环境因素对原生动物群落特征的影响

1999年12月至2000年11月,对华中科技大学华瑜池的原生动物群落进行了研究,共检出原生动物125种,其中植鞭毛虫19种,动鞭毛虫28种,纤毛虫64种,肉足虫14种,对原生动物群落结构和功能的研究表明：1）自然条件下,PFU原生动物群落的种类组成数及原生动物群落的群集速度相对稳定;2）自然条件下,PFU原生动物群落结构和功能不受季节变化的影响;3）当PFU原和动物群落受到外界胁迫时,不管这种胁迫来自物化因素或是生物因素,其群落结构和功能都会发生破坏性变化;4）用PFU法进行原生动物群落生态学和毒理学研究,所得的结构参数及功能参数能反映客观状况,具有环境现实意义。     

铅锌尾矿废水处理系统中PFU原生动物群落变化特征及其与水质净化的关系

应用国家标准《水质—微型生物群落监测—ＰＦＵ法》对位于广东省韶关的凡口铅锌尾矿废水处理系统中的原生动物群落进行了研究．分析了在该处理系统中原生动物群落的结构和群集过程的特征,并结合水质的理化参数对该处理系统的效能进行了评价．结果表明：在该处理系统中,以动物性鞭毛虫和腐生性纤毛虫为原生动物群落的主要组成部分;随着采样点距排污口的距离延长,原生动物群落的种类数和密度明显增加;群落多样性指数也随之上升．通过对原生动物群落组成与污染物浓度的统计学处理,显示出群落的种类数与各污染物的浓度间存在着显著的负线性相关．各采样点ＰＦＵ原生动物群落群集过程也可以反映出各样点环境间的差异．各采样点数据间的差异说明由于该处理系统中香蒲植物的作用,使得废水中大量的颗粒性悬浮物得到沉降,重金属浓度也明显降低,从而促进了原生动物群落在一定程度上的恢复     

停用氧化塘的污染现状

根据国家标准《水质——微型生物群落监测——PFU法》(GB/T12990 -91),两次对湖北鸭儿湖生物氧化塘进行了生物监测与评价.共检出原生动物192种,其中植鞭毛虫48种、动鞭毛虫46种、纤毛虫82种、肉足虫16种.试验所得生物学参数,即PFU原生动物群落结构和功能参数表明:如今Ⅰ号氧化塘整体状况与1982年相比变化较大,Ⅱ号氧化塘相比1982年也有所变化,但不是很大.其它3个氧化塘,第一次试验结果为从Ⅲ号氧化塘到Ⅴ号氧化塘依次变好;第二次试验结果则按Ⅴ、Ⅲ、Ⅳ顺序变好.两次试验所得此三塘的生物学参数之间差别并不大.鸭儿湖氧化塘水体状况与1982年所得结果相比有了很大改善. 图5表3参13     

利用浮游动物群落结构与功能特征监测乐安江－鄱阳湖口重金属污染

１９９３年５月和１９９４年１０月两次对江西乐安江－鄱阳湖湖口的浮游动物进行了生态调查．分析了浮游动物群落结构与功能特征及其与水质的相互关系，并结合丰水期和枯水期的资料进行了水质的综合评价．结果表明：６个采样站浮游动物结构与功能参数的变化与重金属的含量关系密切．上游受铜矿废水污染严重的采样站，种类数、个体数量、生物量、多样性指数ｄ值和ＰＦＵ原生动物的群集速度都很低．至中、下游采样站，重金属浓度明显下降，浮游动物的各项监测指标均呈上升趋势．群落多样性指数ｄ值与水体中Ｃｕ的含量存在一定的回归关系，其关系式为Ｙ＝１６．４１－１．７７ｌｎＸ．     

