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太湖浮游细菌种群基因多样性及其季节变化规律 总被引：8，自引：3，他引：5
为认识湖泊中浮游细菌的多样性及其变化规律,本研究采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)的方法,研究了太湖梅梁湾和湖心区浮游细菌种群16S rRNA基因多样性以及种群基因组成的季节变化特征.研究结果表明,太湖浮游细菌种群具有丰富的基因多样性.浮游细菌的丰度、DGGE条带数、种群的Shannon-Wiener指数、Simpson 指数和Pielou指数均呈现显著的季节变化规律:夏季及秋季浮游细菌的丰度、基因多样性及种群的均匀度较高,而冬季和春季则较低.浮游细菌种群的基因组成随时间变化.梅梁湾浮游细菌的丰度显著高于湖心.梅梁湾与湖心浮游细菌主要建群种的基因型存在显著差异. 相似文献
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一座新建水库——广东剑潭水库浮游植物动态特征 总被引：3，自引：1，他引：2
剑潭水库是珠江水系东江下游新建水库,2006年10月开始蓄水,2007年6月蓄水完毕.该水库属直流型水库,2008年水力滞留时间为0.46-3.62d.2006-2008年调查了该水库浮游植物的动态特征.结果表明,调查期间浮游植物丰度为182-6267cells/ml,从空间变化看,在调查期间,浮游植物丰度由上游向下游呈上升趋势.从年间变化看,蓄水后第一年坝区浮游植物丰度不仅明显高于蓄水前和蓄水期间,并且浮游植物最高丰度出现在蓄水后第一年的枯水期(12月).与此同时,在蓄水过程中,浮游植物群落结构也逐渐发生了变化,蓝藻相对丰度明显上升,绿藻相对丰度呈下降趋势.水力滞留时间、透明度和总磷是影响剑潭水库浮游植物时空变化的重要因素.高的平流损失率和低的透明度使得浮游植物现存量与水库氮、磷水平并不相符.相对较长的水力滞留时间、较高的透明度和总磷导致了浮游植物在蓄水后第一年(2008年)的枯水期出现一个峰值. 相似文献
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丹江口水库是南水北调中线工程水源地,库湾是水库型湖泊水质安全敏感区,动态调水过程库湾水质直接关系到调水安全.为探究动态调水过程中丹江口水库库湾浮游植物季节变化规律和驱动因子,2018年7月—2019年7月,从丹库入库口到渠首调水口,按季节对18个样点进行水质和浮游植物群落组成分析.从整个丹库来看,浮游植物全年总丰度变化范围为0.43×10~3～4.7× 10~6 cells/L,夏季最高,秋季最低;Shannon-Wiener指数春季最高,秋季最低.春季群落为硅藻—绿藻型,夏季为绿藻—硅藻型,秋季为蓝藻型,冬季为蓝藻—绿藻—硅藻型,秋季蓝藻相对丰度最高.位于丹库准保护区内的库湾胡寨,秋季水体电导率、总氮、总磷和叶绿素a浓度最大,蓝藻丰度最高.从入库口经库湾到调水口,浮游植物群落组成存在明显演替.从水文因子来看,秋季水库水位较高,调水流速和流量增加,线性回归分析表明,水位对ShannonWiener指数的影响最为明显,水位越高则多样性指数越低;流量和流速与Shannon-Wiener指数也呈负相关,但相关性较低.方差分解分析发现,水文因子和理化因子共同影响了浮游植物群落组成;偏Mantel分析显示3个库湾浮游植物群落组成与水温、氧化还原电位、化学需氧量、总氮和总磷浓度相关;典范对应分析也表明,总氮是影响库湾浮游植物群落组成最显著的环境因子.人类干扰活动改变了库湾水质理化性质,强干扰提高了蓝藻门丰度.因此,控制库湾人类干扰强度,尤其在水位和调水量较高的秋季,对于改善水体藻类组成、保护整个丹江口水库水质具有重要意义. 相似文献
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Phytoplankton distributions and their relationship with the environment in the Changjiang Estuary, China 总被引：27，自引：0，他引：27
This study was carried out in the Changjiang Estuary from 19 to 26 May 2003. Based on the data collected from 29 stations, including two anchor stations, phytoplankton taxonomic composition, abundance, diurnal variability and spatial distribution were examined. Eighty-seven species, including 54 species of diatoms and 16 red tide causative species, were identified. Average diversity index (H') and evenness (J) values were 1.04 and 0.40, respectively. A bloom in abundance of certain phytoplankton species, especially Prorocentrum dentatum and Skeletonema costatum, was thought