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1.
The Aliakmon River originates in the North Western part of Greece, traverses the Western part of Macedonia, and discharges into the Thermaikos Bay in the North Aegean Sea. Proton induced X-ray emission (PIXE) method with external beam was used for the determination of the metallic elements in the waters and sediments of the Aliakmon River. the pH, dissolved oxygen, conductivity, and total phosphate and nitrate concentrations were also monitored in the water samples. Data collected for a 20-month period indicate that the Aliakmon River can be still considered as an unpolluted river.  相似文献   

2.
Aquatic plants along the North Canal in Beijing were studied to identify the community structure of aquatic plants and vegetation index of biotic integrity (VIBI), and to provide scientific basis for the management and protection of urban rivers. Aquatic plants from 49 sampling sites along the North Canal were investigated during June 2015. Based on the field data, distributing range analysis, discriminatory power analysis, and correlation analysis were used stepwise to select core metrics from candidate metrics to establish the VIBI assessment system. The VIBI value of each sampling site was calculated as the average of the scaled values of all core metrics. Thirty-six aquatic plant species, including 14 hygrophytes, 13 emergent species, 6 submergent species, 2 floating-leaved species, and 1 floating species were collected. Species diversity was low in the North Canal, and no aquatic plants were recorded in 28 sampling sites, of which 9 sampling sites were dried up. Five sites were in excellent condition (VIBI > 0.60), 5 were good (0.60 > VIBI > 0.38), 7 were fair (0.38 > VIBI > 0.23), and 4 were poor (VIBI < 0.23). Based on the distribution of VIBI, Shahe River and Wenyu River upstream, and Fenghe River located in suburbs had a higher VIBI. Downstream tributaries, such as Qinghe River, Bahe River, and Liangshui River, had a lower VIBI. Correlation analysis showed that habitat quality, habitat complexity, and vegetation diversity along riparian zones were the important factors affecting VIBI along the North Canal, Beijing. Aquatic plants along the North Canal showed low species diversity owing to human disturbance. VIBI along tributaries with limited disturbance from human activities was higher; however, VIBI along tributaries disturbed by frequent human activities was lower. © 2018 Science Press. All rights reserved.  相似文献   

3.
于2009年5月(枯水期)、8月(丰水期)、11月(平水期)对天津地区蓟运河、潮白新河、永定新河、金钟河、北塘排污河、黑猪河、海河、大沽排污河、独流减河、青静黄排水渠、子牙新河和北排水河12条主要河流的水质进行监测,并对监测数据进行主成分分析,构建水质评价指标体系,采用水质标识指数进行水质评价。结果表明,主成分分析与水质标识指数相结合的评价方法客观可靠。从时间分布来看,枯水期水质最差,58.3%的河流为劣Ⅴ类水质,部分河流已经黑臭,8月水质较好。从综合水质标识指数来看,海河以南河流污染较为严重。该地区河流NH3-N污染最为严重,其次是BOD5、CODMn和TP,属于有机型及富营养化污染。  相似文献   

4.
The Sands of Forvie, National Nature Reserve, Scotland is a complex coastal sand dune system which is associated with the dynamic estuary of the River Ythan. The dune system has developed over more than 5000 years. The south part is a peninsula of dunes, sand hills, sand arcs, erosion and deflation surfaces. The north part is superimposed on a rock plateau with a cliff coastline. This plateau is covered in glacial deposits and is essentially an upland heath landscape. Some of the best examples of large active parabolic dunes in Britain are found in North Forvie. The sequence of geomorphic development is described. As a nature reserve with a rich ecology it has been managed for conservational purposes since 1960s. As such it is an excellent case study of how conservational management has changed to become more flexible and more aware of the importance of dynamic processes.  相似文献   

5.
The Sands of Forvie, National Nature Reserve, Scotland is a complex coastal sand dune system which is associated with the dynamic estuary of the River Ythan. The dune system has developed over more than 5000 years. The south partis a peninsula of dunes, sandhills, sand arcs, erosion and deflation surfaces. The north part is superimposed on a rock plateau with a cliff coastline. This plateau is covered in glacial deposits and is essentially an upland heath landscape. Some of the best examples of large active parabolic dunes in Britain are found in North Forvie. The sequence of geomorphic development is described. As a nature reserve with a rich ecology it has been managed for conservational purposes since 1960s. As such it is an excellent case study of how conservational management has changed to become more flexible and more aware of the importance of dynamic processes.  相似文献   

