阳宗海和滇池中紫色非硫细菌数量和种群结构的比较

在2002年平水期对高原湖泊阳宗海和滇池中的紫色非硫细菌(PNSB)数量和种群结构进行了比较研究。对两湖中的各因子进行t检验,发现各因子和PNSB数量都有极显著差异,富营养化湖泊滇池中的PNSB数量远远多于贫营养化湖泊阳宗海;两湖中PNSB的优势种是红假单胞菌属,也有少数的红螺菌属。两湖种群结构的区别是滇池有红微菌,而阳宗海有大量红细菌。     

不同植被防护措施对三峡库区土质道路边坡侵蚀的影响

为了探明沙湖浮游动物密度、生物量、分布与水环境因子之间的关系,运用多元逐步回归分析、通径分析和典范对应分析方法对2009年4月、7月、10月、2010年1月测定的沙湖浮游动物密度、生物量数据与水环境因子进行多元分析。结果表明:沙湖浮游动物密度与叶绿素a含量、总氮、总磷之间呈显著线性相关,影响沙湖浮游动物密度的主要水环境因子依次为叶绿素a含量、总氮、总磷;浮游动物生物量与叶绿素a含量、总氮、透明度、化学需氧量(CODMn)之间呈显著线性相关,影响浮游动物生物量的主要水环境因子依次为叶绿素a含量、总氮、透明度、化学需氧量;叶绿素a含量和总氮对浮游动物的直接影响作用最强,其他水环境因子主要通过影响叶绿素a含量间接影响浮游动物密度及生物量。浮游动物与水环境因子的CCA排序结果将分别适应不同水环境的16种浮游动物分为3组,叶绿素a含量、化学需氧量、水温和总磷是影响沙湖浮游动物群落特征及时空分布的主要水环境因子。     

淀山湖蓝藻季节动态及其影响因子

为了掌握淀山湖蓝藻门浮游植物群落及其与环境因子的关系,于2009年5月—2010年4月在全湖选取9个点位对浮游植物群落进行了调查,应用CANOCO4.5软件对获得的蓝藻门种类和环境因子数据进行典范对应分析(CCA),并绘制了物种与环境因子关系的二维排序图。结果表明:调查期间共出现蓝藻门15属46种,微囊藻属占69.9%,其次颤藻属占20.5%;蓝藻数量分布具有明显的季节性,密度变化范围为9.0×104～7.6×106 cells·L-1,蓝藻细胞密度与叶绿素a、总氮、营养状态指数TSIM(chl-a)和TSIM(TN)相关性较好,表明总氮浓度对蓝藻细胞密度影响较大,而密度和相对丰度影响着湖泊中的叶绿素含量和透明度等;CCA分析表明,春季水体受水温、生物需氧量、总磷影响较大,夏季水体受总磷、BOD5、透明度影响较大,秋季环境因子影响类型较为集中但不显著,冬季各环境因子影响较夏、秋两季明显,水体与铵态氮、透明度(SD)均呈正相关;分析了蓝藻中作为全湖优势种类的铜绿微囊藻和弱细颤藻与环境因子之间的关系,前者与水温、总氮呈显著正相关,与pH值呈现负相关;后者四季均有出现,数量变化受水温影响最大,在夏季与较低的pH值有关;环境因子改变与蓝藻季节演替内在联系表现为蓝藻群落在春冬2季受水温影响最大,夏季受TP、TN影响显著,秋季则与水体的透明度相关性最大。本实验对于理解淀山湖蓝藻优势种季节演替特征及对其开展监测治理具有指导意义。     

千岛湖水体叶绿素a与相关环境因子的多元分析

1999年1月至2000年12月对千岛湖水体的叶绿素a和理化因子进行了为期2年的逐月监测,对监测数据进行了多元逐步回归分析,找出与叶绿素a显著相关的环境因子,建立了多元回归方程．同时分析了叶绿素a含量的时空分布情况,并应用修正的卡尔森营养状态指数(TSI)对各监测点位的营养状态进行了排序．结果表明,湖区各监测点叶绿素a含量时空差异较大,新安江来水中叶绿素a含量变化较大．在5～30mg·m^-3之间,湖区内部监测点叶绿素a含量基本在5mg·m^-3以下,春季和秋季含量高于冬季和夏季含量．东南出水湖区大坝、密山和姥山点位的TSI<37。属贫营养型。其余湖区的TSI<53,为中营养型,与20世纪90年代中期的调查一致．湖区内部各监测点位的叶绿素a与理化因子关系比较复杂．在不同的监测点位。对藻类有显著影响的环境因子各有不同,但水温、总磷表现为正相关,透明度则表现为负相关．     