to be the cause of the low diversity index and evenness values. Total phytoplankton abundance averaged 6.75 x 10(5)cells l(-1), and was much higher than previous investigation carried out in the same month in 1986. Abundance increased seaward showing a distinct spatial difference, and the dominant species varied with salinity. Correlation between phosphorus and abundance further supported the former conclusion that phosphorus is the controlling factor in phytoplankton growth in the Changjiang Estuary where light is not limiting. Based on the relationship between DO, pH and abundance, it is likely that the bloom was caused by rapid in situ growth of phytoplankton with high nutrients and sufficient light. The data also indicated that the duration of the bloom was not long and 相似文献
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太湖不同生态类型湖区浮游甲壳动物群落结构季节变化比较 总被引：1，自引：0，他引：1
水体富营养化会对整个水生态系统产生重要影响.为了解太湖富营养化对浮游甲壳动物群落结构的影响,于2012年3月至2013年2月对太湖3个典型湖区——藻型湖区(梅梁湾)、草型湖区(胥口湾)和强扰动湖区(湖心区)开展浮游甲壳动物群落结构季节变化比较研究.3个湖区中,湖心区营养水平最高,胥口湾最低.梅梁湾浮游甲壳动物密度和生物量最高,其次是湖心区,胥口湾最低.梅梁湾、湖心区和胥口湾的浮游甲壳动物年平均密度分别为199、150和91 ind./L,年平均生物量分别为1.950、1.557和0.743 mg/L.在整个研究期间,梅梁湾、胥口湾和湖心区的浮游甲壳动物种类数分别为13、11和11;3个湖区的浮游甲壳动物优势种均为中华窄腹剑水蚤和简弧象鼻溞,其中中华窄腹剑水蚤在梅梁湾、胥口湾和湖心区的年平均密度分别为57、25和36 ind./L,简弧象鼻溞在3个湖区的年平均密度分别为40、22和32 ind./L.胥口湾浮游甲壳动物生物多样性指数显著低于梅梁湾和湖心区.相关分析表明,浮游甲壳动物密度与叶绿素a浓度呈极显著正相关.研究表明,同一湖泊不同生态类型湖区浮游甲壳动物会对水体富营养化产生不同的生态响应. 相似文献
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2012年夏季三江平原湿地抚远地区浮游植物群落结构及多样性 总被引：2，自引：0，他引：2
2012年6月(夏季)对三江平原湿地抚远地区水域的浮游植物进行调查,设置了10个采样点,经鉴定共有浮游植物262个分类单元,包括239种19变种4变型,隶属于7门9纲22目32科73属.通过对浮游植物群落结构的初步分析,得出三江平原湿地抚远地区水域浮游植物群落结构组成以绿藻门、硅藻门、裸藻门为主,种类数为绿藻门(42.6％)＞硅藻门(22.8％)＞裸藻门(20.9％),细胞密度在3.88×104～278.07×104cells/L之间.聚类分析结果显示,可以将10个采样点分为两组,即农场区5个样点为一组,非农场区5个样点为另一组,两大区域的浮游植物群落结构差异明显,水体类型及生态环境的不同是其存在差异的主要原因.浮游植物多样性指数相对较为一致,Shannon-Wiener多样性指数均在2左右,Margalef丰富度指数均大于3,Pielou均匀度指数在0.3 ～0.5之间.综合群落结构以及多样性分析表明,三江平原湿地抚远地区水域浮游植物物种丰富度较高,多样性良好. 相似文献
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于2008-2009年按照季节调查西藏地区尼洋河浮游动物群落的组成、丰度和多样性,并运用多元统计方法定量分析浮游动物的空间和季节变化特征及其与主要环境因子之间的关系.结果显示,尼洋河浮游动物包括原生动物、轮虫、枝角类和桡足类,其中原生动物9目13科14属,轮虫1目7科17属,枝角类仅1目1科1属,桡足类2目2科2属.原生动物以砂壳虫和瞬目虫属为主,轮虫则以橘轮虫属和单趾轮虫属为主.尼洋河浮游动物的物种丰富度和生物量随尼洋河海拔高度不断提升呈现递减的趋势,夏季浮游动物生物量、物种丰富度、总丰度较低,其中夏季浮游动物物种丰富度最低,而浮游动物生物量和总丰度则仅高于冬季.受到水体稳定性的影响,尼洋河浮游动物Shannon-Wiener多样性指数和均匀度指数在交汇处较低;季节方面,夏季最低,冬季次之.尼洋河原生动物和轮虫总丰度在季节方面存在相似的演替规律,即出现2次高峰和2次低谷,2次高峰分别出现在春季和秋季,2次低谷分别出现在夏季和冬季.