Population Genetic Structure of Rock Bream (<Emphasis Type="Italic">Oplegnathus fasciatus</Emphasis> Temminck &amp; Schlegel, 1884) Revealed by mtDNA COI Sequence in Korea and China     

Hyun Suk Park  Choong-Gon Kim  Sung Kim  Yong-Joo Park  Hee-Jung Choi  Zhizhong Xiao  Jun Li  Yongshuang Xiao  Youn-Ho Lee 《Ocean Science Journal》2018,53(2):261-274

The rock bream, Oplegnathus fasciatus, is a common rocky reef game fish in East Asia and recently has become an aquaculture species. Despite its commercial importance, the population genetic structure of this fish species remains poorly understood. In this study, 163 specimens were collected from 6 localities along the coastal waters of Korea and China and their genetic variation was analyzed with mtDNA COI sequences. A total of 34 polymorphic sites were detected which determined 30 haplotypes. The genetic pattern reveals a low level of nucleotide diversity (0.04 ± 0.003) but a high level of haplotype diversity (0.83 ± 0.02). The 30 haplotypes are divided into two major genealogical clades: one that consists of only Zhoushan (ZS, East China Sea) specific haplotypes from the southern East China Sea and the other that consists of the remaining haplotypes from the northern East China Sea, Yellow Sea, Korea Strait, and East Sea/Sea of Japan. The two clades are separated by approximately 330~435 kyBP. Analyses of AMOVA and F_st show a significant population differentiation between the ZS sample and the other ones, corroborating separation of the two genealogical clades. Larval dispersal and the fresh Yangtze River plume are invoked as the main determining factors for this population genetic structure of O. fasciatus. Neutrality tests and mismatch distribution analyses indicate late Pleistocene population expansion along the coastal waters of Korea and China approximately 133–183 kyBP during which there were periodic cycles of glaciations and deglaciations. Such population information needs to be taken into account when stock enhancement and conservation measures are implemented for this fisheries species.  相似文献   

Tide-related Changes in mRNA Abundance of Aromatases and Estrogen Receptors in the Ovary and Brain of the Threespot Wrasse <Emphasis Type="Italic">Halichoeres trimaculatus</Emphasis>     

Dae-Ju Oh  Sung-Pyo Hur  Selma Bouchekioua  Yuki Takeuchi  Shingo Udagawa  Neelakanteswar Aluru  Yong-Ju Park  Ji-Gweon Park  Se-Jae Kim  Thomas W. Moon  Mathilakath M. Vijayan  Akihiro Takemura 《Ocean Science Journal》2018,53(2):239-249

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Fine-scale Microbial Communities Associated with Manganese Nodules in Deep-sea Sediment of the Korea Deep Ocean Study Area in the Northeast Equatorial Pacific     

Hyeyoun Cho  Kyeong-Hong Kim  Seung Kyu Son  Jung-Ho Hyun 《Ocean Science Journal》2018,53(2):337-353

Despite its potential significance for industrial utilization, any activities associated with the mining of manganese (Mn) nodules might have substantial impacts on benthic ecosystems. Because microorganisms respond quickly to changing environmental conditions, a study of microbial communities provides a relevant proxy to assess possible changes in benthic ecosystems associated with mining activities. We investigated fine-scale microbial community composition and diversity inside and on the surface of Mn nodules and in nearby deep-sea sediments in the Korea Deep Ocean Study (KODOS) area located in the Clarion-Clipperton Fracture Zone (CCFZ) of the northeast equatorial Pacific. Although microbial cell density was lower within nodules (3.21 × 10⁶ cells g^-1) than in sediment (2.14 × 10⁸ cells g^-1), nodules provided a unique habitat for microorganisms. Manganese-oxidizing bacteria including Hyphomicrobium and Aurantimonas in Alphaproteobacteria and Marinobacter in Gammaproteobacteria were abundant in nodules, which implied that these bacteria play a significant role in nodule formation. In contrast, Idiomarina in Gammaproteobacteria and Erythrobacter and Sulfitobacter in Alphaproteobacteria were abundant in sediments. Meanwhile, Thaumarchaeota, a phylum that consists of ammonia-oxidizing chemolithoautotrophs, were the predominant archaeal group both in nodules and sediment. Overall, microbial communities in Mn nodules were unique compared to those observed in sediments. Furthermore, the phylogenetic composition of microorganisms in the KODOS area was distinguishable from that in the nodule provinces claimed by China and Germany in the CCFZ and nodule fields in the central South Pacific Gyre, respectively.  相似文献   

Convection in a rotating annulus having sidewalls of height-dependent thermal conductance     

