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。     

邵伯湖藻类特征及蓝藻优势种运动规律探讨

2015年5月~2016年5月对扬州邵伯湖的浮游藻类群落组成与水环境因子进行监测,运用典范对应分析法(CCA)分析了浮游藻类群落结构与环境因子之间的关系,运用垂直运动模型分析了蓝藻中的优势藻在水体生态系统中的运动变化规律。结果显示:邵伯湖群落组成以绿藻、硅藻为主;CCA分析结果显示氨氮和总磷是影响邵伯湖浮游藻类群落分布的主要环境因子;蓝藻中的微囊藻是优势藻,半径大的微囊藻更易运动到水体表面,在不利水文条件下有形成蓝藻水华的风险。     

硅藻指数筛选及水质多指标评价体系构建

为了更科学地监测水质,解决水质理化分析的片面性,在柳江的不同水功能区设置实验点,以构建河水质的多指标评价体系。通过不同水功能区及不同水质等级的实验点的对应分析,认定AMIN,GOLI,DDEL,AMSA,ACLI,NAAN,NRHY等是柳江河流清洁种,菱形藻和端泥生藻是柳江耐污种。典型对应分析表明,河流水质参数是影响硅藻群落分布的主要因素,硝酸盐、氯化物、粪大肠杆菌群和总磷等是主要的变量,因子分析的结果亦表明理化参数是主要变量。研究结果表明,理化变量与硅藻指数IPS,IBD,TID,IDG,SLA的关系紧密,依据水功能区长期水质级别并参考水质参数聚类与硅藻种群聚类,划出3组水质不同的类别,IPS,IBD,CEE硅藻指数对该3组水质状况判别效果较好,而硅藻生物多样性指数不适宜评价柳江河流水质。河流水质及生态质量利用IBD和IPS生物指数、VAN类群划分富营养种百分比及理化参数多指标共同评价,可以提高评价结果的可靠度。     

密云水库浮游藻类特征研究

2008-2010年的监测结果显示,密云水库浮游藻类有7门48属,硅藻、绿藻和蓝藻是主要构成部分.4、5月优势种群为硅藻、绿藻,6-9月为蓝藻,10、11月为绿藻、硅藻.密云水库浮游藻类时空分布差异明显,水温、水深及氮磷等是浮游藻类种群及藻密度变化的主要影响因子,水温与蓝藻呈正相关,与硅藻呈负相关,水深与藻密度呈负相关,氮磷比波动较大,磷为限制性因子.未来几年,在外部环境没有显著改变的前提下,密云水库浮游藻类群落结构不会明显变化,大面积水华发生的可能性较小.     

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。     

水库型水源地浮游植物不同种类季节演替动态模拟研究

针对水库型水源地——金泽水库运行初期的水生态环境特点并结合浮游植物调查结果,基于Mike3软件的Ecolab模块二次开发,构建了可描述硅藻、蓝藻、绿藻3种不同藻类以及沉水植物、浮游动物、碎屑等在水体中相互作用过程的生态动力学模型,模型经验证与实测资料吻合较好。对不同种类浮游植物随季节的动态变化过程进行模拟,结果表明：金泽水库运行初期浮游植物不同种类季节演替表现为春季以硅藻、绿藻为主,8—9月蓝藻大量增殖,10月蓝藻生物量快速回落后以绿藻和硅藻为主的特点;浮游植物生物量在春季(4—5月)和秋季(8—9月)有两个峰值,且春季峰值高于秋季,冬季生物量最低,温度是影响金泽水库浮游植物群落生消演替的重要环境因子。浮游植物生物量的空间分布表明,不同库区的流速和光照条件差异对浮游植物群落的空间分布起到重要的作用,同时,库区沉水植物和浮游植物生长的竞争关系以及沉水植物的克藻效应有效抑制了浮游植物的增殖。     