尼洋河浮游动物沿程变化方面,浮游动物群落4个指标不存在显著差异.尼洋河浮游动物季节变化方面,仅总丰度秋季和冬季之间存在显著差异,其他3个指标在各个季节之间均不存在显著差异.典范对应分析表明,原生动物类群里,砂壳虫属丰度受水体溶解氧浓度的影响较大,前管虫、袋座虫、肾形虫、瞬目虫和斜口虫属丰度受水体矿化度的影响较大,鳞壳虫属丰度则主要与水体中氨氮浓度关联较大;轮虫类群里,单趾轮虫、无柄轮虫、枝胃轮虫、囊足轮虫属丰度与水体的矿化度关联较大,龟甲轮虫属丰度则与总磷浓度有着较大的关联.分类回归树模型预测了尼洋河浮游动物时空分布与主要环境因子之间的定量关系,结果表明尼洋河浮游动物总丰度受到硬度、季节、海拔以及河道底质等因素的影响,Shannon-Wiener多样性指数受到总碱度、季节、硬度和水温的影响,均匀度指数受到总碱度、总磷浓度和水温的影响.这些关键环境因子对尼洋河水域浮游动物的时空变化有着重要的指示作用,建议加强对浮游动物及这些环境因子的关注,推动尼洋河水域生态环境的可持续发展. 相似文献
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于2008-2009年按照季节调查了西藏尼洋河浮游植物群落的组成、丰度和多样性,并运用多元统计方法定量分析了浮游植物的空间和季节变化特征及其与主要环境因子之间的关系.结果显示,尼洋河浮游植物共计7门29科48属,其中硅藻为优势浮游藻类.浮游植物Shannon-Wiener多样性指数(Pielou均匀度指数)在尼洋河中游(尼洋河下游)最高,其他河段呈下降趋势,符合中间高度膨胀假说.尼洋河沿程浮游植物的总丰度、物种丰富度、Shannon-Wiener多样性指数以及Pielou均匀度指数不存在显著差异,夏季的浮游植物物种丰富度与其他季节的存在显著差异,夏季总丰度与秋、冬季的存在显著差异,冬季的浮游植物Shannon-Wiener多样性指数与春季的存在显著差异,冬季的均匀度指数与其他3个季节的存在显著差异.尼洋河浮游植物季节演替依赖于外源性水源补充,沿程演替则与河道底质有着很大关系.典范对应分析(CCA)表明,尼洋河硅藻门舟形藻科的藻类与理化因子铵态氮、表层pH、表层水温相关,部分蓝藻以及绿藻与水质理化因子也存在着关联.分类回归树(CART)模型预测了尼洋河着生藻类时空分布与主要环境因子之间的定量关系,尼洋河浮游植物群落总丰度和均匀度指数受pH值影响较大,pH值低于8.0的水域浮游植物均匀度指数比pH值高于8.0的水域大,尼洋河浮游植物Shannon-Wiener多样性指数受到河道底质影响较大,底质为黏土的水域浮游植物Shannon-Wiener多样性指数较底质为砂石的大.这些关键环境因子对尼洋河水域浮游植物的时空变化有着重要的指示作用,建议加强对浮游植物及这些环境因子的关注,保障尼洋河水域生态环境的可持续发展. 相似文献
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三峡水库香溪河流域梯级水库浮游植物群落结构特征 总被引：7，自引：3，他引：4
于2005年10月、2006年1、4、7月对三峡水库香溪河流域3座水库(古洞口一级水库、古洞口二级水库和香溪河库湾)组成的梯级水库的浮游植物种类组成、优势种、群落结构、密度和生物多样性指数进行了周年调查研究.共鉴定出浮游植物7门58属121种(含变种),以绿藻和硅藻种类最多,绿藻有26属49种,占40.50%;硅藻14属41种,占33.88%;其次是甲藻,3属11种,占9.09%;蓝藻5属7种,占5.79%;隐藻3属7种,占5.79%;其它藻类仅占4.96%.浮游植物在古洞口一级水库共有25属31种,古洞口二级水库29属40种,香溪河库湾46属81种.优势度分析显示:古洞口一级水库藻类优势类群为硅藻门、绿藻门,古洞口二级水库为硅藻门、隐藻门和甲藻门,香溪河库湾为绿藻门、硅藻门、甲藻门和隐藻门.3座水库浮游植物年均密度分别为1.110×106、4.837×105和1.734×106 cells/L;其中,最高密度出现在香溪河库湾(4.87×106 cells/L),最低密度出现在古洞口二级水库(5.76×105 cells/L).运用主成分分析对梯级水库进行水质分析,表明沿着水库的梯度水质逐渐恶化.Shannon-Wiener多样性指数和Pielou均匀度指数在3座水库间无明显差异,而香溪河库湾Margalef丰富度指数显著大于古洞口一级、二级水库.前两个指数与浮游植物优势种的评价结果显示,香溪河流域梯级水库处于中污染状态. 相似文献
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Simone Jaqueline Cardoso Fábio RolandSimoni Maria Loverde-Oliveira Vera Lúcia de Moraes Huszar 《Limnologica》2012,42(3):235-241
