于桥水库藻类群落演替过程及影响因素

解析湖库藻类群落演替过程及影响因素对于湖库富营养化控制具有重要作用，而当前我国大部分湖库缺乏历史藻类群落监测数据.为研究典型水库藻类群落演替过程及主要驱动因素，在于桥水库采集沉积物柱芯，采用137Cs定年和藻类色素反演的方法，重建了于桥水库藻类群落近80年历史演替过程，揭示了气候变化和人类活动对藻类群落演替的影响规律.结果表明:①于桥水库历史主要藻类为绿藻、蓝藻、隐藻、甲藻、硅藻和裸藻，藻类群落演替经历了3个阶段，第Ⅰ阶段为1938—1958年，藻类生物量较低；第Ⅱ阶段为1958—1983年，藻类生物量逐渐升高；第Ⅲ阶段为1983—2019年，藻类生物量显著增长，主要以蓝藻和绿藻为优势种.②1959年建库后水动力条件改变导致藻类群落显著变化，藻类生物量和多样性增加；20世纪80年代开始流域营养物负荷提高导致藻类生物量显著升高.③1951年以来气象资料时段的相关分析显示，TP含量、气温与藻类色素含量具有显著相关性（P < 0.05），表明TP负荷增加和气候变暖对藻类群落演替和生物量增加起到显著促进作用. 

Succession of Phytoplankton Algae Community and Influencing Factors in Yuqiao Resevoir

It is important to analyze the succession process and influencing factors of algal community in lakes and reservoirs for eutrophication control. However, most lakes and reservoirs in China are lack of historical algal community monitoring data. In order to study the succession process and main driving factors of algal community in typical reservoirs in the past 80 years, sediment cores were collected from Yuqiao Reservoir, and the process of algae community succession in recent decades was reconstructed by using ¹³⁷Cs dating and algae pigment methods. The study revealed the impact of climate change and human activities on algae community succession. The results show that: (1) The main algae were green algae, cyanobacteria, cryptoalgae, dinoflagellates, diatoms and naked algae in recent decades. The algae community succession went through three stages. The first stage was form 1938 to 1958, the algae biomass was low; the second stage was from 1958 to 1983, the algae biomass gradually increased; the third stage was from 1983 to 2019, the algae biomass significantly increased, the dominant species were cyanobacteria and green algae. (2) The change of hydrodynamic conditions led to significant changes in algal community and increase of algal biomass and diversity after the construction of the reservoir in 1959. The increase of nutrient load in the basin led to the significant increase of algal biomass since the 1980s. (3) The correlation analysis showed that TP concentration, temperature and algal pigment content were significantly correlated (P<0.05), indicating that TP load and climate warming played a significant role in promoting algal community succession and biomass increase.