三峡水库上游长寿湖浮游藻类的季节变化特征及关键环境影响因子

基于2013年3月-2014年2月的长寿湖浮游藻类以及水质的监测结果,分析浮游藻类物种组成、密度以及多样性指数的季节动态,利用非度量多维尺度和相似性分析检验不同季节浮游藻类群落差异,同时利用典范对应分析法确定影响不同季节浮游藻类群落结构的关键环境因子.结果表明:泽丝藻(Limnothrix sp.)、小尖头藻(Raphidiopsis sp.)、汉斯冠盘藻(Stephanodiscus hantzschii)、具尾逗隐藻(Komma caudata)、鞘丝藻(Lyngbya sp.)和马索隐藻(Cryptomonas marssonii)为长寿湖优势种群,不同季节间浮游藻类群落组成结构存在较大差异.浮游藻类群落结构以春季最为简单,夏季次之,秋、冬季最为复杂.不同季节影响浮游藻类群落结构的环境因子差异较大,水温和营养盐是影响浮游藻类群落结构最重要的环境因子,光照强度、高锰酸盐指数、氧化还原电位、溶解有机碳在秋、冬季节同样成为影响浮游藻类群落结构的关键环境因子.     

太湖浮游细菌种群基因多样性及其季节变化规律

为认识湖泊中浮游细菌的多样性及其变化规律,本研究采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)的方法,研究了太湖梅梁湾和湖心区浮游细菌种群16S rRNA基因多样性以及种群基因组成的季节变化特征.研究结果表明,太湖浮游细菌种群具有丰富的基因多样性.浮游细菌的丰度、DGGE条带数、种群的Shannon-Wiener指数、Simpson 指数和Pielou指数均呈现显著的季节变化规律:夏季及秋季浮游细菌的丰度、基因多样性及种群的均匀度较高,而冬季和春季则较低.浮游细菌种群的基因组成随时间变化.梅梁湾浮游细菌的丰度显著高于湖心.梅梁湾与湖心浮游细菌主要建群种的基因型存在显著差异.     

新疆博斯腾湖浮游甲壳动物群落结构

2010年6-11月和2011年1月,对博斯腾湖的浮游甲壳动物群落进行了调查,并分析了环境因子对其群落结构的影响.结果表明,不管是在种类数量,还是在密度和生物量上,浮游甲壳动物都主要由枝角类组成,且优势物种存在明显的季节变化.在夏季,浮游甲壳动物主要由大型的僧帽潘和短尾秀体溞组成;在秋冬季,随着大型种类现存量的减少,小...     

珠江下游浮游细菌群落结构的时空分布特征

浮游细菌群落对河流变化具有高度响应性,并可能影响河流生境的生物地球化学过程.因此,了解浮游细菌群落的时空特征,阐明其在河流生态系统中的生态功能具有重要科学意义.于2016年6月和12月对珠江下游浮游细菌群落结构的时空特征进行调查研究,并采用16S rRNA高通量测序技术对样品组分进行分析.结果表明细菌群落主要由变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、抗微菌门(Verrucomicrobia)和蓝细菌门(Cyanobacteria)组成.其中变形菌门相对丰度最高,主要包括β-变形菌纲(Betaproteobacteria)、α-变形菌纲(Alphaproteobacteria)和γ-变形菌纲(Gammaproteobacteria).季节上,丰水期Shannon-Wiener和Chao 1多样性指数高于枯水期其中芽孢杆菌纲(Bacilli)和黄杆菌纲(Flavobacteriia)差异显著;空间上,珠江下游可分为西江沿线、珠三角河网中部和广州市周边3个区域.采用RDA分析表明水温(WT)、溶解氧(DO)、磷酸盐(PO_4~(3-)-P)、硅酸盐(SiO_4--Si)、总磷(TP)和透明度(SD)是驱动细菌群落变化最显著的环境因子,可影响细菌的增殖代谢.其中WT和SD是影响季节差异的重要因素将丰水期和枯水期区分开;而DO、化学需氧量(COD)和营养盐(PO_4~(3-)-P、SiO_4~(2-)-Si、TP)是影响空间差异的重要因素将西江沿线、珠三角河网中部和广州市周边区分开.PICRUSt功能预测分析表明,转运体(Transporters)、ABC转运体(ABC transporters)、DNA修复和重组蛋白(DNA repair and recombination proteins)等是珠江下游浮游细菌群落所表达的主要功能其中转运体和ABC转运体功能丰水期明显高于枯水期.研究结果可为珠江下游生态环境保护提供科学参考依据.     