During the high water season, the flooding reduces environmental heterogeneity in aquatic ecosystems of the Pantanal wetland. When the water level recedes, lakes and channels are formed as individual systems. Therefore, we expected the spatial heterogeneity during the low water phase resulting in changes on biological communities leading to high phytoplankton abundance, biomass and diversity within and between habitats. To test this hypothesis, we analyzed eight freshwater systems (five oxbow lakes, two channels, and the river) during the low water period. Phytoplankton biomass, abundance, diversity (alpha, beta, gamma) and diversity metrics as richness (species per sample), Shannon diversity (H′) and evenness were measured in all systems along with nutrient concentrations, zooplankton and bacteria abundances. We found 97 species as gamma diversity. The alpha diversity was unexpectedly low in comparison to most other South American floodplain systems (38 species in river, 24 in channels and 29 in lakes). Also, the systems are relatively similar in composition (beta diversity, 28%). Connectivity differences between systems highlighted differences in phytoplankton abundance and biomass (fresh weight) ranging from 1428 ind mL−1 (river) to 3710 ind mL−1 (lakes) and from 0.71 mg L−1 (river) to 2.9 mg L−1 (lakes), respectively. However, our results did not indicate significant differences in phytoplankton species richness between the systems during the low water. Our main conclusions are that local factors may be responsible for changes on phytoplankton community and the time of isolation during the low water phase was not sufficient to promote changes in phytoplankton diversity between the habitats. 相似文献
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Zusammenfassung Der Vierwaldst?ttersee (Horwer Bucht), Thunersee (H?he Faulensee), Luganersee (Bucht von Lugano) und Mauensee (ein Kleingew?sser
im Schweizerischen Mitelland) wurden im Zeitabschnitt 1965 bis 1967 periodisch untersucht. Durch die chemische Analyse wurden
die folgenden Komponenten erfasst: Sauerstoff, Nitrat— Stickstoff, Phosphat— Phosphor (PO4−P), partikul?rer Phosphor (PP), SBV und pH-Wert. Das Phytoplankton wurde im umgekehrten Mikroskop ausgez?hlt, wobei der quantitativen
Verteilung vonOscillatoria rubescens D. C. in den verschiedenen Tiefenstufen besondere Beachtung geschenkt wurde. Gleichzeitig wurden Temperatur und subaquatische
Ver?nderungen des lichtes gemessen sowie mit der C14-Methode die Prim?rproduktion bestimmt.
In mehr als 80% aller F?lle fielen dieOscillatoria rubescens-Maxima mit jenen Tiefenstufen zusammen, in denen weniger als 14°C gemessen wurde. In diesen Tiefenstufen wurde gleichzeitig
