Evaluation of Extensive Secondary Maximum Contaminant Level Exceedances Following Remediation by In Situ Chemical Oxidation

In situ chemical oxidation (ISCO) with activated persulfate is commonly used for the remediation of petroleum impacted soil and groundwater because of its proven efficiency and the perception that reaction end products are completely innocuous. While the reaction products are less hazardous compared to the contaminants being treated, they may inadvertently prolong site closure in areas that have adopted the U.S. Environmental Protection Agency (EPA) Secondary Maximum Contaminant Levels (SMCLs) as enforceable standards. This study examines the occurrence and persistence of iron, manganese, sulfate, sodium, and total dissolved solids (TDS) in groundwater following persulfate ISCO. The concentrations of these chemicals were observed remaining above their respective regulatory criteria almost 3 years following the chemical application. Background concentrations and mobilization due to the petroleum contamination and ISCO application are also evaluated. Baseline sampling revealed substantially higher iron and manganese concentrations inside the plume area compared to the upgradient and downgradient wells suggesting mobilization due to redox reactions occurring inside of the plume. Iron was not a component in the applied chemical formula, yet the iron concentration spiked by 366% in the key monitoring well during the first post-remediation monitoring event. Ionic interactions between the ISCO amendment and native soils are believed to be responsible for displacing significant quantities of iron from the soil. Sulfate, sodium, and TDS exceedances are primarily associated with decomposition products of the ISCO amendments. The iron, manganese, sulfate, sodium, and TDS concentrations are trending downward over time, but still exceed regulatory criteria or pre-ISCO concentrations.     

Activation of Persulfate by Surfactants under Acidic and Basic Conditions

Activated persulfate is a commonly used oxidant source used for in situ chemical oxidation (ISCO) for remediation of subsurface contamination. Surfactants are sometimes used in ISCO to desorb contaminants and dissolve nonaqueous phase liquids (NAPLs). The potential activation of persulfate by such surfactants was investigated, and the reactive oxygen species generated by persulfate in the presence of anionic, nonionic, and cationic surfactants were determined. Twenty surfactants were screened; most activated persulfate to generate reductants + nucleophiles at acidic and basic pH. The most reactive anionic, nonionic, and cationic surfactants (Lankropol 4500, polyethylene glycol 400, and Ethoduomeen T/25) were investigated in more detail. All three surfactants activated persulfate; however, the cationic surfactant showed the most potential for persulfate activation with high fluxes of hydroxyl radical and reductants + nucleophiles. The results of this research demonstrate that surfactants added to ISCO systems often activate persulfate to generate reductants at both acidic and basic pH, and hydroxyl radical at basic pH. These findings provide a new paradigm for persulfate activation in surfactant in situ chemical oxidation (SISCO) systems; pH regimes >11 may not be necessary for persulfate activation resulting in cost savings and potentially more effective activation of persulfate.     

Biostimulation and Bioaugmentation to Enhance Reductive Dechlorination of TCE in a Long‐Term Flow Through Column Study

Large laboratory columns (15.2 cm diameter, 183 cm long) were fed with groundwater containing trichloroethylene (TCE), were biostimulated and bioaugmented, and were monitored for over 7.5 years. The objective of the study was to observe how the selection of the carbon and energy source, i.e., whey, Newman Zone^® standard surfactant emulsified oil and Newman Zone nonionic surfactant emulsified oil, affected the rate and extent of dechlorination. Column effluent was monitored for TCE and its degradation products, redox indicators (nitrate‐N, Fe(II), sulfate), and changes in iron mineralogy. Total bacteria and Dehalococcoides mccartyi strains were quantified using q‐PCR. Complete dechlorination was only observed in the whey treated columns, occurring 1 year after bioaugmentation with addition of a culture known to dechlorinate TCE to ethene, and 3 years later in the non‐bioaugmented column. The addition of the emulsified oils with or without bioaugmentation resulted in dechlorination only through cis‐DCE and vinyl chloride. While Dehalococcoides mccartyi strains are the only known bacteria that can fully dechlorinate TCE, their presence, either natural or augmented, was not the sole determiner of complete dechlorination. The establishment of a supporting microbial community and biogeochemistry that developed with continuous feeding of whey, in addition to the presence of D. mccartyi, were necessary to support complete reductive dechlorination. Results confirm that careful selection of a biostimulant is critical to the success of TCE dechlorination in complex soil environments.     