6.
九龙江流域经济发展与河流水质时空关联分析   总被引:6,自引:0,他引:6  
以闽西南地区的九龙江流域为例,综合采用数理统计、GIS技术和环境库兹涅茨曲线(EKC)方法,对该流域1981—2009年经济发展与河流水质变化进行时空关联分析。结果表明,九龙江流域呈现"第1产业缓增,第2、3产业产值增加较快"的总体经济格局,农业污染突出;农业种植面积呈现先增加后减少趋势,流域氮、磷肥平均施用强度呈线性增加趋势;氮、磷肥平均折纯施用量之比从1981年的4∶1下降到2009年的2∶1,引起水化学改变并增加水华发生风险;各县(市、区)污染源结构存在明显差异,河流水质变化和沿程分布与流域社会经济布局有很好的空间相关性;北溪流域畜禽养殖业的过快发展、西溪流域以经济作物为主的农业种植结构和高强度施肥、低效率利用是导致河流水质从20世纪90年代开始富营养化的主要原因;EKC曲线尚未出现明显拐点,若农业污染不能得到有效控制,流域水环境将持续恶化;九龙江水质演变规律是流域社会经济布局、污染源排放强度和方式发生变化的综合作用结果。  相似文献   

7.
The water quality of the River Rhine has improved and might again suit the critically endangered European sturgeon A. sturio L, which was extirpated from the river by 1950. This study describes the tracking of 43 juvenile hatchery-reared A. sturio, in the Dutch part of the Lower Rhine and Delta, originating from an ex situ measure of the River Gironde population. Observing in situ juvenile downstream migration could help to identify essential habitats and potential threats, before actual stocking. Fish were implanted with transponders of the NEDAP Trail® system and released in two batches, in May (n?=?13) and June 2012 (n?=?30). Detections collected (n?=?26) exhibited no upstream movement. Test-fish moved downstream with the flow. Because the historic estuary is disconnected from the North Sea by a sea lock “Haringvlietdam”, the migration of the fish followed the re-directed river discharge into the Port of Rotterdam (161 km). 96 % (n?=?19) of the detections was collected from the harbor in brackish water, where fish presumably acclimatized to higher salinities. 14 % (n?=?6) of the sturgeons were recaptured in coastal waters by beam trawlers, five within 1 month after release. It is concluded that sustainable coastal fisheries is a key-condition for rehabilitation of the European sturgeon. Adapted management of the sea lock will reconnect the estuary to the North Sea and create more favorable conditions for the species in the Lower Rhine and Delta.  相似文献   

8.
With a variety of ecosystem services, river ecosystem plays an important role in the process of human society development. On the other hand, health condition of most aquatic ecosystems is seriously threatened by human activities. Restoring and maintaining a healthy ecosystem has already become a vital goal of river management. As a basis of river management, river health assessment is therefore particularly important. Based on indices of physics, chemistry and aquatic organisms, this research tried to establish a comprehensive evaluation system of aquatic ecological health suitable for the situation of Shaying River Basin. The system included 6 factors including riparian zone, river morphology, nutrients, oxygen balance, periphyton and benthic macroinvertebrates, which were defined into 19 indices reflecting the aquatic ecological health from different aspects. The assessment results indicated that the health condition of overall basin was normal, varying among different parts of the region, with Shahe River, Lihe River and Beiru River in the upper part sub-healthy, and Jialu River in the same part sub-sick. The middle region was generally in normal or sub-sick level; the health condition of the lower part was comparatively better due to a good condition. Within the indices, the nutrients and benthic macroinvertebrates were the major constraining factors to the health condition of Shaying River Basin for their poor health condition. The health conditions showed significant differences among the rivers (P < 0.01), with Jialu River being the worst. The result indicated that the aquatic ecological health of Shaying River Basin is affected by many factors, with urban and industrial sewage being the main ones, And that different protective measures should be employed for rivers of different conditions. The result can provide theoretical basis for the ecological restoration of Shaying River Basin and reasonable exploitation and conservation of the water resource of the whole Huaihe River Basin.  相似文献   

