不同温度下水流对铜绿微囊藻生长的影响模拟

在蓝藻暴发机理研究中,水动力是一个非常重要的参数,目前多数研究在模拟各种流速环境的同时,未能实现实验过程中恒定的光、温条件控制.本研究采用小型环形槽模拟不同水体流速,在恒定的光、温条件下研究铜绿微囊藻(Mi-crocystis aeruginosa905)在流动水体中的生长情况,并对比了两种典型温度(15℃和25℃)条件下的差异.结果表明,水流使微囊藻生长滞后,改变其对数生长期持续时间和比增长率,直接影响微囊藻的最大生物量;不同流速的水流对微囊藻生长的影响与一定温度范围内的温度条件有关,15℃时,水体流动不利于微囊藻的生长繁殖;而在25℃时,微囊藻细胞生理活性增加,微囊藻对水体流动环境适应能力增强,水体流动更有利于微囊藻的生长繁殖,且流速在15cm/s时微囊藻获得最大生物量.     

富营养化湖泊蓝藻—芦苇碎屑堆积分解过程及其潜在的共代谢效应

为探究富营养化浅水湖泊所富集的有机物对湖泊碳循环和水质的影响,本研究构建微宇宙系统,模拟蓝藻和芦苇碎屑单独分解及混合分解过程.通过测定各组上覆水营养盐浓度、有机质含量及结构的变化,揭示富营养化湖泊藻草残体混合分解过程中养分和有机碳的释放特征.结果 表明,在实验0～88 h内,在添加相同的碳源条件下,蓝藻和芦苇混合处理组...     

Nutrients and organic matter in the surface sediment of a submerged macrophyte zone in a eutrophic lake:Implications for lake management

Little is known about the distribution and risk levels of nutrients and organic matter(OM) in the surface sediment of shallow submerged macrophyte-dominated lakes. In the current study, sixty surface sediment samples were collected from Xukou Bay, a typical submerged macrophyte-dominated zone in Lake Taihu, China. A 60-day degradation experiment of Potamogeton malaianus, a dominant species in the bay,was done in the laboratory. The results demonstrated that the ranges of total nitrogen(TN) and t...     

The effects of nutrients and zooplankton community structure on phytoplankton growth in a subtropical Australian reservoir: An enclosure study

Patterns of zooplankton–phytoplankton interactions in subtropical lakes of the Southern Hemisphere may deviate from those established for north-temperate lakes. We tested the responses of phytoplankton growth to different community structures of zooplankton and nutrient enrichment in a subtropical Australian reservoir for the prediction of potential outcomes of lake biomanipulation. Two zooplankton communities were created in lake enclosures over 4 weeks: a rotifer-dominated community developed in the presence of planktivorous fish (Hypseleotris spp.) and a Ceriodaphnia-dominated community developed in the absence of fish. Biomass gradients of both communities were established in 20 L containers and several separate containers received no additions (controls) or were enriched with nitrogen and/or phosphorus. The growth rate of total phytoplankton significantly increased in response to nutrient enrichment, indicating nutrient limitation. Most phytoplankton taxa were not markedly affected by grazing of either zooplankton community. However, both communities had significant stimulatory effects on the growth of inedible chlorophytes. The ability of zooplankton grazing to negatively affect phytoplankton growth during the summer was counteracted regardless of zooplankton community structure, possibly by nutrients regenerated by zooplankton. We hypothesise that in the subtropical system studied, changes in food web nutrient recycling may be more important for the outcome of biomanipulation than grazing impacts.     

强化生态浮床原位修复技术对污染河流浮游动物群落结构的影响

对强化生态浮床原位修复技术修复南方重污染感潮河流过程中浮游动物的种群动态变化进行研究,探讨浮游动物群落结构变化特征与河流水质改善状况的相互关系.结果显示,经强化生态浮床处理后,重污染感潮河流水质得到改善,浮游动物的种类由修复工程实施前的5种增加到49种,且由单一耐污种转变为多种种类共存;示范区各月浮游动物个体丰度较对照...     

