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1.
东海浮游介形类生态适应分析 总被引：2，自引：0，他引：2
根据1997~2000年东海23°30'~33°N,118°30'~128°E海域4个季节海洋调查资料,用浮游介形类物种丰度和同步表层温、盐度数据进行曲线拟合,构造数学模型,计算介形类分布最适温度和盐度值,并参考其地理分布和生态适应特征分析,确定东海浮游介形类主要物种的生态类型.结果表明:在浮游介形类优势种中,后圆真浮萤(Euconchoecia maimai)、短棒真浮萤(E.Chierchiae)、针刺真浮萤(E.aculeata)、细长真浮萤(E.elongata)和齿形海萤(Cypridina dentata)等为亚热带外海种.这些种具有广泛的分布,如果冬、春季在较低水温出现,与东海北部外海暖流带入有密切的关系.腹突拟浮萤(Paraconchoecia decipiens)、猬刺拟浮萤(P.echinata)、棘刺拟浮莹(P.spinifera)、长拟浮萤(P.oblonga)、大浮萤(Conchoecia magna)和葱萤(Porroecia porrecta)等是热带大洋种,这些种主要分布在黑潮暖流、台湾暖流和台湾海峡水域.同心假浮萤(Pseudocon-choecia concentrica)和Paraconchoecia sp.最适温度较低,但地理分布特征显示前者是亚热带外海种,后者是暖温带外海种.所提到介形类其他物种最适盐度大多超过34,但最适温度在15~20℃之间.依据有关文献,这些种在我国从东海到南沙海域都有分布,分布虽广但数量稀少,难有证据表明这些种分布与暖流有密切的关系,是亚热带外海种. 相似文献
2.
东海浮游翼足类(Pteropods)数量分布的研究 总被引：10，自引：1，他引：10
根据1997～2000年东海海域23°30'～33°00'N,118°30'～128°00'E的4个季节海洋调查资料,运用定量、定性方法,探讨了东海浮游翼足类总丰度的平面分布、季节变化及变化的动力学机制.结果表明,东海翼足类总丰度和出现频率有明显的季节变化,均为秋季最高,夏季次之,春季最低;总丰度在各个季节基本上呈东海南部高于北部、外海高于近海的分布趋势;春季的尖笔帽螺(Creseis acicula)、夏季的锥笔帽螺(Creseis virgula)、秋季的蝴蝶螺(Desmopterus papilio)和冬季的马蹄螔螺(Limacina trochiformis)是导致总丰度季节变化的最主要的种类;冬、春和夏3个季节丰度变化及4季总丰度的变化同表层或10m层水温有非常显著的线性相关关系,与底层温度及盐度的相关关系不显著.夏季翼足类高丰度区位于台湾暖流与黑潮暖流的分支处;从夏季到秋季,翼足类随着台湾暖流向北扩展,并在与长江冲淡水,闽浙沿岸水团,黄海水团等交汇处形成高丰度(大于500×10-2个/m3)和较高丰度(250×10-2～500×10-2个/m3)分布区.水温和海流是影响东海翼足类总丰度分布的主要环境因素. 相似文献
3.
近来的研究表明,一些所谓的环球或环极地分布的广布种实际上包含着一些局限性分布的隐存种,物种多样性可能被低估。本文采用形态学和DNA条形码技术相结合的方式,对印度洋和西北太平洋海域的龟螺属(Cavolinia)和小龟螺属(Diacavolinia)的种类进行了分类学研究和物种鉴定。结果表明,线粒体16S rRNA基因数据不支持小龟螺属形态种的划分,分布于西北太平洋的D. grayi、D. vanutrechti、D. pacifica、D. elegans、D. angulosa等多个形态种可能属同一个种,即长吻小龟螺(D. longirostris)。COI基因数据也不支持钩龟螺(C. uncinata)亚种和变形的划分。许多形态特征不能作为种或种下分类单元的区分依据。钩龟螺、球龟螺(C. globulosa)和长吻小龟螺在COI系统树中均形成2个地理支系,其内部可能存在隐存种。西北太平洋海域长吻小龟螺的核基因组中存在线粒体假基因,对DNA条形码分析产生严重干扰。 相似文献
4.
台湾暖流深层水变化特征的分析 总被引：4，自引：0，他引：4
潜居于闽、浙外海深、底层的台湾暖流深层水(又称东海上层水或东海次表层水),是东海陆架西部海域的主要水团之一。台湾暖流深层水的消长变化,对于东海陆架西部海域的水文状况,以及渔业生产的影响非常显著。关于台湾暖流深层水,国内、外海洋学者曾对其温、盐度特性和来源作过一些研究,但对其变化(季节变化和多年变化)特征研究尚少。探讨这一问题,将有助于进一步了解该水团的基本特征。 相似文献
5.
