背景下多环境过程的相互作用.
[Abstract]:Jiren, a high mountain lake, is located above the tree-line of western Sichuan Plateau and is affected by modern glacial melt water supply. By means of ~ (210) Pb/~ _ (137) Cs dating and multi-environmental proxy index analysis of Jiren fault sedimentary borehole, principal component analysis and redundancy analysis were used. The high resolution reconstruction of the assemblage and environmental change of Khiren in the past 200 years has been carried out. The results showed that, although the assemblage was dominated by coastal species in the past 200years, it still underwent three distinct stages of change. After 1850 AD, Alonella nana,Chydorus sphaericus and Pleuroxus sp. in the Cladocera combinations were observed. The increase of Alona rustica and Alona guttata abundance indicated the increase of water temperature and pH value of water body. The increase of Cladocercus flux after 1900 AD did not synchronize with the change of combination, which indicated that the nutrition of lake began to increase. This inconsistent change represents the effects of atmospheric nitrogen deposition and regional warming, respectively. In the past 150 years, direct and indirect effects (river basin glacier melting process and vegetation-soil process) between climate change and air pollution deposition have been obtained by comprehensive analysis of multiple indicators. The physical processes of lakes (water temperature rise and non-glacial period lengthening), nutrient processes (nitrogen and phosphorus nutrition increasing) and acid-base balance processes (alkalinity enhancement) have changed the growing season of lake organisms, and by promoting algae development, The changes of community combination and biomass of Cladocera were finally caused by the synchronous change of community structure and lake environment of Artemisia and algae before and after 1945 AD, which responded to the interaction of multi-environment process under the background of continuous warming.
【作者单位】：中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室;
【基金】：国家重点研发计划项目(2016YFA0600500) 国家自然科学基金项目(41272379)联合资助
【分类号】：P467;Q915

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