南流江玉林城区河段藻类多样性与水质评价

通过对南流江玉林城区水体藻类植物水样的采集、观察及分类,鉴定了南流江玉林城区河段分布的浮游藻类共6门,28属,58种。绿藻门为优势种,达12属22种,硅藻门为亚优势种,为6属16种,蓝藻门5属11种、裸藻门3属7种,隐藻门、甲藻门最少,均为1属1种。根据藻类植物与生境的关系,采用藻类种类商和藻类污染指数2种生物学评价方法,对南流江玉林市城区水体的水质进行评价,可评价其水质为重富营养型。     

白洋淀藻类现状分析

2010年5—11月,对白洋淀藻类状况进行了调查和分类鉴定。结果表明,白洋淀藻类有7门35属,其中绿藻门(20属)种类较多,其次为硅藻门(6属)和蓝藻门(4属);泥李庄样点藻类物种最丰富,共鉴定出6门32属;蓝藻和隐藻为白洋淀夏季藻类主要优势种类;叶绿素a浓度在6、9月较高,藻细胞密度高峰出现在6、7月。     

长江干流宜昌段浮游植物群落结构初步研究

为探索长江干流宜昌断面浮游植物群落结构分布状况和生物多样性特征及其与水文要素等环境因子的关系,2015年对长江干流宜昌段浮游植物群落结构进行了月度监测。结果共鉴定出浮游植物8门41属,其中蓝藻门7属,隐藻门1属、甲藻门2属,金藻门、黄藻门各1属,硅藻门14属,裸藻门2属,绿藻门13属。春季优势种为绿藻,夏季为蓝藻和硅藻,秋季为硅藻,冬季为绿藻和硅藻。Shannon-Weaver多样性指数和Pielou均匀性指数显示宜昌断面主要为中污染和轻污染状态,该结果与水体综合营养状态评价结果基本一致。通过环境因子间的相关关系分析可知,在三峡水库调度影响下,水动力学条件的变化成为影响现阶段宜昌段浮游植物群落结构特征与水质的主要因素。     

鄱阳湖浮游植物群落结构时空分布特征及其影响因素

为研究鄱阳湖浮游植物群落结构时空分布特征及其影响因素,于2014—2016年夏季对鄱阳湖浮游植物群落结构及水体理化因子进行了调查研究,发现鄱阳湖共有浮游植物71种,分属6门：绿藻门36种、硅藻门17种、蓝藻门9种、裸藻门5种、隐藻门2种、甲藻门2种。2014—2016年年平均生物量分别为3.49 mg/L、3.89 mg/L、1.54 mg/L;年平均丰度分别为9.45×10⁶ cells/L、7.76×10⁶ cells/L、3.91×10⁶ cells/L。优势种主要集中在蓝藻门、绿藻门及硅藻门种类。环境因子对浮游植物群落的解释率为25.32%,水位、透明度、电导率是影响其空间分布的主要因子。基于Shannon-Weiner多样性指数(H′)和Pielou均匀度指数(J)的水质评价表明,鄱阳湖夏季水质处于寡污至中污染之间。研究结果可为鄱阳湖浮游植物研究及水生态保护提供理论基础。     

丹江口库湾浮游植物群落与环境因子关系研究

为掌握丹江口库湾富营养化状况,确保南水北调中线水源安全,于2017年分季节对丹江口库湾浮游植物群落结构和14项水文水环境因子进行了4次监测,并运用相关分析、冗余分析(RDA)等多元统计方法定量分析了浮游植物群落结构与环境因子的关系。监测发现,丹江口水库共鉴定出浮游植物7门57属,年均藻类密度4.89×10~6 cells/L,变幅2.73×10~6～6.87×10~6 cells/L。丹江口水库群落组成以硅藻、蓝藻和绿藻为主;结构变化规律为由春季的硅藻、蓝藻向夏季的绿藻、蓝藻和隐藻,以及秋、冬季的硅藻、隐藻和蓝藻转变。蓝藻门的束丝藻和隐藻门的隐藻为库湾四季的优势种。通过Shannon-Wiener指数、Margalef指数和Pielou指数分析认为,夏季藻类多样性高,绿藻优势度高,冬季藻类多样性相对较低,种群数量差异不显著。根据综合营养状态指数评价的结果可知,库湾富营养化程度处于中营养和富营养化水平,其中总氮贡献较大,总氮浓度范围在1.08～1.88 mg/L之间,均值为1.47 mg/L,磷为库湾富营养化的限制因子。RDA分析结果表明,除氮、磷营养盐外,温度、二氧化硅和电导率等也是影响库湾浮游植物群落分布的重要环境因子。     

