福建沿海巨蛎属牡蛎的主要种类及其分布

本实验采用了多重种类特异性PCR（multiplex species—specific PCR）技术，研究了巨蛎属（Crassostrea）牡蛎主要种类在福建沿海的分布．从沿海11个采样地点共采集了657个野生牡蛎样本，随机抽取了327个牡蛎样本进行基因组DNA的提取和线粒体COI基因的鉴定，结果发现200个个体为葡萄牙牡蛎（Crassostrea angulata），101个个体为近江牡蛎（Crassostrea ariakensis），20个个体为熊本牡蛎（Crassostrea sikamea），6个个体为香港巨牡蛎（Crassostrea hongkongensis）．此次实验中未发现长牡蛎（Crassostrea gigas）．结果表明，福建沿海有葡萄牙牡蛎、近江牡蛎、熊本牡蛎和香港巨牡蛎4种巨蛎属牡蛎分布．     

广西北部湾沿海牡蛎的种类及其分布

采用DNA条形码(DNA barcoding)技术, 基于COI基因序列鉴定牡蛎种类, 研究了牡蛎科(Ostreidae)牡蛎在广西沿海的分布。本次研究从广西沿海16个采样地点的潮间带共采集550个野生牡蛎样本, 随机抽取了367个牡蛎样本进行基因组DNA的提取和线粒体COI基因的鉴定, 共检测出4属7种牡蛎。巨牡蛎属有4种, 分别为熊本牡蛎(Crassostrea sikamea)108个, 葡萄牙牡蛎(Crassostrea gigas angulata)43个, 香港巨牡蛎(Crassostrea hongkongensis)15个, 近江牡蛎(Crassostrea ariakensis)18个, 囊牡蛎属(Saccostrea)的多刺牡蛎(Saccostrea echinata)61个, 爪蛎属(Talonostrea)的猫爪牡蛎(Talonostrea talonata)112个, 齿牡蛎属(Dendostea)的齿缘牡蛎(Dendostea crenulifera)10个。结果表明, 广西沿海牡蛎物种丰富, 至少7种牡蛎分布于潮间带, 其中优势种为猫爪牡蛎和熊本牡蛎, 在广西沿海各采样点均有分布。多刺牡蛎和葡萄牙牡蛎次之, 香港巨牡蛎、近江牡蛎、齿缘牡蛎数量较少, 分布较集中。     

辽宁沿海巨蛎属牡蛎的分布

作者采用多重种特异性PCR(multiplex species-specific PCR)技术,研究了巨蛎属(Crassostrea)牡蛎在辽宁沿海的分布。从辽宁沿海的共11个采样点共采集802个牡蛎样本,通过对COI基因的扩增,随机检测了其中的531个牡蛎样本,结果517个个体为长牡蛎(Crassostrea gigas),14个为近江牡蛎(Crassostrea ariakensis),未发现其他巨蛎属牡蛎。结果表明,辽宁沿海有长牡蛎和近江牡蛎等2种巨蛎属牡蛎分布,其中长牡蛎为优势种,分布于潮间带和潮下带,近江牡蛎为稀有种,分布于潮下带,而且在黄海和渤海海域均有分布。     

基于DNA条形码研究浙江沿海牡蛎的种类多样性及其分布特征

利用DNA条形码技术,基于线粒体基因细胞色素c氧化酶亚基I(Cytochrome c Oxidase Subunit I,COI)和核基因28S核糖体RNA(28S rRNA)序列鉴定牡蛎种类,研究牡蛎在浙江沿海的种类多样性及其分布特征。在浙江沿海的7个采样海域共采集550个牡蛎样品,抽取其中232个牡蛎样品进行基因组DNA的提取以及COI基因和28S rRNA基因的鉴定,共检测出3属10种牡蛎。巨牡蛎属(Crassostrea) 5种分别为熊本牡蛎(Crassostrea sikamea) 127个、福建牡蛎(Crassostrea angulata) 64个、日本巨牡蛎(Crassostrea nippona) 4个、近江牡蛎(Crassostrea ariakensis) 1个和长牡蛎(Crassostrea gigas) 1个;牡蛎属(Ostrea) 2种分别为疏纹牡蛎(Ostrea circumpicta) 4个和密鳞牡蛎(Ostrea denselamellosa) 2个;小蛎属(Saccostrea) 3种分别为棘刺牡蛎(Saccostrea kegaki) 20个、多刺牡蛎(Saccostrea echinata) 8个和小蛎属未定种(Saccostrea sp.) 1个。分析结果表明:浙江沿海的牡蛎种类多样性高,并且在南北纵向和离岸远近水平方向上存在较大差异,其中熊本牡蛎和福建牡蛎为浙江沿海牡蛎的优势种。     

