转基因鲤鱼对大型底栖动物群落及多样性的影响

为了对转基因(CAgcGH)鲤的生态风险评估提供参考依据,于2004~2006年在梁子湖畔的人工隔离湖泊开展了转基因鲤对其主要饵料生物--底栖动物群落结构及多样性影响的研究。结果表明：投放转基因鲤1 a后,底栖动物物种组成、丰度和多样性指数均出现不同程度下降。底栖动物总物种数从65种下降为36种;总密度从4973 ind/m2下降到3707 ind/m2;总生物量(湿重)从77136 g/m2上升到97558 g/m2。单因素方差分析显示：总物种数、寡毛类、毛翅目和摇蚊科物种数有显著降低。寡毛类、毛翅目和腹足类密度有显著下降。毛翅目生物量有显著下降。幽蚊〖WTBX〗(Chaoborus 〖WTBZ〗sp.)和环棱螺〖WTBX〗(Bellamya 〖WTBZ〗sp.)取代纹沼螺(〖WTBX〗Parafossarulus striatulus)和苏氏尾鳃蚓(Branchiura sowerbyi)〖WTBZ〗成为优势种。底栖动物多样性呈现显著下降,3种多样性指数平均减少19%~44％,物种丰富度则减少了38%。〖WTBX〗K〖WTBZ〗优势曲线显示了同样结果。转基因鱼与对照鱼在捕食压力和摄食选择偏好上的差异,可能是造成隔离湖泊内底栖动物群落结构和多样性变化的重要原因之一.     

以底栖动物为指示物种对长江流域水生态进行评价

采用底栖动物作为指示物种对长江流域的水生态进行了调查研究和生态评价。在长江上游支流、中下游干流及沿江湖泊上选取36个代表性样点进行生态考察和底栖动物采样、鉴定和分析。采用Hilsenhoff生物指数和水化学分析对样点水质进行评价,对比分析了各样点底栖动物的结构组成及多样性。上游支流大部分样点水质清洁;中游干流及沿江湖泊水质受到轻度到中度污染;下游干流水质污染加重。底栖动物多样性在上游支流中最高,中游湖泊较高,干流中下游较低。总结得出了4种河床演变条件下的底栖动物群谱。上游支流河床稳定的河流底栖动物密度较大,物种丰富,多样性高;侵蚀下切的河流底栖动物密度、物种数和多样性较低;淤积抬升的河流底栖动物密度、物种数和多样性更低一些;河势散乱且河床运动剧烈的支流物种丰度和密度均很低甚至为零,生态条件差。     

以底栖动物为指示物种对长江流域水生态进行评价

采用底栖动物作为指示物种对长江流域的水生态进行了调查研究和生态评价。在长江上游支流、中下游干流及沿江湖泊上选取36个代表性样点进行生态考察和底栖动物采样、鉴定和分析。采用Hilsenhoff生物指数和水化学分析对样点水质进行评价，对比分析了各样点底栖动物的结构组成及多样性。上游支流大部分样点水质清洁；中游干流及沿江湖泊水质受到轻度到中度污染；下游干流水质污染加重。底栖动物多样性在上游支流中最高，中游湖泊较高，干流中下游较低。总结得出了4种河床演变条件下的底栖动物群谱。上游支流河床稳定的河流底栖动物密度较大，物种丰富，多样性高；侵蚀下切的河流底栖动物密度、物种数和多样性较低；淤积抬升的河流底栖动物密度、物种数和多样性更低一些；河势散乱且河床运动剧烈的支流物种丰度和密度均很低甚至为零，生态条件差。     

Ecological-biogeochemical role of macrophytes in aquatic ecosystems of urbanized territories (an example of small water bodies of St. Petersburg)

The accumulation of heavy metals (Fe, Mn, Zn, Cu, Cr, Ni, Pb, Cd) and biogenic elements (P, S, K, Ca, Na) in leaves has been studied in macrophytes of different ecological groups growing in small water bodies of St. Petersburg. The ecogeological and biogeochemical role of macrophytes in the water-aquatic plants-bottom sediments system and their contribution to the stability of aquatic ecosystem functioning under conditions of a megalopolis are considered. Prospects for using macrophytes for bioindication and phytoremediation of polluted aquatic ecosystems are discussed.     