漂流性鱼卵安全漂流的临界水动力条件实验研究

漂流性鱼卵安全漂流的水动力条件对于生态流量目标制定、鱼类生境保护和早期资源量恢复具有重要意义。为了探求近天然条件下鱼卵安全漂流的临界水动力条件,本文通过建设室外大型明渠,对56种不同工况下,不同流速、水深、水面宽以及水流雷诺数对鱼卵漂流的影响进行了实验研究。结果表明：水面宽一定时,鱼卵安全漂流对流速的要求随水深的升高而降低;水深一定时,在一定流速范围内,水面越宽,鱼卵收集率越高;相比于单一流速条件,以水流雷诺数作为漂流性鱼卵能否安全漂流的判别条件更加科学合理,在明渠均匀流中,水流雷诺数达到7.9×10⁴以上时,鱼卵收集率超过90%,实现安全漂流。相关成果对于开展天然河流鱼类产卵期敏感生态需水目标制定、鱼卵漂流轨迹模拟、水利工程生态调度等具有支撑作用。     

基于GAM模型的硅藻群落与环境因子相关性分析

底栖硅藻水质生物监测技术是被广泛研究与使用的一种监测河流水质及生态质量的理想手段。通过将CCA排序和GAM分析两种方法相结合,分析了对龙江区域河流附生硅藻群落分布影响较大的环境因子。GAM模型画出了各个水环境因子对硅藻完整性指数IBI的响应机制,偏CCA分析进一步确认了营养盐因子对河流硅藻群落的重要性。将两种方法的结果进行比较,最终得出营养盐和电导率是影响龙江附生硅藻群落结构变化的主要因子,流速和水温为次要影响因子。两种分析方法相结合增加了结果的可靠性。     

三峡水库蓄水前后库区干流浮游藻类变化分析

为了研究三峡水库蓄水前后库区干流水体中浮游藻类的变化情况,结合库区地形和城市分布情况,设立了监测断面。利用1999~2008年的监测资料,对三峡库区藻类变化情况及影响因素进行了分析。结果表明：蓄水后,库区TP、高锰酸盐指数等含量总体稳定,水体悬浮物含量下降,藻类光合作用条件改善,使库区干流藻细胞密度总体增加,且呈库尾至库首逐步上升的趋势。藻密度峰值出现季节由蓄水前的冬季转变为蓄水后的春季;但蓄水前后,库区干流浮游藻类种群结构组成基本一致,均是硅藻、绿藻、蓝藻占主体,蓄水后群落结构总体仍表现为河流型生态群落结构特点,只是库首段水体喜静水性的藻类在蓄水后检出频度有所上升。     

东辽河流域浮游植物群落及其与水环境因子的典范对应分析

2010年9月对东辽河流域的浮游植物群落进行了调查,共检出浮游植物6门,浮游植物主要由硅藻、绿藻和裸藻组成.文中运用典范对应分析（CCA）对东辽河流域所有采样点的主要浮游植物与6个水环境因子关系进行研究.结果表明,总氮和溶解氧是影响东辽河流域浮游植物群落分布的主要水环境因子.     

衡水湖湿地沉积硅藻组合与水质关系研究

衡水湖湿地对维护区域生态平衡和促进地区经济社会可持续发展具有重要作用。基于主成分分析法和综合营养指数法对衡水湖湿地水质进行了研究,分析了沉积硅藻组合与水质的关系。主成分分析结果表明,衡水湖四季水质变化较大,冬季水质最好,为Ⅰ类水,夏秋较差,已超标,引起水质恶化和影响藻类生长的主要环境因子是TP、DO和TN;综合营养指数法分析结果确定衡水湖为中-富营养型湖泊。沉积硅藻组合显示,衡水湖是以附生种、浮游种和底栖兼浮游种多生态型硅藻组合为特点,且耐营养度较低指示污染水体的Achnanthes minutissima（20.90%）和Cymbella microcephala（18.83%）为优势种,可较好地反映衡水湖富营养状况,衡水湖湿地水质与沉积硅藻组合的关系密切。     

Influence of the St. Marys River Plume on Northern Lake Huron Phytoplankton Assemblages

