A lower trophic ecosystem model including iron effects in the Okhotsk Sea     

Takeshi Okunishi  Michio J. Kishi  Yukiko Ono  Toshihiko Yamashita 《Continental Shelf Research》2007

We applied a three-dimensional ecosystem-physical coupled model including iron the effect to the Okhotsk Sea. In order to clarify the sources of iron, four dissolved iron compartments, based on the sources of supply, were added to Kawamiya et al.'s [1995, An ecological-physical coupled model applied to Station Papa. Journal of Oceanography, 51, 635-664] model (KKYS) to create our ecosystem model (KKYS-Fe). We hypothesized that four processes supply iron to sea water: atmospheric loadings from Northeastern Asia, input from the Amur River, dissolution from sediments and regeneration by zooplankton and bacteria. We simulated one year, from 1 January 2001 to 31 December 2001, using both KKYS-Fe and KKYS. KKYS could not reproduce the surface nitrate distribution after the spring bloom, whereas KKYS-Fe agreed well with observations in the northwestern Pacific because it includes iron limitation of phytoplankton growth. During the spring bloom, the main source of iron at the sea surface is from the atmosphere. The contribution of riverine iron to the total iron utilized for primary production is small in the Okhotsk Sea. Atmospheric deposition, the iron flux from sediment and regeneration of iron in the water column play important roles in maintaining high primary production in the Okhotsk Sea.  相似文献   

Heavy Metal Removal from Soils Using Magnetic Separation: 1. Laboratory Experiments     

Nan Feng  Gabriel Bitton  Philip Yeager  Jean-Claude Bonzongo  Ali Boularbah 《洁净——土壤、空气、水》2007,35(4):362-369

The removal of Cu, Zn, and Cd from a sandy soil was investigated using iron filings as an adsorbent, and subsequently recovering the iron filings by magnetic separation. The best treatment was obtained by using 5% iron filings and 3 h contact time between iron filings and the soil. The metal removal efficiency from soil extracts was evaluated, using MetPLATE^TM, a toxicity test that is specific for heavy metals, and the 48 h Ceriodaphnia dubia acute toxicity test. The toxicity removal was generally higher than 95% for Cu after a single treatment. With regard to Zn-spiked soil, the toxicity removal was 96.1%, 70.0%, and 49.6% after single treatment at the input concentration of 200 mg/kg, 400 mg/kg, and 800 mg Zn²⁺/kg soil, respectively. After two or three successive treatments, more than 90% of the toxicity was removed for 400 mg/kg and 800 mg/kg Zn-spiked soils. In the case of Cd-spiked soil, a single treatment removed 51.1% of the toxicity from 200 mg/kg Cd-spiked soil extracts while more than 90% of the toxicity was removed after two or three treatments. Chemical analysis and a mass balance study were also carried out to investigate the Cu distribution in the soil fractions. The results indicate that, before treatment, a large portion of Cu was immobilized in the soil matrix. Following magnetic separation, Cu was removed from both the soil matrix and extracts and was indeed adsorbed and concentrated on the iron filings. The retrieval of Cu by iron filings was further examined by energy dispersive X-ray spectroscopy (EDS).  相似文献   

Quantitative Separation of As(III) and As(V) from a Synthetic Water Solution Using Ion Exchange Columns in the Presence of Fe and Mn Ions     

Prasenjit Mondal  Chandrajit Balomajumder  Bikash Mohanty 《洁净——土壤、空气、水》2007,35(3):255-260

The quantitative separation of As(III) from a water sample containing As(III) and As(V) in the presence of Fe and Mn in an ion exchange resin (AG1 X8) column for the speciation of arsenic is described. Individual and combined effects of Fe and Mn on the separation of As(III) from the solution have been studied separately. In absence of Fe and Mn, the ratio between the As(T) concentration in the eluent and the As(III) concentration in the original sample has been found to be 0.9717 under optimum process conditions. The presence of Fe(II) in the water sample increased the As(T) concentration in the eluent whereas Mn(II) decreased it. Combined effects of Fe and Mn on the percentage increment in the eluent arsenic concentration have been expressed by additive and interactive models. The interactive model has been developed by a statistical software with a 95 % confidence level. In most of the cases the error on the determination of the As(III) concentration had a minimum when using the interactive model.  相似文献   