Jae Min Hyun  Chang Yeong Kim 《地球物理与天体物理流体动力学》2013,107(3):149-162

Abstract

Thermal convection in a vertically-mounted, rotating annulus of a particular design proposed by Davies and Walin (1977) is investigated. The annulus used in the present study differs from the conventional type in some important aspects: the sidewalls are finitely conducting, and the thermal conductance of the sidewalls is height-dependent. The theoretical model due to Davies and Walin is briefly recounted. The present study aims to verify the theoretical model; we have acquired numerical solutions to the governing Navier-Stokes equations. The numerical results are supportive of the theoretical contentions. The near-linear dependence of the isothermal slope on the parameter D, which is a function of Ω and ΔT, is corroborated within reasonable limits. New data on the vertical and radial structures of the meridional and azimuthal flows are presented. The numerical results also confirm that the shape of the sidewall thickness has a substantial influence on the meridional flow patterns. In the bulk of the interior flow field, the dominant azimuthal flow field and the temperature field are linked by the thermal wind relation.  相似文献   

The role of eddies in solute transport and recovery in rock fractures: Implication for groundwater remediation          下载免费PDF全文

Seung Hyun Lee  In Wook Yeo  Kang‐Kun Lee  Won Sang Lee 《水文研究》2017,31(20):3580-3587

A better understanding of solute transport and retention mechanism in rock fractures has been challenging due to difficulty in their direct observations in microscale rough‐walled fractures. Six representative troughs in a rough‐walled fracture were selected for microscale observations of eddy formation with increasing flow velocity and its effect on spatiotemporal changes of solute concentration. This experimental study was enabled by a microscale visualization technique of micro particle image velocimetry. With increasing flow velocity (Re ≤ 2.86), no eddies were generated, and solutes along the main streamlines transported rapidly, whereas those near the wall moved slowly. A larger amount of solutes remained trapped at all troughs at Re = 2.86 than Re < 1. For Re = 8.57, weak eddies started to be developed at the troughs on the lee side, which little contributed to overall solute flushing in the fracture. Accordingly, a large of amount of water was needed for solute flushing. The flow condition of 1 < Re < 10, before a full development of eddies, was least favourable in terms of time and amount of remediation fluid required to reach a target concentration. After large eddies were fully developed at troughs on the lee side for Re = 17.13, solutes were substantially reduced by eddies with less amount of water. Fully developed eddies were found to enhance solute transport and recovery, as opposed to a general consensus that eddies trap and delay solutes. Direct inflow into troughs on the stoss side also made a great contribution to solute flushing out of the troughs. This study indicates that fully developed eddies or strong inflows at troughs are highly possible to form for Re > 10 and this flow range could be favourable for efficient remediation.  相似文献   

An object-oriented knowledge representation structure for exploration data integration     

P. An  W. M. Moon  G. F. Bonham-Carter 《Natural Resources Research》1994,3(2):132-145

Knowledge representation structure and reasoning processes are very important issues in the knowledge-based approach of integrating multiple spatial data sets for resource exploration. An object-oriented knowledge representation structure and corresponding reasoning processes are formulated and tested in this research on the knowledge-based approach of integrating spatial exploration data. The map-based prototype expert system developed in this study has self-contained knowledge representation structure and inference mechanisms. It is important to distinguish between lack of information and information providing negative evidence for a map-based system because the spatial distribution of data sets are uneven in most cases. Error and uncertainty estimation is also an important component of any production expert system. The uncertainty propagation mechanisms developed here work well for this type of integrated exploration problem. Evidential bellef function theory provides a natural theoretical basis for representing and integrating spatially uneven geophysical and geological information. The prototype system is tested using real mineral exploration data sets from the Snow Lake area, northern Manitoba, Canada. The test results outline the favorable exploration areas successfully and show the effectiveness of the knowledge representation structure and inference mechanisms for the knowledge-based approach.  相似文献   

Radial growth rates and Pb ages of hydrothermal massive sulfides from the Juan de Fuca Ridge     

Kim Hyun Kim  Gary M. McMurtry 《Earth and Planetary Science Letters》1991,104(2-4)

Activities of ²³⁸U, ²²⁸Ra, ²²⁶Ra and ²¹⁰Pb were determined in submarine hydrothermal massive sulfides by nondestructive, gamma-ray spectrometry. The samples were collected by the manned submersible DSRV “Alvin” from active hydrothermal fields on the Endeavour Segment and Axial Seamount of the Juan de Fuca Ridge. ²¹⁰Pb activities are mostly below the equilibrium level with ²²⁶Ra, which is linearly correlated with the concentration of Ba, Sr and Ca in the deposits. The ratios of²²⁶Ra to the alkaline earth elements indicate that hydrothermal alteration of the underlying oceanic crust is the dominant source of Ra in the sulfide deposits.The ²¹⁰Pb/Pb ratios measured in many of the sulfides are higher than the ratio obtained for a basalt source of ²¹⁰Pb, probably because of ²¹⁰Pb ingrowth from ²²⁶Ra within the sulfide deposits. An isochron approach employing ratios of ²¹⁰Pb/Pb and ²²⁶Ra/Pb yielded an initial ²¹⁰Pb/Pb ratio in the range of 0–0.57 dpm/μg Pb, implying that the crustal residence time of the hydrothermal fluid in the Endeavour Segment is very short ( < 10 years) and that basalt alteration is the only source of the ²¹⁰Pb and Pb. For the hydrothermal fluid in Axial Seamount, a residence time of 10–20 years is estimated on the basis of the initial ²¹⁰Pb/Pb and ²²⁸Ra/²²⁶Ra ratios of a sulfide chimney. Both residence time estimates are consistent with the results of previous studies. We have estimated the upper limits of sample ages ranging from tens to a hundred years for 12 samples, with the remaining seven samples indicating ages close to or older than 150 years, the practical limit of the ²¹⁰Pb/Pb dating technique.A concentrically sectioned sulfide chimney from Axial Seamount yielded mean radial growth rates ranging from a few tenths to a few mm/year based on gradients of ²¹⁰Pb/Pb and ²²⁸Ra/²²⁶Ra activity ratios, whereas a similarly sectioned chimney from the Endeavour Segment, although collected from the top of an active “black smoker” vent, displayed no ²¹⁰Pb or ²²⁸Ra activity. Our results have implications for the duration and periodicity of hydrothermal circulation and associated mineral deposition at mid-ocean ridges.  相似文献   