Nematode species at risk--a metric to assess pollution in soft sediments of freshwaters

Soft sediments are often highly polluted as many of the toxic chemicals introduced into surface waters bind to settling particles. The resulting accumulation of pollutants in the sediments poses a risk for benthic communities. However, pollution induced changes in benthic communities have been difficult to determine when using macro-invertebrates as bioindicators, as these organisms are often absent in soft sediment. The present study therefore examined the ability of meiofaunal organisms, specifically, nematodes, to assess the ecological status of soft sediments. Over a 9-year period, nematode communities present in sediments collected from large rivers and lake Constance in Germany were studied. These sediments showed a large range of physico-chemical properties and anthropogenic contamination. After the degree of metal and organic contamination was translated into ecotoxicologically more relevant toxic units (TUs), multivariate methods were used to classify nematode taxa in species at risk (NemaSPEAR) or not at risk (NemaSPE(not)AR). This approach clearly distinguished the influence of sediment texture from that of the toxic potential of the samples and thus allowed classification of the nematode species according to their sensitivity to or tolerance of toxic stress. Two indices, expressing the proportion of species at risk within a sample (NemaSPEAR[%](metal), NemaSPEAR[%](organic)), were calculated from independent data sets obtained in field and experimental studies and showed good correlations with the toxic potential (field data) or chemical concentrations (microcosm data). NemaSPEAR[%] indices for metal and organic pollution were therefore judged to be suitable for assessing the impact of chemical contamination of freshwater soft sediments.     

Field observations of the effects of protracted low levels of ionizing radiation on natural aquatic population by using a cytogenetic tool

In the present study, an effort is attempted to record the impact of chronic radiation on natural aquatic populations exposed to protracted doses (lower if compared to intervention levels but higher if compared to typical background) and to chemical pollution. The methodology is based on the analyses of chromosome aberrations observed in cells. Therefore, some preliminary research results on the cytogenetic effects on aquatic organisms of various taxa, in coastal ecosystems are presented, considering some selective regions of elevated natural gamma radiation and conventional pollution. These areas are the geothermal spring areas in the island of Ikaria-Eastern Aegean Sea and the port of Pireus, in Greece. The data are compared to the findings recorded in some organisms collected from the North Aegean Sea the early period after the Chernobyl accident. With regard to the different species examined, a first evaluation of the results is made using the reported field findings for the wide area of Chernobyl. The environmental assessment of the studied areas in terms of radiation impact is based on the cytogenetic injuries observed, and evidence of ecosystem disturbance is also pointed out. The final environmental assessment based on the quantified effects observed in the organisms from the studied areas takes into account a published conceptual model of zones of radiation dose rates and the resulting organism responses in a step function scale.     

Release,distribution, and impacts of polychlorinated biphenyls (PCB) induced by dredged material disposal activities at a deep-water estuarine site

The aquatic disposal field investigation initiated in Elliott Bay, Puget Sound, WA, in February 1976, was designed to evaluate the ecological effects of open-water disposal of dredged material. The experimental disposal site was located at a depth of 60 m in marine estuary with generally weak circulation. Approximately 114,000 m³ of dredged material contaminated with polychlorinated biphenyls (PCBs) were dumped at the site from split-hull barges. The material presented in this paper is limited to a discussion of PCB impacts. It imcludes (a) a summary of results from the studies conducted between 1976 and 1977 to assess short-term impacts during and after the disposal of PCB contaminated sediments at the Elliott Bay disposal site; (b) a presentation of preliminary results from the continuation studies initiated in February 1979 to determine long-term impacts of the disposal operations. The preliminary data indicate that both dredged-material deposit and the associated PCBs appear to be stable. No major long-term impact on benthic organisms is apparent from this analysis.     