松花江哈尔滨段浮游植物分布研究

研究于2020年春、秋两季(5月和10月),在松花江哈尔滨段设置了6个采样点,对化学需氧量、总氮和总磷等理化指标进行测定,同时对其浮游植物种类组成、群落结构及环境因子相关性进行研究。结果表明:松花江干流哈尔滨段共计浮游植物6门90种属。其中,绿藻门的种类最多,为35种属,占38.89%;硅藻门的种类次之,为29种属,占32.22%;蓝藻门为12种属,裸藻门7种属,隐藻门4种属,共占25.56%;甲藻门为3种属,共占3.33%。从种类组成来看,主要以硅藻门的小环藻、短小舟形藻、微绿舟形藻、克洛脆杆藻、肘状针杆藻、尖针杆藻、帽状菱形藻、颗粒直链藻和隐藻门的蓝隐藻为优势种。典范对应分析(CCA)表明,影响松花江哈尔滨段浮游植物群落分布的主要因子是温度和pH值,其次电导率、总磷和总氮也是影响其分布的重要因素。     

白洋淀浮游生物群落结构的季节变化及其与环境因子的关系

浮游生物是水生态系统的重要组成部分,由于其对水环境状况的敏感性常被用来作为水环境优劣的指示生物。为研究白洋淀浮游生物群落特征及其与环境因子的关系,于2018年春季(5月)、夏季(8月)和秋季(10月)分别对白洋淀淀区5个采样点的浮游生物及环境因子进行调查分析,并采用Pearson相关性分析法分析白洋淀浮游生物群落结构变化和主要环境因子的相互关系。结果表明:根据TP、NH₃-N、COD_Mn、TN等水质参数浓度值进行水体质量评价,白洋淀水体夏季为Ⅴ类水,春季和秋季为Ⅳ类水。白洋淀研究区域共检出浮游植物6门74种,浮游动物3门22种。白洋淀浮游生物的群落结构季节间变化显著,两类浮游生物夏季丰度均达到最大值。浮游植物春、夏季以蓝藻门和绿藻门占绝对优势,秋季则出现硅藻门、裸藻门、甲藻门和隐藻门等优势类群。浮游动物在各个季节均以轮虫为优势类群。根据浮游生物群落特征指数进行水质类别分析,白洋淀在不同季节大部分指数显示为中污染。浮游生物多样性指数反映的水质污染状况与理化因子水质评价结果与季节变化趋势相对一致。浮游植物多样性指数与TP、COD_Mn     

新乡定国湖浮游植物群落结构及其水质评价

为全面了解新乡定国湖浮游植物群落结构及水质状况,于2017年7月、2017年10月、2018年1月、2018年4月对定国湖进行了采样调查,结果表明:定国湖共发现浮游植物8门67属109种,其中绿藻门和蓝藻门最多,硅藻门次之;浮游植物丰度、相对丰度以及优势种存在明显季节变化,秋季浮游植物丰度最高,以蓝藻门的大型集胞藻为绝...     

曝气对富营养化景观水体藻类群落结构的影响

采用微宇宙培养法,模拟研究了不同曝气方式(底泥曝气、水曝气)对富营养化景观水体中浮游藻类群落结构的影响及影响因子。结果表明:水曝气使得水体溶解氧(DO)急剧增加,从而促进了水体藻类的生长,优势藻种由绿藻门急剧迁移到黄藻门的黄丝藻属;由于泥曝气对底泥中P释放的抑制作用,及浊度增加导致占藻类主要成分的蓝藻门藻类的不断消亡,而明显的抑制了藻类的生长,优势藻种也由绿藻门迁移到硅藻门。因此,在景观水处理技术中加入人工曝气时,应采用泥曝气的方式。     

