【作者】 刘雪花；

【导师】 周忠泽；

【作者基本信息】 安徽大学 ， 生态学， 2012， 硕士

【摘要】 菜子湖位于安徽省,原是长江流域通江湖泊中受人为影响较小的湖泊。但是近年来,由于养殖业的大力发展,食草性鱼类和螃蟹的量增殖,导致大型水生植物明显减少,其植被盖度明显降低,从2000年的80%到2007年的50%再到2009年的3%。本研究是基于近年的对菜子湖浮游植物群落结构的研究结果,结合本课题组2006—2007年对菜子湖浮游植物群落结构的调查结果,以探讨在水生植被显著改变背景下浮游植物群落结构的变化动态。于2010年1月,3月,5月,7月9月、11月对菜子湖浮游植物群落进行取样调查,并运用优势度指数(Y)、Margalef丰度指数D、香农一韦弗(Shannon-Weaver)多样性指数(H’)、Pielou均匀度指数(J)、Jaccard相似性指数(X)和聚类分析等方法对浮游植物的多样性和群落结构进行分析。调查研究了2010年对菜子湖浮游植物种类组成。结果显示菜子湖6个月份10个断面所采得的浮游植物,共检测到绿藻门、硅藻门、蓝藻门、裸藻门、黄藻门、金藻门、隐藻门、甲藻门等8个门类,其中绿藻、硅藻和蓝藻的种类较多且种类组成变化相对较大,是引起菜子湖浮游植物群落结构季节变化的原因之其中3月份浮游植物种类数最多,1月份浮游植物种类数最少。调查研究了2010年对菜子湖浮游植物优势种类的季节变化规律。通过对优势度分析,结果显示蓝藻存在全年高峰,其优势种为近旋颤藻(Oscillatoria subcontorta)、小型念珠藻(Nostoc minutum)、多变鱼腥藻(Anabaena variabilis)、马氏平裂藻(Merismopedia marssonii)、细浮鞘丝藻(planktolyngbya subtilis)、水华束丝藻(Aphanizomeno flos-aquae);硅藻存在1、5、9、11月的高峰,其优势种有颗粒直链藻(Melodira granulate)、尖针杆藻(Synedra acus)、肘状针杆藻(Synedra ulna)、颗粒直链藻极狭变种(Melodira granulata var. angustissima)；黄藻存在于1月、3月、5月三个高峰,其优势种为小型黄丝藻(ribonema minus)、近缘黄丝藻(Tribonema affine);金藻存在于1月份1个高峰,其优势种为长锥形锥囊藻(Dinobryon bavaricum);绿藻门存在于11月份的高峰,其优势种为狭形纤维藻(Ankistrodesmus angustus)；隐藻门存在5月份的高峰,其优势种为啮噬隐藻(Cryptomonas erosa)。浮游植物密度具有一定的时间变化规律,其周年变化趋势表现为夏秋季节较高,冬春季节较低。7月份最高,为(66.13±8.58)×10.cells/L,1月份最低,为(12.78±0.61)×105cells/L,冬季硅藻占优势,春季黄藻占优势,夏秋季节蓝藻占优势；浮游植物生物量具有一定的时间变化规律,秋季的生物量明显的高于其它三个季节。9月份生物量最高,为(2.80±0.17)mg/L,5月份最低,为(0.72±0.03)mg/L。通过对Jaccard相似性指数(X)的分析,显示菜子湖全年浮游植物群落结构季节演替明显。其值变化在0.25-0.57之间,显示各月份间浮游植物种类相似性差,群落结构变化较大,生境差异较大。9月与11月的相似性指数最大,为0.57；1月份与7月份的相似性指数最小,为0.25；其它月份之间的相似性指数均介于0.26～0.50之间。通过对三个多样性指数的分析,揭示了物种多样性的季节变化规律。Margalef丰度指数(D)(1.51-3).Shannon-Weaver多样性指数(H’)(1.41-3.01).Pielou均匀度指数(J)(0.39-0.66),各指数表现为冬春季节大于夏秋季节,3月份最高,7月份最低。聚类分析的结果显示,在不同季节影响浮游植物群落结构分布的主要因素不一致。7月份主要受植被影响,11月份主要受地域影响,1月份主要受水位高低的影响。结合前期的研究结果,探讨了植被变化对浮游植物群落结构演替的影响。2007年相比,2010年浮游植物物种数有明显下降,由340种下降到285种,细胞密度明显上升,由(5.91±0.90)×10.cells/L上升到(33.81±10.10)×105cells/L,群落结构变化较大,贫营养型和固着型藻类都有所减少,富营养型藻类、丝状藻类和浮游性藻类增多。认为这种变化主要是与植被显著减少有密切相关性。更多还原