Analysis of phytoplankton samples from the Straits of Mackinac region yielded high species diversity and species richness values at the outfall of the St. Marys River due to entrained benthic diatoms. Epilithic, psammonic, epipelic, and epiphytic diatoms originating in the St. Marys River and Detour Passage area were removed from their primary habitats and transported into northern Lake Huron. Southward movement of the St. Marys River plume, as determined from suspended benthic diatom distribution and abundance, was strongly indicated for 3 km. Moderate influence of the plume was noted at 6 km and weaker association with the plume was detected for as far as 32 km. Apparently, loss of suspended riverine species from the upper water column in this area was primarily due to sinking. Sinking, calculated from residence times based on river discharge data, was estimated to range between 0.76 and 5.99 m/day. Total phytoplankton abundance and chlorophyll a values were lower near the rivermouth. Conversely, ¹⁴C uptake was significantly greater near the river. Benthic populations comprised as much as 40% of the assemblage and an additional amount of dead and fragmentary diatoms was also observed. Viable benthic diatoms may contribute as much as 25% of the algal assemblage on a cell volume basis. Upon death and decomposition, they may constitute an important source of carbon and nutrients in the immediate vicinity.     

Can Tolerant Diatom Taxa be Used for Effective Assessments of Human Pressure?

Because lately the low bioindicative value of tolerant species from different taxonomic groups is often questioned, in this study, we hypothesized that tolerant diatoms may be used for effective temporal assessments of human pressure. We tested this on the lowland Bzura River in central Poland, on 156 diatom samples (DSs) from two study periods of 1972 with extremely severe point‐source water pollution and of 2002–2004, where the complex wastewater management in the river catchment improved water quality considerably. Out of the total 295 diatom species recorded in the samples, only 133 tolerant ones were included in the study. Patterns in their abundance were recognized with a Kohonen artificial neural network (self‐organizing map, SOM), whereas the species significantly associated with each SOM cluster of diatom samples were identified with the indicator value (IndVal) index and the Monte Carlo test. If the hypothesis tested was not supported, the assignation of DSs to the SOM clusters would be random. However, the separation of DSs from 1972 and 2002–2004 was almost perfect because the number of exceptions was as low as 4.5%. In addition, the relatively high number (64 out of 133) of tolerant species significantly associated with any SOM cluster (and respective environmental conditions at sites from which samples assigned to it come) supports the hypothesis tested. This means that almost half of the studied species are not evenly distributed in particular clusters as might be expected for highly tolerant species. The study proves that the abundances of many diatom species, currently classified as tolerant, carry quite precise information on the differences in the quality of the environment, and indicates those tolerant diatom species whose bioindicative potential may be highest. Copyright © 2014 John Wiley & Sons, Ltd.     

The effects of run‐of‐river dam spill on Columbia River microplankton

Dams, increasingly common in riverine systems worldwide, are particularly prevalent on the Columbia River (CR) in the United States. Hydroelectric projects, including both storage and run‐of‐river (i.e., minimal storage) structures, on the mainstem CR highly manage water flow, often by releasing water over (rather than through) dams as “spill.” To test the effects of run‐of‐river dam spill on microplankton abundance and composition, we sampled above and below two dams in the lower CR before and during spill conditions in spring 2016 and during and after spill conditions in late summer 2007. We tested the effects of location (i.e., above vs. below dams), spill condition (i.e., before, during, and after spill), and their interaction on microplankton abundance. Generally, diatoms were most abundant during springtime, whereas cyanobacteria were most abundant in late summer. Most taxa were not significantly different in abundance above and below dams, regardless of spill status; although cyanobacteria abundance was marginally higher below dams in summer 2007 (p = .04). Abundances of all taxa were significantly different between pre‐spill and spill periods in spring 2016, whereas only diatom and flagellate abundances were significantly different between spill and post‐spill periods in summer 2007. We conclude that spill conditions may influence microplankton abundance, but are not likely to affect microplankton communities on either side of run‐of‐river dams on the CR. This is important information for dam managers concerned about ecosystem impacts of spill.     

Distribution of Diatoms in Lake Superior Sediments

Four maps showing semiquantitative abundance patterns of diatoms throughout Lake Superior were made by examination of 170 cores at sediment depths of 0–1, 10, 20, and 50 cm. These maps show a decrease in diatom abundance with sediment depth and an absence of diatoms in most open-lake sediments. Diatoms in surficial sediments are most abundant in Jive regions in Lake Superior: Thunder Bay, Keweenaw Bay, the Thunder Bay and northshore troughs, and a region to the southwest of Isle Royale. Only three of these five regions still show relatively abundant diatoms at the 50-cm sediment depth. Diatom abundance in the sediments is positively correlated with sedimentation rates, water depth, and proximity to shore. Nearshore deep-water troughs act as depositional traps for diatoms in western Lake Superior and Keweenaw Bay. Later transport of diatoms by waves and currents generally erases any relationship between diatom abundance in the sediments and diatom biomass in the overlying water. Diatom abundances at 10- and 20-cm depths correlate positively with sedimentation rates, suggesting that biogenous and terrigenous components are eroded, transported, and redeposited as a mixture, rather than being hydraulically separated. Diatoms are abundant at 0–1 cm in regions of both low and high sedimentation rates.     

