Biodegradation of <Emphasis Type="Italic">Enteromorpha</Emphasis> polysaccharides by intestinal micro-community from <Emphasis Type="Italic">Siganus oramin</Emphasis>     

Zhibiao Zhang  Xuefeng Han  Yan Xu  Jin Li  Yuanyou Li  Zhong Hu 《中国海洋大学学报(英文版)》2016,15(6):1034-1038

Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal micro-communities involved in the biodegradation of Enteromorpha polysaccharides (EP) were seldom reported. In order to obtain the EP-degrading micro-community, the intestines of Siganus oramin was obtained to isolate the micro-communities, which were enriched by 0.3% of EP as the sole carbon source. A stable micro-community with EP degradative capability was achieved after seven generations of subculture, named H1. Results showed that H1 was able to degrade 75% of EP within 24 hours, and the activity of EP lyases reached 500 U mL^?1 in 32 hours. With denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library analysis, ten bacteria closely related to Marinomonas pontica, Microbacterium sp., Leucobacter chironomi, Cyclobacterium sp., Algoriphagus winogradskyi, Pseudoalteromonas sp. and Vibrio sp. were determined. Furthermore, compared with the DGGE bands sequence and the clone library analysis, the dominant bacteria of the EP-biodegrading micro- community were Pseudoalteromonas sp. and Vibrio sp., with the respective proportion of 38% and 46%, and they should play an important role in EP degradation together with other degrading bacteria in the micro-community H1.  相似文献   

Depth classification of underwater targets based on complex acoustic intensity of normal modes     

Guang?Yang  Jingwei?YinEmail author  Yun?Yu  Zhenhua?Shi 《中国海洋大学学报(英文版)》2016,15(2):241-246

In order to solve the problem of depth classification of the underwater target in a very low frequency acoustic field, the active component of cross spectra of particle pressure and horizontal velocity (ACCSPPHV) is adopted to distinguish the surface vessel and the underwater target. According to the effective depth of a Pekeris waveguide, the placing depth forecasting equations of passive vertical double vector hydrophones are proposed. Numerical examples show that when the sum of depths of two hydrophones is the effective depth, the sign distribution of ACCSPPHV has nothing to do with horizontal distance; in addition, the sum of the first critical surface and the second critical surface is equal to the effective depth. By setting the first critical surface less than the difference between the effective water depth and the actual water depth, that is, the second critical surface is greater than the actual depth, the three positive and negative regions of the whole ocean volume are equivalent to two positive and negative regions and therefore the depth classification of the underwater target is obtained. Besides, when the 20 m water depth is taken as the first critical surface in the simulation of underwater targets (40 Hz, 50 Hz, and 60 Hz respectively), the effectiveness of the algorithm and the correctness of relevant conclusions are verified, and the analysis of the corresponding forecasting performance is conducted.  相似文献   

The Impact of Large-Scale Reclamation on Hydro-Dynamic Environment——A Case Study of Xinghua Bay     

YU Jing  BAO Xianwen  DING Yang  ZHANG Wei  ZHOU Lingling 《中国海洋大学学报(英文版)》2016,15(4):583-592

A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s^-1. On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s^-1. The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.  相似文献   

An Investigation of Digestion Methods for Trace Elements in Bauxite and Their Determination in Ten Bauxite Reference Materials Using Inductively Coupled Plasma‐Mass Spectrometry          下载免费PDF全文

Wen Zhang  Liang Qi  Zhaochu Hu  Cunjiang Zheng  Yongsheng Liu  Haihong Chen  Shan Gao  Shenghong Hu 《Geostandards and Geoanalytical Research》2016,40(2):195-216

