松花江哈尔滨段水域硅藻植物群落及其水质的初步评价

2005-2006年5-9月、12月的两年间,在松花江哈尔滨段水域进行了硅藻植物的调查采集,经观察鉴定,共发现硅藻植物72种43变种3变型,分别隶属于2纲6目9科23属,共计118个分类单位。本文对松花江哈尔滨段水域的环境特征,硅藻植物群落组成、种类丰度的季节性变化进行了研究,利用硅藻植物与环境相关性特点对水质进行了初步评价。研究结果表明松花江段哈尔滨水域的硅藻植物群落,总体来说以普生种类(共计86个分类单位)为每年的常见种类,还有一些嗜碱种类和冷水种类出现;硅藻种类的丰度随季节变化明显,从夏季到秋季逐渐增多。硅藻的群落结构变化主要受pH,温度,TN,BOD_5,氨氮的影响,从优势种的组成来看,β-中污以上的污水指示种类数量最多,一些富营养化种类和耐污种类也有出现,说明2005-2006年松花江流域水质污染呈中度至重度污染。     

洪泽湖3种沉水植物附着细菌群落结构及多样性

沉水植物茎叶表面附着的藻、菌及其他物质,不仅影响沉水植物自身生长,而且影响水体物质循环过程,附着藻类的研究已经有不少报道,但附着细菌的报道相对较少.采用末端限制性片段长度多态性(T-RFLP)技术,研究洪泽湖典型沉水植物——菹草(Potamogeton crispus)、篦齿眼子菜(Potamogeton pectinatus)、金鱼藻(Ceratophyllum demersum)在生长旺盛期叶表面附着细菌的群落结构及多样性特征,并采用冗余分析法探讨环境因子对附着细菌丰度的影响.结果表明,(1)3种沉水植物附着细菌群落结构有明显的差异性.143 bp T-RF在菹草和篦齿眼子菜中的相对丰度平均达到了20%和11%,而在金鱼藻中的相对丰度小于1%;89 bp T-RF在金鱼藻中的相对丰度平均约为13%,而在菹草和篦齿眼子菜中相对丰度小于5%.94 bp T-RF在菹草样品中相对丰度超过15%,而在其他样品中未被检测出.(2)从多样性角度分析,3种沉水植物附着细菌多样性大小依次为篦齿眼子菜菹草金鱼藻.(3)部分限制性片段的丰度受环境因子的影响较大,如89、94、143和227 bp T-RFs.而如167 bp T-RFs在3种沉水植物中的相对丰度分布较为稳定,受上述环境因子的限制较小.根据细菌比对结果,洪泽湖附着细菌的优势菌群可能属于拟杆菌门(Bacteroides)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)3个门类.     

洱海硅藻群落结构的时空分布及其与环境因子间的关系

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.     

硅藻群落结构的差异:比较样本采集过程与空间梯度

硅藻种群的分布与其所处的生境条件密切相关,但在实际过程中的一些人为因素,例如取样方法、样本的制备以及藻种鉴定都可能会干扰到种群结构的分析结果.因此很有必要探究这些人为因素是否会对真实的硅藻群落生态学研究产生误导性的判断,以免干扰硅藻生物水质评价的客观性.选取采样方法及样本制备为代表的人为因素对硅藻群落生态分析结果引入的误差大小进行评估.结果显示,子样本之间(同一样品重复制作的玻片样本)和样品之间(同一样点重复取样)群落结构差异大小分别是1.26%和1.97%,同一条河流的样点之间则为3.38%,而所选定的跨河流研究区域的样点间群落结构差异最大(42.03%).生态学的排序结果和数理统计分析表明,在硅藻群落结构分析中,现场取样方法和样本制备过程相对于不同生境条件所引起的变化,并不会带来较大的差异.因此在河流附生硅藻的群落生态学研究中,可基本不考虑取样方法等因子的干扰,而是侧重于环境因子对硅藻生态分布的影响.     