Fates of cadmium introduced into channels microcosm

Five 10 μg Cd·l^?1 were continuously input to aquatic microcosm channels for one year. Cadmium accumulation in both biotic and abiotic components was determined. Cadmium inputs and outputs equilibrated within approximately 20 days of initial Cd inputs. Most community components accumulated Cd proportional to Cd water concentrations. Equilibrium Cd concentrations of sediments, aufwuchs, macrophytes, chironomids, and mosquito fish exposed to 10 μg Cd·l^?1 were 0.59, 55, 250, 40, and 40 μg Cd·g^?1, dry weight, respectively. Cadmium was rapidly eliminated from all biotic components when Cd inputs were terminated. Cadmium concentrations were similar to those in control channels within a few weeks in the aufwuchs community to a few months in macrophytes after Cd inputs were terminated. Cadmium uptake fluxes by the aufwuchs community and mosquito fish were first order, with respect to Cd concentration in the water. The rate constants for uptake and depuration for the aufwuchs community were 0.42 and 0.66 d^?1, respectively (concentration basis). The rate constants for uptake and depuration of Cd by mosquitofish were approximately 25 and 0.004 d^?1, respectively (concentration basis). Cadmium concentrations in organic headpool sediments had not significantly decreased six months after cessation of Cd inputs, which indicates that the abiotic half time for contaminated organic sediments is very long. Half times for elimination from channel sand sediments were 72 and 38 d for 5 and 10 μg·l^?1 exposure, respectively, after Cd inputs were terminated Cd concentrations in macroinvertebrates varied seasonally. The carrying capacity of the channels microcosm limited the number of samples of secondary and tertiary consumers which could be sampled. It was concluded that concluded that experimental channels of the size described here were not appropriate as screening tools for the fates of trace contaminants, but were effective for the study of trace contaminants, especially in conjunction with mathematical modeling efforts and less complex laboratory studies.     

Screening ecological risk assessment of persistent organic pollutants in Mediterranean sea sediments

A screening ecological risk assessment (ERA) was conducted for the first time in the Mediterranean basin in order to assess the toxicity posed to the benthic community by PCBs, DDTs and HCB in marine sediments. The characterization of the exposure was conducted by means of an extensive literature survey, generating a database with more than 2000 samples. The effects were assessed by the adoption of guidelines previously developed in the literature, because ecotoxicological information about persistent organic pollutants (POPs) in the Mediterranean sediments was lacking. Existing sediment quality guidelines (SQGs) for the target pollutants were compiled and consensus values were calculated for three different categories of toxicity, namely threshold effect concentration (TEC), probable effect concentration (PEC) and extreme effect concentration (EEC). The combination of exposure and effects characterization enabled the identification of some areas of concern in the vicinity of industrial and urban locations and in the mouths of the main Mediterranean rivers. Beyond the Mediterranean continental shelf, the level of toxicity for the benthic community was generally low. The evaluation of the toxicity induced by the mixture of the target pollutants spotted the importance of DDT contamination in the Mediterranean sediments, despite the fact that main inputs to the sea have been significantly reduced during the last decades.     

Ecotoxicological effect of grounded MV River Princess on the intertidal benthic organisms off Goa

The ecotoxicological effects of oil spill from the grounded vessel MV River Princess on the intertidal benthic organisms of Sinquerim-Candolim beach at Goa were investigated. An intertidal expanse of 1 km on either side of the grounded vessel was selected to evaluate the concentration of total petroleum hydrocarbon (TPH) in the sediment and its effects on the composition, abundance and diversity of micro-, meio- and macrobenthos. TPH in the intertidal sediment ranged from 7.8 to 89 microg g(-1) (mean 35.44+/-26.35 SD). Microbenthos comprised of microalgae, protozoans and juvenile forms of meiobenthos. Apart from juvenile nematodes, which were abundant, Coscinodiscus spp., Navicula spp., and Nitzschia spp. representing microalgae were also observed in microbenthic samples. Meiobenthos was represented by 13 taxa and their total density ranged between 92 and 1057 nos. 10 cm(-2). Maximum meiobenthic abundance of 1057 nos. 10 cm(-2) was observed at Sinquerim. Nematodes were the dominant meiobenthic taxa followed by turbellarians and harpacticoid copepods. The macrobenthos was numerically dominated by polychaetes, followed by crustaceans whereas bivalve molluscs were less represented. There was substantial increase in the petroleum concentration in the beach sediment compared to the previously reported values and highest TPH (89 microg g(-1) sediment) values were in the vicinity of the grounded vessel. The polychaete/amphipod ratio and cumulative and partial dominance abundance-biomass curves showed significant negative impact of TPH on macrofauna. The benthic community structure also showed measurable changes, as there was significant decrease (60%) in the number of species. Given that the microalgal counts were low in sediment, it is assumed that the intertidal meiofauna was possibly using oil-degrading bacteria as alternate food source. In conclusion, the results reported here suggest that the grounded ore carrier is not only detrimental to the beach community, that may take longer time for recovery, but also affects the beach morphology which may have long-term impact on local fishery.     

