方斑东风螺人工育苗试验

2003年3月31日至8月31日，在水温25．0～30．0℃，盐度28．3～35．1，pH8．1～8．5时，在广东省湛江雷州市进行了方斑东风螺人工育苗试验，培育出壳高6～10mm幼螺300多万只。结果表明。投喂新鲜海鱼、蟹类、虾类，短时间阴干、流水刺激或流水培育可以诱导方斑东风螺亲螺交配产卵；幼虫培育密度以2．0～2．5万个／m^3为宜，幼虫培育期间投喂多种天然混合饵料，可以提高幼虫成活率，缩短幼虫浮游时间，提前变态；及时投放附着砂，有利于幼虫顺利变态；壳高5～10mm幼螺培育密度保持在1500个／m^2左右，每10～15d清洗一次附着砂，可加速幼螺的生长，提高幼螺成活率，有效防止病害的发生。     

几种环境因子对方斑东风螺稚螺生长与存活的影响

研究了不同的海水温度、盐度、pH值和底质等主要环境因子对方斑东风螺（Babylonia areolata）稚螺生长与存活的影响。结果表明,方斑东风螺稚螺生存和生长的最高和最低临界水温分别为35℃和11℃,适宜水温为14～32℃,最适水温为26～29℃,适温范围内,稚螺的日生长率随着水温的升高而增加,在29℃时达到峰值,为262．5μm／d。方斑东风螺稚螺生存和生长的最高和最低临界盐度分别为38和11,适宜盐度为14～35,最适盐度为17～29,适宜盐度范围内,低盐海水有利于提高稚螺的日生长率,盐度对稚螺生长的影响不如温度的影响明显。方斑东风螺稚螺在pH为8．0时,有最高日生长率,为220．4μm／d,pH高于9．0、低于7．0时,日生长率与成活率显著降低。池底铺砂可显著提高稚螺的日生长率,但对稚螺的成活率无显著影响。     

方斑东风螺养殖技术研究

本工作对方斑东风螺亲螺培育及产卵、种苗培养、幼螺养成过程中的一系列技术进行了研究,并对其行为及生态习性进行了观察.实验结果表明,在方斑东风螺养殖过程中,不同饵料培养效果的优劣顺序为牡蛎 〉鱼 〉鲆饵 〉鳗饵.在培养密度较高时,玻璃缸流水培养效果要优于静水培养.但同为低密度培养时,静水与流水效果差异不大.水泥池养殖结果显示平面养殖每平方米可养壳高15mm以下幼螺1 000～2 000个,壳高15～20mm的1 000～1 200个,壳高20～30mm以上的600～800个.使用鲍笼立体养殖亦可获得很高的成活率与生长率,将壳高20mm以上的幼螺放入鲍笼,4～5层笼叠加立体养殖,每平方米可养1 667～2 333个,笼养60d的成活率达95%以上.     

文蛤MERETRIX MERETRIX LINNAEUS工厂化人工育苗试验

文蛤的人工催产、浮游幼虫培育和稚贝水泥池培养试验结果表明：（1）用阴干与流水结合的方法刺激亲贝能获得理想俏产效果。（2）在水温28．0～29．1℃,比重1．0160—1．0187,pH值8．2－8．4条件下,用亚心形扁藻作文蛤D幼的开口饵料和壳顶幼虫饵料,生长快（日增长高达24．5μm）、成活率高（72．3％）、浮游期短（仅5－6天）。（3）文蛤眼点功出水泥池无砂底附苗试验获得成功,且单位面积附苗量高达433．3万颗／m2。（4）室内水泥池铺砂培养文蛤稚贝,前期生长快,但当壳长达300μm后,稚贝分泌一种粘液,生长和成活受到影响。建议定期翻池洗苗,当壳长达500μm后尽早将苗移至池塘内砂滩培养。     

2种东风螺软体部和生殖腺脂肪酸组成研究

利用气相色谱-质谱(GC-MS)联用技术测定了野生台湾东风螺(Babylonia formosae),方斑东风螺(Babylonia areolata)及养殖方斑东风螺软体部和生殖腺脂肪酸组成及其含量.结果表明,2种贝软体部和生殖腺的15种主要脂肪酸中,不饱和脂肪酸(UFA)含量较饱和脂肪酸(SFA)含量高.野生台湾东风螺、方斑东风螺及养殖方斑东风螺软体部的UFA质量分数分别为68.22%、67.23%和76.05%: 其软体部SFA质量分数分别为28.16%,28.23%和21.53%.多不饱和脂肪酸(PUFA)质量分数高,n-3PUFA和n-6PUFA质量分数占总脂肪酸的39.20%～64.53%,其中二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)质量分数占总脂肪酸的13.82%～34.22%,养殖方斑东风螺的质量分数最高.研究发现,2种东风螺,特别是养殖的小型方斑东风螺,不仅具有较高的营养价值,且是EPA和DHA理想的提取原料.     