铁假说和HNLC海区的现场铁加富实验   总被引：3，自引：0，他引：3  

张武昌  孙松 《地球科学进展》2002,17(4):613-616

20世纪90年代,JohnMart in提出的"铁假说（ironhypothesis）"和以此为中心的海洋铁加富实验（ironenrichments）成为海洋科学领域最受瞩目的事件。"铁假说"的主要内容是：铁限制了HNLC海区中浮游生物的生产力,并进而影响了CO₂由海洋上层向深层的输出;如果在HNLC海区加入铁,就可以促进浮游植物的生长,消耗掉过剩的 N、P营养盐,加速C从海洋表层向深层输出,最终降低大气中CO₂含量,缓解温室效应。在赤道太平洋和南大洋进行的现场加富实验证明,加入铁以后,这些海区的浮游植物生物量增加,N、P等营养盐被消耗。但是,这些实验并没有降低大气中CO₂含量。铁假说只被证实了一半。  相似文献   

电感耦合等离子体质谱联用技术在元素形态分析中的应用进展   总被引：1，自引：0，他引：1  

刘崴  胡俊栋  杨红霞  陈俊良 《岩矿测试》2021,(3):327-339

电感耦合等离子体质谱(ICP-MS)作为一种高灵敏度的分析技术在痕量超痕量无机元素分析方面已被广泛应用,其与色谱分离技术相结合为元素形态分析提供了强有力的检测工具。本文阐述了近年来利用不同ICP-MS联用技术进行元素形态分析的研究进展,主要包括:(1)气相色谱-电感耦合等离子体质谱联用技术(GC-ICP-MS);(2)毛细管电泳-电感耦合等离子体质谱联用技术(CE-ICP-MS);(3)离子色谱-电感耦合等离子体质谱联用技术(IC-ICP-MS);(4)高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)。在此基础上归纳总结了中国元素形态分析领域的主要研究情况,对元素形态分析发展前景作了展望。这些联用技术中,GC-ICP-MS的灵敏度高,样品传输率接近100%,但其适用于易挥发或中等挥发性样品的分离,应用范围相对较窄;CE-ICP-MS的分离效率高,样品和试剂消耗量少,但受到其进样量限制使得最低检出浓度较大;IC-ICP-MS主要分析阴离子和阳离子及小分子极性化合物,是液相色谱的有益补充,具有分离效果好和快速方便等优点,但离子色谱流动相中的盐类会造成ICP-MS进样管和采样锥的堵塞,使得基体效应严重;HPLC-ICP-MS以其广泛的应用范围、简单的接口技术,成为元素形态分析研究中应用最广泛的联用技术。本文认为,元素形态分析研究中开展复杂基体样品前处理方法研究,研制系列元素形态分析标准物质,建立多元素形态同时分析方法是元素形态分析领域的发展方向。  相似文献   

Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January–March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, ≤5 mg GX eq. m⁻² d⁻¹, and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the traps consisting of intact protist plankton, although remains of taxa with hard body parts (diatoms, tintinnids, thecate dinoflagellates and foraminifera) were numerous, far more so than intact specimens of these taxa. Nevertheless, many small flagellates and coccoid cells, belonging to the pico- and nanoplankton, were found in the traps, and these small, soft-bodied cells probably contributed the majority of downward POC flux via mesozooplankton grazing and faecal pellet export. TEP likely played an important role by aggregating these small cells, and making them more readily available to mesozooplankton grazers.  相似文献   

Formation of iron plaque on mangrove Kandalar. Obovata (S.L.) root surfaces and its role in cadmium uptake and translocation     

Jingna Du  Chongling Yan  Zhaodeng Li 《Marine pollution bulletin》2013

In this study, a pot experiment was conducted to investigate the formation of iron plaque under Cd stress and its role in Cd uptake and translocation by mangrove Kandalar. Obovata (S.L.). Results showed:  相似文献   