9.
Freshwater bivalves are among the most endangered groups of organisms in North America. Efforts to protect the declining mussel fauna are confounded by ambiguities associated with recognition of distinct evolutionary entities or species. This, in part, is due to the paucity of reliable morphological characters for differentiating taxa. We have employed allozymes and DNA sequence data to search for diagnosably distinct evolutionary entities within two problematic genera of unionid mussels, Amblema and Megalonaias. Within the genus Amblema three species are recognized based on our DNA sequence data for the mitochondrial 16S rRNA and allozyme data (Amblema neislerii, A. plicata, and A. elliotti). Only one taxonomically distinct entity is recognized within the genus Megalonaias—M. nervosa. Megalonaias boykiniana of the Apalachicolan Region is not diagnosable and does not warrant specific taxonomic status. Interestingly, Megalonaias from west of the Mississippi River, including the Mississippi, exhibited an allozyme and mtDNA haplotype frequency shift suggestive of an east-west dichotomy. The results of this study eliminate one subspecies of Amblema and increase the range of A. plicata. This should not affect the conservation status of "currently stable" assigned to A. plicata by Williams et al. (1993). The conservation status of A. elliotti needs to be reexamined because its distribution appears to be limited to the Coosa River System in Alabama and Georgia.  相似文献   

10.
珠江水质和含氮消毒副产物的时空变化   总被引:2,自引:0,他引:2  
梁艳红  何洪威  周达诚 《环境化学》2012,31(9):1308-1314
研究区域是珠江广东省段的3条干流(西江、北江、东江)及交汇处(广州),目标是研究分析2年内29个采样点的常规水质指标的时空变化及溶解性有机氮(dissolved organic nitrogen,DON)对于消毒副产物生成势(specific disinfection byproduct formation potential,SDBPFP)的影响.结果表明,对于常规水质指标浓度而言,在时间上,西江、北江、东江三者基本无变化,但交汇处有稍微的变化,一般在7、10月份浓度偏高;在空间上,各干流及交汇处沿径流方向浓度呈逐渐增大趋势,且交汇处水质指标的浓度普遍高于干流.水体的PO34-浓度、总氮(total nitrogen,TN)浓度最高分别超出《国家地表水环境质量》Ⅴ类水质标准10倍、4倍.溶解性有机碳(dissolved organic carbon,DOC)浓度与UV254呈良好的线性关系,R2=0.901;但DON与卤乙腈(halogenacetonitrile,HANs)浓度的线性关系较差,R2为0.440.卤乙腈生成势(specific halogen acetonitrile formationpotential,SHANFP)与DOC/DON比值基本无线性关系.  相似文献   

11.
J. D. Dodge 《Marine Biology》1977,40(4):327-336
The south-western quarter of the North Sea (between the Wash and the River Tyne) has been investigated for the presence of dinoflagellates. Extensive net surveys were carried out in March, May and June 1971 and a number of other collections were made in the area. North of Flamborough Head, the spring bloom of diatoms was succeeded by a considerable growth of dinoflagellates, of which Dinophysis norvegica was the most abundant organism. Maximum counts of over 28 million dinoflagellates per m3 were recorded. Distribution charts are given for the most common species. A total of 61 species was found during the course of the survey.  相似文献   

12.
A Freshwater Classification Approach for Biodiversity Conservation Planning   总被引:8,自引:0,他引:8  
Abstract:  Freshwater biodiversity is highly endangered and faces increasing threats worldwide. To be complete, regional plans that identify critical areas for conservation must capture representative components of freshwater biodiversity as well as rare and endangered species. We present a spatially hierarchical approach to classify freshwater systems to create a coarse filter to capture representative freshwater biodiversity in regional conservation plans. The classification framework has four levels that we described using abiotic factors within a zoogeographic context and mapped in a geographic information system. Methods to classify and map units are flexible and can be automated where high-quality spatial data exist, or can be manually developed where such data are not available. Products include a spatially comprehensive inventory of mapped and classified units that can be used remotely to characterize regional patterns of aquatic ecosystems. We provide examples of classification procedures in data-rich and data-poor regions from the Columbia River Basin in the Pacific Northwest of North America and the upper Paraguay River in central South America. The approach, which has been applied in North, Central, and South America, provides a relatively rapid and pragmatic way to account for representative freshwater biodiversity at scales appropriate to regional assessments.  相似文献   

13.
This study investigates the partitioning of metals in surface sediments from the Dan River drainage basin, the source of drinking water for the South to North Water Transfer Project, China, to determine their bioavailability and associated levels of risk. Sediment samples were collected from 99 sites along the Dan River, and the concentration of each element fraction was determined using sequential extraction and inductively coupled plasma-mass spectrometry. The residual fraction was the major phase for most metals sampled. Among the non-residual fractions, greater proportions of Zn, Mn and Cd were transported in in the available phase, whereas Ba, Sb, Pb and As were mainly found in the reducible phase. The oxidisable phase was important for the transport of Ni, Co, Cr and Cu in sediments. This analysis of sediments from the Dan River basin indicates a very high risk of pollution from Cd, Co, Mn, Sb and Zn. Combined with the sediments with extremely high concentrations, the Dan, Laoguan and Yinhua rivers, which have been affected by ore-mining activities, pose a very high risk to the surrounding areas and should be the subject of future studies.  相似文献   

