45 resultados para Rivers.
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During 28-29, September 2005, water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake and Nantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration. To evaluate the feasibility and validity of drawing water as a means of ecosystem restoration, zooplankton populations were studied 3 times (before, immediately after finishing and a month after drawing water) at seven locations from 27 Sept. 2005 to 2 Nov. 2005. Water quality in the lakes was mostly improved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawing water. Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lake because of landform geometry change. Before drawing water, most species in Sanjiao Lake e.g., Brachionus sp. and Keratella sp. were tolerant of contamination. After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged. We conclude that drawing water could be important for improving water quality and favour ecosystem restoration. Dilution of nutrient concentrations may be an important role in the effect.
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Polyurethane foam unit (PFU) systems were collected from 11 lakes and three rivers in the Yunnan Plateau, China and, the PFU extrusion liquids, were analyzed for organochlorine pesticides (OCPs) by gas chromatography with electron capture detection (GCECD). The concentrations of pp'-DDE, HCB and HCHs were undetectable to 1.86 mu g l(-1) (mean 0.27 mu g l(-1)), undetectable to 0.72 mu g l(-1) (mean 0.11 mu g l(-1)), and 0.24-21.95 mu g l(-1) (mean 7.39 mu g l(-1)) respectively in lakes; and those in rivers were undetectable to 0.23 mu g l(-1) (mean 0.08 mu g l(-1)), 0.68-2.93 mu g l(-1) (mean 1.70 mu g l(-1)), and 2.71-37.56 mu g l(-1) (mean 17.01 mu g l(-1)) respectively. Notably, some residue levels of OCPs exceeded the US National Recommended Water Quality Criteria, implying Yunnan has levels of OCPs potentially harmful to human health. Further, the contamination by OCPs showed an obvious spatial distribution pattern. Amongst the lakes, Dianchi, Xingyun, Lugu and Yangzonghai had the highest OCP levels dominated by beta-HCH, whereas among rivers, Nujiang and Lancang Rivers had the highest contents of OCPs dominated by alpha-HCH. This demonstrates that HCHs are the predominant contaminants and some point sources of HCHs may still exist in Yunnan. The pollution levels in Yunnan were compared with other studies, suggesting the PFU method is suitable for long-term on-line monitoring of trace OCPs in aquatic ecosystems. Therefore, continuous studies monitoring OCPs in lakes and rivers are needed to further understand the future trend of contamination. (c) 2006 Elsevier Ltd. All rights reserved.
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We obtained four phases of land cover spatial data sets by interpreting MSS images of middle and late 1970s and three phases of TM images of late 1980s, 2004 and 2008 based on field investigation in Three Rivers' Source Region. We analyzed the temporal and spatial characteristics of land cover and macro ecological changes in Three Rivers' Source Region in Qinghai-Tibet plateau since middle and late 1970s. Indicated by land cover condition index change rate and land cover change index, land cover and macroscopical ecological condition degenerated (7090 period Zc -0.63, LCCI -0.58)-obviously degenerated (9004 period, Zc -0.94, LCCI -1.76)-slightly meliorated (0408 period, Zc 0.06, LCCI 0.33). This course was jointly driven by climate change, grassland stocking pressure and implement of ecological construction project.
Resumo:
Rare earth elements (REEs) of 91 fine-grained bottom sediment samples from five major rivers in Korea (the Han, Keum, and Yeongsan) and China (the Changjiang and Huanghe) were studied to investigate their potential as source indicator for Yellow Sea shelf sediments, this being the first synthetic report on REE trends for bottom sediments of these rivers. The results show distinct differences in REE contents and their upper continental crust (UCC)-normalized patterns: compared to heavy rare earth elements (HREEs), light rare earth elements (LREEs) are highly enriched in Korean river sediments, in contrast to Chinese river sediments that have a characteristic positive Eu anomaly. This phenomenon is observed also in primary source rocks within the river catchments. This suggests that source rock composition is the primary control on the REE signatures of these river sediments, due largely to variations in the levels of chlorite and monazite, which are more abundant in Korean bottom river sediments. Systematic variations in I LREE pound/I HREE pound ratios, and in (La/Yb)-(Gd/Yb)(UCC) but also (La/Lu)-(La/Y)(UCC) and (La/Y)-(Gd/Lu)(UCC) relations have the greatest discriminatory power. These findings are consistent with, but considerably expand on the limited datasets available to date for suspended sediments. Evidently, the REE fingerprints of these river sediments can serve as a useful diagnostic tool for tracing the provenance of sediments in the Yellow Sea, and for reconstructing their dispersal patterns and the circulation system of the modern shelf, as well as the paleoenvironmental record of this and adjoining marginal seas.