in mehr als 65% aller F?lle weniger als 4% der Oberfl?chen-intensit?t des grünen Lichtes (VG 9) beobachtet.
Der Einfluss von Licht und Temperatur auf das Wachstum vonOscillatoria rubescens wurde in einem Lichtthermostat experimentell untersucht. Bei temperaturabh?ngigenI
k-Werten zeigte sich, dass sich diese Alge bei einer Lichtintensit?t von 1500 Lux erst im Bereich von 30°C optimal entwickelt.
Oberhalb 29°C wirkte sich eine Steigerung über 1500 Lux hinaus wieder hemmend aus.
Aus diesen Beobachtungen wurde abgeleitet, dass es sich beiOscillatoria rubescens um eine eurytherme und oligophote Form handelt, und dass das Auftreten vonOscillatoria rubescens-Maxima in der vertikalen Verteilung des Phytoplanktons in einem See durch das Zusammenspiel der beiden Faktoren Licht und
Temperatur bedingt wird.
Summary The Lakes of Lucerne (Horw Bay), Thoune (Faulensee region), Lugano (Lugano Bay) and Lake Mauen, a small lake in central Switzerland, were investigated periodically from 1965 to 1967. The water was analysed in view of determining the following components: oxygen, nitrate-nitrogen, phosphate-phosphorus (PO4−P), phosphorus incorporated in cell mass (PP), Langlier index. Phytoplankton was counted in an inverted microscope with special consideration to quantitative distribution ofOscillatoria rubescens D. C. at various depths. Temperature and light variations in function of depth were measured simultaneously and the production rate was determined by means of the C-14 method. In over 80% of all cases, theOscillatoria rubescens-maxima coincided with depths showing temperatures under 14°C. In over 65% of all cases, the intensity of green light (VG9) in such depths was less than 4% of the surface intensity. The influence of light and temperature on the growth ofOscillatoria rubescens was tested with a light thermostat. It was shown that maximum growth occurred at temperatures around 30°C and light intensities of 1500 Lux. Increase of light intensities above 1500 Lux had a negative effect on the growth rate at temperatures higher than 29°C. Our investigations lead to the conclusion thatOscillatoria rubescens is a eurythermal, oligophotic species and that the occurrence ofOscillatoria rubescens-maxima in the vertical distribution of the phytoplankton in a lake is caused by the combined effects of light and temperature.相似文献
14.
