A new method for the quantification of different redox-species of molybdenum (V and VI) in seawater   总被引：1，自引：0，他引：1  

Deli Wang  Robert C. Aller  Sergio A. Saudo-Wilhelmy 《Marine Chemistry》2009,113(3-4):250-256

A new method for the direct determination of reduced and oxidized Mo species (Mo (V) and Mo (VI)) in seawater was developed and used for the first time. The method includes the complexation of Mo (V) with tartrate, solid phase extraction of the Mo (V)–tartrate complex by a XAD 7HP resin, followed by elution with acidic acetone. In this study, the eluted Mo (V) was quantified by graphite furnace atomic absorption spectrometry. The detection limit of this protocol was on the order of 0.2 nM. The analytical precision was 10% of ~ 10 nM. This method was successfully applied to the determination of Mo (V) and Mo (VI) in surface and bottom waters at the head of Peconic River Estuary. Total Mo (Mo (V) + Mo (VI)) ranged from 100–120 nM in most bottom saline waters, and 2.5–15 nM for surface fresher waters. Concentrations of Mo (V) in these environments ranged from 0 nM to ~ 15 nM, accounting for 0%–15% of the total dissolved Mo pool. The time series experiments showed that the Mo speciation changed within 1 h after the water collection, and therefore it is strongly suggested that speciation analysis be carried out within the first 15 min. However, since these are the first Mo speciation data in concentration ranges typical of normal marine and coastal waters, additional research may be required to optimize the methodology and further explore Mo cycling mechanisms.  相似文献   

鄂霍次克海南部晚第四纪的古海洋学记录   总被引：1，自引：0，他引：1  

孙烨忱  王汝建  陈建芳  高爱国  李秀珠  韩贻兵 《海洋地质与第四纪地质》2009,(2)

鄂霍次克海是太平洋第二大边缘海,在西北太平洋水文环境中扮演重要角色。综合分析了鄂霍次克海南部T00孔沉积物的多种替代性指标,揭示了鄂霍次克海晚第四纪以来的环境变化受季节性海冰变化、大气循环模式、陆源物质通量和表层生产力的共同影响。对比放射虫Cycladophora davisiana的含量曲线与LR04氧同位素记录,该孔沉积物可划分为氧同位素1-7期,底部年龄约为250ka。C.davisiana在间冰期的高含量表明鄂霍次克海中层水是北太平洋中层水的主要源区。蛋白石和有机碳的分析显示鄂霍次克海表层生产力在冰消期突然增大,随后在间冰期逐渐下降,冰期普遍较低。C/N比值曲线的分析说明鄂霍次克海的有机质沉积物主要来源于海洋。沉积物粒度的分析揭示鄂霍次克海冰期时陆源粗颗粒含量较低,至冰消期粗颗粒含量突然增加,而在间冰期陆源粗颗粒含量较高。  相似文献   

The design and the development of a hyperspectral and multispectral airborne mapping system     

Pece V. Gorsevski  Paul E. Gessler 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(2):184-192

Flexible and cost-effective tools for rapid image acquisition and natural resource mapping are needed by land managers. This paper describes the hardware and software architecture of a low-cost system that can be deployed on a light aircraft for rapid data acquisition. The Hyperspectral and Multispectral Cameras for Airborne Mapping (HAMCAM) was designed and developed in the Geospatial Laboratory for Environmental Dynamics at the University of Idaho as a student-learning tool, and to enhance the existing curriculum currently offered. The system integrates a hyperspectral sensor with four multispectral cameras, an Inertial Navigation System (INS), a Wide Area Augmentation System (WAAS)-capable Global Positioning System (GPS), a data acquisition computer, and custom software for running the sensors in a variety of different modes. The outputs include very high resolution imagery obtained in four adjustable visible and near-infrared bands from the multispectral imager. The hyperspectral sensor acquires 240 spectral bands along 2.7 nm intervals within the 445–900 nm range. The INS provides aircraft pitch, roll and yaw information for rapid geo-registration of the imagery. This paper will discuss the challenges associated with the development of the system and the integration of components and software for implementation of this system for natural resource management applications. In addition, sample imagery acquired by the sensor will be presented.  相似文献   

Aequorea taiwanensis n. sp. (Hydrozoa, Leptomedusae) and mtCOI sequence analysis for the genus Aequorea     