亚热带大型河流型水库—富春江水库浮游植物群落及其与环境因子的关系

为了掌握富春江水库浮游植物群落特征,探寻其与环境因子的关系,于2006年1月至2007年12月,对其进行了20次采样调查.鉴定结果表明富春江水库共有浮游植物107种,浮游植物密度范围在0.21×10~5-3.01×10~7cells/L之间.浮游植物组成随季节变化有所不同,春季绿藻、隐藻、硅藻占优势,夏季蓝藻和硅藻占优势,秋冬季硅藻、隐藻占优势.浮游植物群落结构受水文条件的影响较大,浮游植物密度与水体温度呈显著正相关,与透明度在不同范围内表现出不同的相关关系;与TN、TP在不同范围内表现出不同的相关关系,与TN/TP及可溶性硅呈显著正相关.库区总氮和总磷浓度均很高,足够满足藻类生长需要;TN/TP较低,基本在8-30之间,说明氮磷含量不是富春江库区藻类生长的限制因子.水文季节性变化会明显地影响浮游植物群落结构和密度的季节性变化,特别是降雨、水温及水力滞留时间等因子是影响水库浮游植物群落结构及密度变化的主要因子.     

西藏拉鲁湿地浮游植物群落时空分布特征及其驱动因子

为了解西藏拉鲁湿地浮游植物群落时空分布特征及其驱动因子,于2021年7月、10月和2022年5月在拉鲁湿地主要水系进行定性和定量样品采集,共采集浮游植物水样126个,从不同季节和不同生境浮游植物种类组成、多样性等方面入手,探讨拉鲁湿地浮游植物群落时空分布特征及其驱动因子,为研究拉鲁湿地生态系统和稳定发展提供基础资料。结果表明:1)拉鲁湿地共鉴定出浮游植物532种(含变种和变型),隶属于8门13纲36目74科130属,物种组成表现为硅藻-绿藻-蓝藻型。2)拉鲁湿地浮游植物群落特征参数在不同季节和不同生境之间存在差异。夏季浮游植物群落的Shannon-Wiener多样性指数显著高于秋季和春季,Simpson优势度指数显著高于秋季。秋季浮游植物群落的Pielou均匀度指数显著低于夏季和春季。春季浮游植物群落的Margalef丰富度指数显著低于夏季和秋季。沼泽生境的浮游植物群落的Margalef丰富度指数显著高于湿草甸生境。3)季节是浮游植物群落组成差异的关键因素,生境对浮游植物群落组成的影响较弱,夏季的距离衰减模式比秋季和春季更强。4)拉鲁湿地不同的浮游植物群落参数与不同环境因子之间存在显著的关联。5)空间因素在解释浮游植物群落变异方面具有显著贡献,而快速变化的水质变量在决定浮游植物的季节变化中起着重要作用。季节和缓慢变化水质因子的解释能力相对较弱,但仍对浮游植物群落的变异有一定影响。     

