14 resultados para Eco, Umberto 1932 A misteriosa chama da rainha Loana

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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The white cloud mountain minnow Tanichthys albonubes Lin is an endemic species to southern China and the genus has two species, Tanichthys albonubes Lin and Tanichthys micagemmae Freyhof et Herder. The distribution range of T. albonubes Lin and T. micagemmae is very narrow and only found in the mountain brooks of Baiyunshan Mountain (White Cloud Mountain), Huaxian Country and the vicinity of Guangzhou in Guangdong Province and Halong, Quang Ninh Province, Vietnam respectively. The wild populations of this fish had already been on the verge of extinction when Shu-Yan Lin first discovered it in 1932 at the Baiyunshan Mountain. It was believed to be extinct in the wild because there were no reports of this fish in the wild since 1980. In September 2003, a small and isolated population of the fish was discovered in a mountain puddle in the north vicinity of Guangzhou. Additional studies are needed to determine the survival and propagation of the released fish. The protection of their natural habitat should be implemented.

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Eight kinds of plants were tested in channel-dyke and field irrigation systems. The removal rates of TP, phosphate, TN, ammonia, CODcr and BOD, in the channel-dyke system with napiergrass (Pennisetum purpurem Schumach, x Pennisetum alopecuroides (L.) Spreng American) were 83.2, 82.3, 76.3, 96.2, 73.5 and 85.8%, respectively. The field irrigation systems with rice I-yuanyou No.1(88-132) (Oryza sativa L.) and rice II- suakoko8 (Oryza glaberrima) had high efficiency for N removal; the removal rate were 84.7 and 84.3%, respectively. The mass balance data revealed that napiergrass, rice I and II were the most important nutrient sinks, assimilating more than 50% of TP and TN. Plant uptake of N and P as percentage of total removal from wastewater correlated with biomass yield of and planting mode. (C) 2000 Elsevier Science B.V. All rights reserved.

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The impact of the Huanghe (Yellow) River outflows on its estuary was investigated with river gauging and shipboard hydrographic observations. The river flux has been decreasing dramatically; the discharges of water and sediment in the 1990s dropped to 27.4% and 31.9% of those in the 1950s, respectively, resulting in frequent and lengthy events of downstream channel dry-up since the 1970s. There were accumulatively 897 zero-flow days during the 1990s in the river course below the Lijin Hydrological Station, 100 km upstream from the river mouth, which is 82.4% of that in 1972. As freshwater input decreases, river-borne nutrients to the estuarine increased significantly. Concentration of dissolved inorganic nitrogen (DIN) in the 1990s was four times of that in 1950s. Changes in amount and content of the riverine inputs have greatly affected the estuarine ecosystem. Over the past several decades, sea surface temperature and salinity in the estuary and its adjacent waters increased and their distribution pattern altered in response to the reduction of freshwater inflow. The distribution of and seasonal succession in nutrient concentrations in the surface layer have also changed with a shift of river outlet and the decrease in riverine nutrient loads. Furthermore, deterioration of estuarine ecosystem by less river input has decreased primary productivity in the deltaic region waters, and in turn depressed the fishery. (C) 2008 Published by Elsevier Ltd.

