大黄鱼野生与养殖群体遗传结构的比较研究

采用垂直板型不连续聚丙烯酰胺凝胶电泳技术对福建野生与养殖大黄鱼(Pseudosciaena crocea)4个群体(湄洲野生群体、宁德野生群体、宁德养殖群体、连江养殖群体)的遗传结构进行了比较研究。结果表明,4个大黄鱼群体的平均每位点有效等位基因数为1.1250～1.1293,多态位点百分数为12.50%～18.75%,观察杂合度为0.1250,期望杂合度为0.0636～0.0677。湄洲湾野生群体的遗传多样性高于养殖群体。4个大黄鱼群体间的遗传分化很低,4个大黄鱼群体间遗传距离在0.0000～0.0001,平均遗传距离为0.0005,遗传分化系数(Fst=0.0004)低,基因流(Nm=609.6667)大。     

皱纹盘鲍野生与养殖群体遗传多样性的研究

用随机扩增多态DNA（RAPD）技术,对山东长岛（CW）、辽宁大连（DW）两个野生群体和山东崆峒岛（KC）一个养殖群体的皱纹盘鲍遗传多样性进行了分析.结果表明,CW和DW群体间的遗传距离为0.170 3,CW和KC群体间的遗传距离为0.367 3,DW和KC群体间的遗传距离为0.347 7,显示野生群体与养殖群体之间的亲缘关系已发生了变化.CW,DW和KC三个群体的多态位点比例分别为49.22%、50.78%和43.75%;平均杂合度分别为0.350 6,0.340 8和0.307 9.与野生群体相比,养殖群体的多态位点比例和杂合度都有不同程度的降低.     

中国近海皱纹盘鲍不同地理群体的遗传结构与变异研究

皱纹盘鲍(Haliotis discus hannai Ino)是我国重要的经济海洋生物资源，以其营养价值高、味道鲜美而居海产八珍之首。由于资源的过度采捕、日益增加的养殖活动及海区环境污染等，可能会使皱纹盘鲍的遗传结构发生改变，继而影响到其适合度。为了种质资源的保护和可持续利用，同时也为了进一步完善皱纹盘鲍苗种繁育技术工艺，对我国近海皱纹盘鲍野生群体的遗传结构和变异研究是很有必要的。 等位基因酶电泳技术是研究海洋贝类遗传结构与变异的重要手段之一。目前世界上已有近百种海洋贝类的遗传结构和变异得到研究(张国范，1992；张国范等， 1993)，皱纹盘鲍日本分布区不同群体遗传结构和变异研究也有相关报道(Fu jino et al., 1978)。本文作者采用等位基因酶电泳技术，随机选取了24个等位基因位点，对皱纹盘鲍我国分布区内四个野生群体的遗传结构和变异进行研究，为我国皱纹盘鲍种质资源研究和可持续利用提供基础数据。     

多鳞(Sillago sihama)鱚4个野生地理群体的微卫星标记分析

采用微卫星DNA分子标记方法对中国南部沿海多鳞鱚(Sillago sihama)广西北海、广东湛江、汕尾及海南三亚4个野生地理群体进行了遗传多样性及遗传分化等研究。结果表明:(1)用于研究的34对微卫星引物在4个群体中具有丰富的多态性,有效等位基因数介于1.71—20.46之间,多态信息含量PIC介于0.40—0.95之间。4个群体总的平均期望杂合度(He)为0.598,观测杂合度(Ho)为0.572,SY群体的杂合度最大(He=0.606,Ho=0.623),SW群体的最小(He=0.586,Ho=0.508)。(2)群体间F-统计量分析表明,群体遗传分化处于高度分化水平(Fst平均值为0.306);基于奈氏遗传距离(DA)构建的NJ和UPGMA聚类树均显示地理位置相邻的群体聚在一起。     

广东沿海杂色鲍养殖群体遗传多样性的微卫星分析

实验选取的7个杂色鲍(Haliotis diversicolor)养殖群体分别来自广东汕头、汕尾、惠东、湛江和徐闻,深圳野生驯养,利用7对微卫星引物对上述群体进行了遗传多样性和群体遗传结构的分析。结果显示:7个位点产生的等位基因数从7～13个不等,共检测到68个等位基因,平均每个位点的等位基因数为9.71个。有效等位基因数的范围为3.8～8.1,平均观测杂合度范围为0.422～0.906,平均期望杂合度范围为0.748～0.917。7个群体的多态信息含量变化范围为0.657～0.883,PIC值均在0.500以上,表现为高度多态性。与两个野生驯养的养殖群体相比,其他5个养殖群体均存在不同程度的遗传多样性降低。AMOVA分析显示,4.79%的遗传变异来自于群体之间,95.21%的变异来自于群体内的个体之间。研究表明,广东沿岸的杂色鲍具有较高的遗传多样性水平,7个群体之间呈现一定的遗传分化。     