【Abstract】 Caizi Lake is one of the most important lake of the wetland of the Changjiang River in Anhui Province, China.lt was not influencedl by human before,but in the last few years,as the development of aquaculture vigorously,It has been severely disturbed.The increasing of grazing fish and crabs leads to the significantly reduced of aquatic plants and obviously decreased of the vegetation coverage.In2000the vegetation coverage is80%,in2007is50%and in2009is3%.The study is based on the research of phytoplankton structure in recent years of Lake Caizi,comparing to the study of2006-2007,to explore the dynamic of phytoplankton community to the chang of vegetation coverage.The phytoplankton samplings were taken in January,march, may, July September and November in Lake Caizi.The dominant index (Y), Margalef abundance index(D), Shannon-Weaver diversity index (H’), Pielou index (J), Jaccard similarity index (X) and clustering analysis were used to analysis the phytoplankton diversity.The composition of phytoplankton species of2012was studied.Chlorophyta, Diatoms,Cyanophyta, Euglenophyta,Xanthophyta, Chrysophyta, Cryptophyta, dinoflagellates were identified.As for the Chlorophyta, Diatoms,Cyanophyta had the most species they are one of the reason of the phyplankton structure chang. The maximal number of phytoplankton species occurred in March while the minimum appeared in January.The phytoplankton dominant species was studied. Cyanophyta peaked all the year round:Oscillatoria subcontorta,Nostoc minutum,Anabaena variabilis,Merismopedia marssonii.planktolyngbya subtilis.Aphanizomeno flos-aquae; Diatoms had an apparent dominance in January,May, September and November: Melodira granulate, Synedra acus, Synedra ulna, Melodira granulata van angustissima;Xanthophyta also played an important role in January, March and May: ribonema minus,Tribonema affine; Chloroph.yta(Ankistrodesmus angustus) and Cryptophyta(Cryptomonas erosa) dominated in May while Chrysophyta dominated in January, Dinobryon bavaricum.The dynamics of cell density was higher in summer and autumn than that in winter and spring. The maximal density, with the value of (66.13±8.58)×105cells/L, occurred in July while the minimal, with the value of (12.78±0.61)×105cells/L appeared in January.Diatoms dominanted in winter, Xanthophyta dominanted in spring and Cyanophyta dominanted in summer and antumn.The dynamics of biomass was higher in autumn than other seasons, the maximal biomass of phytoplankton,occurred in September and the minimal, appeared in May.The results of Jaccard index (X) shew the obvious phytoplankton structure seasonal succession.It was between0.25-0.57,revealing the poor phytoplankton structure similarity and obvious habitat difference.lt maximum value is0.57between September and November and Minimum value is0.25between January and July.Temporal variations of three indices (including Margalef index, Shannon-Wiener index and Pielou evenness index) were obvious. All the indices were higher in winter and spring than that in summer and autumn. The maximal value occurred in March while the minimal one appeared in July.The phytoplankton community structure was influenced by different factors in different months. As a result, the groups of sampling station changed seasonally according to cluster analysis.The obvious variation of phytoplankton community structure was present in2010compared with that in2007. The number of species decreased from340in2007to285in2010, however, the cell density increased obviously from (5.91±0.90)×105cells/L in2007to (33.81±10.10)×105cells/L in2010. At the same time, both the number of oligotrophic algae and perphytic algae decreased to same extent and eutrophic, filamentous and planktonic algae increased.更多还原