海子水库浮游植物功能群季节演替及其驱动因子

以位于北京市平谷区的北京海子水库为研究对象,以浮游植物功能群调查为基础,于2010年春、夏、秋三季对海子水库进行了生态调查;根据水库水环境特征,在北湖、南湖两个不同生境区域设置采样点,进行浮游植物水样采集,将3个季节中的浮游植物划分为16个功能群,利用典范对应分析方法,对同步取得的电导率、TN、TP、水温等环境因子与浮游植物功能群分之间的相关性进行分析。结果表明:2010年海子水库共鉴定出浮游植物74种(包括变种),分属于6门37属。浮游植物种类组成为:绿藻门20属45种,占种类总数的60.82%;蓝藻门7属11种,占14.86%;硅藻门5属8种,占10.81%;裸藻门2属7种,占9.46%;甲藻门2属2种,占2.70%;隐藻门1属1种,占1.35%。浮游植物丰度春季(801.67×104个/L)秋季(3 589.17×104个/L)夏季(13 806.53×104个/L),三季均值为6065.78×104个/L。代表性功能群的季节演替为:春季(J/Xph/P/C)→夏季(Tc/S2/P/C)→秋季(X1/C)。TP、水温、电导率是海子水库浮游植物功能群演替的主要驱动因子。     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

Spatial and seasonal variations in phytoplankton community structure in alkaline–saline Lake Nakuru,Kenya

Spatial and seasonal variations of phytoplankton, expressed in terms of species composition, cell density, biovolumes and biomass, collected at 10 sampling sites in alkaline–saline Lake Nakuru, Kenya, were investigated monthly from March 2004 to February 2005, in relation to selected physical and chemical water quality parameters. A total of eight species, belonging to five genera and three classes, were recorded. The Cyanophyceae comprised the bulk of the phytoplankton, followed by Euglenophyceae, while Bacillariophyceae were the least abundant. Arthrospira fusiformis was the most dominant species, in terms of density, among the Cyanophyceae, while Euglena spp. and Navicula elkabs dominated the Euglenophyceae and Bacillariophyceae density, respectively. Seasonal variations in phytoplankton species composition, density and biomass were significant (P < 0.05) with minimum cell density and biomass occurring during the dry season, and being maximum following the end of the two rainy seasons from May to November 2004, suggesting the possible influence of various environmental factors on the lake. Sampling sites located close to the inlets of inflowing rivers exhibited significantly (P < 0.05) higher phytoplankton cell density and biomass than those by the inshore sites. Soluble reactive phosphorus, ammonia‐nitrogen, conductivity and total alkalinity accounted for most of the variations in the cell densities of phytoplankton species.     

Planktonic interactions with an austral bias: Implications for biomanipulation

The conceptual model of trophic structure in a typical north temperate lake that underlies attempts at biological manipulation to improve water quality is reviewed in relation to the trophic structure and community composition of planktonic food webs in New Zealand and Australian lakes. New Zealand's relatively simple food webs are characterized by an absence of obligate piscivores and few vertebrate and invertebrate planktivores; manipulation of fish stock to improve water quality has not been attempted. The largest crustacean zooplankton in Australasia, and potentially the most effective grazers of phytoplankton, are Daphnia carinata and calanoid copepods (Boeckella spp.). Their potential capacities to remove algae and colonial cyanobacteria (Microcystis, filamentous forms) from waterways are discussed in relation to colony size and concentration, toxicity, selectivity, and digestibility. The potential of D. carinata to suppress rates of increase in phytoplankton biomass may be lowered by its sensitivity to crowding and starvation, and its susceptibility to predation by fish. Decisions to use biomanipulation as a management tool to improve water quality should be based on the results of a whole lake study and take into consideration relevant obligations to preserve the biodiversity of native species, and curb the spread and dominance of exotic species. Programmes that are based on reductions in biomass of planktivorous fish should be complemented by control of nutrient loads (integrated management).     