太湖梅梁湾与五里湖浮游植物群落的比较

富营养化和风浪是影响大型浅水湖泊浮游植物群落的重要因素,本文于2003年10月至2004年9月对太湖梅梁湾和五里湖理化环境因子(水温、透明度值、悬浮质浓度和氮、磷营养盐浓度)和浮游植物群落进行了逐月监测,通过对两个湖区理化因子和浮游植物群落结构在周年内季节变化的比较研究,探讨富营养化程度以及风浪对浮游植物群落结构的影响,结果为:(1)梅梁湾由于受风浪影响悬浮物含量较高,五里湖则富营养化水平更高.(2)周年内五里湖浮游植物平均生物量(6.85 mg/L)高于梅梁湾的平均生物量(4.99 mg/L),两个湖区都呈现夏秋高峰、冬季低谷的变化特征.梅梁湾浮游植物群落季节演替的模式基本为:冬季硅藻(小环藻属Cyclotella spp.)和隐藻(隐藻属Cryptomonas spp.)-春季绿藻(细丝藻属Planctonema sp.)-夏季绿藻(绿球藻目Chlorococcales种类)和蓝藻(微囊藻属Microcystis spp.和浮游蓝丝藻属Planktothrix spp.)-初秋蓝藻(微囊藻属)和硅藻(浮游直链硅藻Aulacoseira spp.)-秋季隐藻(隐藻属).五里湖的季节演替模式没有梅梁湾明显,全年隐藻(隐藻属)都占优势,在此基础上,秋冬季硅藻(小环藻属和浮游直链硅藻属)占优势,裸藻(裸藻属Euglena spp.)在冬春季占优势,绿藻(绿球藻目种类和团藻目衣藻属Chlamydomonas spp.)在整个春季和初夏的优势地位在夏季被蓝藻(微囊藻属和浮游蓝丝藻属)所取代.群落构成的差异是浮游植物对两个湖区不同风浪条件和富营养化水平的响应结果.(3)通过与PEG(Plankton Ecology Group)模式的比较,梅梁湾和五里湖浮游植物群落的季节演替主要受水温、光照、营养盐(氮、磷)浓度和浮游动物牧食等因子的影响,因此,大型富营养化浅水湖泊浮游植物群落演替规律需要进一步的研究.     

有机和常规农业管理方式下的浮游植物群落特征及其影响因素

为了解不同农业施肥管理方式对水体浮游植物群落的影响,本研究以江苏句容戴庄有机示范村和常规农业管理区池塘浮游植物为对象,分析冬夏两季浮游植物群落特征及相关水环境因子.结果表明：冬季有机和常规农业区域的浮游植物分别检到7门95种和7门111种,夏季分别检到7门102种和6门112种,有机农业区浮游植物由冬季的隐藻—绿藻型向夏季的蓝藻—绿藻型变化,常规农业区从隐藻—绿藻型向蓝藻—硅藻型变化,蓝藻逐渐取代隐藻的优势地位.夏季各池塘浮游植物alpha多样性没有显著的区域差异,但冬季常规农业区浮游植物物种丰富度、蓝藻和裸藻的Shannon-Wiener多样性指数显著较高.指示物种分析显示,谷皮菱形藻(Nitzschia palea)和梅尼小环藻(Cyclotella meneghiniana)为有机农业区指示物种,而梭形裸藻(Euglena acus)、针形纤维藻(Ankistrodesmus acicularis)、肘状针杆藻(Synedra ulna)和狭形纤维藻(Ankistrodesmus angustus)为常规农业区指示物种,此6种藻为中、富营养化藻类,说明水体氮磷营养盐浓度较高,这与...     