广州市区越秀湖浮游纤毛虫群落的季节变化

从 1997年 4月到 1998年 3月之间 ,应用定性观察和定量分析的方法对广州市的城市湖泊——越秀湖进行了浮游纤毛虫群落的种类组成、群落的生物多样性、丰度、生物量、优势种的种群季节变化等群落结构参数进行了研究 .共发现了 76种浮游纤毛虫 ;最大丰度为 6 9.1×10 3 ind.· L-1;最大生物量为 7.16 mg· L-1;群落中的优势种为大弹跳虫 (H alteria grandinella)、尾毛虫 (Urotricha spp.)、尾侠盗虫 (Strobilidium caudatum)、小侠盗虫 (Strobilidium humile)和膜袋虫 (Cyclidium spp.) ;群落的生物多样性指数在 2 .4到 3.0之间 .分析了这个湖泊浮游纤毛虫群落结构参数的季节变化 .通过与文献报道的比较、分析 ,从纤毛虫的优势种、总丰度和生物量确定了该城市湖泊的富营养状况为重度富营养化 .     

巢湖流域双桥河底泥疏浚对浮游甲壳动物群落结构的影响

为研究河流底泥疏浚工程对富营养化河流水生生态系统的影响,选取巢湖双桥河开展为期一年的河流生态监测与调查,对比分析了巢湖双桥河疏浚前和疏浚后的水质指标、浮游甲壳动物群落结构及生物多样性指数.研究发现：底泥疏浚后双桥河水质得到明显改善,其中氮、磷营养盐分别削减48.09%和19.09%;底泥疏浚对浮游甲壳动物群落结构影响显著,疏浚后浮游甲壳动物生物量从1.86 mg/L下降到0.25 mg/L,下降了86.40%;疏浚后生物多样性指数高于疏浚前,且受季节影响较大;浮游甲壳动物与水环境因子相关性研究发现：pH、温度、铵态氮、硝态氮、可溶性氮、总氮和氮磷比对浮游甲壳动物总生物量均有极显著影响.研究结果表明,河流底泥疏浚工程能显著削减水体中氮、磷营养盐,并从一定程度上改善河流浮游甲壳动物群落结构,促进河流水生生态系统向健康、安全的方向发展.因此,对于双桥河这种受城市外源污染影响较大的城市污染型河流,在削减外源营养盐特别是氮输入的条件下,实施底泥疏浚工程可以促进其水生生态系统的修复.     

山东某新建水库浮游藻类的群落结构特征及其环境驱动因子

基于山东某新建水库中2014年4月-2017年12月的浮游藻类和水质监测结果,研究了藻类群落结构特征,采用非度量多维尺度分析了各年份不同季节藻类群落结构的相似性,利用冗余分析探究了藻类群落结构和环境因子的关系.结果表明：尖针杆藻（Synedra acus）、湖泊伪鱼腥藻（Pseudanabaena limnetica）和小球藻（Chlorella vulgaris）为此水库的主要优势藻种.水库藻类群落结构的季节演替不稳定,冬、春季多以硅藻和绿藻占优势,不同年份夏、秋季藻类结构差异较大,蓝藻和硅藻在夏、秋季存在一定的竞争优势.该水库于2013年底开始启用,由于水体环境的波动,藻类群落结构有所变化,整体上是由蓝藻-绿藻-硅藻向硅藻-绿藻-蓝藻变化.水库浮游藻类生长主要受到氮盐和高锰酸盐指数影响,但不同年份的主要环境影响因子存在一定差异.     