用超速CT机检测99例无症状香港中国人降低钙指数     

吴敬文  戴有鼎 《CT理论与应用研究》1994,3(4):34-34

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．  相似文献   

The natural enrichment of ferruginous weathering products and its implication for water quality in the Hunchun Basin, China   总被引：1，自引：0，他引：1  

J.-W. Moon  H.-S. Moon  Y. Song  J. Kang  G. Lee  H.-D. Kim 《Environmental Geology》2001,40(7):869-883

In order to evaluate the extent of a natural enrichment of Fe and Mn over the whole of the Hunchun Basin, the stability of Fe-Mn mineral phases, their status, the weathering rate of source materials, and soil characteristics were determined. A variety of samples were collected from sediments, soil profiles, and surface soils. In the solutions after a sequentially selective dissolution using sodium pyrophosphate (p), acid oxalate (o), and dithionite-citrate-bicarbonate (d), Si, Al and Fe were dominant in the d and p fractions, and Mn in the o and p fractions. The results showed that the existing phases and status of Fe and Mn were distinctly different, and that the abundance of amorphous Mn phases made thermodynamic calculation difficult. An application of these ferruginous weathering products was therefore made to understand basin development. The first terrace of the Hunchun River is more active than the second terrace, which can be inferred from it having a higher value in Fe_d/Fe_t. Amorphous Fe phases such as Fe(OH)₃ and Fe₃(OH)₈ were controlling factors of Fe in the thermodynamic calculations. The transformation of the amorphous Fe phases to more stable phases was hindered by high contents of smectite and gibbsite, amorphous opaline produced from rice roots, and organic phosphate pesticides or fertilizers in soils. Source-rock deduction using water samples suggested granitic weathering. Precipitation around the Hunchun Basin is gradually becoming more acidic. Therefore, in the future it is inevitable that ecological and environmental problems related to the Fe phases mentioned above will occur in the drinking water supply for this area, especially in that of the first terrace.  相似文献   

Secondary dispersion from gold deposits in west Turkey     

Mi?raç Akçay  H.Mustafa Özkan  Charles J. Moon  Barry C. Scott 《Journal of Geochemical Exploration》1996,56(3):197-218

Orientation studies over the Sarpda? prospect in the Biga peninsula and the Arapdagi deposit near Izmir have provided elear evidence for elemental dispersion around west Turkish gold prospects. Although these deposits are of different types, silicification associated with the deposits results in the main part of both deposits forming topographic highs.At Sarpda? gold mineralisation is relatively weak compared with nearby prospects and associated with a silicified cap on the main hill. Comparison of coarse and fine fractions, based on a 190 μm size split of 8 kg of -2 mm material, suggests that gold disperses clastically on the steep slopes, probably within silica, but coarse grains break down giving Au concentrations in the finer fractions at the base of the main slope. Discrete gold grains, that can be panned, only occur 1–2 km downstream within the streams and heavy mineral concentrations are very limited. This interpretation of Au dispersion is consistent with the data from 1 kg samples collected at the higher primary grade, but more contaminated, Arapda?i prospect.Antimony is the most consistent pathfinder both for the silicified cap at Sarpda? and for gold-rich veins at Arpada?i. It gives high contrast anomalies. Arsenic is useful being more mobile than Sb, although contrast may be low. High resolution Ag data can be useful but base metal enrichments are also often associated with Ag anomalies. Most prospects have some base metal enrichments although they can be displaced from the main gold-rich parts of the deposit and anomalies may be weak. Lead and Cu are the more consistently useful elements.The use of large (> 8 kg of -2 mm material) samples produces consistent stream sediment data that can be used to reliably interpret single samples and quantify Au anomalies. A survey around the Halíköy Hg and Emirli Sb mines, using these large samples, confirmed the extension of the known gold-bearing Emirli structure. In contrast the major Hg-bearing Halíköy Fault is gold poor although a structure parallel to it is auriferous.  相似文献