ISCO for Groundwater Remediation: Analysis of Field Applications and Performance

A critical analysis of in situ chemical oxidation (ISCO) projects was performed to characterize situations in which ISCO is being implemented, how design and operating parameters are typically employed, and to determine the performance results being achieved. This research involved design of a database, acquisition and review of ISCO project information, population of the database, and analyses of the database using statistical methods. Based on 242 ISCO projects included in the database, ISCO has been used to treat a variety of contaminants; however, chlorinated solvents are by far the most common. ISCO has been implemented at sites with varied subsurface conditions with vertical injection wells and direct push probes being the most common delivery methods. ISCO has met and maintained concentrations below maximum contaminant levels (MCLs), although not at any sites where dense nonaqueous phase liquids (DNAPL) were presumed to be present. Alternative cleanup levels and mass reduction goals have also been attempted, and these less stringent goals are met with greater frequency than MCLs. The use of pilot testing is beneficial in heterogeneous geologic media, but not so in homogeneous media. ISCO projects cost $220,000 on average, and cost on average $94/yd³ of target treatment zone. ISCO costs vary widely based on the size of the treatment zone, the presence of DNAPL, and the oxidant delivery method. No case studies were encountered in which ISCO resulted in permanent reductions to microbial populations or sustained increases in metal concentrations in groundwater at the ISCO-treated site.     

Release of Chromium from Soils with Persulfate Chemical Oxidation

An important part of the evaluation of the effectiveness of persulfate in situ chemical oxidation (ISCO) for treating organic contaminants is to identify and understand its potential impact on metal co‐contaminants in the subsurface. Chromium is a redox‐sensitive and toxic metal the release of which poses considerable risk to human health. The objective of this study was to investigate the impact of persulfate chemical oxidation on the release of chromium from three soils varying in physical‐chemical properties. Soils were treated with unactivated and activated persulfate [activated with Fe(II), Fe(II)‐EDTA, and alkaline pH] at two different concentrations (i.e., 41 mM and 2.1 mM persulfate) for 48 h and 6 months and were analyzed for release of chromium. Results show that release of chromium with persulfate chemical oxidation depends on the soil type and the activation method. Sandy soil with low oxidant demand released more chromium compared to soils with high oxidant demand. More chromium was released with alkaline pH activation. Alkaline pH and high Eh conditions favor oxidation of Cr(III) to Cr(VI), which is the main mechanism of release of chromium with persulfate chemical oxidation. Unactivated and Fe(II)‐activated persulfate decreased pH and at low pH in absence of EDTA chromium release is not a concern. These results indicate that chromium release can be anticipated based on the given site and treatment conditions, and ISCO system can be designed to minimize potential chromium release when treating soils and groundwater contaminated with both organic and metal contaminants.     

Numerical modeling analysis of hydrodynamic and microbial controls on DNAPL pool dissolution and detoxification: Dehalorespirers in co-culture

Dissolution of dense non-aqueous phase liquid (DNAPL) contaminants like tetrachloroethene (PCE) can be “bioenhanced” via biodegradation, which increases the concentration gradient at the DNAPL–water interface. Model simulations were used to evaluate the impact of ecological interactions between different dehalorespiring strains and hydrodynamics on the bioenhancement effect and the extent of PCE dechlorination. Simulations were performed using a two-dimensional coupled flow-transport model, with a DNAPL pool source and two microbial species, Dehalococcoides mccartyi 195 and Desulfuromonas michiganensis, which compete for electron acceptors (e.g., PCE), but not for their electron donors. Under biostimulation, low v_x conditions, D. michiganensis alone significantly enhanced dissolution by rapidly utilizing aqueous-phase PCE. In co-culture under these conditions, D. mccartyi 195 increased this bioenhancement modestly and greatly increased the extent of PCE transformation. Although D. michiganensis was the dominant population under low velocity conditions, D. mccartyi 195 dominated under high velocity conditions due to bioclogging effects.     

Optimal Field Approaches for Electrokinetic In Situ Oxidation Remediation

Numerical simulations were used to identify and evaluate optimum electrode configurations and approaches for electrokinetic in situ chemical oxidation (EK‐ISCO) remediation of low‐permeability sediments. A newly developed groundwater and EK flow and reactive transport numerical model was used to conduct two‐dimensional scenario simulations of the coverage of an injected oxidant, permanganate, and the oxidation of a typical organic contaminant (tetrachloroethene, PCE). For linear configurations of vertical electrodes, the spacing of same‐polarity electrodes is recommended to be about one‐third to one‐quarter of the anode–cathode spacing. Greater coverage could also be achieved by locating additional oxidant injection wells at the divergence of the electric field in linear electrode configurations. Horizontal electrodes allowed greater contact between the injected permanganate and PCE and resulted in faster degradation of PCE compared to vertical electrodes. Pulsed oxidant injection, closer electrode spacing, and electric field reversal also resulted in faster EK‐ISCO remediation.     