Trace elements from samples of bauxite deposits can provide useful information relevant to the exploration of the ore‐forming process. Sample digestion is a fundamental and critical stage in the process of geochemical analysis, which enables the acquisition of accurate trace element data by ICP‐MS. However, the conventional bomb digestion method with HF/HNO₃ results in a significant loss of rare earth elements (REEs) due to the formation of insoluble AlF₃ precipitates during the digestion of bauxite samples. In this study, the digestion capability of the following methods was investigated: (a) ‘Mg‐addition’ bomb digestion, (b) NH₄HF₂ open vessel digestion and (c) NH₄F open vessel digestion. ‘Mg‐addition’ bomb digestion can effectively suppress the formation of AlF₃ and simultaneously ensure the complete decomposition of resistant minerals in bauxite samples. The addition of MgO to the bauxite samples resulted in (Mg + Ca)/Al ratios ≥ 1. However, adding a large amount of MgO leads to significant blank contamination for some transition elements (V, Cr, Ni and Zn). The NH₄HF₂ or NH₄F open vessel digestion methods can also completely digest resistant minerals in bauxite samples in a short period of time (5 hr). Unlike conventional bomb digestion with HF/HNO₃, the white precipitates and the semi‐transparent gels present in the NH₄HF₂ and NH₄F digestion methods could be efficiently dissolved by evaporation with HClO₄. Based on these three optimised digestion methods, thirty‐seven trace elements including REEs in ten bauxite reference materials (RMs) were determined by ICP‐MS. The data obtained showed excellent inter‐method reproducibility (agreement within 5% for REEs). The relative standard deviation (% RSD) for most elements was < 6%. The concentrations of trace elements in the ten bauxite RMs showed agreement with the limited certified (Li, V, Cr, Cu, Zn, Ga, Sr, Zr and Pb) and information values (Co, Ba, Ce and Hf) available. New trace element data for the ten RMs are provided, some of which for the first time.  相似文献   

Ablation Characteristic of Ilmenite using UV Nanosecond and Femtosecond Lasers: Implications for Non‐Matrix‐Matched Quantification          下载免费PDF全文

Zhen Li  Zhaochu Hu  Detlef Günther  Keqing Zong  Yongsheng Liu  Tao Luo  Wen Zhang  Shan Gao  Shenghong Hu 《Geostandards and Geoanalytical Research》2016,40(4):477-491

Ilmenite (FeTiO₃) is a common accessory mineral and has been used as a powerful petrogenetic indicator in many geological settings. Elemental fractionation and matrix effects in ilmenite (CRN63E‐K) and silicate glass (NIST SRM 610) were investigated using 193 nm ArF excimer nanosecond (ns) laser and 257 nm femtosecond (fs) laser ablation systems coupled to an inductively coupled plasma‐mass spectrometer. The concentration‐normalised ⁵⁷Fe and ⁴⁹Ti responses in ilmenite were higher than those in NIST SRM 610 by a factor of 1.8 using fs‐LA. Compared with the 193 nm excimer laser, smaller elemental fractionation was observed using the 257 nm fs laser. When using 193 nm excimer laser ablation, the selected range of the laser energy density had a significant effect on the elemental fractionation in ilmenite. Scanning electron microscopy images of ablation craters and the morphologies of the deposited aerosol materials showed more melting effects and an enlarged particle deposition area around the ablation site of the ns‐LA‐generated crater when compared with those using fs‐LA. The ejected material around the ns crater predominantly consisted of large droplets of resolidified molten material; however, the ejected material around the fs crater consisted of agglomerates of fine particles with ‘rough' shapes. These observations are a result of the different ablation mechanisms for ns‐ and fs‐LAs. Non‐matrix‐matched calibration was applied for the analysis of ilmenite samples using NIST SRM 610 as a reference material for both 193 nm excimer LA‐ICP‐MS and fs‐LA‐ICP‐MS. Similar analytical results for most elements in ilmenite samples were obtained using both 193 nm excimer LA‐ICP‐MS at a high laser energy density of 12.7 J cm^?2 and fs‐LA‐ICP‐MS.  相似文献   

On the problem of the scale and composition of Paleozoic and Mesozoic granitoid magmatism in the Khilok–Vitim fold belt of Central Transbaikalia     