Phytoplankton primary production, chlorophyll-a and nutrient concentrations in the water column of mountainous Lake Phewa, Nepal

The seasonal patterns of phytoplankton primary production, chlorophyll‐a concentration, cell number and several other limnological variables in Lake Phewa, located in the active monsoon zone in Central Himalaya, Nepal, were studied for a year beginning in April 2001. During the study period, the gross primary production and chlorophyll‐a concentrations were relatively low during the monsoon season. The phytoplankton cell number, represented by 24 genera, also fluctuated seasonally, but tended to increase in the pre‐ and post‐monsoon period. These results suggest that the monsoon plays a crucial role in the primary production and phytoplankton dynamics for Lake Phewa. Among the phytoplankton species, Microcystis aeruginosa, a representative species for eutrophic lakes, was the dominant phytoplankton. At the same time, however, it is clear that the lake is not yet heavily eutrophic. The present study suggests that the exchange of lake water during the monsoon season contributes to maintaining the health of the lake against further degradation. Nevertheless, the silt carried in the monsoon rain run‐off from the lake's catchment area suggests increasingly serious degradation problems for this small mountainous lake.     

洪泽湖浮游藻类变化动态及影响因素

针对2011年7月至2013年10月在洪泽湖11个采样点20次采样获得的湖水表层浮游藻类和水质理化指标数据,采用Shannon-Wiener指数H和优势度指数Y进行数据统计处理,分析洪泽湖浮游藻类时空分布动态及其影响要素。结果表明:洪泽湖浮游藻类共有7门60属144种,主要包括绿藻门66种、硅藻门36种、蓝藻门23种、裸藻门13种。浮游藻类群落具有明显的时空异质性,物种丰富度夏季最高,秋季中等,冬春季最低;西北部(成子湖区)和河流入湖口(溧河洼)高,湖心和河流出湖口(蒋坝)低;浮游藻类细胞密度全湖平均值变幅为157万~604万个/L,夏秋高,冬春--低;成子湖区等静水区高,入湖和出湖口低。浮游藻类组成和细胞密度的时间动态与温度、水位及营养盐(TN、TP等)的季节差异有关,而其空间动态与水动力因素和营养盐(NH3-N)的空间差异有关。建议限制洪泽湖营养盐陆地输入,合理调控洪泽湖水动力,以遏制洪泽湖蓝藻水华的发生。     

长荡湖、滆湖、竺山湾藻类功能群结构组成与环境因子的关系

为研究太湖流域上游长荡湖、滆湖、竺山湾三大典型浅水湖泊藻类功能群结构组成与环境因子的关系,基于2019年2月至2020年10月水文、水质及浮游植物数据,采用Q指数、香农-维纳多样性指数、TLI综合富营养化指数分析了3个湖泊的水质状况,采用非度量多维尺度变换(NMDS)分析了浮游植物群落结构组成特征,采用冗余分析探讨了浮游植物功能群与环境因子的关系。结果表明：长荡湖和滆湖水质整体属于轻度富营养化,竺山湾除冬季外,均属于中度富营养化;长荡湖、滆湖、竺山湾分别有浮游植物7门61属96种、8门75属129种和6门53属124种,分别划分为9、10和11个优势功能群;3个湖泊藻类功能群变化的共同环境因子是水温、高锰酸盐指数和总磷,而总氮和氮磷比对3个湖泊功能群结构变化的作用并不明显。     

Interannual variability of water quality conditions in the Nyanza Gulf of Lake Victoria,Kenya

The Nyanza Gulf of Lake Victoria is considered eutrophic with degrading water quality, as shown by harmful algal blooms formed by cyanobacteria of the genus Microcystis. The dilution of gulf water occurs mainly through the wide Rusinga Channel, whereas the much narrower and shallower Mbita Channel was reopened in May 2017. Specific conductivity and phytoplankton biovolume composition were monitored monthly from July 2017 to July 2018 at three stations and compared with records during 2008 – 2009, when higher eutrophication was observed, in the west gulf (WG, closely located to the Mbita Channel), the mid gulf (central part of the gulf), and the east gulf (EG, close to Kisumu City). As previously observed, conductivity showed a distinct increase from the WG to the EG but compared with records 2008–2009 it had decreased. Water level fluctuations, resulting from wind possibly causing water exchange with the main basin, were related to the decrease in conductivity at the EG. When all three stations were compared, the environmental variable transparency was positively related to most phytoplankton genera, whereas the genera Dolichospermum, Microcystis, and Aulacoseira were related to eutrophication. Compared with the period 2008–2009, the proportion of Microcystis decreased, while the proportion of Aulacoseira increased. Compared with the period 2008–2009, the observed dilution at the EG was primarily related to the overall increased water level in the main basin. The observed dilutional influence might have led to a decline in nuisance phytoplankton and overall improved water quality conditions.     

