沉积物记录的亚高山湖泊环境变化——以鄂东南云中湖为例  

Sedimentary records of environmental changes of subalpine lakes:A case study of Yunzhong Lake in the southeastern Hubei province

作　　者：彭佳 黄春玲 陈旭[1] 

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074

出　　处：《地理研究》2018年第1期220-230,共11页Geographical Research

基　　金：国家自然科学基金项目(41202248;41572343)

摘　　要：根据云中湖27 cm长沉积岩芯进行元素、粒度和硅藻多指标分析以及210Pb测年,结合流域气候和人类活动等历史资料,反演1958年以来云中湖在气候变化和人类活动影响下的环境变化。冗余分析结果显示云中湖沉积硅藻组合变化与Al、Fe、Pb和温度四个变量显著相关。硅藻属种聚类分析的结果表明云中湖环境变化经历了两个阶段:1958-1993年间喜碱性水体的Achnanthes minutissima和Fragilaria nanana属种大量出现与较高CIA指数响应于气候调控下的流域侵蚀过程;1993年以来气候变暖与旅游发展引起入湖营养盐增加是Cyclotella pseudostelligera和Aulacoseira alpigena等中—富营养硅藻种增殖的主要诱因。重建亚高山湖泊在气候变化以及人类活动影响下湖泊生态系统的演化,为保护亚高山湖泊生态环境和改善流域水质提供参考。Subalpine lakes are important reserves of biodiversity and freshwater resource, and their unique ecosystems are responsive to environmental changes. Yunzhong Lake, a subalpine reservoir located in the Jiugong Mountains （southeast Hubei province）, provides important ecosystem services of tourism, water supply, irrigation and electricity generation. However, the lake has suffered environmental degradation （e.g., algal bloom） since 2000, resulting from wastewater input from local tourist hotels. In order to reveal the response of aquatic biota to anthropogenic and climatic disturbances, multi-proxy analysis （element content, particle size and diatom） and 21~Pb dating were applied on a 27-cm length core collected from Yunzhong Lake. The results revealed that sedimentary diatom assemblages were co-dominated by planktonic forms （Aulacoseira and Cyclotella） and benthic forms （Achnanthes and Fragilaria）. The results of redundancy analysis （RDA） revealed that sedimentary diatom assemblages of Yunzhong Lake were significantly related to sedimentary elements （i.e., A1, Fe and Pb） and temperature. The cluster analysis of diatom assemblages showed that environmental changes in Yunzhong Lake had experienced two major phases. During the early period after the damming between 1958 and 1993, high abundances of the species preferring alkaline water （i.e., Achnanthes minutissima and Fragilaria nanana） and relatively high values in chemical index of alteration （CIA） mainly responded to strong weathering in the catchment. After 1993, climate warming and nutrient enrichment induced by the development of tourism were two main driving forces of the proliferation of mesotrophic and eutrophic species, such as Cyclotella pseudostelligera and Aulacoseira alpigena. This study reconstructed the evolution of the subalpine lake ecosystem under the combined effects of climate change and human activities. The results can provide baseline information for eco-environmental protection of subalpine lakes and the re

关 键 词：硅藻组合 气候变暖 富营养化 亚高山湖泊 云中湖 

分 类 号：X524[环境科学与工程—环境工程]