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101.
Occurrence of perfluorinated compounds in water, sediment and mussels from the Cantabrian Sea (North Spain) 总被引:1,自引:0,他引:1
Gómez C Vicente J Echavarri-Erasun B Porte C Lacorte S 《Marine pollution bulletin》2011,62(5):948-955
Perfluorinated compounds (PFCs) have emerged as significant global environmental pollutants with persistent, bioaccumulative and toxic properties. The aim of this study was to determine the occurrence of PFCs in water (wastewater, submarine emissaries and port-waters), sediment and transplanted mussels in estuarine areas of high urban and industrial impact from Northern Spain. Five PFCs of industrial use were studied: perfluorooctanesulfonate, perfluorohexanesulfonate, perfluorobutanesulfonate, perfluorooctanoate acid and perfluorononanoate acid. After selective extraction, samples were analyzed by Ultra Performance Liquid Chromatography coupled to tandem mass spectrometry. ΣPFCs ranged from 0.06 to 10.9 ng/L in water, with higher levels in wastewater treatment plants effluents and port waters than in submarine emissaries. Little accumulation was observed in sediments and mussels with ΣPFCs ranging from 0.01-0.13 ng/g dw and 0.01-0.06 ng/g ww, respectively. Most ubiquitous compounds were PFOS and PFOA. Mass fluxes of PFCs to the Cantabrian Sea are estimated and the impact to the coastal ecosystem is discussed. 相似文献
102.
Bacteria abundance, chlorophyll a, ATP and POC concentrations and respiration rates of microorganisms in the Changjiang Estuary and the plume were determined in July 1986. The high values of bacteria abundance occurred in the river mouth in association with suspended matter. It is assumed that bacteria were the major contributor to ATP and the main consumer of dissolved oxygen, and that the relationship between ATP and POC was present in that area. In the dilution zone (salinity; 25-30), instead of bacteria, phytoplankton was the major contributor to ATP and respiration rates, due to diatom bloom. Close relationships between Chi a and ATP, and ATP and POC were observed. Contribution of microbial carbon to POC was also estimated. 相似文献
103.
研制了一个海-气耦合模式,并用于讨论ENSO现象。在没有异常的外部强迫作用的条件下,该耦合模式再现了观测现象的某些关键特征,其中包括增暖事件多以3—4年的不规则时间间隔重新出现。研究表明,平均海平面温度、风和洋流场确定ENSO距平的特征空间结构。距平的锁相(phase-locking)趋势可以用与平均场年变程有关的耦合强度的变化来解释。敏感性研究发现,振荡的振幅和时间尺度对于影响海-气耦合强度的几个参数是敏感的。较强的耦合意味着较大、较长时间尺度的振荡。模式振荡的关键性因素是赤道海水上部含热量的变化率,赤道地区含热量在增暖事件之前增加,在增暖过程中急剧减少。给出了这种变化率和有关El Nino与非El Nino状态之间转化的理论。还讨论了预报El Nino事件的模式结果的含意。 相似文献
104.
引言世界级的科拉尔金矿田的金矿床,位于印度南部卡纳塔克邦班加罗尔东边80km处。该矿床产于科拉尔绿岩带中。该带是一条长80km、宽3—15km的太古宙上壳岩带,其大部分是由镁铁质火山岩组成。该矿床在古开矿地点上再次被发现后,这个地区自1880年以来是连续开采金矿的。从大约4800万吨矿石中回收金的总产量是790吨,被磨碎矿石的金平均回收品位为16.48克/吨。现在工厂原样品位大约是3.5克/吨,每年生产金大约1.2吨。 相似文献
105.