人工重建的水生植物群落演替动态研究

水生植物群落在湖泊生态修复过程中作用显著,但目前人工重建的水生植物群落抗外界干扰能力弱,群落稳定性差,这就需要我们对人工重建的水生植物群落结构及其演替的生态学过程进行研究,从而探索受损群落的修复途径。于2003年在富营养化水体中采用物理生态工程进行了水生植物群落的重建研究,对群落演替动态变化过程进行了持续3年的观测。结果表明：水生植物之间发生生态位重叠时,其结果往往是以一个物种取代另一个物种,随着生态位重叠程度下降,种间关系和群落结构趋于稳定;而当物种空间位置错开时,生长期相近的物种共存则变为可能,因此在群落的构建过程中应当避免同时引入生态位重叠较高的物种,应注意植物间时间序列及空间结构的分离;此外还通过物种间的竞争表现,对几种常见水生植物构建的群落稳定性做了初步探讨.     

黄盖湖水系河源区——皤河大型无脊椎动物群落与水质评价

2009年7月对黄盖湖水系河源区--皤河的大型无脊椎动物进行调查。共采集到无脊椎动物54种,隶属于4门6纲36科。其中水生昆虫45种,软体动物4种,甲壳动物2种,寡毛类、涡虫纲、蛛形纲各1种。无脊椎动物密度方面的优势类群主要为蜉蝣目稚虫和摇蚊幼虫。宽基蜉(Choroterpes sp.)、微动蜉(Cinygmula sp.)、四节蜉(Baetis sp.)和无突摇蚊 (Ablabesmyia sp.)是最优势的种类,其相对丰度分别占总丰度的4040%、838%、426%和419%。典范对应分析（CCA）显示,海拔和河宽是影响无脊椎动物群落分布的关键环境因子。采用Shannon Wiener指数和BI生物指数对各样点的水质状况进行了评价：二者结果具有一定差异,BI指数的评价结果更符合实际情况     

Studies on heavy metal accumulation in aquatic macrophytes from Sevan (Armenia) and Carambolim (India) lake systems

Aquatic macrophytes are unchangeable biological filters and they carry out purification of the water bodies by accumulating dissolved metals and toxins in their tissue. In view of their potential to entrap several toxic heavy metals, 45 macrophytes belonging to 8 families collected from two different physiographic locations (36 from Sevan Lake, Armenia; 9 from Carambolim Lake, Old Goa, India) were studied for estimation of 14 heavy metals. The study was aimed at understanding the importance of these macrophytes in accumulation of toxic metals and controlling the heavy metal pollution and suggesting the remedial measures, if any, for the preservation and restoration of lake ecosystem. Inductively Coupled Plasma-Atomic Emission Spectrometric (ICP-AES) analyses of these aquatic macrophytes have shown the importance of aquatic macrophytes in accumulation of heavy metals and maintaining the clarity of water bodies beside their role in trophic systems. Accumulation of most of the heavy metals was higher in root system. The representative macrophytes from two different physiographic locations show similar trends and order in accumulating different metals generally. Of the 14 metals investigated, 9 (Ca, Fe, Al, Cr, Cu, Ba, Ti, Co and Pb) showed higher rates of accumulation in the root whereas 3 (Mn, Zn and Mg) showed more accumulation in stem and 1 (Ca) showed higher accumulation in the leaves. In most of the samples Cu was accumulated more in the roots (50+/-47.15 microg/g) and less in flowers (9.52+/-3.97 microg/g). Occurrence of heavy metal was much higher in macrophytes of Sevan Lake than that of the Carambolim Lake. The accumulation of 14 elements was in order of Ca>Mg>Fe>Al>Mn>Ba>Zn>Ti>Cu>Cr>Co>Ni>Pb>Cd. The present study revealed that the aquatic macrophytes play a very significant role in removing the different metals from the ambient environments. They probably play a major role in reducing the effect of high concentration of heavy metals. Therefore, the macrophyte community of the Sevan Lake area needs to be protected and restored on a priority basis. Accumulation of highly toxic metals like--Cr, Cd, Pb and Ni was lower as compared to the essential metals like Ca, Fe and Mn in all the macrophytes from both the lake systems, consequently high metal concentrations observed in both the areas may not directly reflect on the pollution level.     