广州市主要湖泊沉积物重金属污染与生态风险评价

对广州市主要湖泊表层沉积物重金属Cd、Cr、Cu、Ni、Pb和Zn含量及其空间分布特征进行分析,并采用地累积指数法、富集系数法和潜在生态风险指数评价重金属污染现状和潜在生态风险。结果表明,广州市主要湖泊沉积物中Cd、Cr、Cu、Ni、Pb和Zn含量范围分别为0. 50～6. 90、36. 00～197. 40、32. 35～432. 00、17. 35～155. 50、32. 50～162. 70和71. 83～853. 40 mg·kg~(-1),平均值分别为2. 54、92. 27、165. 20、70. 21、90. 48和447. 88 mg·kg~(-1),明显高于广东省土壤重金属背景值。在空间分布上表现为白云湖和东山湖重金属含量高于流花湖和花都湖;地累积指数和富集系数评价结果表明,各重金属污染程度表现为Cd Cu Zn Ni Pb Cr;潜在生态风险指数评价结果表明,Cd为主要生态风险因子,其中白云湖和东山湖重金属污染达到极严重生态风险水平,流花湖和花都湖为严重生态风险水平;多元统计分析结果表明广州市湖泊重金属污染来源主要为城市地表径流和工业、生活污水直接或间接排放。     

铅锌尾矿废水处理系统中PFU原生动物群落变化特征及其与 …

应用国家《水质－微型生物群落监测－ＰＦＵ法》对位 的凡口铅锌尾矿废水处理系统中的原生动物群落进行了研究,分析了在该处理系统中原生动物群落的结构和群集过程的特征,并结合水质的理化参数对该处理系统的效能进行了评价,结果表明：在该处理系统中,以动物性鞭毛虫和腐生性纤毛虫为原生动物群落的主要组成部分;随着采样点距排污口的距离延长,原生动物群落的种类数和密度明显增加;群落多样性也随之上升,通过对原生动物群东     

利用浮游动物群落结构与功能特征监测乐安江—鄱阳湖口重金…

１９９３年５月１９９４年１０月两次对江西乐安江－鄱阳湖湖口的浮游动物进行了生态调查，分析了浮游动物群落结构与功能特征及其与水质的相互关系，并结合丰水期和枯水期的资料进行了水质的综合评介。结果表明：６个采样站浮游动物结构与功能参数的变化与重金属的含量关系密切，上游受铜矿废水污染严重的采样站，种类数，个体数量，生物量，多样性指数ｄ值和ＰＦＵ原生动物的群集速度都很低，至中、下游采样站，重金属浓度明显下降     

氰戊菊酯对原生动物群落的毒性

以PFU采集的原生动物群落为受试对象，研究了氰戊菊酯48h的急性毒性，得出半数致死浓度LC50为15．83mgL^-1安全浓度LC10为2．09mgL^-1．加入氰戊菊酯后，原生动物的群落结构发生变化，各个功能类群均受到不同程度的损伤，一些食菌和碎屑者类原生动物对氰戊菊酯表现出较高的耐受性，随着氰戊菊酯浓度的增加，其在群落中的优势度更加明显．氰戊菊酯的加入致使原生动物群落结构简单化，对生态系统的物质循环和能量流动产生较大影响．图l表1参16。     

安徽沱湖表层沉积物营养盐及重金属分布特征

为了加深对淮河流域过水性湖泊沉积物特征的了解,于2018年8月对沱湖表层沉积物进行调查,测定了营养盐(总氮、总磷)、有机质和4种重金属(镉、铜、铅、铬)的含量,并使用沉积物质量评价标准、有机指数评价法、潜在生态风险指数法对营养盐和重金属污染进行了生态风险评价。结果表明：(1)总氮、总磷、有机质的平均含量分别为(2 535.00±987.97)、(672.99±159.09)和(47.90±19.89)g·kg^-1。(2)总氮和有机质含量的高值区出现在湖泊开阔区和黑鱼沟入湖湖湾,总磷含量的最高值出现在湖泊北部上游过水通道(T2)。(3)镉、铜、铅、铬的平均含量分别为(0.95±0.26)、(25.16±4.00)、(23.03±5.60)和(86.65±17.76) mg·kg^-1。(4)4种重金属元素含量的最高值均出现在黑鱼沟入湖湖湾,低值区则出现在沱河、唐河入湖口和湖泊北部上游过水通道(T2)。(5)表层沉积物受到一定程度的有机污染,且以有机氮污染为主,污染较严重的区域分布在湖泊开阔区和黑鱼沟入湖湖湾。(6)表层沉积物重金属污染具有强生态风...     