Assessment of physico‐chemical properties of water and phytoplankton bloom formation in a eutrophic pond using multivariate analysis

An investigation of the water chemistry and phytoplankton bloom formation characteristics of a seasonal earthen pond located in the Alappuzha District, Kerala (India) was carried out during November 2011 to May 2012. Twelve important physico‐chemical parameters (temperature, Secchi disc transparency, pH, electrical conductivity EC), dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia‐nitrogen, nitrite‐nitrogen, nitrate‐nitrogen, total phosphorus (TP), dissolved iron and chlorophyll a related to phytoplankton growth in the pond were the focus of the present study. Chlorophyll a was used as a measure of phytoplankton biomass. The pond developed subsurface phytoplankton blooms of Chlorella vulgaris, Aphanothece sp., Leptosira sp., Lepocinclis globulus and Lepocinclis fusiformis. Visible scums of Lepocinclis globulus and Euglena proxima was also observed during March 2012. Principal component analysis was performed to understand the biochemical processes in the pond ecosystem leading to the Euglena spp. bloom.     

From River to Lake: Phosphorus partitioning and algal community compositional changes in Western Lake Erie

The Maumee River is an important source of phosphorus (P) loading to western Lake Erie and potentially a source of Microcystis seed colonies contributing to the development of harmful algal blooms in the lake. Herein, we quantified P forms and size fractions, and phytoplankton community composition in the river–lake coupled ecosystem before (June), during (August), and after (September) a large Microcystis bloom in 2009. Additionally, we determined the distribution and density of a newly emergent cyanobacterium, Lyngbya wollei, near Maumee Bay to estimate potential P sequestration. In June, dissolved organic phosphorus (DOP) was the most abundant P form whereas particulate P (partP) was most abundant in August and September. Green algae dominated in June (44% and 60% of total chlorophyll in river and lake, respectively) with substantial Microcystis (17%) present only in the river. Conversely, in August, Microcystis declined in the river (3%) but dominated (32%) the lake. Lake phytoplankton sequestered < 6% of water column P even during peak Microcystis blooms; in all lake samples < 112 μm non-algal particles dominated partP. Lyngbya density averaged 19.4 g dry wt/m², with average Lyngbya P content of 15% (to 75% maximum) of water column P. The presence of Microcystis in the river before appearing in the lake indicates that the river is a potential source of Microcystis seed colonies for later lake blooms, that DOP is an important component of early summer total P, and that L. wollei blooms have the potential to increase P retention in nearshore areas.     

Effects of the Zebra Mussel (Dreissena polymorpha Pallas) on Protozoa and Phytoplankton from Saginaw Bay,Lake Huron

Direct effects of the grazing activities of the zebra mussel, Dreissena polymorpha, on the natural assemblage of planktonic protozoa and algae from Saginaw Bay, Lake Huron, were studied in September and October 1994. Water and mussels collected from two eutrophic sites were incubated in an outdoor “natural light” incubator at ambient temperature for 24 hours. Experiments were conducted in 4-L bottles with screened (40 or 53-μm net) or unscreened water and with and without mussels. Despite relatively high growth rates of protozoa on both dates, mussels lowered protozoan numbers by 70–80% and reduced the species richness of the protozoan community by 30–50%. Large heterotrophic flagellates were reduced up to 100% while peritrichous ciliates attached to the colonies of blue-greens were reduced only by 50%. Dreissena selectively removed nanoplanktonic Cryptomonas and Cyclotella, but had no significant effect on the predominant phytoplankton species, Microcystis. Overall, Dreissena clearance rates were low in the presence of this cyanophyte species. We conclude that zebra mussels, in regions where they are abundant, can cause significant changes in composition of both the protozoan and phytoplankton communities.