白洋淀超微真核藻的空间分布特征及关键影响因子

超微真核藻个体微小、比表面积大,具有高效的碳吸收速率,对水体初级生产力具有重要的贡献.目前对淡水超微真核藻的认知还非常有限.于2017年5月对白洋淀进行采样调查,结合流式细胞术和高通量测序技术探究了白洋淀超微真核藻群落结构的空间分布特征及关键环境影响因子.结果表明,白洋淀超微真核藻的平均丰度为7.59×104cells/ml,且随着营养水平的升高呈现先增加后降低的变化趋势.回归分析表明,超微真核藻丰度在中营养水平水域主要受溶解性总磷和TN/TP影响,在富营养水域主要与盐度有关.测序比对结果表明在纲水平上白洋淀超微真核藻主要以绿藻纲Chlorophyceae、硅藻纲Bacillariophyceae、中心硅藻纲Coscinodiscophyceae、金藻纲Chrysophyceae为主,不同区域差异不大.但在操作分类单元(Operation Taxonomy Units,OTU)水平上,超微真核藻群落结构在白洋淀不同营养状态湖区存在显著差异,中营养水域主要类群为栅列藻科Scenedesmaceae,近囊胞藻属Paraphysomona sp.,定鞭藻纲Haptophyceae和甲藻纲Dinophyceae为主,而富营养水域主要类群为红球藻科Haematococcaceae,金藻纲的Chromulinale sp.和Chrysophycea sp..Bioenv分析表明,对超微真核藻群落组成影响最大的环境因子是溶解性总氮、溶解性总磷、TN/TP、硝态氮、溶解氧.本研究表明超微真核藻的群落结构存在较明显的环境异质性,对白洋淀水体富营养化状态有很好的指示.     

广东流溪河水库异尾轮属(Trichocerca)的分布模式及其影响因素

异尾轮虫是热带亚热带地区轮虫的重要优势类群.为了解其在水库中的分布模式和潜在影响因素,于2013-2014年对广东流溪河水库河流区、过渡区及湖泊区的异尾轮虫群落及环境因子进行逐月调查.2年共采集到异尾轮虫11种,其中对棘异尾轮虫(Trichocerca similis)、圆筒异尾轮虫(T.cylindrica)、暗小异尾轮虫(T.pusilla)和刺盖异尾轮虫(T.capucina)为优势种,主要出现在丰水期,具有明显的季节分布模式.2013-2014年河流区、过渡区和湖泊区异尾轮虫丰度平均值分别为142.9、102.5和53.6 ind./L,3个水域的异尾轮虫总丰度在夏季(5-9月)较高.从水库上游到下游,异尾轮属的物种丰富度和Simpson多样性指数呈现递减趋势,体现了群落对环境的分区和稳定性变化的响应.群落丰度组成的主成分分析表明,主要优势种的丰度全年分布差异较大,而多数种类全年分布差异小.冗余分析表明,叶绿素a浓度、晶囊轮虫丰度、水温+磷酸盐浓度分别为影响河流区、过渡区和湖泊区异尾轮虫群落结构的关键变量,而降雨则是影响整个库区异尾轮虫群落结构的潜在变量.     

浮游藻类三个常见属(颤藻属、直链硅藻属和针杆藻属)学名变更的解释

根据近年来国外文献所涉及的藻类分类学研究进展,着重解释了蓝藻门的颤藻属和硅藻门的直链硅藻属和针杆藻属的一些浮游种类的学名变更情况,同时介绍了国际上最新的蓝藻门颤藻目和硅藻门的分类概况．根据Anagnostidis和Komfirek的分类,原颤藻属的大部分浮游种类进入了新属『浮游蓝丝藻属](Planktothrix),其他种类则分别属于[湖生蓝丝藻属](Limnothrix)、胶鞘藻属(Phormidium)和现在的颤藻属(Oscillatoria)等多个颤藻目的类别．根据Krammer和Lange-Bertalot的分类,原直链硅藻属的浮游种类进入了新属[浮生直链藻属](Aularoseira),另外的种类归属于Orthoseira、Ellerbeckia和现在的直链硅藻属(Melosira)等硅藻类别中：原针杆藻属的浮游种类并入脆杆藻属(Fragilaria),其他种类进入菱形藻属(Nitzschia)、双尖菱板藻属(Hantzschia)和现在的针杆藻属(Synedra)中．     

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%...     