漠斑牙鲆养殖群体微卫星遗传多样性的初步分析

为评估养殖过程对漠斑牙鲆遗传结构的影响, 本研究利用微卫星标记对漠斑牙鲆(Paralichthys lethostigma)山东胶南养殖群体(子一代)和江苏南通养殖群体(子三代)的遗传结构进行分析比较, 结果表明所使用的14 对引物中, 11 对引物在所选取的群体中具有多态性, 两个群体中共检测出了70 个等位基因(42 个有效等位基因), 总群体的平均观察杂合度(Ho)和期望杂合度(He)分别为0.36 和0.60。两个群体的Shannon’s 遗传多样性指数分别为1.18 和1.07, Nei’s 遗传多样性指数分别为0. 56 和0.51, 表明山东胶南群体的遗传多样性显著高于江苏南通养殖群体。两个养殖群体间的两群体间的遗传分化系数Fst 平均为0.1246, 遗传距离(Ds)为0.171, 遗传相似度为0.8432, 表明两个群体中度分化。由此可以得出, 在中国随着漠斑牙鲆累代养殖的开展, 其遗传多样性下降显著, 遗传结构已经出现了显著分化。因此, 在将来的繁育过程中应制定合理的育苗规划以维持漠斑牙鲆的多样性水平并保障产业可持续发展。     

九孔鲍养殖群体遗传变异的RAPD分析

为了解我国养殖九孔鲍Haliotis diversicolor supertexta的遗传多样性和遗传结构,用RAPD技术对我国福建、广东和海南的九孔鲍5个养殖群体进行了遗传变异分析。12条引物共扩增出141条清晰稳定的条带,大小范围为0.2—2.4kb,其中多态性条带97条,多态位点比例为68.8%。基因多样性介于0.210±0.193与0.247±0.187之间,平均为0.224,各群体间没有显著差异。聚类分析表明,福建东山群体和广东惠来群体亲缘关系最近,聚为一支;深圳、湛江和三亚群体亲缘关系较近,聚为另一支。群体间遗传距离介于0.062与0.135之间,福建东山群体与广东惠来群体间遗传距离最小,惠来群体与深圳群体间遗传距离最大。群体间FST值介于0.176与0.326之间,随机组合检验表明,群体间遗传分化已经达到显著水平,但东山和惠来与深圳、湛江和三亚2组之间遗传分化不显著。较高的遗传多样性水平表明近年来九孔鲍大规模死亡事件可能与遗传多样性并无直接相关,而较高的遗传多样性有利于遗传选育。不同地方群体间的显著分化表明,各地方群体应分别作为单独的"管理单元(management unit)"进行遗传资源管理,群体之间的移植应严格监管。     

多鳞鱚(Sillago sihama)4个野生地理群体的微卫星标记分析

采用微卫星DNA分子标记方法对中国南部沿海多鳞鱚(Sillago sihama)广西北海、广东湛江、汕尾及海南三亚4个野生地理群体进行了遗传多样性及遗传分化等研究。结果表明:(1)用于研究的34对微卫星引物在4个群体中具有丰富的多态性,有效等位基因数介于1.71—20.46之间,多态信息含量PIC介于0.40—0.95之间。4个群体总的平均期望杂合度(He)为0.598,观测杂合度(Ho)为0.572,SY群体的杂合度最大(He=0.606,Ho=0.623),SW群体的最小(He=0.586,Ho=0.508)。(2)群体间F-统计量分析表明,群体遗传分化处于高度分化水平(Fst平均值为0.306);基于奈氏遗传距离(DA)构建的NJ和UPGMA聚类树均显示地理位置相邻的群体聚在一起。     

盘鲍和皱纹盘鲍等位酶的生化遗传分析

应用聚丙烯酰胺凝胶电泳技术,对盘鲍(Haliotis discus discus)和皱纹盘鲍(Haliotis discus hannai)的养殖群体进行了10种等位酶的电泳检测和谱带遗传分析。确定了盘鲍的18个等位酶位点及21个等位基因,单态位点有15个;仅有3个位点是多态的,它们是Sod-1,Est-3,Mdh-1(P0.99标准),多态位点的百分数为16．67％,这些多态位点分析到2个等位基因。确定了皱纹盘鲍的18个等位酶位点及20个等位基因,单态位点有16个;仅有2个位点是多态的,它们是Sod-1,Est-3(P0.99标准),多态位点的百分数为11．11％,这些多态位点中也分析到2个等位基因。盘鲍和皱纹盘鲍在所有位点中共享大多数常见等位基因,因此在生化遗传上它们非常相似。该研究揭示了盘鲍和皱纹盘鲍养殖群体等位酶位点及其等位基因带谱的变异式样,为盘鲍和皱纹盘鲍的遗传结构及遗传育种的研究提供了一批等位酶位点及其等位基因的参考图谱。     

虾夷扇贝养殖群体及其子代的遗传多样性分析

虾夷扇贝(Patinopecten (Mizuhopecten) yessoensis)于1982年从日本引进,在中国已经成为一个很重要的产业.本研究利用微卫星标记,对獐子岛海域2个养殖群体虾夷扇贝(大耗岛、褡裢岛),1个日本野生群体遗传多样性进行了评估,并对2个养殖群体的群体内繁育和群体间杂交后代进行了遗传和生长检测.结果表明:养殖群体与日本野生群体相比,其遗传多样性没有显著降低,养殖群体遗传多样性较高,养殖状况暂时良好.TL群体和DH群体遗传距离很近, DH、TL群体和RB群体的遗传距离远大于 TL群体和 DH群体间的遗传距离.说明2个养殖虾夷扇贝群体遗传分化较小.分别对4个子代群体的壳长、壳高在幼苗培育第1、5、10、15、20、100、190天进行测量,结果表明生长性状差异不显著.4个子代群体的遗传多样性差异也不显著,说明养殖群体的遗传背景不清楚,种质资源混交较严重.本研究结果反映了我国虾夷扇贝种质资源评估状况,并为虾夷扇贝的健康养殖提供基础数据.     

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.     

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。     

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.     

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.     

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.