滴水湖叶绿素a时空分布及其与水质因子的关系

根据2011年9月-2012年8月监测数据,分析上海市人工湖泊——滴水湖叶绿素a的时空分布及其与主要环境因子的相互关系.结果表明:滴水湖叶绿素a含量随时间的变化幅度较大,表现为3、7月出现高峰而其他月份较低;叶绿素a含量在空间分布上具有一定的分异性,湖心普遍偏高,其他各点相对较低;对滴水湖叶绿素a采用主成分多元线性回归分析(APCS-MLR),得到描述水质因子的潜变量F1、F2与其相关性较大,建立了潜变量与叶绿素a含量的相关性模型;滴水湖叶绿素a含量与溶解氧(DO)、水温、总溶解磷(TDP)、活性磷(AP)有着密切的相关性;磷为滴水湖水体初级生产力的限制因子;因此,磷是有效控制滴水湖水体富营养化的关键因子.     

钱塘江干流杭州段水体叶绿素a浓度及与环境因子的关系

2006年1月至2007年12月,对钱塘江干流杭州段水体的叶绿素a时空分布及其与环境因子的关系进行研究.结果表明钱塘江干流杭州段的叶绿素a浓度时间差异显著,空间差异不显著.叶绿素a浓度呈现夏秋季节高、冬春季节低的规律.叶绿素a浓度与温度呈显著正相关,叶绿素a与透明度在不同范围内表现出不同的相关关系,叶绿素a与TN、TP之间的相关关系在不同江段有所差异.钱塘江干流杭州段总氮和总磷浓度均很高,足够满足藻类生长需要;氮磷比较低,基本在8～30之间,说明氮磷含量可能不是钱塘江藻类生长的限制因子.     

香溪河库湾春季叶绿素a 浓度动态及其影响因子分析

2005年3月至4月,对三峡水库香溪河库湾的叶绿素a动态及其与TN、TP等环境因子的关系进行了研究。结果表明,从香溪河库湾下游到上游,叶绿素a存在明显的水平分布。在时间分布上,3月17日暴发一次大规模的水华,4月份水华的暴发有一个明显的平面推移的过程。叶绿素a浓度与TN、TP之间存在着一定的负相关关系,TN与叶绿素a浓度的相关性较显著。香溪河库湾极可能是N限制型水体,而不受P限制。叶绿素a与透明度存在反双曲线关系,与溶解氧呈显著正相关关系。     

基于混合演化算法模型的岱海湖泊叶绿素a模拟及预测

基于2013—2017年岱海水质监测数据,分析岱海湖泊叶绿素a浓度时空分布特征,进而通过混合演化算法(HEA)建立湖泊叶绿素a浓度模拟和预测模型,结合生态阈值和敏感性分析,定量揭示和模拟预测湖泊叶绿素a浓度变化及其与环境因子之间的关系。研究表明:(1)岱海富营养化程度的季节变化呈显著性差异,表现为春季显著高于夏季和秋季,但空间变化不具有显著性差异。(2)基于混合演化算法模型的岱海湖泊叶绿素a浓度预测值与实际监测值之间拟合度高(R²=0.95)。(3)混合演化算法的最佳规则集表明,当水体化学需氧量大于172.049 mg·L^–1,且水温在13.97—20.36℃的范围内时,岱海湖泊叶绿素a浓度随水温增高而降低,随pH和水深的增高而增高;反之,叶绿素a浓度与总氮和水深均是负相关关系。混合演化算法模型能够模拟和预测湖泊叶绿素a浓度变化,识别和量化湖泊富营养化与环境因子的生态关系和阈值数据,可为干旱半干旱区内陆湖泊藻类水华的预测预警提供一定的理论依据和技术支撑。     