Impact of fish farming on foraminiferal community, Drvenik Veliki Island, Adriatic Sea, Croatia

This study examined the impact of fish farming on foraminiferal communities in the Adriatic coastal zone. Samples were taken directly beneath the farm, near the edge of the farm, and at a reference station away from the farm. The foraminiferal community near the farm is characterized by Epistominella exigua, Globocassidulina subglobosa, Haynesina germanica and the genera Elphidium, Bulimina and Brizalina. These foraminiferal species are less abundant seaward. Asterigerinata mamilla, Neoconorbina terquemi and genus Cibicides are almost absent below the cages. Total phosphorus (TP) and total nitrogen (TN) in the sediments decrease with distance from the cages. The abundances of E. exigua, G. subglobosa, H. germanica and the genera Elphidium, Bulimina and Brizalina are correlated with TP and TN, indicating their dependence on nutrient input. The absence of A. mamilla, N. terquemi and the genus Cibicides below the cages is a due to a degraded Posidonia community. According to our study, foraminiferal community composition can be used as indicator of organic enrichment caused by fish farm activities.     

Temporal variation of diatom benthic propagules in a monsoon-influenced tropical estuary

Temporal variations in the diatom benthic propagule (DBP) community and their role in the phytoplankton community in a monsoon-affected tropical estuary, Zuari estuary, Goa (India) are presented. The DBP from the sediments was enumerated using an extinction dilution method (most probable number method), which allows estimation of resting stages through examination of germinated vegetative cells in culture. The DBP community was dominated by planktonic species belonging to the genera Skeletonema, Fragilariopsis, Thalassiosira, and Chaetoceros. Benthic propagules (BPs) of Skeletonema costatum and Fragilariopsis sp. were dominant throughout the year. Between these two species, only S. costatum showed a linear relationship between the BP and planktonic cells, indicating that this species is particularly important in coupling of pelagic and benthic ecosystems. During the onset and restart of monsoon after an intermittent break, water column was stratified, with a low-salinity layer arising from riverine discharge and precipitation at the surface and relatively cold, saline, low-oxygen waters at the bottom. Stratification favored blooming of S. costatum and Fragilariopsis sp. in nutrient-rich surface and bottom waters, respectively. The decline in these blooms ensuing nitrate depletion and salinity change resulted in an increased abundance of BP. Chaetoceros bloom was observed during the monsoon break as well as during non-monsoon period and on both the occasions the decline in bloom was coupled with freshwater discharge. During the non-monsoon season, Thalassiosira blooms were encountered subsequent to high nitrate inputs. These findings suggest that in such shallow tropical regions, physical processes during monsoon (freshwater discharge) and non-monsoon seasons (currents, waves and tides) cause resuspension of diatom BP. Since light is not a limiting factor for germination in such regions, the blooming of resuspended BP depends on nutrient availability.     

2002-2017年千岛湖浮游植物群落结构变化及其影响因素

为认识大型水库中浮游植物群落结构的演替特征及其驱动机制,以钱塘江流域新安江水库（下称"千岛湖"）为例,基于2002-2017年16年的水库浮游植物数据,结合同期千岛湖水质与水文气象资料,分析了千岛湖浮游植物结构及优势属的长期变化特征,探讨了影响浮游植物群落结构变化的主要因素.结果表明：2002-2017年千岛湖共鉴定出浮游植物7门93属,主要由硅藻门、绿藻门、蓝藻门及隐藻门种类组成.16年间,浮游植物年均丰度和群落结构经历了4个阶段：2008年前丰度持续低值且蓝藻不是主要类群,2009-2012年丰度较高且蓝藻成为主要类群,及2013-2015丰度降低且蓝藻占比降低,2016-2017年丰度增加且蓝藻再次成为主要类群.浮游植物门类变化的同时伴随着优势属的变化：浮游植物年优势属从2002-2008年的小环藻属（Cyclotella）、隐藻属（Cryptomonas）和蓝隐藻属（Chroomonas）转变为2009-2012年的颤藻属（Oscillatoria）、小球藻属（Chlorella）、小环藻属和蓝隐藻属,2013-2017年又转变为鱼腥藻属（Anabaena）、束丝藻属（Aphanizomenon）、小环藻属、针杆藻属（Synedra）、直链藻属（Melosira）、栅藻属（Scenedesmus）和蓝隐藻属.冗余分析表明,气温、风速、水位、入库流量等气象水文因子和总氮浓度、电导率、氮磷比、透明度等水质因子与浮游植物群落结构变化关系密切.研究结果表明,在千岛湖这种大型贫-中营养水库,浮游植物群落结构不仅受来水营养盐负荷的影响,还在很大程度上受水文、气象条件的影响,给水库藻类水华等生态风险的预测以及水库水质管理带来了挑战.     

