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1.
东海海樽类数量分布及与环境的关系 总被引：1，自引：0，他引：1
提要根据1997—2000年东海23°30′—33°00′N、118°30′—128°00′E海域4个季节海洋调查资料,采用方差贡献和逐步回归分析方法探讨东海海樽类的数量变化和相应的动力学。结果表明,海樽类是东海浮游动物第二大类群,在数量上仅次于桡足类,其丰度春季最高,夏季次之,冬季最低;冬、春和夏季的东方双尾纽鳃樽(Thalia orientalis)和冬、秋季的小齿海樽(Doliolum denticulatum)是影响海樽类数量分布的主要优势种;海樽类高丰度区常位于暖流与各水团交汇处的偏暖流一侧,其数量变化的动力主要来自暖流势力的消长。海樽类在东海出现率较低,集群性强,较高丰度的分布仅局限在暖流势力范围内,其高丰度水域是东海暖流锋面的一个重要标志。 相似文献
2.
秋季黄海WP2型网采浮游动物的群落特征 总被引：1，自引：0，他引：1
《中国海洋大学学报(自然科学版)》2015,(7)
中国传统的海洋浮游动物调查方法存在对中小型浮游动物数量低估的情况。为了较全面地掌握黄海浮游动物群落特征、弥补黄海浮游动物研究的有关不足,作者采用国际通用的WP2型浮游生物网,于2012年11月对黄海海域(121°00′E~124°30′E,32°00′N~39°44′N)的中型浮游动物的种类组成、丰度和优势种进行调查,并结合环境因子对浮游动物的群落结构进行分析。本航次共鉴定浮游动物成体119种,浮游幼虫25类。该海区浮游动物平均丰度(不含夜光虫)为4 331.0ind/m3。优势种以小拟哲水蚤和拟长腹剑水蚤小型桡足类为主。根据各站位间浮游动物组成的相似程度和地理分布,将黄海区域的浮游动物分为北黄海群落、黄海中部群落、苏北沿岸群落和东海近岸混合水群落。与以往大型浮游生物网采资料相比,本次调查的浮游动物丰度要高出一个数量级,体型较小的浮游动物的优势地位显著提升,但群落划分结果没有明显差别。 相似文献
3.
基于2011年5月至2012年4月(12月和翌年1—2月冰期除外)在渤海莱州湾逐月网采的数据资料,进行了莱州湾浮游桡足类胸刺水蚤(Centropages)种类组成、生态分布和生产力估算的研究。结果显示:莱州湾最为常见的胸刺水蚤是腹胸刺水蚤(Centropages abdominalis)和背针胸刺水蚤(C.dorsispinatus)。腹胸刺水蚤主要出现在冬、春季,该种5月丰度最高,月均丰度为435ind./m~3;背针胸刺水蚤主要出现夏、秋季(7—11月),该种9月丰度最高,月均丰度(76ind./m~3)明显低于腹胸刺水蚤相应值。成体中,两种胸刺水蚤的雌/雄比介于1—2。水温较高时,两种胸刺水蚤的桡足幼体和成体的前体长较小。腹胸刺水蚤密集区(100ind./m~3)主要分布于莱州湾湾口外东北侧,该水域水温多低于20°C;而背针胸刺水蚤密集区主要分布于水温介于21—25°C的湾内西侧近岸水域。粗略估算得到腹胸刺水蚤和背针胸刺水蚤桡足幼体和成体的月均生物量值分别为471μg C/m~3和50μg C/m~3,日生产力分别为89μg C/(m~3·d)和15μg C/(m~3·d)。两种胸刺水蚤具有明显季节更替和丰度空间分布互补性。背针胸刺水蚤已取代了2000年以前的优势种瘦尾胸刺水蚤(C.tenuiremis),成为莱州湾夏、秋季主要的胸刺水蚤。 相似文献
4.
利用现场海水培养实验,结合浮游动物网样数据,研究长江口邻近海域几种优势桡足类(中华哲水蚤、背针胸刺水蚤、太平洋纺锤水蚤和精致真刺水蚤)对微型浮游动物的摄食影响。结果表明,精致真刺水蚤虽然属于肉食性种类,但几乎不摄食微型浮游动物;其余三种杂食性桡足类中华哲水蚤、背针胸刺水蚤和太平洋纺锤水蚤对微型浮游动物(纤毛虫+异养甲藻)的摄食率分别为0.66、0.09和0.59μg C/(ind·d),分别占其日总摄食量的29%、24%和37%。其中,异养甲藻在初始生物量和对桡足类饵料贡献上分别占整个微型浮游动物的30%和28%,是微型浮游动物中一个重要的组成类群。中华哲水蚤对微型浮游动物的摄食率与初始食物浓度有显著的正相关关系,并且对体长20μm纤毛虫的清滤率要明显高于对体长20μm的纤毛虫(P0.01)的清滤率,表明其偏好摄食较大个体的食物。通过Chesson选择性指数显示,尽管微型浮游动物在生物量上远小于浮游植物,但桡足类能优先选择摄食微型浮游动物;进一步结合网采浮游动物数据,获得各站三种优势桡足类丰度平均占桡足类总丰度的77%,但它们对微型浮游动物现存生物量的摄食压力仅为0.8%,表明桡足类对微型浮游动物群落的下行控制作用并不明显,仍有大部分微型浮游动物生物量未通过摄食途径进入到桡足类群落中。 相似文献
5.