利用星团谱样本的星族合成方法,研究了邻近巨椭圆星系NGC5018中的星族成分和其内部的恒星形成历史,给出了星系中不同年龄和金属丰度星族的成分占有比.星族合成结果表明,NGC5018中不仅存在大量金属丰度低的年老恒星成分,而且较年轻的星族成分(T=5×108yr)对星系光度贡献也很重要.星系吞并和相互作用过程可能是触发这些较年轻星族形成的物理原因,椭圆星系内部的恒星形成历史可能是2次爆发或者多次爆发过程.这些结果可以很好地解释NGC5018颜色偏蓝、Mg2谱指数强度偏弱等观测特征. 相似文献
106.
电离层水平不均匀结构是引起掩星资料反演的主要误差源.本文模拟不均匀结构对无线电掩星资料反演的影响.首先利用3-D全球射线追踪技术进行了模拟.结果指出:电离层电子密度20%的变化可能引起GPS的时延增加约12m.其次,将90%的掩星时延对应的路径长度,定义为电离层掩星测量的水平分辨率,其值为1200-2000 km.最后,计算了不同纬度电离层当地正午、子夜和日出时的电离层水平不对称指数.它表明:低纬夏季日出时,不对称指数达-78%,反演结果可能有较大误差. 相似文献
107.
Qin YANG Puyu GUO Elena Y.ABIDUEVA Elena V.LAVRENTYEVA Irina M.LISEVICH Ilya A.OSTERMAN Petr V.SERGIEV Shaowei LIU Chunmei XUE Chenghang SUN 《海洋湖沼学报(英文)》2023,(4):1307-1320
To explore pharmaceutical actinobacteria from salty environments in Siberia, 8 soil samples were collected from different depths of Gudzhirganskoe saline lake, the Republic of Buryatia, Russia.Totally, 635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches. The predominant genus was Streptomyces(74.5%), followed by Microbacterium(4.9%), Agromyces(3.5%), Nocardiopsis(3.0%), and Kitasatospora(2.5%). Seven strains showed relati... 相似文献
108.
A field work has been carried out to identify the occurrence of oil and oil products pollution in mangrove sediment from Red Sea of Yemen. The concentration of total petroleum hydrocarbons is from 700ng/g at Kamaran Island station to 400 ng/g at Al-Hodiedah station, and the total organic carbon (TOC) in samples ranges from 0. 07% at Dhubab station to 0. 03% at Kamaran Island station. This pollution is as a result of localized oil pollution and/or heavy ship traffic in the Red Sea and Gulf of Aden. 相似文献
109.
The Voisey’s Bay Ni-Cu-Co sulfide deposit is hosted in a 1.34 Ga mafic intrusion that is part of the Nain Plutonic Suite in Labrador, Canada.The Ni-Cu-Co sulfide mineralization is associated with magmatic breccias that are typically contained in weakly mineralized olivine gabbros, troctolites and ferrogabbros, but also occur as veins in adjacent paragneiss.The mineralization is associated with a dyke-like body which is termed the feeder dyke.This dyke connects the shallow differentiated Eastern Deeps chamber in the east to a deeper intrusion in the west termed the Western Deeps Intrusion.Where the conduit is connected to the Eastern Deeps Intrusion, the Eastern Deeps Deposit is developed at the entry line of the dyke along the steep north wall of the Eastern Deeps Intrusion.The Eastern Deeps Deposit is surrounded by a halo of moderately to weakly mineralized Variable-Textured Troctolite (VTT) that reaches a maximum thickness above the ENE-WSW axis of the Eastern Deeps Deposit. At depth to the west, the conduit is adjacent to the south side of the Western Deeps Intrusion, where the dyke and intrusion contain disseminated magmatic sulfide mineralization.The Reid Brook Zone plunges to the east within the dyke, and both the dyke and adjacent paragneiss are mineralized.The Ovoid Deposit comprises a bowl-shaped body of massive sulfide where the dyke widens near to the present-day surface.It is not clear whether this deposit was developed as a widened-zone within the conduit or at the entry point into a chamber that is now lost to erosion. The massive sulfides and breccia sulfides of the Eastern Deeps are petrologically and chemically different when compared to the disseminated sulfides in the VTT; there is a marked break in Ni tenor (Ni content in 100% sulfide, abbreviated to [Ni]100) and Ni/Co of sulfide between the two.The boundary of the sulfide types is often marked by strong sub-horizontal alignment of heavily digested and metamorphosed paragneiss fragments, development of barren olivine gabbro, and by a change from typically massive sulfides and breccias sulfides into more typical variable-textured