中文关键词抚仙湖硅藻群落时空分布水温营养盐 英文关键词Fuxian Lakediatom communityspatio-temporal distributionwater temperaturenutrients

作者	单位	E-mail
李蕊	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500	790811996@qq.com
陈光杰	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500	guangjiechen@gmail.com
康文刚	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
陈丽	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
王教元	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
陈小林	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
刘园园	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
冯钟	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500
张涛	云南师范大学旅游与地理科学学院, 高原地理过程与环境变化省重点实验室, 昆明 650500

中文摘要 抚仙湖是我国重要的深水型淡水湖泊且水体水质总体处于I类水平，近年来在流域开发、全球变暖等影响下其生态环境功能呈现退化的趋势，需要对湖泊生物的群落组成、分布模式及其驱动因子进行系统评价.本研究于2015年选取抚仙湖的南、中、北湖区共3个采样点开展了表层水体硅藻群落和水环境特征的逐月分析.样品中共发现硅藻31个属、166个种且以浮游类型为主，其中云南特有硅藻种Cyclotella rhomboideo-elliptica基本消失.硅藻群落结构的逐月变化在3个采样点中均呈现明显的季节演替特征，其中1、2月优势种主要为Fragilaria crotonensis，3月优势种为Aulacoseira granulata，4月C.ocellata与F.crotonensis同为优势种，而在其余月硅藻群落结构较为单一且优势物种皆为C.ocellata（相对丰度占~80%）.而空间尺度上，硅藻优势属种分布和群落结构具有较高的一致性.主成分分析显示，不同湖区的硅藻群落结构组成和水体环境在时间尺度上存在较大差异，而在空间尺度上差异较小；冗余分析和变差分解等分析结果进一步表明，影响群落结构时空变化的主要驱动因子是气象与物理因子（包括水温、风速和透明度），共解释了硅藻群落变率的27.6%，表明了该深水湖泊水体热力分层的厚度与持续时间是影响硅藻群落构建的重要过程.同时，湖泊营养水平与水体离子浓度也对硅藻群落结构产生了明显影响，分别解释了硅藻群落变率的21.2%和9.4%.因此，持续的区域变暖和流域开发明显影响了抚仙湖的生物群落构建与生态系统健康，对抚仙湖的生态保护不仅需要控制营养盐等流域污染物的输入，同时应该积极应对气候变化的长期影响. 英文摘要 Fuxian Lake is an important deep lake in China with trophic status generally categorized as class I. However, there exists a trend of degradation in its ecological and environmental health under the increasing impacts derived from catchment development and recent global warming. Therefore, it is important to evaluate the community composition, distribution patterns, and driving factors of lake biota. In order to uncover the spatio-temporal variations in water quality and diatom communities, a monthly survey of diatom community composition and limnological characteristics was carried out in the surface waters of three sampling sites from the south, middle, and north of the lake basin in Fuxian in 2015. A total of 166 diatom species belonging to 31 genera were identified, which was dominated by planktonic diatoms with the extirpation of Cyclotella rhomboideo-elliptica, an endemic species for Yunnan. Diatom community structure showed significant seasonal succession across the three sites, which were dominated by Fragilaria crotonensis in January and February, by Aulacoseira granulata in March, by Cyclotella ocellata and F. crotonensis in April, and by C. ocellata for other months (i.e., relative abundance of ~80%). Over the spatial scale, the distribution of the dominant diatoms displayed a high degree of similarity. Principal component analysis further showed that there existed significant difference in the diatom community structure and lake environment over the temporal scale, but no significant deviance was found across the three sites. The results of redundancy analysis and variation partitioning revealed that the key driver included meteorological and physical factors (i.e., water temperature, wind velocity, and Secchi depth), which accounted for 27.6% of the total variance in diatom community changes. In combination with the thermocline analysis, the change in lake hydrodynamics may have influenced the thickness and duration of the thermal stratification of lake water, resulting in the reorganization of the diatom community. At the same time, the lake-water nutrients and ions also exerted an important influence on community structuring, which explained the 21.2% and 9.4% of the diatom variation, respectively. Therefore, regional warming and catchment development have significantly structured the biological community and ecosystem health of Fuxian Lake. In all, measures should be taken not only to control the watershed input of pollutants but also to actively mitigate the long-term impact of climate change for the protection and ecological remediation of Fuxian Lake.

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