枝角类亚化石揭示的湖北太白湖过去百余年环境演变

Environmental evolution of Lake Taibai(Hubei Province)over the past century revealed by cladoceran subfossils

近百年来长江中下游地区的浅水湖泊经历了气候变化及日益增强的人类扰动,造成了普遍的湖泊富营养化、水动力条件和水生生态系统的状态转变,水体的生态服务功能明显退化.枝角类作为一种重要的水生生物,敏感地响应于湖泊及其流域的环境变化,但目前对亚热带湖泊中的枝角类亚化石的环境指示意义,与其它古生态指标如硅藻、摇蚊等对环境变化的响应差异尚未明确.因此,本文以浅水湖泊太白湖为研究对象,结合流域历史资料和监测数据,基于沉积岩芯中枝角类群落过去百年来的期演化序列,重建了近百年来太白湖的历史环境演变过程及机制.对比硅藻及摇蚊的群落演化特征,探讨了多门类古生态指标对环境变化的响应差异.本文重点讨论了枝角类对湖泊鱼类产量指示意义及利用枝角类亚化石来重建历史环境的应用前景及不足.

During the past century,shallow lakes in the middle and lower reaches of the Yangtze River experienced climate change and increasing human disturbance,resulting in widespread lake eutrophication,regime shifts of hydrodynamic condition and aquatic ecosystem,and significant degradation of their ecological functions.Cladoceran,as an important aquatic organism,is sensitive to environmental changes in lakes and surrounding catchments.However,the environmental significance of cladoceran subfossils in subtropical lakes and their unique response patterns to environmental changes from other paleoecological indicators,such as diatoms and chironomids,are not clear yet.Based on the local historical data and monitoring data,this paper reconstructed the past developing process of environment and mechanism of Lake Taibai in the past 100 years from the subfossil cladoceran communities in a sediment core.With significant differences to the response pattern of diatom and chironomid communities,cladoceran exhibited a more complicated manner along with environmental changes.The significance of cladocerans to fish yield and the potential and limitation of using cladoceran subfossils in reconstructing historical environments are discussed.