不同光照周期对铜绿微囊藻和绿色微囊藻生长的影响

研究了不同光照周期对铜绿微囊藻(Microcystisaeruginosa)和绿色微囊藻(Microcystisviridis)生长的影响.按光照周期不同将两种微囊藻各分为五组处理组I[2L/22D]、Ⅱ[5L/19D]、Ⅲ[7L/17D]、Ⅳ[9L/15D]、对照组[12L/12D],试验期为20d.试验表明铜绿微囊藻实验中处理组Ⅳ[9L/15D]的比增长率和最大细胞数均最大,超过了对照组[12L/12D].绿色微囊藻实验中对照组[12L/12D]的最大细胞数和比增长率最大.随光照周期的延长两种微囊藻的最大细胞数有增加的趋势.绿色微囊藻对光照周期较铜绿微囊藻敏感.两种微囊藻在每日2h的光照周期下生长均受到抑制.     

湖北省西凉湖浮游动物群落周年动态变化及其与环境因子的关系

2007年11月至2008年10月对西凉湖浮游动物进行了4次调查,共检出浮游动物224种,其中原生动物112种,轮虫90种,枝角类15种,桡足类7种.秋季浮游动物物种数最多,为111种,冬季最少,为75种,春季和夏季分别为107种和88种.冬季浮游动物丰度最高,为126731 ind./L,春季最低,为71356ind...     

铜绿微囊藻生长对培养液pH值和氮转化的影响

在不同初始pH值条件下培养蓝藻水华优势种铜绿微囊藻(Microcystis aeruginosa),研究其生长过程对培养液的pH值和氮转化的影响,结果表明,处于延迟期和对数生长期的铜绿微囊藻使培养液的pH值上升,pH从初始的7.2、8.0和8.8分别上升到最大值10.02、10.34和10.94;稳定期和衰亡期的微囊藻使培养液pH值降低,初始pH值为8.8时,最终pH降至8.66,在微囊藻生长过程中,培养液中NO3-含量逐渐降低,NO3-含量先升高再降低,分别在60d和67d后降至零.试验结束时,不同pH值培养液中总氮含量比起始时分别下降了25.97%、27.52%和28.16%,说明化合态无机氮可以经过反硝化作用生成氮气而溢出培养液,因此,较大密度水华水体中存在反硝化的脱氮过程.     

Microbial community of cyanobacteria mats in the intertidal zone of oil-polluted coast of Saudi Arabia

Cyanobacterial mats are found at various locations along the coast of the Eastern Province of Saudi Arabia. Those mats were affected by severe oil pollution following 1991 oil spill. In this study, samples from Abu Ali Island were collected at three selected sampling sites across the intertidal zone (Lower, Middle, and Upper) in order to understand the effect of extreme environmental conditions of high salinity, temperature and desiccation on distribution of cyanobacteria along the oil polluted intertidal zone. Our investigation of composition of cyanobacteria and diatoms was carried out using light microscopy, and Denaturant Gradient Gel Electrophoresis (DGGE) technique. Light microscopy identification revealed dominant cyanobacteria to be affiliated with genera Phormidium, Microcoleus, and Schizothrix, and to a lesser extent with Oscillatoria, Halothece, and various diatom species. The analysis of DGGE of PCR-amplified 16S rRNA fragments showed that the diversity of cyanobacteria decreases as we proceed from the lower to the upper intertidal zone. Accordingly, the tidal regime, salinity, elevated ambient air temperature, and desiccation periods have a great influence on the distribution of cyanobacterial community in the oil polluted intertidal zone of Abu Ali Island.     