动态调水过程水文和理化因子共同驱动丹江口水库库湾浮游植物季节变化

丹江口水库是南水北调中线工程水源地,库湾是水库型湖泊水质安全敏感区,动态调水过程库湾水质直接关系到调水安全.为探究动态调水过程中丹江口水库库湾浮游植物季节变化规律和驱动因子,2018年7月—2019年7月,从丹库入库口到渠首调水口,按季节对18个样点进行水质和浮游植物群落组成分析.从整个丹库来看,浮游植物全年总丰度变化范围为0.43×10~3～4.7× 10~6 cells/L,夏季最高,秋季最低;Shannon-Wiener指数春季最高,秋季最低.春季群落为硅藻—绿藻型,夏季为绿藻—硅藻型,秋季为蓝藻型,冬季为蓝藻—绿藻—硅藻型,秋季蓝藻相对丰度最高.位于丹库准保护区内的库湾胡寨,秋季水体电导率、总氮、总磷和叶绿素a浓度最大,蓝藻丰度最高.从入库口经库湾到调水口,浮游植物群落组成存在明显演替.从水文因子来看,秋季水库水位较高,调水流速和流量增加,线性回归分析表明,水位对ShannonWiener指数的影响最为明显,水位越高则多样性指数越低;流量和流速与Shannon-Wiener指数也呈负相关,但相关性较低.方差分解分析发现,水文因子和理化因子共同影响了浮游植物群落组成;偏Mantel分析显示3个库湾浮游植物群落组成与水温、氧化还原电位、化学需氧量、总氮和总磷浓度相关;典范对应分析也表明,总氮是影响库湾浮游植物群落组成最显著的环境因子.人类干扰活动改变了库湾水质理化性质,强干扰提高了蓝藻门丰度.因此,控制库湾人类干扰强度,尤其在水位和调水量较高的秋季,对于改善水体藻类组成、保护整个丹江口水库水质具有重要意义.     

Structure and seasonal dynamics of bacterial communities in three urban rivers in China

Although a large number of recent ecological studies have focused on freshwater bacterioplankton populations, knowledge of the primary factors influencing bacterial communities in urban rivers is limited. Bacterial community structure in three rivers located in Shanghai city was studied over a 1-year period using denaturing gradient gel electrophoresis (DGGE). Subsurface samples were collected every 2 months from two study sites in each river. Water was characterized when biological samples were collected by measuring temperature, pH, chloride ion, total dissolved solids (TDS), total N and total P. complex DGGE band patterns indicated high bacterial diversity in the rivers. Analysis of similarity (ANOSIM) showed that variation of the bacterial communities was higher between rivers than it was between samples from the same river. When evaluated using principal component analysis, samples collected during warmer months from any particular river tended to group together while cold-season samples generally clustered, suggesting significant seasonal impacts. Redundancy analysis was used to identify relationships between environmental factors and bacterial community composition in each individual river. Temperature, TDS, pH, TP and salt concentration were all identified as being related to bacterial community structure, with temperature being the most influential parameter in all three rivers. Our results indicated that bacterial community composition was different in the three different rivers. Even though the rivers were located in heavily disturbed urban ecosystems, temperature was the major driver of bacterial community composition, just as it is in natural systems.     

Impact of environmental factors on bacterial communities in floodplain lakes differed by hydrological connectivity

We analysed total bacterial number and mean volume of cells at three sites in each of ten floodplain lakes in the Middle Basin of the Biebrza River, North-Eastern Poland to test bacterioplankton communities change according to the distance to the river. The composition of the bacterial communities was determined by fluorescent in situ hybridization method. Total number of bacteria in the lakes ranged from 4.0 to 7.48 cells × 10⁶ mL⁻¹ with dominance by Actinobacteria, the contribution of which was positively correlated with water level. Old river channels (side-arms) featured Alpha- and Gammaproteobacteria. The community of Betaproteobacteria was limited by concentration of dissolved organic carbon. Archaea, in spite of a minor role (<3.65% of DAPI-4′,6-diamidino-2-phenylindole) in the communities, showed a positive relation to floodplain lake isolation. Multivariate analysis demonstrated that bacterioplankton in riverine lakes was similar to that in rivers, while lakes with limited water exchange showed a similarity to fertile lakes. Water level and nutrients were among the factors determining bacterial community structure.     