Resumo:
本研究建立了沉积物中氯化石蜡(CPs)的分析方法,对莱州湾和该区域主要河流的表层沉积物中多氯萘(PCNs),多溴联苯醚(PBDEs)和CPs进行了分析,获得了他们在研究区域的含量水平、空间分布和单体分布模式,并初步探讨了它们在环境中的来源和迁移规律,估算了这三类污染物在莱州湾表层沉积物中的储量,初步评估了莱州湾沿岸的工业排放与人类活动对海洋生态环境的影响。 莱州湾海洋和河流沉积物PCNs的含量分别为65-470 pg/g dw,52-5100 pg/g dw,平均值分别为260 pg/g dw,1100 pg/g dw。莱州湾沉积物中PCNs的含量较低,与发达国家的背景值相当,主要河流沉积物与其他地区的近海、海湾、湖泊沉积物的含量相当。该区域的PCNs主要以5-Cl和6-Cl为主,为工业来源,主要受化工行业的影响。石化工厂热过程产生的低氯组分可能也是该区域PCNs的一个重要来源。莱州湾的PCNs主要来自水体颗粒的输入,而大气沉降来源的贡献不明显。 河流沉积物ΣPBDEs(不包括BDE-209)的含量分别为0.01- 53 ng/g dw,BDE-209的含量为0.74- 280 ng/g dw,平均值分别为4.4 ng/g dw,51 ng/g dw。在组成上,BDE-209占绝对优势,比低溴代BDEs高1-2个数量级,这是由于我国市场上十溴联苯醚是最主要的溴代阻燃剂。ΣPBDEs与亚洲一些地区含量相当,比北美和欧洲一些地区要低;BDE-209含量含量高出北美和欧洲一些地区,处于较高的水平。河流沉积物中BDE-47与-99,BDE-183与-153、-154具有很好的相关性,而且这几种单体质量分数相当,说明莱州湾区域存在五溴和八溴两种工业BDE阻燃剂来源。海洋沉积物中ΣPBDEs的含量为nd- 0.66 ng/g dw,平均值为0.32 ng/g dw,处于较低水平,BDE-209的含量为0.66- 12 ng/g dw,平均值为5.1 ng/g dw,与欧美一些地区相当,主要来自水体颗粒的输入。 本研究用电子捕获低分辨质谱(ECNI-LRMS)建立了沉积物中CPs的分析方法。该方法基于ECNI质谱对SCCP的响应与其氯含量在一定范围内呈线性关系的特性,建立SCCP的总响应因子与氯含量的工作曲线,从而建立定量方法。重点改进了传统方法中由于SCCP标准品和样品中氯含量不同所造成的响应因子的差别,不再要求标准品的含氯量与样品一致,从而提高了SCCP的分析效率与方法准确性。实验发现,当SCCP的实际氯含量在51%-63%之间时,二者线性关系良好(r2>0.96)。用不同氯含量的标准参考品测试,误差为8%-43%。仪器检测限和方法检测限分别为25-400 μg/L,20 ng/g。类似地,建立了中链氯化石蜡(MCCP)的分析方法,工作曲线的实际氯含量范围为44-57%,仪器检测限40-600 μg/L,方法检测限为6 ng/g。通过对比样品与标准品的峰形特征,严格控制保留时间来辨别SCCP与MCCP,实验证明由于二者叠加导致的误差:SCCP为8%,MCCP为14%,总体来说,用该方法得到的CPs数据是可靠的。本文所使用的净化方法能实现CPs与大部分有机氯化合物的分离。 用该方法对莱州湾的沉积物的CPs进行定量,除了两个河流样品MCCP的计算含氯量低于工作曲线以外,其他样品的SCCP和MCCP的计算氯含量都在工作曲线的范围之内。河流沉积物中SCCP和MCCP的含量分别为1-1200 ng/g dw,1-3300 ng/g dw,MCCP/SCCP均值为1.2;含量分布变化较大,一些河段受到工业排放的影响,CPs浓度高出均值1-2个数量级,MCCP/SCCP值也显著高出平均值。莱州湾区域大部分河流的CPs含量与欧洲、北美和日本一些地区相当,而一些受到点源污染的河段则处于较高的水平。河流中SCCP的质量分布在不同的站位不一样,在受到点源影响的样品中,C13的质量分数明显增大,占优势地位,可能是由MCCP携带的SCCP组分所致。MCCP的质量分布在河流和海洋中没有区别,都是C14占绝对优势。从氯取代的组分来讲,所有样品都是以6-8氯取代为主。海洋沉积物中SCCP和MCCP的含量分别为3-18 ng/g dw,1-13 ng/g dw, MCCP/SCCP均值为0.68,显著低于河流沉积物;SCCP的质量分布较为一致,都是以C10和C11为主。研究发现莱州湾区域SCCP与MCCP来源相似,但迁移规律有的不同。海洋环境中的MCCP可能主要来自水体颗粒的输入,而溶解态输入也是海洋环境中SCCP的重要来源。 对这三类污染物在莱州湾表层沉积物中的储量估算得到PCNs、ΣPBDEs、BDE-209、SCCP和MCCP在莱州湾表层0-10 cm沉积物中的储量分别为0.20t,0.25t,3.95t,6.52t,4.30t。拥有10%的渤海海域面积的莱州湾ΣPBDEs和BDE-209的储量分别占渤海海区总量的18-23%,18-32%,远远超过渤海的平均值。
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Fishes of the genus Crossocheilus in China is reviewed on the basis of specimens in Kunming Institute of Zoology, Chinese Academy of Sciences. Crossocheilus multirastellus is described from the upper Irrawaddy and upper Salween rivers. It is distinguished from all of its congeners by having two black longitudinal stripes on sides of body, 36-38 lateral line scales, 18-25 gill rakers, anus at midpoint between ventral fin and anal fin insertions, ventral fin extending over anus, a large deep blue rhomboid spot above the pectoral fin, and a straight mouth gape almost equal to head width. There are presently two species of Crossocheilus fishes in China. Crossocheilus bamaensis Fang and Crossocheilus liuchengensis Liang, Liu & Wu are recognized here as members of the genus Sinocrossocheilus.
Resumo:
