草藻型稳态转换对湖泊微生物结构及其碳循环功能的影响

Impacts of regime shift between phytoplankton and macrophyte on the microbial community structure and its carbon cycling in lakes

摘要:

湖泊是地球表层系统中水、土、气等各个圈层相互作用的联结点, 对区域物质如碳等元素循环具有重要影响。微生物是湖泊等水生态系统中的重要组成部分, 是湖泊等生态系统中碳等元素物质循环的主要驱动者, 是深入了解湖泊碳循环过程的关键。受人类活动等影响, 湖泊生态系统, 尤其是浅水湖泊生态系统往往表现出以高等水生植物(草型)为主要初级生产者的清水稳定态和以浮游藻类(藻型)为主要初级生产者的浊水稳定态, 而随着湖泊营养负荷和湖泊环境条件的变化, 这两个不同的稳定态之间可以发生转换或者剧变, 这种剧变不仅影响湖泊生态系统中的微生物结构, 而且对湖泊中有机碳的形成、循环过程及其微生物驱动机制产生重大影响。本文重点就湖泊生态系统中有机碳的转换与微生物关系以及草藻型稳定态的转换对微生物结构及其碳循环功能的影响等进行综述, 进一步分析其中的关键科学问题, 以期为深入了解湖泊生态系统中碳等元素循环的微生物驱动过程与机制提供帮助。

Abstract:

Lake is one of the major ecosystems on the earth. Lake ecosystems play an important role in the nutrient cycling in the regional as well as in the global scale due its connection with different interfaces and its functioning as a junction in the catchment. Microbes are key biological components of the lake ecosystems and are the major forces driving the cycling of nutrients including the carbon. Lake ecosystems particularly in shallow lakes always possess two alternative stable states, a turbid state dominated by phytoplankton and a clear state dominated by submersed macrophyte. Such a change of alternative states is always related to the loading of nutrients including phosphorus and nitrogen as a result of human activities and global change. The shift of alternative states has strong impacts on the ecosystem structure and its function. In this review, we focused on responses of microbial community structure under the regime shift between clear state and turbid state, and subsequently the change of microbial carbon cycling driven by the microbes in lakes. Based on these analyses, we further point out the major research priorities in this direction in the future. We hope such a review will be helpful for a better understanding on the carbon cycling and its mechanisms driven by microbes in lakes.