广东雷州半岛东部沿岸潮间带常见牡蛎的种类及其分布

在形态分类的基础上,采用多重PCR(Multiplex Species-Specific PCR)和DNA序列分析,基于细胞色素氧化酶Ⅰ(cytochromeoxidaseI,COI)基因构建系统进化树鉴定牡蛎种类及确定其分类地位,研究了广东雷州半岛东部沿岸牡蛎科(Ostreidae)常见牡蛎的种类及分布。本次研究从雷州半岛东部沿岸的11个地点采集了363个野生牡蛎样品,并对全部样品进行了形态分析和多重PCR的鉴定,对未鉴定出来的114个样品进行COI基因的扩增并测序,构建系统进化树进行种类分析,共检测出3属5种牡蛎。巨蛎属(Crassostrea)有两种,分别为熊本牡蛎(C.sikamea)185个和福建牡蛎(C.gigas angulata)109个;小蛎属(Saccostrea)有两种,棘刺牡蛎(S.echinata)48个和团聚牡蛎(S.malabonensis)19个,牡蛎属未定种Ostreasp.1有2个。结果表明,雷州半岛东部沿岸牡蛎种类丰富,至少有5种牡蛎分布于潮间带,其中优势种为熊本牡蛎和福建牡蛎,分布范围比较广。小蛎属和牡蛎属牡蛎数量较少,分布比较集中。     

福建沿海巨蛎属(Crassostrea)牡蛎的种类及其分布

福建省位于我国东南沿海, 海岸线曲折, 港湾众多, 有多条河流入海, 适宜牡蛎栖息繁衍, 是我国牡蛎资源最丰富的地区之一。迄今关于福建沿海牡蛎种类组成及分布情况的研究报道尚少, 鉴于近20余年福建主要海湾经历了高强度的牡蛎养殖, 有必要了解福建沿海牡蛎自然群体的物种组成和数量占比等自然种质资源状况。基于现场调查取样, 结合采用多重种特异性PCR、ITS2杂交种鉴定和CO I测序共同鉴定福建沿海巨蛎属(Crassostrea)牡蛎种类及其分布情况。研究结果表明, 从福建沿海由北至南牡蛎野生种苗海区的19个采样点共960个样品中发现3种巨蛎属牡蛎, 分别是福建牡蛎(Crassostrea angulata)、熊本牡蛎(C. sikamea)和香港牡蛎(C. hongkongensis), 并未发现以往报道的近江牡蛎(C. ariakensis)。其中福建牡蛎(607个)占63.23%、熊本牡蛎(343个)占35.73%、香港牡蛎(10个)占1.04%。除个别采样点外, 福建牡蛎和熊本牡蛎在各采样海区均有分布。香港牡蛎仅在泉州湾河口湿地自然保护区(新发现群体)有少量分布。研究结果揭示的福建沿海地区巨蛎属的物种种类及其分布为后续开展牡蛎遗传多样性分析和遗传分化等种群遗传研究提供了关键基础资料, 为牡蛎种质资源的保护和利用打下重要基础。     

太平洋牡蛎室内水池固着生态的研究

太平洋牡蛎Crassostrea gigas,日本称真牡蛎,是我国近年来从日本引进的优良养殖种类。它具有体型大、生长快、产量高、适应性强等优点。自1980年以来,我国沿海很多引种单位,为了保种和扩种,在我国沿海形成具有生产能力的自然种群,而开展了人工育苗的试验工作。因此,开展太平洋牡蛎固着生态方面的研究,对于增加苗种产量具有一定的生产意义。     

长牡蛎(Crassostrea gigas)EST串联重复序列的组成和分布

长牡蛎(Crassostrea gigas)串联重复序列分析研究较少,为了研究其在基因组转录本的基本结构特征并为长牡蛎中遗传多样性研究中提供有益的信息,利用NCBI公共数据库中的57 139条长牡蛎ESTs序列对串联重复序列结构类型、分布、丰度等进行系统比较分析.分析结果表明:1)长牡蛎EST中共有小卫星串联重复序列8...     

长牡蛎可溶性黑色素的脱盐研究

该研究是继天然长牡蛎(Crassostrea gigas)黑色素的提取、可溶性长牡蛎(Crassostrea gigas)黑色素的制备之后,对牡蛎黑色素提纯方面的进一步拓展和延伸。运用半透化学材料分离的方法,选取纳滤透析膜为分离介质,对可溶性长牡蛎黑色素的制取产物中多余的盐类无机物进行分离剔除,进而得到纯度较高、品质优良的可溶性长牡蛎黑色素晶体,通过称质量和盐度测量,计算得出该方法对黑色素脱盐率达到98%,证明了该方法可以进行贝类黑色素的脱盐处理工作。     

广西茅尾海牡蛎天然种苗种类鉴定和群体组成的初步分析

了解广西茅尾海牡蛎种质资源现状,有助于提高牡蛎采苗效果。通过在茅尾海采集常见5种牡蛎成体,并在牡蛎不同繁殖高峰期分别采集牡蛎D型幼虫DⅠ、DⅡ,在不同附着期分别采集牡蛎幼苗MⅠ、MⅡ、MⅢ,采用多重PCR技术对牡蛎成体、稚贝及幼虫进行种类鉴定。香港巨牡蛎(Crassostrea hongkongensis)在茅尾海牡蛎稚贝和幼虫高峰期均属于优势种;稚贝中香港巨牡蛎、有明巨牡蛎(Crassostrea ariakensis)和熊本牡蛎(Crassostrea sikamea)3个种类的平均比例分别为88.3%、6.7%和5.0%,香港巨牡蛎与熊本牡蛎、有名巨牡蛎相比差异显著(P0.05),熊本牡蛎与有明巨牡蛎差异不显著(P0.05)。香港巨牡蛎是茅尾海牡蛎优势种,7月12日之前投放采苗器可采集到数量多、种类单一的香港巨牡蛎。7月12日之后投放采苗器,附着的稚贝中有明巨牡蛎和熊本牡蛎比例增加,影响采苗效果及养殖生产。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.