All Sinocrossocheilus species, except S. microstomatus, are reviewed. Four new species, S. labiata, S. papillolabra, S. nigrovittata, and S. longibulla, are described. The genus Sinocrossocheilus differs from other genera of Cyprinidae by the last simple dorsal fin ray being unserrated and unossified, the last unbranched anal fin ray being unserrated and unossified, the 5-branched anal fin rays, the mouth gap being inferior, the rostral cap covering the lower jaw and connecting directly with the lower lip, a row of fleshy lobes on the lower jaw, and a cloudy black spot above the pectoral fin. Sinocrossocheilus labiata is small and has 22 predorsal scales; S. longibulla has a very large air bladder; S. papillolabra possesses a well-developed ventral fin and a wide band covered by fleshy papillae on the lower lip; and S. nigrovittata possesses black longitudinal stripes along the lateral line. Crossocheilus bamaensis and Crossocheilus liuchengensis are transferred to the genus Sinocrossocheilus. Sinocrossocheilus species are endemic to the central and eastern Yunnan-Guizhou Plateau of China, where river systems are anfractuous, including seasonal rivers, cave rivers, underground rivers, and streamlets between mountains. These separated rivers probably provide conditions for the allopatric speciation of the Sinocrossocheilus.
Resumo:
Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.
Resumo:
The population genetic structure of fish parasitic nematode, Camallanus cotti, collected from the Yangtze River, Pearl River and Minjiang River in China was investigated. From these parasites, the similar to 730 bp of the first internal transcribed spacer of ribosomal DNA (ITS1 rDNA) and the 428 bp of mitochondrial cytochrome c oxidase subunit I (COI) gene were sequenced. For the ITS1 rDNA data set, highly significant Fst values and low rates of migration were detected between the Pearl River group and both the Yangtze River (Fst = 0.70, P < 0.00001; Nm = 0.21) and Minjiang River (Fst = 0.73, P < 0.00001; Nm = 0.18) groups, while low Fst value (Fst = 0.018, P > 0.05) and high rate of migration (Nm = 28.42) were found between the Minjiang and the Yangtze rivers. When different host/locality populations (subpopulations) within each river were considered, subpopulations between the Yangtze River and Minjiang River had low Fst values (<= 0.12) and high Nm values (>3.72), while Pearl River subpopulations were significantly different from the Yangtze River and Minjiang River subpopulations (Fst >= 0.59; Nm < 1). The COI gene data set revealed a similar genetic structure. Both phylogenetic analyses and a statistical parsimony network grouped the Pearl River haplotypes into one phylogroup, while the Yangtze River and Minjiang River haplotypes formed a second group. These results suggested that the Yangtze River and Minjiang River subpopulations constituted a single reproductive pool that was distinct from the Pearl River subpopulations. In addition, the present study did not find host-related genetic differentiation occurring in the same drainage. (C) 2009 Published by Elsevier B.V.