The effects of artificial ammonium enhancement on riverine periphytic diatom communities

An experiment to ascertain the influence of artificially enhanced ammonium concentrations on riverine periphytic diatom communities was conducted during an 80 day period in winter 1988/89 (temperature: 5°C). During an initial 47 day enrichment phase, ammonium chloride at different concentrations was added to O₂-saturated river water in experimental channels. Compared to a control, the addition of 1.2 mg NH ₄ ⁺ -N·l^–1 resulted in only slight changes in the species composition of the diatom community. The addition of 5.1 mg NH ₄ ⁺ -N·l^–1 and more (60 µg NH₃-N·l^–1) resulted in a decrease in the biomass and a drastic change in the species composition. After the 42 day enrichment period, the diatom speciesFragilaria capucina var.vaucheriae, Navicula saprophila, Navicula atomus andGomphonema parvulum, all of which are known to be tolerant to organic pollution, were found with relative abundances of 44.8%, 35.6%, 2.3% and 1.5%, respectively. Changes in species composition of the periphytic diatom communities occurred within the first two weeks of the subsequent recovery phase. After a month of recovery, all periphytic diatom communities exhibited a high degree of structural similarity with the control.     

近200年来湖北涨渡湖对江湖联通变化的环境响应

江湖联通状况对湖泊生态系统有着重要影响,但是由于缺乏长期的生态水文监测数据,湖泊系统对其响应的过程与机理仍缺乏认识.本研究选择长江中下游地区典型湖泊——涨渡湖,结合该湖一沉积短柱的²¹⁰Pb、¹³⁷Cs年代测试,通过高分辨率的多指标分析(硅藻、元素地球化学和粒度),揭示近200年来湖泊生态系统对该湖与长江之间联通关系改变的响应过程.与历史文献记载一致,古湖沼学记录揭示出该湖与长江的联通状况经历了3个阶段.1)江湖联通期(1954年以前):该湖与长江自然相通,江湖水体交换频繁,丰富的贫营养浮游种Cyclotella bodanica表明该湖长期处于低营养及湖泊水位相对较高的状态.2)江湖隔绝期(1954 2005年):随着湖坝的兴建,江湖联通关系被隔绝,湖泊换水周期变长,透明度降低,喜好扰动环境的Aulacoseria granulata大量生长.相应地,富营养硅藻的增加、高TOC含量以及较高的沉积物TP、TN浓度表明,该湖营养水平逐渐升高.特别是近20年来,较高含量的富营养硅藻种——C.meneghinena、A.alpigena、Nitzschia palea、Surirella minuta和地球化学记录,包括TOC含量和沉积物TP、TN浓度,表明该湖富营养化程度加剧.3)江湖季节性联通期(2005年后):硅藻以附生种、底栖种为主,但仍有一定含量的富营养化属种,且TOC含量以及沉积物TP、TN浓度仍然保持较高水平,表明富营养程度有所缓解.古湖沼学和历史记录都揭示了自该湖与长江无连通后其生态状况的快速退化、重新联通后生态状况有所好转.因此,在长江中下游洪泛平原区,江湖关系的重新联通将是减轻湖泊生态压力的有效手段.     

辽河太子河流域藻类植物群落结构及其季节变化

2010年9月到2011年9月分4次对太子河流域的藻类植物群落组成、丰度及优势种进行调查分析.共设置17个采样点,经鉴定共有藻类植物8门120属328种(包括21种变种).藻类植物群落以硅藻最多,有36属144种,占总体的43.77%;其次是绿藻,有49属117种,占总体的35.56%;蓝藻居第3位,有22属38种,占总体的11.85%.调查期间,太子河流域藻类植物细胞丰度在夏、秋季较高,丰度平均值分别为6.80×10⁷和3.29×10⁷cells/L;在春季较低,丰度平均值为1.36×10⁷cells/L.优势度分析显示,太子河流域各季节的藻类植物优势种都在5种以上,主要优势种有巨颤藻(Oscillatoria princeps Vauch.)、链丝藻(Hormidium flaccidum(Kütz.)Br.)、偏生毛枝藻(Stigeoclonium subsecundum(Kütz.)Haz.)等.藻类植物的Jaccard种类相似性指数在0.19~0.46之间.太子河流域藻类植物种类组成及细胞丰度均有明显的季节变化.     