材料取于中、日黑潮合作调查期间,日本国水产厅西海区水产研究所“阳光丸”调查船于1986年6月15-28日在日本九州西南部东海黑潮区(29°30'-32°00'N,128°00'-130°30'E)的调查.浮游动物样品使用装有TSK型流量计的北太平洋浮游生物网在50-0m垂直拖取;温、盐度等项目采用CTD测定.调查区初步鉴定浮游桡足类134种(含4spp.),其中多数为热带、亚热带种,少数为暖温带种和世界广布种;群落组成以高温高盐种占主体.主要的优势种有:Oncaea venus-ta、Oithona plumifera、Clausocalanus furcatus、Clausocalanus arcuicornis、Paracalanus aculeatus、Oithona similis、Temora turbinata、Oncaea media、Undinula darwinii、Acartia negligens、Corycaeus speciosus、Scolecithrixdanae等.浮游桡足类总个体数平均367.6个/m3,其平面分布以黑潮流轴区数量较低,而种数则较多.黑潮暖流及中国大陆沿岸流的消长变化影响着浮游桡足类的群聚结构和分布;而水温是浮游桡足类种类组成和数量分布的主要制约因素之一. 相似文献
6.
东海南部黑潮区春季温盐度垂直分布类型及其逆现象成因的初步分析 总被引：3，自引：1，他引：2
用１９８８～１９９６年在东海南部黑潮区共５个航次的春季水文观测资料,分析了该海区温、盐度垂直分布类型的地理分布,讨论了春季温、盐度逆转现象的形成原因。这主要是春季季风已转变为南风,在南风的驱动下,迫使表层水离岸向东向外海扩张,台湾暖流向北伸展,黑潮次表层水的向岸入侵的结果 相似文献
7.
夏季青岛近海浮游动物种类组成、群落结构及多样性 总被引：2，自引：0，他引：2
2006年7月在青岛近海海域(35°19′～36°35′N, 119°50′～121°33′E)进行浮游动物采样调查,研究了青岛近海浮游动物的种类组成、群落结构及多样性.调查共鉴定浮游动物48种,浮游幼虫18类.种类数的平面分布为灵山湾、琅琊台湾附近海区较多,其他海区较少.优势种类有中华哲水蚤(Calanus sinicus)、强壮箭虫(Sagitta crassa)、拟长脚虫戎(Parathemisto gaudichaudi)、长尾类幼虫(Macrura larvae)和短尾类幼虫(Brachyura larvae).调查海区近岸暖温类群、近岸暖水类群、近岸低盐类群、温带外海类群四种生态类群共存,但以近岸暖温类群为主.浮游动物丰度、生物量的水平分布趋势与表层温度、盐度的水平分布趋势相似,都从调查海区的外海区向近岸逐渐降低;Shannon-weiner多样性指数与Pielou均匀度指数水平分布趋势与表层温度、盐度相反,从青岛近岸向调查海区外海逐渐降低.与该区域1959年同月份的调查数据相比,浮游动物主要种类组成、丰度、生物量差别不大,主要种类中华哲水蚤丰度有较大的增加. 相似文献
8.
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
9.
东海浮游介形类(Ostracods)分布特征 总被引：8，自引：1，他引：7
根据1997~2000年东海(23°30'~33°00'N,118°30'~128°00'E)海域四季海洋调查资料,探讨了东海浮游介形类分布特征及与环境的关系.结果表明:东海浮游介形类丰度占浮游动物总丰度的3.47%;春、夏、秋和冬四季平均丰度分别为0.70,1.72,2.57和0.90个/m3;冬春季的短棒真浮萤(Euconchoecia chierchiae),夏季的后圆真浮萤(Euconchoecia maimai)和秋季的齿形海萤(Cypridi-na dentata)分别是各季的主要优势种;夏、秋季介形类总丰度与水文环境因子的线性相关性不显著,春季与表层盐度相关,冬季与表层温度相关.东海北部外海四季均有介形类高丰度区出现,但在东海北部近海长江口及其邻近舟山水域,介形类数量相对较低.在东海南部,冬春季高丰度区位于外海,夏秋季在近海.东海浮游介形类基本上是一大类较为典型的暖水性且具有集群行为的海洋浮游动物.介形类秋季高丰度区和较高丰度区的分布与太平洋褶柔鱼(Todarodes pacificus)、绿鳍马面鲀(Navodon Septentrionalis)、鲐鯵鱼类等渔场的位置基本一致,在渔业上有重要的意义. 相似文献
10.
台湾海峡水运移路径的分析 总被引：1，自引：0，他引：1
本文主要根据1985年9月台湾暖流专题调查所取得的海流和温、盐度资料,对夏末、秋初台湾海峡水进入东海后的运移路径和混合情况,进行了比较详细的分析研究。得出,台湾海峡水进入东海后仍以NNE方向流动,约在福建北部外海(27°N以北,121°45′E以东)开始楔入来自台湾东北的黑潮表层水之中,并与其发生混合形成台湾暖流表层水。这一结果进一步证明了作者以前提出的关于台湾暖流来源的看法是符合客观实际的。 相似文献
11.
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
18.
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