淮河干流浮游动物群落结构特征

2011年3、6、9和12月对淮河干流11个采样点的浮游动物群落结构进行调查研究,共检出浮游动物79属206种,其中原生动物27属69种,占浮游动物总物种数的33.5%;轮虫35属104种,占50.5%;枝角类12属27种,占13.1%;桡足类5属6种,占2.9%.总体上看,从上游至下游,浮游动物物种数呈现逐渐减少的趋势.浮游动物的丰度和生物量分别为3527447 ind./L和2452 mg/L,轮虫和原生动物丰度是淮河干流浮游动物丰度的主体,轮虫生物量是淮河干流浮游动物生物量的主体,浮游动物及各类群丰度和生物量均表现为从上游到中游逐渐增高的趋势,而从中游到下游呈现逐渐降低的趋势.上游浮游动物多样性指数和均匀度指数高于中、下游.结果表明:淮河干流上游水质为轻污染,中、下游水质为中污染或重污染.浮游动物群落结构和环境因子的冗余分析表明,水温、溶解氧和流速是与淮河干流浮游动物群落结构相关性较强的环境因子.     

竞争捕食作用对千岛湖浮游动物群落结构的影响

竞争与捕食作用是调节湖泊和池塘等淡水生态系统结构的主要动力,并且影响着浮游动物的群落结构和种群动态变化.为了阐明生物因素对千岛湖浮游动物群落结构的影响,于2009-2010年对千岛湖浮游动物群落结构变化规律进行调查.利用Pearson相关性分析和多元逐步回归法分析生物因素对千岛湖中浮游动物群落结构的影响.对千岛湖1999、2004、2007-2010年的鲢鳙鱼生物量和浮游动物生物量的统计分析表明,1999年鲢鳙鱼的生物量约为2004、2007-2010年年平均生物量的1/5,而轮虫和桡足类生物量变化不大,枝角类中盔形溞密度下降.鲢鳙鱼放养后浮游植物密度下降,而大型浮游动物(如盔形溞)的密度变化趋势与浮游植物相一致,因此推断鲢鳙鱼的放养将对千岛湖浮游动物群落结构产生影响.     

滇池大泊口水域水生植物种子库时空特征与恢复潜力

以滇池典型生态修复区——大泊口水域为研究对象,研究了富营养化高原湖泊种子库时空特征、种子库与地表覆盖水生植被及水环境的相关关系和恢复潜力.利用高密度样方原位观测与温室控制种子萌发实验相结合,基于20142016共3年的长期定位研究,分析湖泊平均种子库密度、分布格局及与覆盖水生植物S?rensen相似性关系,结果显示:年...     

浮游动物生态学研究进展

本文综述了近年来浮游动物生态学研究的最新进展,内容包括：长期生态学研究,浮游动物种类组成和现存量动态的研究,捕食生态研究,温度、食物等因子对浮游动物影响的研究此外,还对浮游动物分子生物学、微表层浮游动物生态学、大型水利工程和能源设施建设对水生态系和浮游动物的影响及浮游动物大规模高密度培养技术等热点问题进行了讨论．     

热带富营养水库敞水区浮游动物群落结构与季节变化:以广东大沙河水库为例

于2012-2013年对大沙河水库敞水区的浮游动物群落及环境因子进行监测,分析和探讨大沙河水库浮游动物群落结构的变化.2年共采集到后生浮游动物44种,其中桡足类5种、枝角类9种、轮虫30种.浮游动物种类组成季节变化较小,存在较多的常见种.2012、2013年浮游动物总生物量的年际波动范围分别为210.1~2560.5、512.7~3145.6μg/L,2012、2013年枝角类是浮游动物生物量的优势类群,分别占总生物量的45.5%、51.5%;其次是桡足类,分别占总生物量的31%、40%.枝角类的丰度和生物量与轮虫的丰度和生物量没有显著相关性,反映了它们之间的竞争强度较弱.2012与2013年的浮游动物总生物量不存在显著差异,但群落结构差异较大.2012与2013年对应月份的群落平均距离为0.61(SD=0.18),反映群落结构在季节变化上存在较大的随机性.浮游动物总丰度和总生物量存在较为明显的季节性变化:枯水期显著高于丰水期.群落组成与环境变量之间的RDA分析表明,由季风降水导致的水文变化是影响群落结构变化和产生随机性的关键要素.     