基于环境因子对叶绿素影响的典型草原植物生活型优势研究

针对环境因子与草原植物叶绿素含量的联动是否关系到植物生活型优势的问题, 该研究以锡林浩特典型草原为研究区, 选取2020年7月实测的11个样地50种植物共185个牧草样品的叶绿素含量, 运用相关分析、单因素方差分析、冗余分析(RDA)、逐步回归分析和通径分析等方法, 系统性地分析了多环境因子对草原植物不同生活型叶绿素指标的影响, 进而分析植物竞争优势形成的潜在驱动机制。研究结果表明: 1)典型草原区植物叶绿素a、叶绿素b含量均与总叶绿素含量呈极显著正相关关系, 相关系数分别为0.807和0.936, 草原植物总叶绿素含量受叶绿素b含量的影响程度更大; 2)草原植物4类生活型的叶绿素a、叶绿素b和总叶绿素含量均为小/半灌木>多年生禾草>一/二年生植物>多年生杂类草; 3)环境因子对植物生活型叶绿素含量的解释程度存在差异, RDA显示环境因子对小/半灌木的叶绿素含量解释程度最大(28.0%), 其次为一/二年生植物(18.3%)和多年生杂类草(17.7%), 多年生禾草各项叶绿素指标的解释度最低(12.7%); 4)植物生活型各叶绿素指标受多种环境因子的影响, 回归分析显示小/半灌木的叶绿素b含量受到土壤有机碳含量和大气相对湿度的影响, 总叶绿素含量主要受到大气相对湿度的影响, 多年生杂类草叶绿素b含量主要受到地表温度的影响, 一/二年生植物的叶绿素a、叶绿素b、总叶绿素含量主要受到土壤pH的影响; 5)在草原生境中, 通径分析的综合研究显示植物叶绿素a含量主要受到土壤环境因子的影响, 植物叶绿素b和总叶绿素含量主要受到大气环境因子的影响, 相比较而言, 多年生禾草不易受环境因子的牵动, 成为更能忍受外界环境变化的植物种类, 因此, 在群落演替进化中这类植物逐渐占据优势地位。     

长江中下游湖群大型底栖动物群落结构及影响因素

长江中下游地区是我国淡水湖泊分布最为密集的区域,其中面积大于10 km²的湖泊总面积占相同级别中国淡水湖泊总面积的51.3%。目前对本地区湖泊大型底栖动物研究主要是关于单个湖泊或几个湖泊之间的比较,将区域内湖泊作为一个整体来分析的研究较少。为揭示现阶段长江中下游浅水湖泊底栖动物群落现状及其主要影响因素,于2008年和2009年夏季对本地区5个湖群69个湖泊大型底栖动物和水化学进行了调查,并分析区域过程和局域环境条件在决定该地区底栖群落结构中的相对重要性。结果表明水体矿化度、电导率及氮磷指标在不同湖群间具有显著差异,而高锰酸盐指数、叶绿素a及营养状态指数无显著差异。密度方面,以寡毛类和摇蚊幼虫为优势类群的湖泊共46个,占总数量的66.7%,以螺类为优势类群之一的湖泊16个,占总数量的23.2%;生物量方面,以螺类为优势的湖泊数量最多(33个),占总数量的46.4%,但以寡毛类和摇蚊幼虫占优势的湖泊亦有27个,占总数量的39.1%,双壳类仅在9个湖泊占据优势。典范对应分析结果表明该地区底栖动物群落结构是局域环境条件和区域过程共同作用的结果,两类因子共解释了33.9%的底栖动物群落变异,其中局域环境因子占被解释量的48.1%,空间变量占35.4%。空间变量较高的解释量表明对整个长江中下游地区湖泊而言,区域过程对底栖动物的分布也起着非常重要的作用。     

The influence of sampling strategy on the apparent population dynamics of planktonic rotifers

Rotifer composition and density, chlorophyll-a content, secchi depth and temperature were investigated with high sampling frequency (every third day in summer, weekly in winter) in the eutrophic lake Bielersee from April 1981 to April 1982. Long intervals between sampling, especially from spring to autumn, lead to contradictory interpretation of abundance dynamics of both total rotifer community and single species. Short intervals between sampling revealed a sequence of mass developments of the different species. As an example, alternating gradation phases are shown for Synchaeta grandis and Synchaeta stylata.     