太湖底泥中多氯联苯的特征与环境效应

分析了太湖底泥中6种PCB同系物（PCB28、52、101、138、153、180）,其中含量最高的为PCB52,平均为0.983 ng/g,最低为PCB138,平均为0.104 ng/g。表层底泥中,检出率最高的为PCB101,达100%,最低为PCB180,只有58.3%。太湖底泥的多氯联苯含量与底泥中有机质和营养元素几乎不相关,表明大气沉降可能是多氯联苯的重要来源。根据沉积物有关风险评价标准,太湖底泥测定的PCB总量尚未达到毒性评价的低值。尽管底泥中PCBs含量不高,但在底栖生物中可以富集,并通过食物链逐级传递,因而其潜在的危害性仍不容忽视。     

Abundance and diversity of aquatic macroinvertebrate communities in lakes exposed to Chernobyl-derived ionising radiation

Littoral (lake shore) macroinvertebrate communities were studied in eight natural lakes affected by fallout from the Chernobyl accident. The lakes spanned a range in ¹³⁷Cs contamination from 100 to 15500 kBq m⁻² and estimated external dose rates ranged from 0.13 to 30.7 μGy h⁻¹. General linear models were used to assess whether abundance of individuals, taxon richness, Berger-Parker dominance and Shannon-Wiener diversity varied across the lakes. Step-wise multiple regressions were used to relate variation in total abundance, taxon richness, Berger-Parker dominance, Shannon-Wiener diversity, taxon richness within major groups of macroinvertebrates and abundance of the more common individual taxa to the measured environmental characteristics (conductivity, pH, total hardness and phosphate; lake area, lake maximum depth and total external dose) of the lakes. No evidence was found in this study that the ecological status of lake communities has been influenced by radioactive contamination from the Chernobyl accident. Indeed, the most contaminated lake, Glubokoye, contained the highest richness of aquatic invertebrates. Taxon richness in the eight study lakes varied from 22 (Svyatskoe #7) to 42 (Glubokoye) which spans a range typical for uncontaminated lakes in the region. Since ⁹⁰Sr is readily-absorbed by Mollusca, estimated dose rates to this group exceeded those for other invertebrate groups in two lakes (Perstok and Glubokoye). However this study found no association between mollusc diversity or abundance of individual snail species and variation between lakes in the external radiation dose. Indeed Glubokoye, the lake most contaminated by ⁹⁰Sr, had the highest richness of freshwater snails per sample (an average of 8.9 taxa per sample).     

Screening ecological risk assessment for the benthic community in the Venice lagoon (Italy)

According to the risk hypothesis: the sediment as source of potential risk for the benthic community, an Ecological Risk Assessment (ERA) based on the quotient method was undertaken. The exposure of the benthic community to different classes of pollutants (metals, chlorinated organic compounds and polynuclear aromatic hydrocarbons) was inferred by estimating the pollutant stocks in the top 15-cm sediment of the whole Venice lagoon, after application of geostatistic techniques. The risk was calculated by comparing the sediment exposure profiles with the ecotoxicological benchmarks for benthic organisms. Kriging based maps of the spatial distribution of the estimated risk for the benthic community over the whole lagoon were obtained. The highest risk, found in the areas nearest to the sources of contamination (e.g., the industrial district of Porto Marghera and the river mouths), was posed by mercury (40% of the sampling stations showed exposure levels higher than the Probable Effect Level), arsenic and nickel (75% of the sampling stations exceeded the Threshold Effect Level).     