Seasonal dynamics of phytoplankton with relation to physicochemical water parameters above and below the hydroelectric plant on the Pasłęka River (North-East Poland)

The study of seasonal dynamics of net phytoplankton was carried out above and below the hydroelectric plant (HP) on the Pas ka River. Correlations were found between the abundance of diatoms and conductivity, O₂, PO₄; the abundance of cyanobacteria and water temperature and conductivity, and the abundance of chlorophytes and O₂ and N_tot. Multiple correlations revealed the most significant factor for diatom development is PO₄, for cyanobacteria is water temperature, and for chlorophytes is N_tot. A lower abundance and biomass of phytoplankton, and less species diversity and nutrient concentrations were registered below the HP than above it. The seasonal dynamics of phytoplankton abundance provided similar results. The maximum biomass of the assemblage was found earlier below the HP, in April, than above it, in May. However, no differences were recorded in the dominant species within phytoplankton abundance. The phytoplankton biomass was dominated by the Melosira varians and Spirogyra sp., which are typical taxa of plant periphyton and possibly emanate from the concrete elements of the dam. This HP changed the local hydrological and environmental conditions, affecting available nutrients, and thereby phytoplankton development in the vegetative season.     

Spatial and Temporal Patterns of Plankton Assemblage Structure in a High Altitude Saline Lake,Namuka Co in Northern Tibet,China

The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in saline lake Namuka Co, northern Tibet, China. The sampling was carried out at approximately monthly intervals from June 2001 to July 2002. The salinity ranged from 5.5 to 26 g/L. The mean annual air and water temperature showed a clear seasonal pattern, which was approximately 4.4 and 7.4°C, respectively, with the lowest water temperature in winter (from December to March, −1°C) and the highest in June and July (18°C). The results showed that 36 taxa of phytoplankton and 16 taxa of zooplankton were identified. Both the biomass and abundance of total phytoplankton were lower in the winter and peaked once or twice during the summer and spring in the early August (8.23 mg/L and 158.2 × 10⁶ ind./L). The seasonal variation in total zooplankton biomass and abundance was characterized by lower values in both winter and early spring, and one maximum (90.5 mg/L and 935 ind. L⁻¹) occurred in the late summer. Major phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Ulothrix sp., and Spirogyra sp. And major zooplankton species included Vorticella campanula, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, Arctodiaptomus stewartianus. The production of D. tibetana was 420.3 g m³ a⁻¹. The total number of plankton species has a significant negative correlation with the salinity.     

Diatom thanatocoenosis in a middle Galician Ría: Spatial patterns and their relationship to the seasonal diatom cycle in the water column and hydrographic conditions

Modern diatom distribution patterns in the surface sediment of the Ferrol Ría and their relationship to the hydrography and diatom patterns in the water column were studied to determine the hydrographic influence on the record of these biogenic components. Diatom abundance in the water column was assessed for different oceanographic periods and compared with the biosiliceous sedimentary record. Very low abundances were found in the water column during the winter, whereas in spring and summer, diatoms proliferated. Chaetoceros spp. formed the bulk of the water column community during spring and summer, followed by Thalassionema nitzschioides and Rhizosolenia spp. Nitzschia longissima represented a significant portion of the winter assemblage, together with Paralia sulcata and benthic taxa. Leptocylindrus danicus, N. longissima and Skeletonema costatum characterized the autumn campaign, when stratification of the waters occurs, with L. danicus being especially abundant in the outer ría.Seasonal hydrographic and associated productivity patterns govern the abundance and assemblage of the diatoms preserved in surface sediments. Samples located in the inner ría area and its margins exhibited the highest abundances of diatoms, and were primarily dominated by benthic species. The freshwater group, crysophycean cysts and phytoliths were present in the landward stations influenced by river runoff. The middle ría was characterized by P. sulcata and Thalassiosira spp., with minor occurrences of the benthic and freshwater group. Chaetoceros R.S., L. danicus R.S. and T. nitzschioides typified the outer ría, an assemblage that corresponds to nutrient-rich coastal areas of high productivity influenced by oceanic waters, demonstrating the impact of oceanic waters flowing into the embayment due to enhanced tidal mixing through the narrow channel. Therefore, sediment diatom assemblages reflect diatom production patterns in the water column of the Ría. However, we must proceed with caution when interpreting the paleorecord in the inner area due to the high contribution of allochthonous taxa, which is indicative of low water depths. This paper contributes to a better understanding of diatom thanatocoenosis in the Galician Rías, where very few studies of this kind have been done to date.     