Interface Treatment of Petroleum Hydrocarbon‐impacted Lower Permeability Layers by Activated Sodium Persulfate to Reduce Emissions to Groundwater

Nonaqueous phase liquid (NAPL)‐impacted lower permeability layers in heterogeneous media are difficult to fully remediate and can act as persistent sources of groundwater contamination through diffusive emissions to transmissive aquifer zones. This work investigated the benefits of partial remediation involving treatment focused near the high‐low permeability interface, with the performance metric being emissions reduction. A sequential base‐activated persulfate (S₂O₈ ^2?) delivery treatment strategy was studied in this work, involving 13–14 d deliveries of 10% w/w sodium persulfate (Na₂S₂O₈) and 14–28 d deliveries of 19 g/L sodium hydroxide (NaOH). Treatment and control experiments were conducted in 1.2‐m wide × 1.2‐m tall × 5‐cm thick physical model tanks containing two soil layers differing in hydraulic conductivity by three orders of magnitude. The top 10 cm of the lower permeability layers contained 7400–7800 mg‐NAPL/kg‐soil; the NAPL was comprised of benzene, toluene, ethylbenzene, p‐xylene, o‐xylene, n‐propylbenzene, and 1,3,5‐trimethylbenzene (TMB) mixed in octane. Approximately 0.1 g‐Na₂S₂O₈ was delivered per cm²‐interface area over 13–14 d. The S₂O₈ ^2? and SO₄ ^2? concentration profiles suggest higher oxidant reaction rates when NaOH is delivered prior to, rather than after Na₂S₂O₈. After 264 d and two treatments, hydrocarbon emissions from the NAPL source were reduced by 60% to 73% compared to a no‐treatment control tank. The incremental benefit of the second treatment was only about 10% of the effect of the first treatment.     

洪泽湖鱼类群落结构及其资源变化

根据2017-2018年在洪泽湖湖心、成子湖湾、保护区湖湾和淮河入湖口进行的鱼类资源调查,结合历年渔业捕捞统计数据,分析了该水域的鱼类群落结构及资源变化趋势.调查共采获鱼类51种,隶属10目16科41属,其中鲤形目种类最多,占总数的62.7%;群落优势种为鳙（Aristichthys nobilis）、（Hemiculter leucisculus）、鲫（Carassius auratus）、刀鲚（Coilia nasus）等7种,鱼类群落的丰富度指数、多样性指数和均匀度指数处于一般至较丰富水平.不同类型湖区间鱼类种类及优势种组成存在一定差异,其中湖心、淮河入湖口的生物多样性指数整体高于成子湖湾、保护区湖湾.与历史资料相比,洪泽湖鱼类的物种数量下降,鱼类资源组成结构发生较大变化,鱼类个体小型化趋势明显,捕捞强度过大、水位波动和水质污染是洪泽湖渔业资源衰退的主要因素.     

