Phytoplankton community structure in Lake Ulungur in Xinjiang Uygur Autonomous Region

Abstract

于2006年11月至2007年7月按季度对乌伦古湖浮游植物进行了取样调查,共发现浮游藻类164种(包括若干未定名种),隶属于8门90属,其中Anabaena bergii为新疆新记录种,两种硅藻Chaetoceros sp.和Thalassionema sp.属于海产种类.各季种类组成均以绿藻门和硅藻门为主,蓝藻门和裸藻门次之,甲藻门、金藻门、黄藻门、隐藻门种类均比较少.秋季种类最多,有141种;其次是夏季和春季,分别为128种和121种;冬季种类最少,仅有95种.中华小尖头藻、微小四角藻、小形月牙藻、小球藻及尖针杆藻为全年可见优势种;肘状针杆藻在春季、夏季和秋季构成优势种群;扭曲蹄形藻和椭圆小球藻仅在夏季构成优势种群,而水溪绿球藻和粗刺四棘藻仅在冬季构成优势种群.藻类生物量周年变动模式为单峰型,生物量的峰值出现在夏季(6.77mg/L),最低值出现在冬季(1.45mg/L).结合历史资料分析发现,30年来,乌伦古湖浮游藻类不仅在种类组成上发生了明显的变化,在数量上也显著着一定的增长,并以绿藻和硅藻类群的增长最为显著.;The phytoplankton of Lake Ulungur was investigated seasonally from November, 2006 to July, 2007. A total of 164phytoplankton species (including a number of unconfirmed species) was detected, which belonged to 90 genera, 8 phylum. Amongthem, Anabaena bergii was a new record species of cyanophyta in Xinjiang Uygur Autonomous Region, and two species ofbacillariophyta, Chaetoceros sp. and Thalassionema sp., belonged to marine algal. In each season, the phytoplankton compositionwas dominated by Chlorophyta and Bacillariophyta, secondly dominated by Cyanophyta, Euglenophyta, Xanthophyta, Chrysophyta,Cryptophyta and Pyrrophyta. The number of phytoplankton species was the highest in autumn (141 species), followed by the summer(128 species) and spring (121 species), the lowest in winter (95 species). There was an obvious seasonal characteristiscs for thedominant species. Raphidiopsis sinensia, Teraëdron minimum, Selenastrum minutum, Chlorella vulgaris and Synedra acus were dominant species in the whole year, while Synedra ulnacould only be found in spring, summer and autumn. Kirchneriella contorta and Chlorellaellipsoidea dominated in summer, and Chlorococcum infusionum and Treubaria crassispina dominated in winter. The standing cropof phytoplankton peaked only in summer with a biomass of 6.77mg/L and the minimum biomass of 1.45mg/L occurred in winter.Compared with historical data, the phytoplankton composition had remarkable changes. The growth of green alga and diatom weremost notable, while the number of the phytoplankton increased many fold in the past 30 years.