Relationship between river surface level and fish assemblage in the Ocklawaha River,Florida

Understanding the relationship between river flows and levels and fish communities is important to setting minimum flow and level regulations designed to prevent ecological harm. We reviewed a long‐term Florida Fish and Wildlife Conservation Commission data set from the Ocklawaha River, Florida, to evaluate trends in fish abundance and fish communities relative to historical river levels. Fish data were collected using electrofishing at the Ocklawaha River, Florida, during 1983–1994. Electrofishing data were used to estimate catch per minute and biomass per minute of selected species, fish diversity, richness and evenness. Catch rate variables were compared among years and significant differences in abundance and community indices were related to historical water levels using multiple regression models. Results indicated that differences in abundance and community indices among years were more common at the site with increased river level variability. Regression models indicated that fish abundance and species richness were positively related to river levels, and species diversity was negatively related to variability in river level during the two years prior to sampling. Spotted sunfish Lepomis punctatus exhibited the most variability in species‐specific catch per effort and spotted sunfish abundance was positively related to river levels. Low river levels negatively influenced fish abundance and fish communities, and minimum flows in Florida should manage for the periodicity of low flow events to prevent sequential years of adverse effects on fish populations. Copyright © 2005 John Wiley & Sons, Ltd.     

附生硅藻作为指示生物的研究进展

通过筛选斯普林格、爱思唯尔和中国知网中关于硅藻良好指示特性的研究结论,按照指示变量的特征可归纳为水体环境变量、硅藻指数、生态毒理学、古环境古气候、土地利用和生态水文要素6个类目。大量研究结果证实,基于附生硅藻的种类分布和个体特征,使得硅藻具有上述变量的良好指示效应,特别在指示水体环境和古环境方面。     

Abundance Patterns of Diatoms on Cladophora in Lake Huron with Respect to a Point Source of Wastewater Treatment Plant Effluent

Epiphytic diatoms on Cladophora were collected from July to September, 1979, at various distances from a point source of municipal wastewater treatment plant effluent to Lake Huron. Diatom accumulation rates were positively related to distance from the point source. Despite higher nutrient concentrations nearest the point source, low accumulation rates of Cladophora-epiphyte assemblage biomass and epiphytic diatoms indicated moderate growth inhibition by an undetermined factor. Evaluation of epiphytic diatom population abundance and ecology plus diatom taxocene species diversity supported our conclusions. A curvilinear relationship between diatom species diversity and impacts of growth inhibition is proposed and discussed. The diatom proportion of Cladophora-epiphyte assemblage biomass was positively related to distance from the point source of sewage effluent.     

2018年汉江中下游水华成因分析与治理对策

2018年2月汉江中下游再次暴发硅藻水华,从2月8日至3月中下旬,历时30余天,是有资料记载以来最长的一次。自水华暴发后,长江水利委员会及时启动应急预案,利用汉江中下游梯级水库群进行了水量调度,以控制水华的进一步发展,同时在汉江中下游河段设置了6个监测断面进行逐日监测。调查结果显示：此次硅藻水华优势种为汉氏冠盘藻（Stephanodiscus hantzschii）,暴发期其藻密度最高达到了3200万cell/L,水华影响范围从原先的武汉至仙桃段延伸至了兴隆库区。根据调查结果,分析了水华发生的几点原因,包括硅藻优势种种源问题、污染源控制问题以及特殊的水文气象情势等,并提出了严控污染输入、优化水量调度方案、完善管理机制等几点治理对策。但要永久解决汉江水华问题,还需地方各级政府在当前河长制要求下积极作为,全面保护汉江水生态环境,彻底解决流域面源污染问题。