ZHENG Lianming  LIN Yuanshao  LI Shaojing  CAO Wenqing  XU Zhenzu  HUANG Jiaqi 《海洋学报(英文版)》2009,28(1):109-115

Aequorea taiwanensis, a new hydrozoan species from the Taiwan Strait was described using morphological and molecular characteristics. Both morphological and mitochondrial cytochrome oxidase subunit I (mtCOI) data supported A. taiwanensis n. sp. as a valid species. Sequence divergence and genetic distance of A. taiwanensis n. sp., A. papillata and A. conica were analysed based on the mtCOI gene sequences. The mtCOI sequences from these three species of the genus Aequorea showed high variation frequency, with sequence divergences ranging from 9.10% to 11.9%, and pairwise genetic distances ranging from 0.097 to 0.130. MtCOI sequence analysis provided diagnostic molecular systematic characteristics for accurate identification and discrimination of the species of Aequorea or their populations, and will be used to resolve evolutionary relationships among them.It was suggested that 10%—20% pairwise mtCOI sequence differences indicated the specieslevel divergence among congeneric species in the Hydromedusae.  相似文献   

Anammox bacteria and the anaerobic oxidation of ammonium in the oxygen minimum zone off northern Chile     

《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(16):1021-1031

Anammox is the anaerobic oxidation of ammonium by nitrite or nitrate to yield N₂. This process, along with conventional denitrification, contributes to nitrogen loss in oxygen-deficient systems. Anammox is performed by a special group of bacteria belonging to the Planctomycetes phylum. However, information about the distribution, activity, and controlling factors of these anammox bacteria is still limited. Herein, we examine the phylogenetic diversity, vertical distribution, and activity of anammox bacteria in the coastal upwelling region and oxygen minimum zone off northern Chile. The phylogeny of anammox bacteria was studied using primers designed to specifically target 16S rRNA genes from Planctomycetes in samples taken during a cruise in 2004. Anammox bacteria-like sequences affiliated with Candidatus “Scalindua spp.” dominated the 16S rRNA gene clone library. However, 62% of the sequences subgrouped separately within this cluster and together with a single sequence retrieved from the suboxic zone of the freshwater Lake Tanganyika. The vertical distribution and activity of anammox bacteria were explored through CARD-FISH (fluorescence in situ hybridization with catalyzed reporter deposition) and ¹⁵N labeling incubations, respectively, at two different open-ocean stations during a second cruise in 2005. Anammox bacterial CARD-FISH counts (up to 3000 cells ml⁻¹) and activity (up to 5.75 nmol N₂ L⁻¹ d⁻¹) were only detected at the station subjected directly to the upwelling influence. Anammox cell abundance and activity were highest at 50 m depth, which is the upper part of the OMZ. In this layer, a high abundance of cyanobacteria and a marked nitrogen deficit were also observed. Thus, our results show the presence of a new subcluster within the marine anammox phylogeny and indicate high vertical variability in the abundance and activity of anammox bacteria that could be related to an intensification of carbon and nitrogen cycling in the upper part of the OMZ.  相似文献   

The influence of topography on the forest surface temperature retrieved from Landsat TM,ETM + and ASTER thermal channels     

Martin Hais  Tomáš Kučera 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(6):585-591

  相似文献   

Genetic diversity and differentiation of three populations of Penaeus monodon Fabricus     

WANG Guizhong  TAN Shuhu  LI shaojing  YE Haihui 《海洋学报(英文版)》2008,27(1):113-121

Genetic diversity of two wild Penaeus monodon populations sampled from the coastal waters of Qinglan （ Hainan Province of China, HN） and Malaysia （KD）, and the F1 generation of a Thailand broodstock population （CP） were examined by vertical polyacrylamide gel electrophoresis. Of 21 loci encoded by ten enzymes, 11 were polymorphic. The mean proportions of polymorphic loci of HN, KD and CP were 36. 36%, 45.45% and 50.00% , with the average heterozygosities of 0.135, 0.181 and 0.191, and the effective numbers of alleles per loci were 1. 300, 1. 330 and 1. 329, respectively. The divergent indexes of HN, KD and CP were0.023, 0.124, and 0.117, respectively. The genetic distance between the two wild populations was 0.005, and the gene differentiation coefficient was also very low （0.014）. The results indicated that the F1 generation population had a higher genetic diversity than the two wild populations, and that the HN population had the lowest one. There was no significant differentiation between HN and KD populations and all populations existed with a slight heterozygote excess.  相似文献   