Seasonal changes in vertical distribution of zooplankton in an oligotrophic, subarctic lake (Lake Takvatn, Norway)

Zooplankton vertical distribution was studied in Lake Takvatn (69°07′ N) by discrete sampling of the water column during the open water season. Attention was focused on predation risk and competition to understand when, where and to what degree a given species should aggregate along the water column. Temperature profiles and phytoplankton abundance and composition were recorded to assess degree of heterogeneity and food availability in the pelagic zone. Vertical segregation was evident during thermal stratification. Rotifers partitioned the water column, with species less susceptible to predation (e.g. Conochilus unicornis) in the epilimnion, where they overlapped with the predators Asplanchna priodonta and Polyphemus pediculus, and species more vulnerable to these predators (e.g. Keratella cochlearis) in the hypolimnion. Cladocerans remained in the epilimnion, in a year when predation by fish was limited. The copepodites of Eudiaptomus graciloides and Cyclops scutifer maintained different depths staying respectively near surface and in the meta-hypolimnion. A broader distribution with increasing density was evident among rotifers and C. scutifer nauplii. Density-dependent habitat selection behaviour is considered as a mechanism explaining the observed distribution of predators and competing prey and promoting species coexistence.     

Toxicity-directed Fractionation of Tannery Wastewater Using Solid-phase Extraction and Luminescence Inhibition in Microtiter Plates

A four-step solid-phase extraction (SPE) method is presented for toxicity-directed fractionation of industrial wastewater. This fractionation procedure serves as a key step for identifying unknown organic toxicants in complex samples. Toxicity was determined as luminescence inhibition of Vibrio fischeri using microtiter plates. This method was compared to standard tests in glass cuvettes using both 37 standard chemicals and 24 wastewater fractions with EC₅₀ values covering five orders of magnitude. Results of both methods correlated well. 22 tannery wastewater samples were sequentially extracted using C₁₈e and polystyrene-divinylbenzene phases in combination with pH-changes. Final solid-phase filtrates showed low inhibition, so toxicity of inorganics could be neglected. Using 1/EC₅₀ values, the SPE eluates showed clearly different toxicity patterns. Even in eluates of the fourth extraction step, high toxic effects could be observed. In several cases, luminescence inhibition was increasing at the anaerobic treatment step compared to the corresponding untreated samples. After aerobic treatment, toxicity of most wastewater fractions was greatly diminished. HPLC/DAD analyses of the wastewater fractions showed a fair separation concerning compound polarity. However, the samples were still too complex to identify single compounds responsible for the detected toxicity. Therefore, a further clean-up step accompanied with toxicity testing is needed.     

Feeding of European cisco (Coregonus albula and C. lucinensis) on the glacial relict crustacean Mysis relicta in Lake Breiter Luzin (Germany)

Lake Breiter Luzin, located in north-eastern Germany, is known for the rare occurrence of sympatric populations of European cisco, Coregonus albula and C. lucinensis. Moreover, the lake is inhabited by the glacial relict crustacean Mysis relicta, currently found in only three other lakes in Germany. In the present study, the role of M. relicta in the diet of ciscoes was investigated. Between 2001 and 2002 ciscoes, mysids and zooplankton were caught in Lake Breiter Luzin and stomach contents of ciscoes were analysed. There were seasonal changes in the food items in the stomachs, largely reflecting changes in prey availability. The main food items were copepods (45–81%) and mysids (5–26%). Cladocerans had high amounts in the diet only in summer. Seasonal changes in selectivity were also noted for most prey groups. There were also some consistent patterns of prey preference, with an overall preference for mysids. In general, the prey composition in cisco stomachs did not show significant diet changes, but there were some significant differences between day and night feeding in single prey groups, such as cladocerans. Diet composition of ciscoes varied with the different depth strata in which the fish were caught. With increasing depth, the proportion of mysids in the diet significantly increased, whereas that of copepods significantly decreased. Between C. albula and C. lucinensis, no distinct differences in feeding were evident. Mysids provided an additional and important food resource to ciscoes, and were mainly consumed when the availability of other prey organisms decreased, as in autumn and in the deeper strata of the water column. However, mysids preyed on the same food organisms as ciscoes, indicating a strong competition for food between fish and mysids.     