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海洋沉积环境中多氯联苯(PCBs)和多环芳烃(PAHs)的研究对于揭示其污染历史、来源途径、迁移转化以及评价其对环境的潜在生态风险都有重要的科学意义和应用价值,本研究选择我国典型近海中比较开阔的南黄海和受人为影响严重的渤海湾沉积物中的PAHs和PCBs作为主要研究对象,结合对生态环境对应关系的剖析,系统研究了沉积物中PAHs和PCBs的地球化学分布特征、影响控制因素、演变趋势、潜在生态风险等,获得了以下系统的认识: 1.南黄海表层沉积物中多环芳烃和多氯联苯的分布与沉积类型及模式相一致,受控于“沉积类型-动力过程-来源途径”。PCBs含量(范围:518~5848 pg/g,平均值:1715 pg/g)低于受人为影响严重的长江口、珠江口和渤海,分布具有中部海区>东部海区>西部海区的特征;PCBs随着沉积物粒径的减小和粘土含量的增加而增加,且与总有机碳(r=0.61,p<0.01)含量呈显著线性正相关,表明PCBs在沉积物中的分布受控于被水动力过程原动力控制的沉积类型与沉积模式。 2. 1914~2004年间,南黄海沉积物中PAHs和PCBs的变化比较显著,在时间序列上经历了三个明显的不同阶段。近90年来,PAHs和PCBs在柱状样中垂直分布随深度的增加而降低,即近年南黄海沉积物中PAHs和PCBs的残留水平比上世纪初明显增加。其中1914~1932年间,PAHs和PCBs保持在较低的水平;1932~1962年间,PAHs和PCBs的含量发生急剧的变化,在1932~1944和1956~1962年两个时间段,PAHs和PCBs的含量达到峰值;自1962年至今,PAHs和PCBs呈稍有增加趋势。PAHs的组成和特征组分比值分析显示,1920~1944年间PAHs主要来自石油产品泄漏,1944~1980年间,主要来自草/木材/煤燃烧,1980年至2004年则显示出石油和燃烧产物混合来源的特征。 3.渤海湾沉积物中的PAHs、PCBs、DDTs和HCHs的分布模式不同,反映了这四种污染物的地球化学行为存在着明显的差异性。PAHs、PCBs、DDTs和HCHs的含量范围为149.0~393.4 ng/g,360.8~1728.3 pg/g,462.2~2007.3 pg/g和4.31~33.8 ng/g。马颊河口、海河口和黄河口附近的海区的沉积物中PAHs和PCBs的含量显著高于渤海湾内其它站位,DDTs在湾外沉积物中的含量大于湾内,在海河口附近站位测得HCHs含量的最高值,在其它站位其浓度变化不大。PAHs特征成分的比值显示渤海湾沉积物中PAHs主要来源于草/木材/煤燃烧的产物经过大气的输运过程进入水体;DDTs和HCHs的组成显示,在DDTs和HCHs被禁用后仍有新的输入源。 4.南黄海沉积物POPs总体水平不高,其环境污染危害和潜在生态风险不大,从沉积物POPs的角度来说南黄海的环境质量较好。潜在生态危害指数评价表明,渤海湾沉积物中芴可能会产生潜在的生态风险,DDTs和HCHs的含量低于一类沉积物质量标准值,总体而言,其沉积物质量良好,潜在生态风险较低。 论文的创新性点在于:1)首次研究了近百年南黄海沉积物中多环芳烃和多氯联苯的演变趋势,判断了其来源并对近百年二者的潜在生态风险进行评价。2)系统剖析了南黄海及渤海湾的生态环境与PAHs和PCBs的耦合关系,对阐明POPs的毒理效应有重要的科学意义。3)系统解析了渤海湾沉积物中PAHs,DDTs和HCHs的污染现状,来源和迁移途径,可为科学开发和利用渤海海域提供重要的理论依据。

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In this paper, the spatial distribution and source of the PCBs in surface sediments of the Southern Yellow Sea (SYS) and influencing factors, such as the sediment characteristics (components, relative proportions and total organic carbon contents), and hydrodynamic conditions were analyzed. PCB concentrations in the surface sediments ranged from 518-5848 pg/g, with average values of 1715 pg/g decreasing sharply compared to last year. In the study area, the PCB pollution level in the middle area was the highest, followed by that of the east coast and the west coast, respectively. Although the PCB level in the coastal areas was lower than that in the middle areas, it was proven in our study that the Yellow Sea obtained PCBs by virtue of river inputs. There was a positive and pertinent correlation between the clay proportion and PCB concentrations, and the increase of the PCB concentrations was directly proportional to the increase of TOC contents, with r = 0.61, but it was contrary to the sediment grain size. Consequently, the factors controlling PCB distribution had direct or indirect relationships with sediment grain size; moreover, the hydrodynamic conditions determined the sediment components and grain size. In conclusion, hydrodynamic conditions of the Yellow Sea were the most important influencing factors effecting the distribution of PCBs in the surface sediments of the SYS. (C) 2007 Elsevier Ltd. All rights reserved.

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Two new urostylid ciliates, Metaurostylopsis songi n. sp. and Metaurostylopsis salina n. sp. and Metaurostylopsis marina (Kahl 1932) are investigated using live observation and protargol impregnation. These species were isolated in Korea from intertidal sediments, saline ponds, and coastal waters. Metaurostylopsis songi is in vivo about 120 pm x 25 mu m, has a slenderly ellipsoidal body, colorless cortical granules in rows on ventral and dorsal body sides, about 54 macronuclear nodules, 28-47 adoral membranelles, five frontal, two or three frontoterminal and six or seven transverse cirri, and 9-12 midventral cirral pairs followed posteriorly by 1-3 single cirri. In vivo M. salina is about 60 pin x 25 mu m, has a pyriform body, colorless cortical granules irregularly arranged, about 45 macronuclear nodules, 18-23 adoral membranelles, three frontal, three to five frontoterminal and two to five transverse cirri, and four or five midventral cirral pairs followed posteriorly by five to seven single cirri. Both species have three marginal cirral rows on each body side and 3 long dorsal kineties. The Korean specimens of M. marina match the Chinese population in all main features. Metaurostylopsis songi differs from M. marina by the more slender body, the number of frontal cirri (invariably five vs. four), and the arrangement of cortical granules (in rows on dorsal and ventral cortex vs. only along dorsal kinetics and anterior body margin). Metaurostylopsis salina differs from its congeners by the distinctly smaller size, the pyriform body shape, the scattered cortical granules (vs. in rows), and number of frontal cirri. It differs from M. marina also by the number of midventral cirral pairs (four or five vs. seven to 11).