云贵高原湖泊夏季浮游植物组成及多样性 总被引：2，自引：2，他引：0
浮游植物是水生生态系统中重要的初级生产者,对维持水生态系统的平衡起着十分重要的作用.根据2008年云贵高原湖泊丰水期浮游植物调查数据,系统地分析了云贵高原13个湖泊中浮游植物的种群密度、生物量、组成及其多样性.云贵高原13个湖泊中共鉴定出浮游植物7门109种(绿藻52种、蓝藻23种、硅藻20种、其他14种).13个湖泊浮游植物Shannon-Wiener指数在0.5-2.2之间,其值大小与单个环境因子无显著相关.相关分析发现浮游植物总量与总氮、总磷、CODMn、硝态氮含量显著正相关,物种丰富度与总氮、总磷(0.1mg/L范围内)、CODMn含量亦显著正相关.另外,研究也发现各湖泊间浮游植物组成的相似性与各湖泊间营养状态差异显著负相关.由此可见,湖泊的营养状态不仅影响浮游植物的总量、组成以及物种丰富度,而且也影响各湖泊物种组成的相似性. 相似文献
15.
基于FVCOM的太湖梅梁湾夏季水温、溶解氧模拟及其影响机制初探 总被引：6，自引：1，他引：5
水体中的溶解氧是表征水生生态系统健康与否的重要参数之一.本研究基于太湖2008年8月16 20日的风速、风向、短波辐射等气象场资料以及实测的相关水质参量,利用FVCOM(即非结构化网格有限体积近海海洋模型)模式对太湖梅梁湾三维水温以及水体中溶解氧进行模拟,模拟结果与实测值基本吻合,水温的验证回归方程为y=1.02x,R2为0.690;溶解氧的R2为0.760.同时对溶解氧浓度的时空分布,梅梁湾溶解氧的"源"和"汇"及其贡献进行了分析.结果表明:太阳辐射、风速是影响水温日成层现象的重要因子;受水温和光照的影响,夏季梅梁湾的溶解氧存在垂直差异,呈现出"双峰双谷"的日变化特征;浮游植物光合作用制氧是水中溶解氧的最重要来源,水下光衰减直接控制着初级生产力的垂直分布;浮游植物呼吸及死亡是溶解氧的最大消耗者,余下依次为底泥耗氧、碳化需氧、细菌呼吸耗氧和硝化作用耗氧. 相似文献
16.
The present state of knowledge regarding the input of anthropogenic pollutants into Narragansett Bay, Rhode Island was reviewed and benthic infaunal communities present at four depositional environments within the upper Bay were characterized. Inter-station differences in species composition and abundance of these assemblages were examined in relation to established pollution gradients.Using diversity curves and multivariate statistics, evidence of significant anthropogenic impact on the structure of benthic macrofaunal communities in Narragansett Bay was identified. The magnitude of this impact was greatest at stations closest to the Bay’s urban centers, where exposure to multiple stressors had resulted in communities of opportunistic taxa which persisted in a state of low faunal diversity characteristic of early stages of species succession. As was expected based on historic models of faunal succession; the apparent maturity of benthic assemblages in Narragansett Bay increased along the north-south gradient of decreasing anthropogenic stress. 相似文献
17.