14.
贺振  贺俊平 《生态环境》2012,(10):1655-1659
植被是土地覆盖中的最主要部分,是连接土壤、大气和生物等要素的自然“纽带”。植被覆盖动态变化对全球能量循环和物质循环具有重要影响,是全球变化研究的重要内容之一。黄河流域作为我国重要的粮食生产基地,其环境变化直接影响到流域经济的可持续发展。为了快速准确地提取地表植被状况,了解黄河流域生态环境,利用1998—2011年的SPOT-VGT遥感数据,结合地理信息技术,采用均值法和趋势分析法对黄河流域植被NDVI时空分布特征和变化趋势进行了动态监测。结果表明,(1)黄河流域14年NDVI均值的空间分布整体特征是东南部平原、盆地和西部山地植被状况要好于北部地区。其次,黄河流域属于干旱半干旱地区,植被发育主要依赖于水文条件,所以沿黄河干流和支流区域也具有较高的植被NDVI值。(2)黄河流域植被NDVl年均值近14年间整体呈缓慢增长趋势,1998--2000年呈现急剧减少态势,2001--2003年出现了较为快速的增长,2004--2011年又出现了较长时间的连续增长过程。(3)黄河流域植被NDVI基本不变的区域约占研究区总面积的71.13%;植被NDVI轻微改善的区域约占流域总面积的27.30%,且主要分布于流域东南部的盆地、平原和西部的山地、丘陵地区,植被NDVI退化的区域面积约占流域总面积的0.98%。黄河流域自1998年以来,植被NDVI整体在不断提高,生态环境在不断改善。  相似文献   

15.
用大型底栖动物和ODP系统评价珠江的有机污染   总被引:1,自引:2,他引:1  
采用大型底栖动物需氧有机体百分率ODP(oxygen demander percentage)法对广州珠江前航道、西航道和流溪河的下游段进行河流有机污染评价.结果显示:底栖动物需氧类群密度在三河段间分布确有显著性差异,并根据其ODP可以判断流溪河水质相对较好,水质级别为中国地表水环境质量标准(EQSSW)Ⅳ级,西航道和前航道水质级别都为Ⅴ级.通过测试,这一方法能成功地应用在珠江及流溪河,且该法可以较好地匹配于EQSSW五级评价系统,初步认为ODP系统可以成为一个较好的河流水质生物监测方法.图3表4参13  相似文献   

16.
The objective of this study was to investigate the salinisation characteristics of a semi-arid river network in northern China and highlight the influencing factors and risks. The Ziya River Basin, a typical semi-arid river network located in the North China Plain, is studied herein. Overlying water, surface sediment and riparian soil samples were collected in July and December of 2014 in the Ziya River Basin. The results showed that the average concentrations of salt content in the overlying water and surface sediment of 10 rivers in the Ziya River Basin were 1105.64 and 2159.35?mg/L, respectively. High level of salinisation was found in most rivers not only in overlying water, but also in surface sediment. The impact of the salinisation of overlying water on riparian soil diminished with distance away from the shore and had no impact beyond 15 m from the shore. Heavy pollution can contribute greatly to the salinisation of the water column and can cause significant impacts on river sediment and riparian soil. Salinisation in the overlying water affects the sediment and riparian soil, and reveals that the high risk of salinisation in the Ziya River Basin has been underestimated.  相似文献   

17.
Abstract: We present evidence of the first successful natural spawning of Atlantic salmon (   Salmo salar ) documented on the Pacific coast of North America. Twelve juvenile Atlantic salmon composed of two year classes were captured in the Tsitika River, British Columbia. We analyzed restriction-length polymorphisms of PCR-amplified 5S rDNA and mtDNA to confirm that these individuals were Atlantic salmon. Scale analysis strongly suggested they were the products of natural spawning by feral adults. The gut contents, size, and condition of these individuals suggest that Atlantic salmon are successfully maturing in the Tsitika River, British Columbia. This event has raised concerns that the presence and possible establishment of feral Atlantic salmon may further jeopardize the continued persistence of already fragile native Pacific salmonids through competition for resources and occupation of niches that are currently underutilized.  相似文献   