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The concentrations of major anions and cations, nitrogen and phosphorus, dissolved and particulate trace elements, and organic pollutants were determined for the middle and lower reaches of the Yangtze River (Changjiang) from below the Three Gorges Dam (TGD) to the mouth at Shanghai in November 2006. The concentration of dissolved inorganic phosphate (DIP) was constant at a low level of 6-8 mu gP/L, but the concentration of nitrate (NO3-) approximately doubled downstream and was closely correlated with K+. This translated to a daily load of well over 1000 It of dissolved inorganic nitrogen (DIN) at Datong. The average concentrations of dissolved Pb (0.078 +/- 0.023 mu g/L), Cd (0.024 +/- 0.009 mu g/L), Cr(0.57 +/- 0.09 mu g/L), Cu (1.9 +/- 0.7 mu g/L), and Ni (0.50 +/- 0.49 mu g/L) were comparable with those in other major world rivers, while As (3.3 +/- 1.3 mu g/L) and Zn (1.5 +/- 0.6 mu g/L) were higher by factors of 5.5 and 2.5, respectively. The trace element contents of suspended particles of As (31 +/- 28 mu g/g), Pb (83 +/- 34 mu g/g), and Ni (52 +/- 16 mu g/g) were close to maximum concentrations recommended for rivers by the European Community (EC). The average concentrations of Cd (2.6 +/- 1.6 mu g/g), Cr (185 +/- 102 mu g/g), Cu (115 +/- 106 mu g/g), and Zn (500 +/- 300 mu g/g) exceeded the EC standards by a factor of two, and Hg (4.4 +/- 4.7 mu g/g) by a factor of 4 to 5. Locally occurring peak concentrations exceed these values up to fourfold, among them the notorious elements As, Hg, and Tl. All dissolved and particulate trace element concentrations were higher than estimates made twenty years ago [Zhang, J., Geochemistry of trace metals from Chinese river/estuary systems: an overview. Estuar Coast Shelf Sci 1995; 41: 631-658.]. The enormous loads of anthropogenic pollutants disposed to the river were diluted by the large water discharge of the Yangtze even during the lowest flow resulting in the relatively low concentration levels of trace elements and organic pollutants observed. We estimated loads of e.g. As, Pb and Ni to the East China Sea to be about 4600 kg As d(-1), 3000 kg Pb d(-1), and 2000 kg Ni d(-1). About 6000 t d(-1) of dissolved organic carbon (DOC) was delivered into the sea at the time of our cruise. We tested for 236 organic pollutants, and only the most infamous were found to be barely above detection limits. We estimated that the load of chlorinated compounds, aromatic hydrocarbons, phenols, and PAHs were between 500 and 3500 kg d(-1). We also detected eight herbicides entering the estuary with loads of 5-350 kg d(-1). The pollutant load, even when at low concentrations, are considerable and pose an increasing threat to the health of the East China Sea ecosystem. (c) 2008 Elsevier B.V. All rights reserved.
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We report on taxa from the diatom genera Gomphonema and Cymbella (Cymbellales, Bacillariophyta) found in the Jolmolungma Mountain region of China. This region is unique for its diversity of habitats, which include rivers, springs, moist soil, snowfields, swamps and lakes. We re-examine diatom taxa found in samples first documented in 1973 (Jao et A, 1973) and incorporate recent taxonomic revisions from the literature. In the genera Gomphonema and Cymbella we report 113 species and varieties. Of these 113 taxa, 59 are new record for China; 1 new combination, Encyonema jolmolungmensis, is made. Morphometric data and habitat features are reported for each taxon. Their distribution is strongly correlated to their microhabitats.