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1.
于2010 年5 月和10 月在渤海湾南部进行了10 个站位的浮游动物生态调查,分析了强壮滨箭虫对浮游动物的摄食
压力,结果表明,春季强壮滨箭虫（Aidanosagitta crassa）的数量分布受控于温度和盐度,强壮滨箭虫的生物量为279 mg/m3,
丰度为33.8 ind/m3,摄食率为0.95mg C/m2·d,强壮滨箭虫对浮游动物总生产力和现存量的摄食压力分别为6.98 %和0.21 %,
优势种中华哲水蚤（Calanus sinicus）的数量分布与强壮滨箭虫呈现显著相关,相关系数为0.648,中华哲水蚤是强壮滨箭虫
主要的食物来源之一。秋季,强壮滨箭虫生物量和丰度分别为66 mg/m3和30.5 ind/m3,摄食率为0.50 mgC/m2·d,强壮滨箭虫
对浮游动物总生产力和现存量的摄食压力分别为3.43 %和0.72 %,强壮滨箭虫的数量与桡足类的数量呈显著相关,中小型
桡足类是强壮滨箭虫的主要食物来源。研究表明,温度和黄海海流是强壮滨箭虫摄食压力变化的主要因素。 相似文献
2.
根据对胶州湾外一站位连续1年逐月采样所获得的资料,研究报道了南黄海强壮箭虫(Sagittacrassa)的生活史特征。南黄海强壮箭虫共有5个世代:(1)春季世代(2—5月),生长率为0.0066/d;(2)夏季世代(6—8月),生长率为0.0038/d;(3)夏季世代(6—9月),生长率为0.0090/d;(4)夏季-秋季世代(7—11月),生长率为0.0152/d;(5)秋季-春季世代(10—5月),生长率为0.0160/d。强壮箭虫的生产力和摄食率分别为0.67gC/(m2·a)和2.33gC/(m2·a)。本研究结果表明,南黄海强壮箭虫5个世代中的夏-秋世代和秋-春2个世代的生长率较高;南黄海强壮箭虫的全年平均生产力显著低于东京湾,但对南黄海浮游动物的摄食压力却与东京湾相当。 相似文献
3.
以2015年5月(春季)和10月(秋季)在日照岚山港北作业区邻近海域进行的浮游动物调查数据为例,分析了该海域浮游动物的群落结构特征。调查海域两季共发现浮游动物成体20种,浮游幼虫7类,其中春季成体12种,浮游幼虫4类,秋季成体19种,浮游幼虫6类;春、秋两季调查浮游动物平均丰度分别为128.1 ind./m3、103.3 ind./m3;平均生物量(湿重)分别为1 129.9 mg/m3、954.3 mg/m3;平均多样性指数分别为2.39、2.01;平均丰富度指数分别为0.85、1.21;平均均匀度指数分别为0.87、0.62;春季调查优势种为强壮箭虫(Sagitta crassa)、中华哲水蚤(Calanus sinicus)、真刺唇角水蚤(Labibocera euchaeta)、太平洋纺锤水蚤(Acartia pacifica)、球型侧腕水母(Pleurobrachia globosa),秋季调查优势种为太平洋纺锤水蚤、小齿海樽(Doliolum denticulatum)、强壮箭虫、真刺唇角水蚤;聚类分析表明,调查海域浮游动物可划分为3个群落。本研究可为深入研究该海域浮游动物群落结构提供重要的基础数据。 相似文献
4.
毛颚动物是浮游动物中的重要类群,是典型的海洋浮游动物(仅Spadella属的种类生活于浅海岩石或海藻之间)。它的分布遍及世界海洋。在数量上也相当可观,根据1976年我们在东海两次采集的资料，夏、秋季它在浮游动物总生物量中的比例可达40%。
毛颚类是肉食性浮游动物中的饕餮者,不仅大量消耗桡足类,有时也能吞噬个体较小的燐虾、端足类和仔稚鱼等。它的数量高峰往往出现在其他草食性浮游动物的数量高峰之后。然而,它本身又是一些鱼类和肉食性浮游动物的食料。可见它在海洋食物网中所处地位的重要。在水域生产カ研究中,毛颚类的研究是了解某一海区生态转换效率的一项重要内容。
许多毛颚类是水团或海流的良好标志,例如,强壮箭虫(Sagitta crassa)可以作为黄海水团和日本内海低盐水的指标种,秀箭虫(Sagitta elegans)可以作为亲潮和里门寒流的指标种,锯齿箭虫(Sagitta serratodentata)在大西洋可以作为湾流的指标种,而多变箭虫(Sagitta decipiens)在印度西岸可以作为上升流的指标。又如人们所熟知的，Russell曾根据毛箭虫(Sagitta setosa)和秀箭虫的分布来推断北海低盐水团和天西洋高盐水团在英吉利海峡的相互推移和消长的情况。这类例子很多,兹不赘述。总之,毛颚类作为海流或水团的指标已日益受到各国海洋学工作者的重视。
本文根据东海陆架区综合考查1976年6-7月及8-9月,在127°E以西,北起32°N,南至26°30′N(6-7月在黄海南部增加一斜断面),用大型浮游生物网自底到表垂直拖网样品85份加以分析,对调查期间此海域内毛颚动物的分布作一概述。 相似文献
5.