北方地区秋季日本对虾室内高密度精养的试验

为充分利用每年的8月以后直到翌年3月份都处于休闲状态的育苗场设施资源，笔者于1999年8月在河北黄骅进行日本对虾室内高密度精养的试验。在水温23－28℃、盐度28－32下，8月27日放苗，11月24日收成，养殖时间87d，单位水体产量平均为0．818kg/m^3，平均存活率为50．1％，旬生长率平均为0．75cm，成虾体长平均8cm，饵料系数为2．51，投入与产出比为2．5，平均单位水体创利63．83元／m^3，其结果说明本养殖模式不仅是可行的，而且具有利用率和效益高、实用性强的优点。本文还就相关问题进行了讨论。     

渤海1999年4月运动类铃虫的平面分布

研究了1999年4月末用浅海Ⅲ型网在渤海30个站住采集的浮游生物样品中的砂壳纤毛虫,发现砂壳纤毛虫种类单一,几乎全部为运动类铃虫(Codonellopsis mobilis Wang 1936),丰度为32～10731个／m^3,碳生物量为0～1．52mg／m^3。     

低盐度对方斑东风螺摄食与生长的影响

方斑东风螺的适宜盐度在21以上，适应盐度下限应为15．在21～33的盐度范围内，小水体的实验条件下，平均体重0．27g、平均壳长11．2mm的方斑东风螺．投喂小管枪乌贼，日平均掇食率10．2％～11．6％，体重日均生长11．3～12．0mg，壳长日均生长123．1～141．91μm，盐度逐渐降至15时，方斑东风螺的摄食率和生长速度都明显下降．把近岸自然海水的盐度29作为盐度瞬间下降或上升的起点和终点．当盐度从29瞬间下降时，不影响其摄食和生长的最低终点盐度应高于21．当盐度瞬间上升至29时，不影响其摄食和生长的最低起点盐度应高于18．     

盐度对方斑东风螺耗氧率和排氨率的影响

采用实验生态学方法研究盐度对方斑东风螺Babylonia areolata耗氧率和排氨率的影响。根据方斑东风螺个体大小设立A、B、C(壳高分别为6.86±0.24、4.75±0.37、3.15±0.12cm,软体部干重分别为11.064±0.361、4.245±0.690、2.015±0.122 g)3组,盐度设13、18、23、28、33等5个梯度,实验水温为27—28℃。结果表明:(1)盐度、个体大小对方斑东风螺的耗氧率有显著的影响(p<0.01)。盐度在13—28之间时,3组方斑东风螺的耗氧率都随盐度的升高而增加;当盐度升至33时,耗氧率下降。方斑东风螺的软体部干重(W)与单位体重耗氧率(O)之间的关系符合幂函数方程O=aWb,其中a值的范围为1.365 5—3.072 2,平均值是2.236 8,b值的范围为-0.195 2—-0.093 6,平均值为-0.130 6。(2)盐度、个体大小以及二者的交互作用均对方斑东风螺的排氨率有显著的影响(p<0.01)。盐度在13—28之间时,3组方斑东风螺的排氨率随着盐度的升高而增加;当盐度升至33时,排氨率下降。方斑东风螺的软体部干重(W)与单位体重排氨率(N)之间的关系也符合幂函数方程N=c Wd,其中c值的范围为261.769 4—360.427 9,平均值为320.643 4,d值的范围是-0.325 3—-0.189 0,平均值是-0.248 5。(3)单位体重耗氧率和排氨率与盐度(S)、软体部干重(W)的二元线性回归方程分别为:O=1.208-0.039W+0.039S(R=0.578,F=10.517,显著性概率=0.000)、N=-210.442-9.255W+2.965S(R=0.813,F=40.834,显著性概率=0.000)。     

两种东风螺幼虫附着和变态的化学诱导研究

在持续24h作用下,12×10-3mol/dm3 K+可有效地诱导台湾东风螺(Babylonia formosae)和方斑东风螺(B.aerolata)的浮游幼虫90%以上完全变态.持续作用24h,15×10-3mol/dm3 K+对方斑东风螺幼虫有毒害作用,但作用12h可取得较好的诱导效果.增加K+诱导变态的稚贝能正常活动和摄食.增加K+诱导的幼虫变态率随幼虫平均壳高的增大而提高.L-多巴、肾上腺素和去甲肾上腺素在5.5×10-6～5.5×l0-5mol/dm3时对方斑东风螺幼虫的变态无诱导活性,而多巴胺在10-4mol/dm3时可诱导较12×10-3mol/dm3 K+约少一半的变态率.钾通道阻滞剂TEA对K+诱导两种东风螺幼虫变态无阻抑作用.根据添加KCl诱导幼虫变态试验结果,初步认为幼虫获得变态能力时的壳高,在台湾东风螺是860.2～1009.8μm,在方斑东风螺是849.6～956.0μm.两种东风螺的浮游幼虫均有变态延迟现象.     

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.     

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.     

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,     

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.