A. Yu. Antonov  A. V. Travin 《Russian Journal of Pacific Geology》2016,10(2):105-122

The paper presents a study of the gneissic granitoids of the Malkhan Complex and the intruisve granitoids of the Daur and Bichur complexes developed within the Khilok–Vitim fold belt of Central Transbaikalia. In the state geological map, these complexes have been attributed to the Early and Late Paleozoic. New ⁴⁰Ar/³⁹Ar geochronological data indicate that these rocks are Mesozoic rather than Paleozoic in age, which suggests the much broader manifestation of the Mesozoic granitoid complexes in this area. The studied Mesozoic granitoid massifs exhibit temporal and compositional zoning reflected in a westward decrease in age (from Early to Late Mesozoic) and increase in total alkalinity and potassium content at the appropriate trace-element characteristics. The obtained results of study of the Khilok–Vitim Belt are interpreted in the framework of the model of the formation of domal–cupola structures by the multiple activity of deep thermochemical plumes.  相似文献   

Problems of Paleogene–Neogene stratigraphy of the Zerkal’naya depression,East Sikhote Alin     

B. I. Pavlyutkin  I. Yu. Chekryzhov  T. I. Petrenko 《Russian Journal of Pacific Geology》2016,10(4):283-298

The Paleogene–Neogene stratigraphic scale of the Zerkal’naya River basin is modified with account for new isotopic and paleobotanical data. It is established that the Tadushi Formation and underlying volcanics, which were previously considered as representing transitional Cretaceous–Paleocene strata, are separated in the section of the Ustinovka quarry by a significant stratigraphic hiatus. According to the new data, the volcanics and the Tadushi Formation are established as Campanian and Late Paleocene in age, respectively. The Bogopol Formation in the type section is dated back to the Middle–Late Paleocene. The Svetlyi Formation is now considered to be Early Eocene in age, rather than Late Eocene–Oligocene as previously thought. A new variant of the stratigraphic scale is proposed for the Paleogene–Neogene deposits of the Zerkal’naya depression.  相似文献   

Petrophysical features of the tectonic structures of the Okhotsk continent–ocean transition zone     

E. G. Ivolga  V. G. Gurovich  N. P. Romanovsky  Yu. O. Manilov 《Russian Journal of Pacific Geology》2016,10(5):351-364

Petrophysical characteristics are determined for the rock complexes of the Okhotsk margin within the continent–ocean transition zone. Petrophysical maps showing the major inhomogeneities of the main tectonic elements of the studied area are constructed. Petrophysical inhomogeneities and the corresponding geophysical field anomalies are compared. A relationship between the magnetic field anomalies and subsurface rock complexes is revealed. The gravity field anomalies are related to deep inhomogeneities and are almost independent of the subsurface rock complexes of relatively low thickness.  相似文献   

Tectonics and metallogeny of the Khakandzha ore district in the Okhotsk–Chukotka volcanic belt     

Yu. P. Yushmanov  A. M. Petrishchevsky 《Russian Journal of Pacific Geology》2016,10(5):337-350

The data on the structure, geodynamics, and metallogeny of the Khakandzha ore district in northwestern Okhotsk region are analyzed and the two main factors responsible for the localization of ore deposits are defined. The magmatic factor controls the confinement of the ore district to the tectono-magmatic structure of the central type (source of ore matter), which determines the concentric zoning patterns in the distribution of ore mineralization. The tectonic factor determines the confinement of the ore districts, deposits, and ore occurrences of the region to the meridional left-lateral shear structure, which controls the magma and fluid distribution. Local extension (transtension) in this structure against the background of general lateral compression (transpression) provided tectonic environments most favorable for ore accumulation.  相似文献   

Biodegradation of atrazine by Arthrobacter sp. C3, isolated from the herbicide-contaminated corn field     

H. Wang  Y. Liu  J. Li  M. Lin  X. Hu 《International Journal of Environmental Science and Technology》2016,13(1):257-262

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