沉积色素定量重建湖泊系统变化研究进展

REVIEW ON INVESTIGATING CHANGES IN LAKE ECOSYSTEMS USING SEDIMENTARY PIGMENTS

湖泊生态系统是陆地生态系统的重要组成部分，其对气候变化和人类活动的响应是研究全球变化背景下湖泊生态功能和服务的重要基础。湖泊沉积物含有丰富的沉积色素，可以用来研究湖泊生态系统中初级生产者（光合生物）群落的历史变化。光合生物生命周期结束后自水体逐渐沉降到沉积物中，其包含的色素在沉积和保存过程中会发生降解，但是保存在沉积物中未降解的色素仍可以很好地反映初级生产者的群落结构和丰度变化。结合湖泊沉积物中的气候变化信息，沉积色素可以用来研究湖泊初级生产力的变化及其与气候变化和人类活动的关系。本文通过阐述湖泊沉积色素从产生、沉降、埋藏，到保存在沉积物中的降解机制，综述近些年来关于色素降解的几个典型模型，并论述湖泊沉积色素与浮游植物群落之间的关系，探索沉积色素作为生物标志化合物在湖泊气候、环境和生态研究中的潜力。

Lake ecosystem is one of the most important component of terrestrial ecosystem on the Earth. Lakes provide essential ecological services, such as drinking water, tourism and aesthetics to humans. However, it remains unclear that how the lake ecosystems would change under the current global change pressure. It is extremely important to understand how the lake ecosystems respond to climate change as well as human activities, which would be very helpful for predicting their future changes. In order to do this, it requires longer dataset than instrumental measurements and observation. Lake sediments contain valuable information on past changes in climate, environment, and ecosystems, which could be used to investigate the influence of climate and human activities on lake ecosystems. Sedimentary pigments have been proposed as useful proxy indicators for algae and bacterial populations. Pigments were biosynthesized by phytoplankton, photosynthetic bacteria and aquatic plants and were preserved long after the end of their life cycles, which could be used to study past changes in primary productivity, phytoplankton community. Recently, a number of pigments could be better separated by reversed-phase High Pressure Liquid Chromatography. Pigments degrade in both water column and sediments. Despite losses during deposition, such as exposure to light, oxygen and zooplankton grazing, sedimentary pigments have been shown to be well correlated with changes in phytoplankton abundance and community through time, so long as there is little change in lake regions. Sedimentary pigments could be used to study changes in phytoplankton community, climatic and other environmental changes, lake stratification and redox, UV radiation, trophic sate, acidification and food-web in lakes. Pigments are also used to investigate anthropogenic influence on lake ecosystem. In this paper, we reviewed the complexity of pigments from production to sediment burial, mathematical techniques for analysis of pigment data （using CHEMTAX software and R software with BCE package） and various decay models. We suggest that sedimentary pigments could work as valuable tools to study past changes in phytoplankton community.