淡水湖泊浮游藻类对富营养化和气候变暖的响应

水体富营养化和气候变暖是淡水生态系统面临的两大威胁。文章分别阐述了富营养化和气候变暖对淡水湖泊浮游藻类直接和间接效应, 并总结气候变暖可能通过影响水体理化性质、水生植物组成、食物链结构从而直接或间接改变浮游藻类生物量或群落结构。作者重点分析了气候变暖下湖泊生态系统蓝藻水华暴发机制, 比较了不同湖泊蓝藻对气候变暖和富营养化响应的异同点, 发现气候变暖和富营养化对湖泊生态系统影响存在相似性, 表现在均促进湖泊由清水-浊水稳态转变、增加蓝藻水华发生频率和强度。然而二者对湖泊浮游藻类影响的相对重要性取决于分层型湖泊和混合型湖泊的差异性、不同营养型湖泊和不同类群蓝藻组成差异性。作者认为, 开展气候变暖和富营养化下, 湖泊浮游藻类功能群响应研究亟待进行。

A REVIEW: RESPONSES OF PHYTOPLANKTON COMMUNITIES TO EUTROPHICATION AND CLIMATE WARMING IN FRESHWATER LAKES

Currently, freshwater ecosystems are suffering from eutrophication and climate warming. We enumerated both direct and indirect effects of eutrophication and climate warming on phytoplankton communities of freshwater lakes. It was indicated that climate warming might alter algae biomass or community structure through influences on physic-chemical properties, aquatic plants composition and food-chain structure. We further analyzed potential mechanisms of cyanobacterial-blooms by comparing diversified responses of different lakes to climate warming and eutrophication. The results demonstrated that eutrophication and warming played similar roles in affecting lake ecosystems. Both eutrophication and warming promoted regime shift from clear-water state to turbid ones and accelerated the increase of cyanobacterial biomass and bloom intensity. However, the relative contribution of the two factors on biomass was dependent on lake types (Hierarchical or Hybrid), trophic level and phytoplankton community structure. Finally, we suggest that further studies on responses of phytoplankton functional groups to eutrophication and warming are necessary and obligatory.