太湖富营养化湖区秋季水体和沉积物中硝化微生物分布特征及控制因素

微生物参与下的氮循环是富营养化湖泊十分重要的生物地球化学循环过程.采用基于amoA功能基因和16S rRNA基因的荧光定量PCR、PCR-DGGE与高通量测序等分子生物学技术,调查秋季太湖不同水体和表层沉积物中氨氧化古菌(AOA)、氨氧化细菌(AOB)和亚硝酸盐氧化菌(NOB)群落丰度和组成,探讨影响硝化微生物分布的关键环境因子.结果表明,中度富营养化的梅梁湾湖区水体表层、中层和底层水样和表层底泥中AOA amoA基因的丰度分别低于轻度富营养化的湖心区,而不同层水样中AOB amoA基因的丰度分别高于湖心区.梅梁湾湖区和湖心区水样中AOA群落组成基本相似,2个湖区表层沉积物样品中AOA群落组成亦基本相似,水体中AOA群落组成与表层沉积物中AOA群落组成有差异,AOA群落丰度显著受硝态氮、pH和DO影响;表层沉积物中AOB群落丰度有明显差异且显著受总氮含量影响,表层沉积物中NOB群落丰度也有明显差异且显著受亚硝态氮含量影响.太湖梅梁湾湖区和湖心区水体与表层沉积物AOA群落包括Nitrosopumilium和Nitrosotalea两大属;表层沉积物AOB群落主要包括亚硝化单胞菌(Nitrosomonas)和亚硝化螺菌(Nitrosospira)两大属,NOB群落主要包括硝化刺菌(Nitrospina)和硝化螺菌(Nitrospira)两大属,其中硝化螺菌属是淡水湖泊中比较少见的亚硝酸盐氧化菌.影响太湖水体和沉积物中AOA和AOB丰度的最主要环境因子为总氮、总磷与铵态氮.研究表明典型富营养指标(总氮、总磷、铵态氮、硝态氮和硝态氮等)是影响太湖梅梁湾和湖心区水体和沉积物中AOA或AOB丰度以及硝化微生物群落丰度的重要因素.     

Zooplankton response to the lake restoration in the drinking-water source in Meiliang Bay of subtropical eutrophic Lake Taihu, China

A 3-year ecological engineering project was carried out from 2003 to 2005 in the drinking water source in Meiliang Bay, Lake Taihu, China. The project area was divided into three zones: Zone C (outside the area), Zone B (pelagic part within the area) and Zone A (littoral part within the area). The community composition, density and biomass of zooplankton were studied as a part in the lake restoration study. Also, the abundance, biomass and composition of fish in the engineering area were annually analyzed in the littoral zone (Zone A). The average density of cladocerans decreased from the outer part to the inner part of the lake, i.e., from Zone C to Zone A, while the average density of copepod did not significantly vary among the 3 zones. The average densities of rotifer and ciliate increased from Zone C to Zone A. RDA analysis indicated that Microcystis biomass more impacted the zooplankton compositions after temperature. In Zone A, many planktivorous fishes, e.g., Coilia nasus, Hemiculter leucisculus, Pseudorasbora parva, dominated the fish community, which caused a marked decrease in the abundance of cladocerans, especially large-sized cladoceran Daphnia galeata and Daphnia obtusa. Our results suggested that both fish predation and other environmental factors such as the Microcystis bloom greatly affected the zooplankton community during the restoration of subtropical eutrophic lakes.     

Freshwater mollusc biodiversity and conservation in two stressed Mediterranean basins

This paper reviews the environmental factors that influence biodiversity of freshwater mollusc communities and conservation status of watercourses in two Mediterranean acid mine drainage-impacted basins of the southern Iberian Peninsula. We found 17 mollusc species: 14 gastropods (10 native and 4 introduced) and 3 bivalves. We found five distribution patterns: native headwater (Arganiella wolfi, Stagnicola palustris, Unio delphinus, Pisidium casertanum and Pisidium personatum) and mouth (Hydrobia acuta, Peringia ulvae and Myosotella myosotis) sensitive-stenochoric species, intermediate sensitive-widely distributed species (Planorbarius metidjensis and Radix balthica), insensitive-eurychoric species (Ancylus fluviatilis), and erratic-distribution pattern species (Galba truncatula and Planorbis carinatus). The highest biodiversity indices have been found in non-impacted headwaters and, to a lesser extent, in tidal streams. The biodiversity of the middle reaches, with varying degrees of impact by acid mine drainage and high water deficit, was scarce and dominated by introduced species. Over 30% of the variation in native and introduced species richness is explained by environmental gradients related to heterogeneity (instream macrophytes cover and Fhi and Qbr indices) and acid runoffs (pH, conductivity, turbidity and concentration of sulphides). Severely impacted sites have no mollusc species. The conservation status of watercourses is also very remarkably influenced by the heterogeneity and contamination of the environment. Conservation values are higher in water bodies located in protected northern and southern sites in both basins.     