18.
Nutritional indices were used to develop biochemical correlates of feeding and growth rates for juvenile summer flounder, Paralichthys dentatus (Linnaeus), from North Carolina (NC) and Delaware (DE). Six parameters (Fulton's condition K=104xweight/(length3), wet weight/dry weight, [protein], [RNA], [DNA], and RNA:DNA) were related to feeding and growth rates of fish from previously reported 10 to 14-d experiments at temperatures ranging from 2 to 20 °C with varying feeding levels (0 to 100% and libitum). RNA:DNA ratios were the best predictors of growth rates, but inclusion of a temperature term improved the relationship between RNA:DNA ratios and growth rate for Delaware fish. Feeding rates were poorly correlated with all parameters. RNA:DNA ratios of fish in the laboratory changed significantly within 1 d of starvation and refeeding at 16 °C. RNA:DNA of juvenile summer flounder collected from one site in Indian River Bay, DE and two sites in the Newport River Estuary, NC, between January and June 1992 were used to estimate in situ growth rates following settlement. Predicted growth rates in both estuaries were close to maximum (suggesting ad libitum feeding) until early May. Growth rates of juveniles from Delaware were <0% d-1 from December through early March, and were higher (0.6 to 3% d-1) from April through early June. However, growth rates of DE juveniles during May were <50% of maxinum. North Carolina juveniles had growth rates of 2 to 5% d-1 from February through early April. Juveniles from one of the Newport River sites (a marsh habitat) were also severely growth limited (<20% of maximum) after April. Prolonged periods of sub-optimal growth may be important to survival and recruitment of juvenile summer flounder in northern mid-Atlantic estuaries. A model is presented which illustrates the potential impact that small changes in temperature and growth limitation can have on recruitment success in both delaware and North Carolina estuaries.  相似文献   

19.
Populations of the marine wood-boring isopod Limnoria tripunctata Menzies were cultivated and interbred in the laboratory in order to determine whether geographically separated populations would interbreed. Two series of interbreeding studies were conducted. In the first, field populations from 11 Atlantic and Caribbean sites and 3 Pacific sites were interbred with a North Western Atlantic population from Beaufort, North Carolina (USA). Viable crossings, to at least F 1, occurred in all but one case—that of a BeaufortxChatham (Massachusetts, USA) cross. In the second series of experiments, field populations from 9 Atlantic and Caribbean sites were crossed with populations from St. Teresa, Florida, Gulf of Mexico. In this case also, all crosses except one produced viable offspring, not only to the F 1, but to the F 2 generations as well. The St. Teresa x Chatham cross was not successful. Geographic distance was not a factor in the success of crossbreeding between disjunct populations. Chatham populations (mainly) are now believed to represent a valid but previously obscure species, Limnoria tuberculata Sowinski, and not a variant of L. tripunctata Menzies. Enhanced viality or vigor, as determined from rate of wood destruction, population growth rate and survival, was indicated in several crossings, but this was not necessarily correlated with distance between populations. Observations were made on the manner in which the species has achieved a worldwide distribution, and a hypothesis is put forward to explain the evolution of species related to L. tripunctata.Contribution from Zoology Department, Duke University, Durham, North Carolina, and Duke University Marine Laboratory, Beaufort, North Carolina, and the Department of Oceanography, No. 289, Florida State University, Tallahassee, Florida. Support in part from NSF Grant No. GB-6898.  相似文献   

20.
沿黄河下游湖泊湿地植物群落演替及其多样性研究   总被引:2,自引:0,他引:2  
沿黄河下游湖泊湿地是黄河健康生命系统的重要组成部分,其植物群落演替及其多样性研究对湿地及其生物多样性保护有重要意义。通过野外样地调查,分析了沿黄河下游湖泊湿地植物物种组成及其群落的演替模式,并计算了群落植物多样性特征指数,包括物种丰富度指数(S)、多样性Simpson指数(D)、Shannon-wiener指数(H′)、均匀度指数Pielou(E)。结果表明,研究区湖泊湿地共有77种植物,属于28科61属,除榆树Ulmus pumila Linn.为木本植物外,其余76种为草本植物,其中有1种轮藻门植物,1种蕨类植物;从空间来看植物群落演替过程为沉水植物菹草群落→纯水烛群落→水烛群落→水烛+扁秆藨草群落→藨草群落→芦苇群落,青龙湖湿地水环境的变化,使湿地植物群落的类型也随之发生变化;群落多样性指数Shannon-wiener指数均低于1.12,Simpson指数为0.41~1,Pielou均匀度指数为0.8左右;芦苇群落的物种数最多,有32个物种,水烛群落以12种次之,菹草群落、水烛+扁秆藨草群落和扁秆藨草群落中的物种数差别不大。沿黄河下游湿地植物群落多样性水平较低,湿地系统有向陆地系统过渡的趋势。  相似文献   

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