Black carbon and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of China’s marginal seas   总被引：8，自引：0，他引：8  

康延菊  王旭晨  戴民汉  冯桓  李安春  宋茜 《中国海洋湖沼学报》2009,27(2):297-308

This study investigates the distribution of black carbon (BC) and its correlation with total polycyclic aromatic hydrocarbons (ΣPAH) in the surface sediments of China’s marginal seas. BC content ranges from <0.10 to 2.45 mg/g dw (grams dry weight) in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents (average 2.18 mg/g dw), which comprises a significant fraction (27%–41%) of the total organic carbon (TOC) preserved in the sediments. In ...  相似文献   

White spot syndrome virus envelope protein VP124 involved in the virus infection     

ZHU Yanbing  WU Chenglin  YANG Feng 《海洋学报(英文版)》2008,27(4):130-136

White spot syndrome virus （WSSV） is one of the major shrimp pathogens causing large economic losses to shrimp farming. In an attempt to identify the envelope proteins involved in the virus infection, purified WSSV virions were mixed with three antisera against WSSV envelope proteins （VP39, VP124 and VP187 ）, individually. And then they were injected intramuscularly into crayfish （Procambarus clarkii） to conduct in vivo neutralization assays. The results showed that for groups injected with virions only and groups injected with the mixture of virions and antiserum against VP124, the crayfish mortalities were 100% and 60% on the 8th day postinfection, individually. The virus infection could be delayed or neutralized by antibody against the envelope protein VP124. Quantitative PCR was used to further investigate the influence of three antisera described above on the virus infection. The results showed that the antiserum against VP124 could restrain the propagation of WSSV in crayfish. All of the results suggested that the viral envelope protein VP124 played a role in WSSV infection.  相似文献   

Size-fractionated uranium isotopes in surface waters in the Jiulong Estuary in China   总被引：1，自引：1，他引：0  

L&#; E  ZHANG Lei  CHEN Min  QIU Yusheng  XING N  YANG Weifeng  LI Yanping  HUANG Yipu 《海洋学报(英文版)》2008,27(1):29-41

Surface water was collected from the Jiulong Estuary for determination of activity concentrations of uranium isotopes in different size fractions, namely, greater than 53, 10 -53, 2 - 10, 0.4 -2 μm, 10 000 u -0.4 μm and less than 10 000 u fractions by microfihration and cross-flow uhrafiltration technologies. Results indicated that most of the dissolved uranium （ 〈 0.4 μm） exis- ted in the low molecular mass fraction （ 〈 10 000 u）, and the colloidal uranium-238 （10 000 u -0.4 μm） only contributed less than 1% of the dissolved uranium-238. The fractions of colloidal uranium in the dissolved phases decreased with the increasing sa- linity. A positive linear relationship between uranium-238 activities and salinities was observed for the dissolved, colloidal and low molecular mass fractions, indicating a conservative behavior of uranium in the Jiulong Estuary. In the particulate phases （ 〉 0.4 μm）, the partitioning of uranium isotopes among different size fractions was controlled by the partitioning of particle concentrations. In the regions with salinities below 20, the partitioning of uranium-238 among different size fractions was as follows： 10 - 53 μm 〉 2 - 10 μm 〉 0.4 - 2 μm greater than above 53 μm. However, the order at the offshore station with salinities above 30 changed as follows ： 0.4 - 2 μm 〉 10 - 53 μm 〉 2 - 10 μm greater than above 53 μm. The fraction of the 0.4 - 2 μm particles increased at the offshore station, suggesting the increased contribution of the authigenic uranium. The activity ratio of uranium-234 to uranium-238 in the dissolved phases, including the low molecular mass fraction and the colloidal fraction, was larger than unity, showing the occurrence of excess uranium-234. In contrast, the activity ratio of uranium-234 to uranium-238 in all size fractions of the particulate phase was close to the equilibrium value （1.0）. The observed different values of the activity ratio of uranium-234 to uranium-238 in the dissolved phase and the partic  相似文献