Purple non-sulphur bacteria and plant production: benefits for fertilization,stress resistance and the environment

Purple non-sulphur bacteria (PNSB) are phototrophic microorganisms, which increasingly gain attention in plant production due to their ability to produce and accumulate high-value compounds that are beneficial for plant growth. Remarkable features of PNSB include the accumulation of polyphosphate, the production of pigments and vitamins and the production of plant growth-promoting substances (PGPSs). Scattered case studies on the application of PNSB for plant cultivation have been reported for decades, yet a comprehensive overview is lacking. This review highlights the potential of using PNSB in plant production, with emphasis on three key performance indicators (KPIs): fertilization, resistance to stress (biotic and abiotic) and environmental benefits. PNSB have the potential to enhance plant growth performance, increase the yield and quality of edible plant biomass, boost the resistance to environmental stresses, bioremediate heavy metals and mitigate greenhouse gas emissions. Here, the mechanisms responsible for these attributes are discussed. A distinction is made between the use of living and dead PNSB cells, where critical interpretation of existing literature revealed the better performance of living cells. Finally, this review presents research gaps that remain yet to be elucidated and proposes a roadmap for future research and implementation paving the way for a more sustainable crop production.     

太原汾河蓄水区浮游植物细胞密度及其与营养元素的关系

水体营养元素是影响水体生态系统的重要因素,决定着水体中不同的浮游生物群落结构,也是评价水质和水体营养状态的重要指标。对太原汾河蓄水区9个样点浮游植物和各项水环境及营养元素进行了调查与分析,调查期间发现(1)该流域蓝藻和绿藻为主要优势类群,即构成了以蓝-绿藻门为主要的浮游群落。平水期与丰水期优势种均以蓝藻门的微小色球藻(Chroococcus minutus)、微小平裂藻(Merismopedia tenuissima)、小颤藻(Oscillatoria tenuis)、铜绿微囊藻(Microcystis aeruginosa)为主,其丰度分别占平水期和丰水期藻细胞总数的42.95%和59.24%。叶绿素a含量随地理位置变化明显,中下游显著高于上游。(2)太原汾河蓄水区水质均达到富营养状态。由于太原汾河蓄水区沿途的生活垃圾、污水的不合理排放,导致汾河中总氮、总磷等指标偏高,最终导致整个水体处于轻度富营养状态或中度富营养状态。(3)叶绿素a含量与水温、总氮、总磷呈显著正相关,与有机物含量呈极显著正相关,总磷的影响最为明显,说明磷可能是该地区浮游植物生长的限制因子。     

灞河城市段浮游生物群落结构时空变化及其与环境因子的关系

为了解灞河城市段浮游生物群落结构及其与环境因子之间的关系,于2016年9月至2017年7月每2个月进行一次采样分析。调查期间共鉴定出浮游植物7门63属,其中绿藻门种类数最多(34.9%),其次为硅藻门(30.2%);浮游动物4类45种,以轮虫(48.9%)和原生动物(24.4%)为主。浮游植物和浮游动物的丰度分别为0.73×10~4—98.5×10~4个/L和20—1084个/L,在时空分布上均呈现下游高于上游的趋势,峰值均出现在夏季。根据水体透明度、溶解氧、总磷、总氮、高锰酸盐指数和重金属等理化指标、浮游生物丰度、Shannon-Wiener多样性指数和Margalef丰富度指数对灞河城市段水质状况进行综合评价,结果显示,所研究流域总体为中污状态,上游景观河道内的水生植物对水体具有一定的修复能力。典范对应分析表明,水温、总氮、pH、溶解氧和汞是浮游植物群落分布的主要影响因子;影响浮游动物群落分布的主要因子为水温、总氮、总磷、叶绿素a和汞。     

The thermal, oxygen and light regimes in isolated columns of water in a turbid impoundment

SUMMARY. Temperature, oxygen and secchi disc transparency were measured in 5-m diameter isolation columns positioned in water approximately 4 m deep. In general the difference in thermal conditions between the adjacent open water and columns was slight. Oxygen levels in bottom waters in the enriched columns were often slightly lower than in the open water but never dropped below 50% saturation. It seems unlikely that sufficient depletion occurred to markedly increase release of phosphorus from the sediment. Light penetration in the columns was more varied than in the open water but was seldom sufficient to permit the development of large stands of benthic algae.     