Spatial and temperal patterns in bacterioplankton communities across a river-lake continuum

Bacterioplankton play critical roles in biogeochemical cycling. Although spatial and temporal variations in bacterioplankton community compositions (BCCs) within individual habitat have been reported, knowledge gaps remain for studies conducted within different habitats. In this work, we examined the seasonal and spatial variability of BCCs in Nanfei River and Lake Chaohu which had significant environmental heterogeneity using a high-throughput sequencing technique of 16S rRNA gene amplicons. The results showed that spatial variation has a more obvious impact on the BCCs than seasonal changes. The microbial diversity gradually decreased and BCCs changed obviously along water flow direction from Nanfei River to the western and estern parts of Lake Chaohu over all seasons. LEfSe analysis showed that Nanfei River had higer abundance of species belonging to the orders Rhodocyclales, Methylococcales, Campylobacterales and Flavobacteriales, samples from eastern part of Lake Chaohu were abundant in taxonomies including the order Rickettsiales, while the western part had high abundance of taxonomies belonging to the order Chroococcales. The redundancy analysis (RDA) indicated that BCCs in Nanfei River were associated with high nutrient (TP, PO₄-P, TN, NH₃-N, NO₂-N and NO₃-N) concentrations and electrical conductivity. Variance partitioning RDA analysis indicated that the combined effects of all variables may be most important affecting BCCs. This study may provide a framework for modeling the change in bacterioplankton communities through different habitats from a river to lake.     

The dynamics of phytoplankton, bacteria and heterotrophic flagellates at two Banks near Magdeburg in the River Elbe (Germany)

The main objectives of this study were to describe the seasonal standing stock dynamics of phytoplankton, bacterioplankton and heterotrophic flagellates in the highly eutrophic River Elbe (Germany), and to compare the seasonal patterns observed with other streams. Emphasis was placed on examining and assessing abiotic and biotic controlling factors influencing the structure and dynamics of the riverine plankton. All the physico-chemical and biological parameters determined were within the range or somewhat higher (in the case of phytoplankton abundance and biomass) than reported for other large streams. The underwater light conditions resulting from atypically short phytoplankton growth periods of about 6 months per year and the low phytoplankton carbon to chl a ratio of 23 were identified as a major limiting factor for phytoplankton development in the River Elbe. The seasonal distribution pattern of bacterioplankton indicated probable tight trophodynamical coupling both with phytoplankton and with heterotrophic flagellates, whereas heterotrophic flagellates showed a more trophic link with bacterial densities. Although approximately constant DOC and DON levels throughout the year sustained bacterial growth rates, during the phytoplankton growing season an increase of bacterial standing stocks was observed. Although the left-bank sampling site of the Elbe is strongly influenced by the tributaries Mulde and Saale containing higher concentrations of chloride, nitrogen nutrients, heavy metals and organic pollutants, no clear differences were observed between the two sides of the river concerning the biological parameters measured. Possible reasons and the slightly higher phytoplankton abundance and diversity at the right bank are discussed.     

水体叶绿素a和硅藻群落时空分布及影响因子的对比分析——以云贵高原异龙湖为例

藻类是湖泊生态系统中重要的初级生产者,物种多样性高且对水环境变化敏感,其生产力水平与群落构建模式是反映湖泊环境梯度和生态系统特征的可靠指标。其中硅藻优势属种的演替模式及其环境条件识别,是开展湖泊生态健康和环境质量评价的重要内容。本文选择亚热带地区浅水湖泊异龙湖开展季节调查,对20个采样点的叶绿素a和硅藻群落组成等指标开展分布特征及其驱动因子的定量评价,系统分析藻类变化的时空模式、驱动因子及其指标异同。2020年12月一2021年9月,异龙湖水环境特征的季节波动明显,综合营养指数TSI平均为74.76,总体处于富营养水平。在80个水体样品中共发现硅藻21属68种,群落结构以浮游类型(平均占比79.33%±20.69%)的耐中富营养种为主;在4个季节的调查中,膜糊直链藻Aulacoseira ambigua(61.62%±20.26%)为优势种。主成分分析显示,硅藻群落组成存在明显的空间差异和季节变化。冗余分析和方差分解等结果表明,水体营养因子(TN、TP和N:P)是影响叶绿素a浓度空间变化的重要因子(解释方差为19.08%±11.4%),水温和水深梯度的影响较小(9.63%±11.31%...