不同水力调度模式的两座调水型水库轮虫群落结构的比较

为了解水力调度对轮虫群落结构的影响,于2016年8月-2017年7月对调水水源相同而水力调度模式不同的两座水库（直流型水库和中等水力滞留时间水库）的轮虫种类、生物量及环境因子进行逐月观测.两座水库中共鉴定出轮虫37种,常见属为臂尾轮属（Brachionus）、异尾轮属（Trichcerca）、龟甲轮属（Keratella）、三肢轮属（Filinia）和多肢轮属（Polyarthra）,它们的种类数分别占直流型水库和中等水力滞留时间水库所检出轮虫总种类数的58%和64%.两座水库轮虫种类虽基本一致,但轮虫优势种（相对生物量大于10%）有较大差异.直流型水库轮虫优势种以角突臂尾轮虫（Brachionus angularis）、镰状臂尾轮虫（B.falcatus）、裂足臂尾轮虫（B.diversicornis）、剪形臂尾轮虫（B.forficula）、截头皱甲轮虫（Ploesoma truncatum）、尖尾疣毛轮虫（Synchaetidae stylata）和真翅多肢轮虫（Polyarthra euryptera）为主;中等水力滞留时间水库主要以卜氏晶囊轮虫（Asplanchna brightwelli）、裂足臂尾轮虫（B.diversicornis）和镰状臂尾轮虫为轮虫优势种.两座水库Bray-Curtis相异系数为0.42~0.77,表明轮虫群落结构差异较大.冗余分析表明,叶绿素a浓度和温度是影响两座水库轮虫群落结构的重要因素.两座水库轮虫群落结构的Bray-Curtis相异系数与基于叶绿素a浓度和水温的环境欧氏距离呈显著正相关（R_adj²=0.426,P<0.05）.结果表明,虽然具有相同的调水水源,但由于两座水库的水力调度不同,叶绿素a浓度和水温有显著差异,轮虫群落结构趋于相异.     

黑龙江扎龙湿地不同功能区浮游植物群落与环境因子的关系

为研究黑龙江扎龙湿地不同功能区浮游植物群落结构分布及其与环境因子的关系,于2010年7—8月在扎龙湿地4个功能区340个研究点进行水环境样品采集分析.样品共鉴定出浮游植物6门80属354种,各门类细胞密度变化范围为0.06×10~6~37.82×10~6cells/L.主要优势种为普通小球藻(Chlorella vulgaris)、梅尼小环藻(Cyclotella meneghiniana)、旋转囊裸藻(Trachelomonas volvocina)等.各功能区浮游植物优势种差异较大,核心区中放射舟形藻(Navicula radiosa)、弯棒杆藻(Rhopalodia gibba)、扁圆卵形藻(Cocconeis placentula)等为优势种类,而排污区中梅尼小环藻、普通小球藻、巨颤藻(Oscillatoria princes)、固氮鱼腥藻(Anabaena azotica)等处于优势地位.主成分分析表明在扎龙湿地水环境中浊度和总磷浓度是影响浮游植物生长的主要因素,典范对应分析结果表明总氮浓度、总磷浓度、电导率、浊度对浮游植物属种分布影响较大,梅尼小环藻、箱形桥弯藻(Cymbella cistula)、美丽星杆藻(Asterionella formosa)、普通小球藻、旋转囊裸藻等受环境因子的影响较为明显.     

基于环境DNA宏条形码的丹江口水库浮游生物多样性及群落特征

为了解丹江口库区浮游生物群落的多样性,本研究于2020年7月在丹江口库区丹库、汉库和入库支流等区域共计9个样点采集水体样品,抽滤并提取总DNA样本后,基于18S和16S分子标记进行单分子实时测序,分别探究真核和原核浮游生物群落的多样性及其群落特征.结果表明：（1）真核浮游生物群落的主要优势类群包括节肢动物、链型植物、绿藻门、硅藻门等;本研究在种水平上鉴定出库区分布广泛且相对丰度较大的物种,包括弯曲隐藻、对蛋白核隐藻和空球藻等,它们与库区化学需氧量密切相关;库区化学需氧量是影响真核浮游生物群落格局的重要环境因子.（2）原核浮游生物群落的主要优势类群为变形菌门;原核生物中相对丰度较大的不动杆菌Acinetobacter是污水污染的指示菌群;群落中起重要作用的Limnohabitans与水体的富营养化密切相关;尽管库区蓝藻相对丰度较低,但与蓝藻关系密切的CL500-29_marine_group和hgcI_clade两类细菌在浮游生物群落中也起着重要作用;原核生物群落中的各类物种均指示丹江口水库的水生态健康存在一定风险,需要加强监测以预防生态环境的恶化.（3）丹江口水库不同区域的浮游生物群落异质性较大,tb-RDA分析显示丹江口的浮游生物群落可以分为丹库型、汉库型和入库支流型,其组间差异要大于组内差异.综上所述,丹江口水库的浮游生物群落具有明显的空间异质性,整个库区的群落结构与水体富营养化、水体有机污染和污水污染等方面相关,需要加强对丹江口库区的水生态监测.