Impact of stress and disturbance factors on the phytoplankton communities in Northeastern Brazil reservoir 总被引：1，自引：1，他引：0
Naithirithi T. Chellappa Thiago Chellappa Fabiana R.A. Cmara Odete Rocha Sathyabama Chellappa 《Limnologica》2009,39(4):273-282
The ecology of phytoplankton reservoir communities plays a pivotal role in their management and in the development of inland fisheries in the water scarce semi-arid regions of Rio Grande do Norte State, Brazil. The hydrological conditions characterizing these reservoirs include infrequent rainfall and high evaporative loses. The phytoplankton assemblages in tropical climate are structured primarily on dry and wet cycles, not the annual temperature and light regime. The purpose of the current study was to investigate the ecological aspects of phytoplankton communities from three reservoirs during the period of July 2003–June 2004, which include atypical summer rainfall and reservoir overflow. The environmental data broadly divided into two categories, stress factors and disturbance factors. The stress factors deals with the impact of high particulate organic matter and low dissolved oxygen concentrations and disturbance factors, linked to water level fluctuation through flushing and reservoir drawdown, and these events are associated with the phytoplankton assemblages. Results indicated that the three distinct hydroperiods determined the structure of phytoplankton and chlorophyll levels and limited the presence and relative abundance of cyanobacterial species. Phytoplankton succession accompanied changes in clear and turbid water phase represented by the alternate dominance between diatoms and chlorophytes. Inundation and complete filling of reservoir stimulated “s” and “r” strategists species (<20 um) of unicellular and some colonial members of chlorophytes and cryptomonads in highly turbid water environment, and “c” strategist species in rest of the wet period following disturbance gradients. Statistical analysis elicited a significant relationship between particulate organic matter and relative abundance of smaller chlorophytes, which was deemed as stress factor. The flushing and reservoir drawdown indicate disturbance gradient and as a consequence high diversity. Furthermore, a substantial reduction in chlorophyll levels was registered in turbid water phase is related to the reduction of light penetration and re-suspension of sediments. Considering these results, it can be suggested that the well-managed reservoir drawdown can possibly maintain an environment free of eutrophication and cyanobacterial dominance. 相似文献
18.
Elzbieta Lysiak-pastuszak Natalia Drgas Irena Ciszewska Elzbieta Niemkiewicz 《Ocean Dynamics》1998,50(2-3):109-127
Summary In July and at the beginning of August 1997 a study was undertaken in the Gulf of Gdańsk and Pomeranian Bay to follow the
immediate effects of the flood which occurred within the Polish rivers — Wisla and Odra — drainage areas. The study included
measurements and observations of meteorological and hydrodynamic parameters, basic physico-chemical variables, certain persistent
organic pollutants as well as heavy metals and the level of sanitary pollution. The paper presents an overview of environmental
conditions in the bays, based on hydrochemical data, subsequent to the inflow of the flood crests. Results of biological investigations,
carried out solely in the Pomeranian Bay, on phytoplankton abundance, biomass, species composition and Zooplankton diversity
are also presented in the paper. The results of measurements were evaluated in comparison with long-term (1979–1996) monitoring
data and control measurements carried out in the last decade of August. It was found out that the impact of flood water was
restricted to internal areas of both bays and the negative environmental effects appeared only locally.
Umweltuntersuchungen in der Danziger und der Pommerschen Bucht nach der Sommerflut 1997
Zusammenfassung Im Juli und Anfang August 1997 fand in der Danziger und in der Pommerschen Bucht eine Untersuchung mit dem Ziel statt, die unmittelbaren Auswirkungen der Flut, die sich in den Einzugsgebieten der polnischen Flüsse Weichsel und Oder ereignet hatte, festzustellen. Die Untersuchung umfa?te Messungen und Beobachtungen meteorologischer, hydrodynamischer und physisch-chemischer Parameter, bestimmter best?ndiger organischer Schadstoffe sowie Messungen von Schwermetallen und Messungen zum Grad der Verunreinigungen durch Colibakterien. Die Arbeit gibt einen überblick über Umweltbeeintr?chtigungen in den betroffenen Gebieten im Anschlu? an den Einstrom des Hochwassers basierend auf hydrochemischen Daten. Ergebnisse biologischer Untersuchungen in der Pommerschen Bucht, speziell auf den Gehalt an Phytoplankton, Biomasse und deren Zusammensetzung sowie auf Zooplanktonvielfalt, werden gezeigt. Die Ergebnisse der Messungen wurden im Vergleich mit Daten aus Langzeitreihen (1979–1996) und Kontrollmessungen in der letzten Dekade des August bewertet. Es wurde festgestellt, da? der Einflu? des Hochwassers sich auf die inneren Gebiete beider Buchten beschr?nkte und negative Umweltver?nderungen nur lokal auftraten.相似文献
19.