鲁东昌邑古元古代BIF铁矿矿床地球化学特征及矿床成因讨论   总被引：9，自引：6，他引：3  

蓝廷广  范宏瑞  胡芳芳  杨奎锋  郑小礼  张华东 《岩石学报》2012,28(11):3595-3611

昌邑铁矿位于华北克拉通东部的胶北地体,为赋存于古元古代粉子山群变质岩中的条带状铁建造(BIF)铁矿。矿体主要呈透镜状、似层状,以(含)角闪石英磁铁岩为主要矿石,经历了温度高达636℃的角闪岩相变质作用。铁矿石富SiO₂和Fe₂O₃^T(SiO₂+Fe₂O₃^T=82.5%~97.7%),含少量Al₂O₃、MgO和CaO等,显示主要为化学沉积但有少量碎屑或泥质加入的特征。与PAAS相比轻稀土元素亏损、高的Y/Ho比值以及La和Y正异常表明铁矿沉淀于海相环境,而高的Ti/V比值、高Cr、Co和Ni含量以及Eu的正异常表明火山热液的参与,成矿物质来源于火山活动。无明显的Ce负异常表明当时可能存在一个缺氧的大气环境。昌邑铁矿与华北克拉通太古宙BIF相比,总体上没有显著差别,但Al₂O₃、CaO、MgO和K₂O含量相对较高,Eu正异常相对较弱,表明其可能形成于具有更多碎屑物质和更少热液参与的浅水环境。  相似文献   

渤海中部表层沉积物中重金属赋存相态及来源   总被引：1，自引：1，他引：0  

刘明  范德江  廖永杰  陈彬  杨作升 《海洋学报(英文版)》2016,35(9):98-110

近年来由于环渤海经济圈的快速发展,渤海接受了来自周边河流、沿岸排污及海上油气开采所产生的大量的重金属等污染物质,使得渤海的生态环境系统面临前所未有的压力。本文采用电感耦合等离子质谱仪（ICP-MS）对采自渤海中部的25个表层沉积物样品中的Cu、Co、Ni、Zn、Pb、Cr、Cd等重金属元素的含量和赋存相态进行了分析,探讨了重金属分布规律、污染状况及来源。研究结果表明,Cu、Co、Ni、Zn、Cr在渤海湾的近岸区域和渤海中部泥质区有较高的含量,而Pb和Cd则在整个研究区的含量都较高;表层沉积物中Cu、Co、Ni、Zn、Cr主要以残渣态形式存在,而Pb和Cd则具有较高的非残渣态含量;生态风险评价结果表明该区表层沉积物未受到Co、Ni、Cr的污染,Cu、Zn、Pb和Cd则为未污染-中等程度污染。重金属元素Co、Ni、Cr以自然来源为主,在沉积物中的分布主要受沉积物物质组成的影响,而Cu、Zn、Pb,尤其是Cd,则受到了人类活动的显著影响。黄河沉积物是研究区表层沉积物中重金属的主要来源,影响范围涵盖了本区大部分区域,但在研究区的北端受到滦河来源物质的影响,渤海湾和研究区中部则受到海河物质和大气沉降来源重金属的一定影响。  相似文献   

河南省安林矽卡岩型铁矿的成岩时代和成矿物质来源探讨   总被引：4，自引：1，他引：3  

陈艳  张招崇  朱江 《岩石学报》2014,30(5):1307-1321

位于华北克拉通中部的河南省安林铁矿是典型的邯邢式矽卡岩型铁矿,矿体产于闪长质岩石和中奥陶统灰岩的接触带。LA-ICPMS锆石U-Pb定年结果表明安林闪长岩体的侵位年龄为123.38±0.81Ma,略晚于华北克拉通东部地区的含矿岩体,形成于岩石圈大规模减薄伸展时期。但其中含有古老的锆石说明岩浆经历了地壳的混染。闪长质岩石具有相对低SiO2、高Mg#、高碱,富集Ba、Sr和LREE大离子亲石元素,亏损Nb、Ti、Ta等高场强元素的特点,暗示了其形成于岩石圈地幔。岩相学特征以及Harker图解指示了岩浆经历了较强的分离结晶作用,因此推断安林闪长岩可能是软流圈地幔上涌导致富集的岩石圈地幔发生部分熔融形成原始的辉长质岩浆在上升过程中或岩浆房中发生了以铁镁矿物为主的分离结晶作用,同时受到地壳物质的混染的结果。安林地区矿石具有和闪长岩体相似的稀土元素地球化学特征,反映铁的成矿作用与岩浆作用密切相关。矿床中闪长岩体、矽卡岩、矿石和碳酸盐围岩的主量元素对比研究表明钠交代作用引起Na、K、Fe、Si等元素在各岩类间的迁移,其中迁移出的铁为成矿提供了物质基础。安林地区初始岩浆富含水,分离结晶作用使残留岩浆水饱和而发生出溶;且岩浆在演化过程中受到区内膏盐层和碳酸盐地层的混染,促进了岩浆中流体的出溶并使出溶的流体富含Cl-,为有利于铁质活化的富Cl-岩浆流体的形成创造了条件。  相似文献