Impact of wastewater effluent on the diatom assemblages structure of a brackish small stream: Oued Hassar (Morocco)

The impact of the wastewater input of Médiouna agglomeration (southeastern area of Casablanca) on the diatom flora and water quality of Oued Hassar stream (Morocco) was studied from July 1997 to August 1998. This wastewater effluent, which was highly loaded with ammonia, orthophosphates and organic matters, had disturbed the diatom assemblages structure and water quality of this stream.The study of the epilithic algal assemblages revealed the presence of 130 taxa of diatoms, 21 of which, according to the available literature, were recorded for the first time in the Moroccan inland waters. Almost all the latter taxa are mesohalobic or oligohalobic-indifferent. Nitzschia inconspicua Grun. was the most abundant species (47.7%) and grows particularly at the source of the stream. Navicula subminuscula Manguin, Nitzschia capitellata Hust. and Nitzschia desertorum Hust. have their dominance in the highly polluted zones, especially downstream the wastewater input.     

Diatom community dynamics in a tropical,monsoon-influenced environment: West coast of India

Diatom communities are influenced by environmental perturbations, such as the monsoon system that impact the niche opportunities of species. To discern the influence of the monsoon system on diatom community structure, we sampled during two consecutive post-monsoons (2001 and 2002) and the intervening pre-monsoon at Mumbai and Jawaharlal Nehru ports along the central west coast of India. Characteristic temporal shifts in diatom community structure were observed across the sampling periods; these were mainly driven by temperature, salinity and dissolved oxygen saturation. The nutrient-poor pre-monsoon period supported low abundance yet high species richness and diversity of diatoms. Coscinodiscus, Cyclotella, Thalassiosira, Triceratium, Pleurosigma, Skeletonema and Surirella were the most dominant genera. Both the post-monsoon periods, following dissimilar monsoon events, were dominated by Skeletonema costatum, but differed in some of the residual species. Thalassiosira and Thalassionema spp. dominated mostly during post-monsoon I whereas Triceratium and Pleurosigma spp. dominated during post-monsoon II. To understand the underlying ecological mechanisms involved in such dynamics, we focus on the dominant diatom species in post-monsoon periods, S. costatum, that contributes up to 60% to total diatom cell numbers. This research is relevant in light of the fluctuating monsoon regimes over the Asian continent, the confounding effects of anthropogenic eutrophication and the resulting cascading effects on trophic web dynamics.     

三峡库区支流底栖硅藻功能群特征及其驱动因子分析——以汝溪河为例

以三峡库区重要支流汝溪河为研究区域,分析汝溪河中底栖硅藻功能群季节演替特征,并探讨影响其季节演替的驱动因子.结果表明,3个水情期(平水期、枯水期及丰水期)共鉴定出底栖硅藻168种,隶属8科27属,共划分为B、C、D、L_O、MP、P、X3和T_B8个功能群,其中MP在3个水情期中均占主导地位.通过冗余分析(RDA)发现,汝溪河中底栖硅藻功能群季节演替的主要驱动环境因子为亚硝酸盐浓度、电导率、溶解性磷酸盐浓度、高锰酸钾指数和温度.