《Limnologica》2019
Algal assemblages have been widely used as an ecological indicator of aquatic ecosystem health conditions because of their specific sensitivity to a wide variety of environmental conditions. In turbid rivers, as in other aquatic systems, phytoplankton structure plays an important role in structuring aquatic food webs. Worldwide, phytoplankton is less studied in turbid, large tropical rivers compared to temperate river systems. The present study aimed to describe the phytoplankton diversity and abundance in a turbid tropical river (the Red River, northern part of Vietnam from 20°00 to 25°30 North; from 100°00 to 107°10 East) and to determine the importance of a series of environmental variables in controlling the phytoplankton community composition. Phytoplankton community was composed of 169 phytoplankton taxa from six algal groups including Bacillariophyceae, Chlorophyceae, Cryptophyceae, Euglenophyceae, Dinophyceae and Cyanobacteria. Community composition varied both spatially and with season. Sixteen measurement environmental variables were used as input variables for a three-layer backpropagation neural network that was developed to predict the phytoplankton abundance. Phytoplankton abundance was successfully predicted using the tagsig transfer function and the Levenberg-Marquardt backpropagation algorithm. The network was trained to provide a good overall linear fit to the total data set with a slope (R) and mean square error (MSE) of 0.808 and 0.0107, respectively. The sensitivity analysis and neutral interpretation diagram revealed that total phosphorus (TP), flow discharge, water temperature and P-PO43− were the significant variables. The results showed that the developed ANN model was able to simulate phytoplankton abundance in the Red River. These findings can help for gaining insight into and the relationship between phytoplankton and environmental factors in this complex, turbid, tropical river. 相似文献
20.
One of the possible consequences of climatic change for streams and rivers in the pampean region of South America is an increment in nutrient loads. To analyze this possible perturbation on a biological scale, the response of oligochaetes to an experimental eutrophication of the La Choza Stream, Argentina was studied. We proposed that the addition of nutrients could increase the abundance, biomass, and species composition of the stream. Two stretches (Control and Treatment sites) were selected, with bimonthly samples being taken (March 2007 through February 2009) in two habitat types: the sediments and the aquatic vegetation. On each sampling occasion the environmental variables were measured. The nutrient addition consisted in the continuous dissolution of a commercial fertilizer. The oligochaete mean density and total biomass, the taxonomic richness, the Shannon diversity (H′), and the evenness (E) were calculated and the BACI ANOVA design used to compare the differences between the sites. Thirty-three species of the families Naididae (Naidinae, Pristininae, Tubificinae, and Rhyacodrilinae), Opistocystidae, Enchytraeidae plus Aphanoneura Aeolosomatidae were collected. The oligochaete abundance and biomass increased significantly in the sediments and on the aquatic vegetation, especially among the Naidinae and Pristininae during their asexual reproductive phase. The diversity and evenness varied significantly in the sediments with the nutrient addition. Significant differences in the species richness and diversity were found on the aquatic vegetation, with both increasing at the treatment site after the fertilization. A significant correlation (Spearman) was observed between the oligochaete density in the sediments and the NO3-N and NH4-N concentration in the water. The increment in the naidines resistant to the fertilizer throughout the experiment could be explained by the greater nutrient availability, their mode of reproduction, and their short life cycles. The results of our study suggested that the incorporation of nutrients modified the composition of the oligochaete assemblage in favor of herbivores and detrivores. The usefulness of these indicator organisms in monitoring freshwater systems is subsequently discussed. 相似文献