Factors affecting metal toxicity to (and accumulation by) aquatic organisms — Overview

This literature review encompasses aquatic environmental toxicities of metals and metalloids. The emphasis is on the influencing factors on metal toxicity to aquatic organisms. The effects of environmental factors on metal uptake are also discussed. The factors can be divided into biotic and abiotic. The biotic factors include tolerance, size and life stages, species, and nutrition related to the test organisms. The abiotic factors include organic substances, pH, temperature, alkalinity and hardness, inorganic ligands, interactions, sediments, and others. These factors can alter metal toxicity in the aquatic environment substantially, mostly causing attenuating effect. The literature shows divergent results. For example, the interactions between Cd and Zn were reported to be synergistic by some researchers and antagonistic by others. It is recommended that environmental hazard assessment takes into consideration the results of standard toxicity tests and site-specific conditions which can moderate metal toxicity considerably.     

The influence of a whole-lake addition of stable cesium on the remobilization of aged 137Cs in a contaminated reservoir

To document the short-term dynamics of Cs, 4 kg of (133)Cs were introduced into an 11.4-ha, 157 000 m(3) reservoir previously contaminated with (137)Cs from past reactor operations at the US Department of Energy's Savannah River Site near Aiken, South Carolina, USA. The (133)Cs addition resulted in an increase of 6.1 MBq of (137)Cs (1.9 mug (137)Cs) in the water column over the following 260 days. Possible sources for the increased (137)Cs included (1) release from the sediments, (2) release from the approximately 26 000 kg of aquatic macrophytes that occupied 80% of the reservoir, and (3) wash-in from the pond's watershed. Data are presented to indicate that release from the sediments was the principal source of the (137)Cs increase. The fraction of (137)Cs released from the sediments (0.7%) is consistent with laboratory measurements of (137)Cs desorption from neighboring ponds on the Savannah River Site.     

Acute toxicity of herbicides to freshwater fish and midge larvae, Chironomus tentans

Acute toxicity of three herbicides, tafazine, bladex, and aresin, were studied for three species of freshwater teleost, namely, Labeo rohita, Mystus vittatus, and Cirrhinus mrigala, and benthic macroinvertebrate, midge larvae, Chironomus tentans, L. rohita and C. mrigala were found susceptible to all three herbicides as compared to M. vittatus and C. tentans, which were more susceptible to the tafazine toxicity. The toxicity of the three herbicides was in order of tafazine>bladex>aresin. Investigation leads to the conclusion that some herbicides, though quickly degradable, form hazards for aquatic life even at very low levels. Their application must be monitored to prevent aquatic pollution.     

水文连通性对湖泊生态环境影响的研究进展

水文连通性对湖泊水资源调节、水质净化和生态安全等具有重要作用,但同时也可能带来潜在风险。因而厘清水文连通性对其生态环境的影响规律,对于开展水文连通性修复工作具有重要指导意义。基于广泛的文献调研,介绍了水文连通性的定义与内涵,分别综述了水文连通性对湖泊水文水动力、水质、水生态系统影响的研究进展。在此基础上,总结归纳了水文连通性通过改变水文水动力过程影响生态系统的路径：一是直接改变生境面积、植被格局和生物迁移繁殖特征,二是通过改变水质和沉积物特征而作用于生物的生长发育及其体内污染物累积转化过程。最后,对水文连通性变化的生态环境效应研究进行了展望：(1)加强对垂向连通性的研究以及拓展不同维度连通性耦合转化研究;(2）借助水动力-水质-水生态耦合模型研究水文连通性变化下的生态环境效应;(3）开展水文连通性的生态环境风险研究,并基于生态环境效益和社会经济效益权衡确定适宜的水文连通性。