江苏省不同营养状况湖泊底栖动物群落结构与多样性比较

为了解江苏省湖泊底栖动物群落结构和多样性并研究其对水环境质量变化的响应,于2012年春秋两季对江苏省16个湖泊51个采样点湖泊底栖动物群落结构与多样性以及湖泊综合营养状态指数进行调查,分析水质指标与底栖动物指数间Pearson相关关系。结果表明,江苏省16个湖泊营养状态指数范围为35.5~66.4,其中约81.2%的湖泊处于轻度-中度富营养状态,表明水质从好到中度污染;湖泊底栖动物优势种为寡毛类的霍甫水丝蚓(Limnodrilus hoffmeisteri),优势度为13.0%;香浓多样性指数(Shannon-Wiener diversity index)范围为0.00~2.20,级别范围由极贫乏到较丰富状态,表明水质污染程度从重度到轻度污染。从全省尺度看,水质评价结果与生物学(香浓多样性指数、Pielou均匀度指数和Biotic Index(BI)指数)评价结果存在一定差异。与历史数据相比,江苏省湖泊底栖动物清洁敏感物种减少甚至消失,总体群落结构趋于小型化。16个湖泊水体总氮和总磷与底栖动物密度呈显著负相关,而综合营养状态指数与底栖动物指数(香浓多样性指数、Pielou均匀度指数和BI指数)间关系不显著。上述研究结果表明综合营养状态指数无法完全客观反映湖泊水生态健康状况,因此需要综合水质、水文、水生生物、生境状况等因素发展新的评价指标体系。     

富营养化对浅水湖泊轮虫种群结构影响研究

石臼湖和固城湖是长江中下游两个浅水湖泊,富营养化问题日益突出。为探索湖泊富营养化对轮虫的影响,于2012年平水期和枯水期对这两个湖泊轮虫种群结构进行了调查,并检测水体理化因子,分析轮虫分布与水环境因子及水体富营养状况的关系。水质检测结果显示,平水期石臼湖除个别点水体综合营养状态指数（TLI）〉50为轻度富营养状态外,大多数站点TLI50,处于轻度-中度富营养化状态。水生生物调查检出轮虫35种,其中石臼湖33种,固城湖27种,平水期种类多于枯水期。出现的轮虫以臂尾轮虫（Brachionus）和异尾轮虫（Trichocerca）居多,优势种主要有螺形龟甲轮虫（Keratella cochlearis）、广生多肢轮虫（Polyarthra vulgaris）、疣毛轮虫（Trichocerca sp.）、沟痕泡轮虫（Pompholyx sulcata）、异尾轮虫属和臂尾轮虫属等。轮虫平均密度3023.19 ind·L-1,平均生物量745.72μg·L-1。现存量季节变动明显,大部分站点平水期大于枯水期。轮虫多样性指数也是平水期大于枯水期,石臼湖轮虫多样性大于固城湖。水体综合营养状态指数（TLI）与轮虫种类数和多样性成显著负相关,随着富营养化加剧,轮虫种类减少,多样性降低。典范对应分析（Canonical Correspondence Analysis,CCA）表明,影响轮虫种群分布的主要环境因子为NH4＋-N、TN、TP和CODMn。按轮虫丰度分布与水环境因子的关系排序,2次调查的24个站点可大致分成3个组。轮虫种群结构受水体富营养状态影响,每组站点的代表性种类对水体营养状态有较好的指示作用。组1的代表性种类为曲腿龟甲轮虫,指示营养级别O-β;组2代表性种类萼花臂尾轮虫,指示的营养级别为β-α;组3以O营养级种类为主。     

Fish Faunas of the African Great Lakes: Origins, Diversity, and Vulnerability

The largest African Great Lakes, Tanganyika, Malawi, and Victoria, which have the richest lacustrine fish faunas of any of the world's lakes, provide a unique comparative series for studies of evolutionary mechanisms, community ecology, and fish behavior. Their colorful littoral fishes are also known to aquarists worldwide. This paper examines the origins of their fish diversity, looking at the history of the lakes, colonization from river systems, and evolution of endemic faunas within each lake. All three lakes support fisheries of great socioeconomic importance for the rapidly rising human populations. The paper also examines the vulnerability of the faunas to fishing pressures and introductions of exotic species. In Malawi and Victoria, bottom-trawling has altered the cichlid species composition. The loss of an estimated 200 taxa of endemic cichlid species from Lake Victoria's fauna, following introductions of exotic fishes (tilapias and predatory centropomid Lates ) 40 years ago, stresses the need to protect the unique fish faunas in Lakes Tanganyika and Malawi.     