台湾海峡西部海域浮游桡足类的生态 总被引：6，自引：0，他引：6
本文根据1984年5月—1985年2月在台湾海峡中线以西海域不(含海岸带水域)4个季度月综合调查及海潭岛南部外海定点昼夜垂直分层采集所获浮游动物样品进行分析,结果表明,本海域浮游挠足类188种(国内新记录7种,本海区首次记录19种),主要的优势种有锥形宽水蚤、中华哲水蚤、精致真刺水蚤、普通波水蚤等。其群落组成以热带和亚热带种为主,少数为暖温带种。根据其生态习性及分布特点可分为近岸低盐、外海高盐及广温广盐三个生态类群。海潭岛南部外海浮游挠足类的昼夜垂直移动可分为移动显著和不显著两种类型。本海区浮游桡足类种数的季节变化和平面分布均与温、盐度的变化趋势基本一致,其不同生态习性的浮游桡足类的分布与影响本海区的水系的消长密切相关。 相似文献
6.
台湾以北海域浮游桡足类生物海洋学特征的研究：I.数量分布 总被引：4，自引：3，他引：1
根据１９８７￣１９９０年间在台湾以北海域进行的６个航次的调查资料,对该海域浮游桡足类数量分布作了探讨,结果表明,本区浮游桡足类丰度在春季最高,冬季最低,夏、秋季介于中间;黑潮锋内侧的桡足类丰度一般高于黑潮锋外侧,较高丰度区的分布具夏季最向外海、冬季最靠近岸、其他两季居民的趋势,这与黑潮锋位的季节摆动趋势基本相一致;浮游桡足类丰度的较高值区一般出现在不同水系的交汇区,尤其是黑潮次表层水涌升域的近岸边 相似文献
7.
东海浮游动物昼夜垂直移动的初步研究 总被引：12，自引：0，他引：12
于 1 994年 4月 (春季 )和 1 1月 (秋季 )在东海 41 0站 ( 1 2 4°5 9′E ,2 9°32′N ,水深 85m)对浮游动物的昼夜垂直移动变化规律进行 2 4h定点连续观测。结果表明 ,春季和秋季浮游动物总数量的昼夜垂直移动变化均不明显 ,其数量主要分布在 0— 1 0m的表层水域 ;在桡足类的优势种中 ,个体较大的中华哲水蚤第V期和成体、精致真刺水蚤 ,以及磷虾类的中华假磷虾和太平洋磷虾等 ,其昼夜垂直移动比较明显。而一些个体较小的种类 ,如小拟哲水蚤、近缘大眼剑水蚤和其他种类的幼体、被囊类的优势种长尾住囊虫等 ,无论是在春季还是在秋季 ,它们的昼夜垂直移动均不明显 ,主要集中在 0— 1 0m的表层水域 相似文献
8.
根据１９９０年春季至１９９１年冬季采自南日岛海域浮游动物样本，初步鉴定出９８种浮游动物和１２类浮游幼虫。桡足类种类和数量均占优势。精致真刺水蚤、中华哲水蚤、肥胖箭虫、中华假磷虾和短尾类氵蚤状幼虫为优势种。本文报道了浮游动物总生物量，总个体数和种类数的季节分布及平面分布，讨论其分布与环境的关系。 相似文献
9.
本研究基于2017年秋季在渤海湾海域以浅水Ⅰ型浮游生物网采集的浮游动物样品,分析了浮游动物的种类组成、丰度分布和生物多样性;通过结合现场获取的环境参数,探讨了环境因子与浮游动物群落特征之间的关系。结果如下:秋季浮游动物调查共鉴定各类浮游动物22种、浮游幼虫6类,合计种类数为28。桡足类为最为优势的类群,其在浮游动物的物种丰富度中占46.4%。渤海湾秋季浮游动物的优势种类共5个,包括中华哲水蚤、小拟哲水蚤、真刺唇角水蚤、近缘大眼水蚤和强壮箭虫。秋季浮游动物平均丰度为86.9ind./m3,平均湿重生物量为640.7mg/m3,香农-威纳指数和物种丰富度指数分别为1.87和1.08。浮游动物丰度与环境因子间的相关性分析表明,秋季影响渤海湾海域浮游动物分布的主要环境因子组合为盐度、叶绿素和浊度。与同期历史数据相比,浮游动物的丰度和生物量均有所下降。 相似文献
10.
长江口及邻近海域浮游端足类分布特征 总被引：1，自引：0，他引：1
根据2002—2003年长江口28°00'~32°00'N,122°00'~123°30'E海域4个季节的海洋调查数据,运用定量、定性方法探讨了长江口及邻近海域浮游端足类总丰度的平面分布、季节变化及与渔场的关系,分析了优势种的数量变动和对浮游端足类总丰度的贡献,并与东海外海种类的生态特征做了比较。结果表明,长江口及邻近海域浮游端足类丰度季节变化主要受温度的影响,而平面分布变化则与盐度相关。平均丰度在夏季最高(2.75个/m3),在冬季最低(0.10个/m3)。本次调查共发现浮游端足类49种,江湖独眼钩虾(Monoculodes limnophilus)和裂颏蛮(Lestrigonus schizogeneios)是最主要的优势种,江湖独眼钩虾在四季中对端足类总丰度都有很大贡献,在春秋冬三季为第一优势种,说明江湖独眼钩虾对相对较低的温度具有一定的适应能力,裂颏蛮则只在春夏秋季有较大贡献,其中夏季裂颏蛮贡献率为0.87,高于江湖独眼钩虾,这与裂颏蛮具有较高温度的环境适应能力有关。浮游端足类种类数与总丰度都与表层温度的线性相关显著,同表层盐度的相关不显著。作为长江口鱼类的重要饵料之一,浮游端足类的数量分布对长江口和舟山海域渔场的形成有重要的意义。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
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. 相似文献
12.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
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. 相似文献
13.
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. 相似文献
14.
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。 相似文献
15.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
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. 相似文献
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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. 相似文献
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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. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
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. 相似文献