于2004-2005年间对洱海水体的硅藻群落进行逐月监测及研究,共发现71个种,分属于18个属.硅藻群落结构的季节变化显著,主要优势种为耐营养的属种.不同季节的硅藻优势种类有明显区别,冬季的主要优势种为Fragilaria crotonensis,春季Aulacoseira ambigua与F.crotonensis的组合占优势地位,夏季以Cyclotella ocellata为主,秋季则A.ambigua与Cyclostephanos dubius组合为优势种.空间上除1*点外,硅藻分布虽然在相对丰度上存在一定的南北差异,但优势属种在全湖具有较好的一致性.说明洱海全湖的水质都已处于中富营养状态.对除1*点外的11个采样点的硅藻及水化学数据进行平均,得到逐月数据,通过数理统计分析的手段,探讨硅藻群落变化与环境因子之间的关系,结果表明影响季节尺度硅藻群落发生变化的最主要因子是气象条件,其次是营养盐.%A total of 71 diatom species belonging to 18 genera were indentified from Lake Erhai in Yunnan Province (Southwest China) from February 2004 to January 2005. Results revealed a distinct seasonal succession of diatom communities, which dominated by eutrophic-tolerant species. Dominant species were different in each season: Fragilaria crotonensis was the main species in winter; Aulacoseira ambigua and F. crotonensis in spring; Cyclotella ocellata in summer; and A. ambigua and Cytdostephanos dub' ins in autumn. Except 1 *, the dominant diatom species were almost same in the whole lake, with a little difference in percentage between the north and the south part of the lake. It may suggest that the water quality of the whole lake was moderate to heavily polluted. Average monthly data of the diatom and water chemistry of all the sampling sites except 1* and the RDA analysis showed that meteorological condition was the key factor, and the nutrient was the second.
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