Metacommunity assembly and sorting in newly formed lake communities

new habitats are created, community assembly may follow independent trajectories, since the relative importance of dispersal limitation, priority effects, species interactions, and environmental gradients can vary as assembly proceeds. Unfortunately, tracking community colonization and composition across decades is challenging. We compiled a multiyear community composition data set and reconstructed past communities with remains from sediment cores to investigate cladoceran assembly dynamics in six older (1920s) and two more recently formed (1950s) lakes. We found that current communities cluster along a gradient of thermal stratification that is known to influence predation intensity. Assembling communities showed evidence for a greater influence of species sorting and a reduced influence of spatial structure since the first colonizations. However, lake community trajectories varied considerably, reflecting different colonization sequences among lakes. In the older lakes, small-bodied cladocerans often arrived much earlier than large-bodied cladocerans, while the two younger lakes were colonized much more rapidly, and one was quickly dominated by a large-bodied species. Thus, by combining contemporary community data with paleoecological records, we show that assembly history influences natural community structure for decades while patterns of ecological sorting develop.     

The Effects of Predation by Nile Perch, Lates niloticus L., on the Fish of Lake Nabugabo, with Suggestions for Conservation of Endangered Endemic Cichlids

As in Lake Victoria and Lake Kyoga, most of the native fish species of Lake Nabugabo have either been depleted or have disappeared since Lates niloticus , Nile perch, and Oreochromis niloticus , a tilapiine, were introduced. L. niloticus, O. niloticus, Schilbe intermedius, Brycinus jacksonii , and Rastrineobola argentea are the only species still abundant and widespread in the lake. Of the five haplochromine species endemic to Lake Nabugabo, at least one has vanished and the remaining ones are very rare. The prey of the Nile perch in Lake Nabugabo, with the exception of the prawn Caridina nilotica , which is absent from the lake, are similar to those the predator switched to in Lakes Victoria and Kyoga after haplochromines had been depleted. These consist of ephemeropterans—especially Povilla , the anisopteran nymphs R. argentea , tilapiines, and juvenile Nile perch. Three small lakes adjacent to Lake Nabugabo—Lake Kayanja, Lake Kayugi, and Lake Manywa—contain large numbers of Oreochromis esculentus and two haplochromine species previously known only in Lake Nabugabo. These three lakes should be designated conservation areas for the cichlids and other native species that were previously abundant in Lakes Victoria, Kyoga, and Nabugabo. The swamps around these lakes should be protected so that the Nile perch does not spread into them. Further research should be carried out to ensure the preservation of the endemic species.     

Biogeography of bacterioplankton in lakes and streams of an Arctic tundra catchment

Bacterioplankton community composition was compared across 10 lakes and 14 streams within the catchment of Toolik Lake, a tundra lake in Arctic Alaska, during seven surveys conducted over three years using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified rDNA. Bacterioplankton communities in streams draining tundra were very different than those in streams draining lakes. Communities in streams draining lakes were similar to communities in lakes. In a connected series of lakes and streams, the stream communities changed with distance from the upstream lake and with changes in water chemistry, suggesting inoculation and dilution with bacteria from soil waters or hyporheic zones. In the same system, lakes shared similar bacterioplankton communities (78% similar) that shifted gradually down the catchment. In contrast, unconnected lakes contained somewhat different communities (67% similar). We found evidence that dispersal influences bacterioplankton communities via advection and dilution (mass effects) in streams, and via inoculation and subsequent growth in lakes. The spatial pattern of bacterioplankton community composition was strongly influenced by interactions among soil water, stream, and lake environments. Our results reveal large differences in lake-specific and stream-specific bacterial community composition over restricted spatial scales (<10 km) and suggest that geographic distance and connectivity influence the distribution of bacterioplankton communities across a landscape.     