Effects of nitrogen and phosphorus on phytoplankton composition and biomass in 15 subtropical, urban shallow lakes in Wuhan, China

This study aims at investigating the composition and biomass of the phytoplankton community in 15 urban shallow eutrophic lakes as well as the effects of main environmental factors, including nutrient concentrations and the ratio of nitrogen to phosphorus, temperature, COD, BOD, water depth, etc. on the phytoplankton community structure. Lake water samples were taken and analyzed on a bimonthly basis during the period from March 2004 to March 2006. The redundancy analysis (RDA) and regression analysis (RA) were performed to identify the effects of nutrients on the phytoplankton community and biomass in these typical urban lakes. The results indicate that most of these urban lakes were hypertrophic due to high concentrations of total phosphorus (TP) and total nitrogen (TN), with mean levels of 490 and 5380 mg m⁻³, respectively. The phytoplankton community was dominated by Microcystis aeruginosa and Euglena caudate in summer and Cryptomonas ovata and Cyclotella meneghiniana in winter. The mean biomass of the phytoplankton reached 456.87 mg L⁻¹ in summer months and the annual level was 189.24 mg L⁻¹. Temperature and TP content were found to be the principal limiting factors for phytoplankton growth on an annual basis. On the other hand, the results of RDA and RA demonstrate that the dominant phytoplankton species were not nutrient-limited during summer months. Low TN:TP ratios (<10) were detected accompanied with fewer occurrences of N-fixing cyanobacteria and other filamentous algae in most lakes in summer, which implies that low N:P ratio does not always shifts the dominance of phytoplankton community to the N-fixing cyanobacteria. Moreover, TP always had higher correlation with chlorophyll a (Chl-a) than TN, even when the TN:TP ratios of most samples were lower than 10. Therefore, it is concluded that the TN:TP ratio is not always a suitable index to determine whether nitrogen or phosphorus limits the phytoplankton biomass in urban shallow eutrophic lakes.     

福建山美水库浮游动物群落结构时空特征及其影响因子分析

山美水库既是福建省泉州市饮用水源地,也肩负着为台湾省金门县供水的功能,但春夏季过高的pH值影响了水库水质.为此,从2020年起,调整水库鱼类放养结构和捕捞策略,并研究鱼类群落调控后山美水库浮游动物群落结构的响应及其与环境因子的关系.本研究于2020年和2021年连续两年的1月（冬季）、4月（春季）、7月（夏季）、10月（秋季）调查山美水库21个采样点的浮游动物群落结构和水环境因子.结果共鉴定出浮游动物68属102种,其中轮虫21属41种（40.20%）,原生动物32属41种（40.20%）,枝角类8属13种（12.75%）,桡足类7属7种（6.86%）.2020—2021年山美水库浮游动物平均密度为（1443.05±360.02） ind./L,平均生物量为（1.21±0.27） mg/L,2021年浮游动物密度和生物量显著高于2020年,其中,2021年枝角类和桡足类的密度分别显著高于2020年枝角类和桡足类的密度,2021年库首、库中和库尾区域枝角类生物量显著高于2020年对应区域;2021年桡足类生物量显著高于2020年.春冬季浮游动物群落的优势种主要为原生动物,夏秋季浮游动物群落的优势种主要为轮虫.根据浮游动物密度和生物量评价水体营养状态,夏季山美水库处于中营养状态,春、秋和冬季处于贫营养状态.影响浮游动物群落结构分布的主要环境因子为电导率、水温、溶解氧、硝态氮、透明度和高锰酸盐指数.研究表明调整鱼类放养和捕捞措施提高了浮游动物密度和生物量,基于此提出了通过调整鱼类群落结构改变浮游动物群落结构,进而改善水环境的建议,可为湖泊水库水环境保护和水生生物资源高效利用提供科学依据.