troctolites with heavy to weak disseminated sulfide.Sulfides hosted in the feeder dyke tend to have low metal tenors ([Ni]100=2.5%-3.5%); sulfides in Eastern Deeps massive and breccia ores have intermediate Ni tenors ([Ni]100=3.5%-4%) and disseminated sulfides in overlying rocks have high Ni tenors ([Ni] 100=4%-8%) . Conduit-hosted mineralization and mineral zones in the paragneiss adjacent to the Reid Brook Deposit tend to have lower Ni tenor than the Ovoid and Eastern Deeps Deposits.The tenor of mineral hosted in the country rock gneisses tends to be the same as that developed in the conduit ; the injection of the sulfide into the country rocks likely occurred before formation of monosulfide solid solution.The Ovoid Deposit is characterized by coarse-grained loop-textured ores consisting of 10cm-2msized pyrrhotite crystals separated by chalcopyrite and pentlandite.A small lens of massive cubanite surrounded by more magnetite-rich sulfide assemblages represents what appears to be the product of in-situ sulfide fractionation. Detailed exploration in the area between the Reid Brook Zone and the Eastern Deeps has shown that these intrusions and ore deposits are connected by a branched dyke and chamber system in a major westeast fault zone.The Eastern Deeps chamber may be controlled by graben-like fault structures , and the marginal structures appear to have controlled dykes which connect the chambers at different levels in the crust.The geological relationships in the intrusion are consistent with emplacement of the silicate and sulfide laden magma from a deeper sub-chamber (possibly a deep eastward extension of the Western Deeps Intrusion where S-saturation was initially achieved) .The silicate and sulfide magmas were likely emplaced through this conduit into the Eastern Deeps intrusion as a number of different fragment laden pulses of sulfide-silicate melt that evolved with different R factors and in response to some variation in the degree of evolution of the parental magma.S isotope and S/Se data coupled with geological evidence point to a crustal source for the sulfur , and the site of equilibration of mafic magma and crustal S is placed at depth in a sulfidic Tasiuyak Gneiss. The structural control on emplacement of small intrusions with transported sulfide is a feature found in different nickel sulfide deposits around the world.Champagne glass-shaped openings in sub-vertical chonoliths are a common morphology for this deposit type (e.g.the Jinchuan , Huangshan , Huangshandong , Jingbulake , Limahe , Hong Qi Ling deposits in China , the Eagle deposits in the United States , and the Double Eagle deposit in Canada) .Some of the structures of the Midcontinent Rift of North America also host Ni-Cu-(PGE) deposits of this type (e.g.the Current Lake Complex in the Quetico Fault Zone in Ontario , Canada and the Tamarac mineralisation in the Great Lakes Structural Zone of the United States) .Other major nickel deposits associated with flat structures adjacent to major mantle-penetrating structures include the Noril’sk , Noril’sk II , Kharaelakh , NW Talnakh , and NE Talnakh Intrusions of the Noril’sk Region of Russia , the Kalatongke deposit in NW China , and Babel-Nebo in Western Australia.These deposits are all formed in mantle-penetrating structural conduits that link into the roots of large igneous provinces near the edges of old cratons. 相似文献
110.
Leitzinger M Odert P Kulikov YN Lammer H Wuchterl G Penz T Guarcello MG Micela G Khodachenko ML Weingrill J Hanslmeier A Biernat HK Schneider J 《Planetary and Space Science》2011,59(13):1472-1481
We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68REarth) and Kepler-10b (∼1.416REarth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects. 相似文献