An experimental study on recolonization and succession of marine macrobenthos in defaunated sediment

Hypoxia/anoxia in coastal waters is a world wide problem which often results in mass mortality and defaunation of benthos. In this study, field experiments were carried out to examine recolonization and succession of macrobenthic infauna in defaunated sediments, and the time required for recovery from complete defaunation to a stable community. Trays (33 cm length × 25.5 cm width × 11 cm depth) of defaunated sediment were exposed at the subtidal of a pristine site in subtropical Hong Kong. Temporal changes of macrobenthic communities in defaunated sediment were analyzed by univariate and multivariate statistics, and compared with those in undisturbed natural sediment at the same site. Initial colonization of macrobenthos occurred rapidly. A total of 42 species was found, with an average of 258 animals per tray and 24 species per tray recorded in the first month. Abundance showed a small peak (496 animals per tray) after 3 months, reached a sharp peak (1154 animals per tray) after 6 months, and declined thereafter. Species number increased gradually, reached a maximum (68 species per tray) after 9 months, and then decreased. Recolonization was predominantly contributed by larval settlement rather than adult migration. Temporal changes in abundance, species number and diversity of the macrobenthic community in defaunated sediment resemble the spatial changes along a decreasing pollution gradient previously defined by other authors. Results of this experiment suggest that newly available sediment may allow more species to colonize (or coexist) than sediment pre-occupied by an established community. This is probably due to less interspecific competition in the former habitat. No significant difference in abundance or species richness was observed between defaunated and natural sediments after 15 months, suggesting that a stable community had been achieved, although minor variations in species composition were still discernible between defaunated and natural sediments. Received: 24 May 1999 / Accepted: 20 October 1999     

中国东部浅水湖泊沉积物总氮总磷基准阈值研究

受人类活动的影响,东部浅水湖泊沉积物中总氮、总磷负荷很高,当外来污染源得到控制时,底泥中的营养盐会逐渐释放出来,对湖泊水质与生态系统影响很大。为合理削减湖泊内源污染,控制沉积物中营养盐向上覆水体释放,研究制定东部浅水湖泊沉积物总氮、总磷基准阈值,分别测定了100个湖泊的896个表层沉积物样品和8个典型湖泊11个柱芯的沉积物总氮（TN）、总磷（TP）含量,分析了沉积物TN、TP浓度剖面分布特征。通过频度分布法对100个湖泊沉积物总氮总磷的污染状况进行评价,通过背景值比较法确定了8个典型湖泊沉积物的TN、TP背景值。结果表明,100个湖泊的表层沉积物TN浓度范围在479.70~5 573.65 mg·kg-1,TP浓度范围在248.44~1000.33 mg·kg-1,不同湖泊表层沉积物中TN、TP值差异较大。8个典型湖泊沉积物总氮、总磷含量整体上表现出随着深度增加而下降变化趋势,在深层沉积物中含量保持稳定。所调查8个湖泊TN均值为1443.83 mg·kg-1,变化范围为247.45~3719.46 mg·kg-1,各湖泊中TN均值表现为：沱湖〉焦岗湖〉花园湖〉七里湖〉北民湖〉大通湖〉城东湖〉瓦埠湖;TP均值为519.62 mg·kg-1,变化范围为225.41~1944.89 mg·kg-1,各湖泊中TP均值表现为：北民湖〉大通湖〉七里湖〉焦岗湖〉沱湖〉瓦埠湖〉城东湖〉花园湖。不同湖泊沉积物总氮、总磷背景值差异很大。通过对100个湖泊表层沉积物TN、TP的频度分析发现,沉积物营养盐含量上25%点位对应的TP质量浓度398.51mg·kg-1,TN质量浓度为1106.24 mg·kg-1,沉积物营养盐含量下25%点位对应的TP质量浓度664.58 mg·kg-1,TN质量浓度为2916.66 mg·kg-1。通过互相之间的比较分析,推荐采用背景值比较法确定的各湖泊沉积物总氮、总磷背景值均值与频度分步法25%点位对应的总氮值和40%点位对应的总磷值作为东部浅水湖泊沉积物总氮、总磷基准阈值。因此,?