细胞松弛素B诱导盘鲍三倍体的研究

每次在盘鲍三倍体诱导试验之前,都进行预试验,观察和了解在该温度下受精卵第一极体和第二极体出现的时间.当40%～50%的盘鲍受精卵出现第一极体时,采用以不同浓度的细胞松弛素B进行不同持续时间的处理抑制受精卵第二极体出现的方法诱导其三倍体.试验结果表明,在水温24.5℃下,诱导的起始时间为27min,诱导的浓度为0.70mg/dm^3,诱导的持续时间为10min,是三个诱导参数的较佳组合,其三倍体率达75%以上,并且胚胎的孵化率达75%,幼体的畸形率较低,为50%.本文还就诱导三倍体的一些问题进行了讨论.     

中国对虾三倍体的诱导研究——Ⅱ.细胞松弛素B处理

用细胞松驰素B(C.B)处理中国对虾(Penaeus chinensis)的受精卵,诱发三倍体,经培养已获得溞状幼体.实验所用C.B浓度为0.1～2.5mg/dm3.处理的起始时间是在受精后5～20min,处理的持续时间为10～40min.三倍体的诱导率达62.5%.C.B处理浓度越高,对极体排放的抑制力越强,但胚胎畸形率和非整倍体数量则增多.对虾三倍体的诱导成功,为对虾的多倍体育种提供了可能.     

华贵栉孔扇贝的三倍体诱导及生长比较

分别和细胞松驰素Ｂ和低温处理诱导华贵栉孔扇贝Ｃｈｌａｍｙｓｎｏｂｉｌｉｓ产生三倍体。抑制第一极体的三倍体诱导率分别４４．１％和３１．８％；抑制第二极体的三倍体诱导率分别为９０．２％和７２．７％。ＣＢ处理组幼虫的日增长率显著超过二倍体。     

静水压休克诱导大黄鱼三倍体

采用静水压休克方法诱导大黄鱼三倍体，在水温20-26℃条件下，卵受精后2min用450kg/cm^2的静水压处理大黄鱼受精卵2min，三倍体诱导率65.6%，孵化率相对对照组达70%。文中还就处理条件与三倍体诱导率和胚胎存活率关系进行了讨论。     

细胞松驰素B诱导栉孔扇贝产生三倍体的研究

本实验用细胞松驰素B(CB)抑制栉孔扇贝Chlamys(Azumapecten) farreri(Jones & Preston)第一极体的排出产生三倍体。抑制第一极体排出的最佳时间是在卵子受精后10min。25℃下,卵子受精后10min,0.05ppm的CB持续处理20min,获得了50％的三倍体。23℃下,卵子受精后10min,0.1ppm的CB持续处理15min,得到了39％的三倍体。     

利用咖啡因和热休克诱导太平洋牡蛎三倍体

报道采用咖啡因和热休克相结合的方法 ,抑制受精卵第二极体释放诱导太平洋牡蛎三倍体的优化方案。实验结果表明 ,三倍体诱导率随着咖啡因浓度的增高而增高 ,D形幼虫的孵化率却随着咖啡因浓度的增高而降低 ;所进行 30～ 36℃热休克温度试验 ,其对三倍体诱导率影响不大 ,但对孵化率影响明显。在 2 3～ 2 5℃条件下 ,当 50 %受精卵出现第一极体时 ,用浓度为 2 g/ L的咖啡因 ,结合 33℃± 1℃的热休克 ,处理牡蛎受精卵 15min,三倍体诱导率达 80 %以上 ,孵化率在 4 5%左右。通过此法诱导的三倍体群幼虫的成活与生长情况与其二倍体群体无明显差异。     

低渗诱导栉孔扇贝三倍体及与其它方法的比较

采用低渗抑制受精卵第2极体(PB2)的释放诱导栉孔扇贝(Chlamys farreri)三倍体。水温20℃时,分别进行不同盐度处理(8~20)、不同起始处理时间(受精后15~40 min)和不同持续处理时间(10~25 min)的实验,对三倍体处理组和对照组幼虫的生长进行观察,同时将低渗、6-DMAP、热休克、冷休克4种诱导方法进行对比。结果表明:受精后30 min开始处理20 min,诱导率最高,可达(92.36±2.41)%,卵裂率为(49.78±6.51)%,孵化率为(61.82±1.63)%;D形幼虫期,处理组幼虫表现出明显的生长优势(P0.01),不仅生长速度快,而且发育到变态时个体比二倍体大;低渗诱导的三倍体率与6-DMAP相比无显著差异(P0.05);与热休克和冷休克相比差异显著(P0.01)。     

利用不同盐度诱导长牡蛎三倍体的研究

采用低盐度(4、6、8、10、12、14、16)和高盐度(40、45、50、55、60、65、70)在40%~50%受精卵出现第一极体时处理10和15min,进行长牡蛎三倍体的诱导。在低盐度诱导三倍体实验中,随着盐度降低,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率差异显著(P0.05),孵化率差异不显著(P0.05)。当盐度为8时,处理受精卵10与15min,三倍体诱导率最高分别可达84.4%和91.0%,两处理组三倍体诱导率差异显著(P0.05)。在高盐度诱导三倍体实验中,随着盐度升高,D型幼虫孵化率逐渐降低,处理10和15min的卵裂率和孵化率均差异显著(P0.05)。当盐度为55时,处理受精卵10min,三倍体诱导率最高为80.3%;当盐度为60时,处理受精卵15min,三倍体诱导率最高为97.1%,两处理组三倍体诱导率差异显著(P0.05)。研究发现,在盐度为8和60条件下,40%~50%的受精卵出现第一极体时,处理15min,长牡蛎三倍体诱导率最高。     

6-DMAP诱导缢蛏三倍体的研究

用6-DMAP抑制受精卵第二极体排放的方法诱导缢蛏三倍体的试验．结果表明：6-DMAP在100～500μmol／dm^3处理浓度范围内均可以诱导出三倍体，随着药物处理浓度和处理时间的提高，三倍体倍化率和D形幼虫畸形率有不同程度的提高，而D形幼虫孵化率会随之下降．综合来看，在30％卵子受精并出现第一极体，6-DMAP浓度为300μmol／dm^3和处理持续时间为20min时的处理组的处理效果优于其他处理组组合．     

细胞松弛素B对菲律宾蛤仔三倍体诱导及早期胚胎发育的影响

采用0.25 mg/L、0.5 mg/L、0.75 mg/L、1.0 mg/L细胞松弛素B(CB)抑制第二极体(PB2)的释放诱导菲律宾蛤仔三倍体,观察三倍体蛤仔的早期胚胎发育。结果表明:CB的浓度对菲律宾蛤仔三倍体的诱导以及胚胎发育影响显著(P<0.05),0.5与0.75 mg/L CB处理组诱导率较高,分别达89.4%与89.2%;各组第一极体(PB1)同步释放,处理组PB2受到明显抑制;CB处理浓度与胚胎发育速度呈负相关,与各发育阶段的畸形率及畸形程度呈正相关。综合诱导率及早期胚胎发育状况,0.5 mg/L是CB诱导菲律宾蛤仔三倍体的适宜浓度。     

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.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

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。     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

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.     

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.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

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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,