Diversity of purple nonsulfur bacteria in shrimp ponds with varying mercury levels

This research aimed to study the diversity of purple nonsulfur bacteria (PNSB) and to investigate the effect of Hg concentrations in shrimp ponds on PNSB diversity. Amplification of the pufM gene was detected in 13 and 10 samples of water and sediment collected from 16 shrimp ponds in Southern Thailand. In addition to PNSB, other anoxygenic phototrophic bacteria (APB) were also observed; purple sulfur bacteria (PSB) and aerobic anoxygenic phototrophic bacteria (AAPB) although most of them could not be identified. Among identified groups; AAPB, PSB and PNSB in the samples of water and sediment were 25.71, 11.43 and 8.57%; and 27.78, 11.11 and 22.22%, respectively. In both sample types, Roseobacter denitrificans (AAPB) was the most dominant species followed by Halorhodospira halophila (PSB). In addition two genera, observed most frequently in the sediment samples were a group of PNSB (Rhodovulum kholense, Rhodospirillum centenum and Rhodobium marinum). The UPGMA dendrograms showed 7 and 6 clustered groups in the water and sediment samples, respectively. There was no relationship between the clustered groups and the total Hg (Hg_T) concentrations in the water and sediment samples used (<0.002–0.03 μg/L and 35.40–391.60 μg/kg dry weight) for studying the biodiversity. It can be concluded that there was no effect of the various Hg levels on the diversity of detected APB species; particularly the PNSB in the shrimp ponds.     

Seasonal Dynamics of Planktonic Community Metabolism in Newly Constructed Tropical Ponds in a Swampy Area

Studies on community metabolism in newly constructed ponds on a swampy area were made over a period of twenty-four months from November, 1981 to October, 1983. The fluctuations in the gross and net primary productions, photosynthetic efficiency and assimilation efficiency are discussed. The productivity of ponds was apparently influenced by the physico-chemical and biological environment of the water. pH, secchi disc transparency, phosphate and nitrate-N were negatively correlated with gross primary productivity, while temperature, conductivity, total alkalinity and ammonium-N showed positive correlation. The phytoplankton also exhibited positive correlation with primary production. The P/R ratio ranged between 1.79 and 2.91, indicating a high degree of self maintenance of the system. The solar energy conversion efficiency through photosynthesis ranged between 0.17 % and 1.08 % in the first year and 0.09 % and 0.05 % in the second year. Annual average assimilation efficiency ranged between 37.32 % and 56.58 %.     

Decolorization of Reactive Red 159 by a consortium of photosynthetic bacteria using an anaerobic sequencing batch reactor (AnSBR)

This experiment aimed to decolorize Reactive Red 159 using a high potential of a consortium of purple nonsulfur bacteria (PNSB) with an application of response surface methodology through a central composite design in open system. The three factors of hydraulic retention time (HRT), sludge retention time (SRT) and dye concentration were applied to the design. The decolorization was operated in an anaerobic sequencing batch reactor until the system reached to a pseudosteady state for 30?cycles in each experiment. The optimal condition was 6,500?mg/L of Reactive Red 159 concentration with 20 days of SRT and 8 days of HRT, achieving dye effluent of 142.62?±?5.35?mg/L, decolorization rate of 264.54?±?7.13?mg/L/h and decolorization efficiency of 97.68?±?0.74%. The results revealed that PNSB efficiently decolorized the high concentration of Reactive Red 159 and they were a high potential of microorganisms for dyes contaminated wastewater treatment.     

Biodiversity in eutrophicated shallow lakes: determination of tipping points and tools for monitoring

Nutrient-rich freshwater ecosystems are generally considered as having low ecological quality and low associated biodiversity. In such systems we analysed the effects of water quality on biodiversity of several species groups, to determine tipping points and tools for monitoring. We investigated the water quality of 99 eutrophic and hypertrophic shallow lakes with extensive fish culture during a 3-year study, through the measures of physico-chemical parameters, phytoplankton biomass and structure. In a second step, we related the water quality with richness of aquatic plants, macroinvertebrates and dragonflies. With concentrations of chlorophyll-a above 30 or 70 μg l^?1, shallow lakes are normally classified, respectively, in a poor or bad ecological state. However, our results show that chlorophyll-a concentrations up to 78 μg l^?1 could be found together with relatively high species or family richness of aquatic plants, invertebrates and dragonflies. We identified most tipping points with 50–60 μg l^?1 of chlorophyll-a, values above which a significant decrease of species diversity was found. For monitoring of these shallow lakes we propose to use chlorophyll-a concentrations in combination with water transparency during spring. These parameters are easily applicable and cheap and they yield a good forecast of the biodiversity for the species groups studied.