基于1959、1984、1990与2004年曹妃甸海域的历史调查资料,分析了曹妃甸海域浮游动物群落的长期变化特征。结果表明:曹妃甸海域浮游动物生物量和丰度整体上呈现增长的趋势,春季尤为显著。2004年春季生物量和丰度分别达到了1093.8 mg/m3和775.8 ind/m3,为1959年的4.75倍和5.15倍。浮游动物丰度的季节变化由1959年的夏季高于春季转变为2004年的春季高于夏季的趋势。曹妃甸北部和东北部海域春、夏两季浮游动物生物量和丰度均较高,尤其东北侧龙岛附近海域形成一个极高值区。浮游动物优势种季节变化明显,春季主要为中华哲水蚤(Calanus sinicus)与双毛纺锤水蚤(Acartia bifilosa);夏季以强壮箭虫(Sagitta crassa)为主。此外,水母类浮游动物在夏季明显增多。 相似文献
6.
强壮箭虫是我国温带海域的浮游动物优势种。本文通过2009年7月至2010年6月在北黄海獐子岛海域的逐月综合调查,研究了大网浮游动物中强壮箭虫丰度的周年变化及其与环境因子的关系。结果显示,强壮箭虫年平均丰度为22.6 ind/m3,高峰值出现在12月（47.5 ind/m3）,最低值出现在8月（7.8 ind/m3）;在水平分布上,除了夏季的8月,全年近岸海域强壮箭虫丰度均高于外海海域,且在10月及次年2月差异显著（P<0.05）。相关性分析显示,作为肉食性浮游动物,强壮箭虫丰度时空变化除了受温度和盐度影响外,还与饵料生物（主要是桡足类）丰度有关。我们认为,这是其丰度周年变化规律在不同海域出现明显差异的主要原因。 相似文献
7.
于2018年1—11月对胶州湾海域进行了春、夏、秋、冬4个航次的调查,研究了该海域强壮箭虫的水平分布和季节变化,并运用聚集度指标法分析其聚集特征。结果显示,浅水Ⅰ型浮游生物网中强壮箭虫年平均丰度值为17.92 ind/m~3,呈现冬季夏季春季秋季的变化规律;浅水Ⅱ型浮游生物网中强壮箭虫年平均丰度值为41.17 ind/m~3,呈现夏季冬季秋季春季的变化规律。在水平分布上,2种网型中的强壮箭虫都在近岸和河流入海口附近有高丰度值。强壮箭虫在胶州湾海域呈聚集状态分布,强壮箭虫的分布与多种环境因子有关,其中温度和桡足类丰度是影响其分布的重要因素。浅水Ⅰ型网中的强壮箭虫大约是浅水Ⅱ型网中的2.3倍,对比历史资料发现,本次调查的强壮箭虫丰度较低。 相似文献
8.
毛颚类(Chaetognaths)是海洋浮游动物中的一个特殊类群,其种类和数量分布对探索海流和水团变化以及海洋食物链中能量传递具有重要意义。文章根据2011年4~5月在印度洋东北海域(80°E~98.5°E,5°S~6°N)29个站的调查资料,分析了毛颚类种类组成、丰度分布和群落结构特征。共鉴定毛颚类14种,以暖水大洋广布种为主,其中肥胖箭虫Sagitta enflata、太平洋箭虫Sagitta pacifica、飞龙翼箭虫Pterosagitta draco和凶形箭虫Sagitta ferox是调查海域的优势种。依据调查站位设置及环境特征,将调查海域分东部断面、赤道断面和西部断面。种数变化范围为5~14种,种数分布不均匀,东部断面每站一般低于10种,而赤道断面及西部断面的种数相对较丰富。毛颚类平均丰度为5.35(±2.82)ind·m-3,分布亦不均匀,西部断面的丰度比赤道和东部断面均高。群落结构分析表明,调查海域毛颚类可分3个组群(相似度水平50%),组群I包括11种,是调查海域的主要种类,分布较广,而另外两个组群仅3种,主要出现在东部和西部断面的少数调查站;调查站之间的相似度较高,特别是西部断面站位之间的相似度70%。西部断面受沿岸水和涌升水的影响,出现较高的物种多样性和丰度。 相似文献
9.
三亚湾浮游动物的种类组成与数量分布 总被引：27，自引：2，他引：27
根据1998年10月至1999年8月在三亚湾的调查资料,分析了浮游动物的种类组成、数量分布和季节变化。已鉴定出终生浮游动物118种和浮游幼虫11个类群,其中桡足类种数最多,其次为水母类。调查区的浮游动物群落可划分为河口内湾类群、暖温带类群、暖水沿岸类群、广布暖水外海类群等4个生态类群,并以后二者的种类占绝大多数。浮游动物优势种的季节演替不明显,以肥胖箭虫(Sagittaenflata)占主导地位。浮游动物生物量季节变化显著,呈单周期型,秋季为高峰期,春季为低谷期。浮游动物年平均生物量为129mg·m-3,除秋季外,平面分布比较均匀。毛颚类的数量居首位。浮游动物生物量与浮游植物密度的季节变化趋势相一致。 相似文献
10.
根据国家海洋局1977年12月份至1978年11月份在黄海南部和东海(28°~34°N,120°30'~127°00'E)广大海域进行周年逐月份的12航次综合调查资料,对该海域毛颚类数量变动、时空分布及其与环境因子的关系进行了分析.结果表明,本调查区毛颚类的数量以6~9月份较高,7月份为年最高值.1~4月份为年低值期,尤以4月份为最低谷.其中在数量上取主导作用的种类是肥胖箭虫(Sagitta enflata)、强壮箭虫(S.crassa)拿卡箭虫(S.nagae)和百陶箭虫(S.bedoti)等种类.在平面分布上,长江口以北毛颚类数量一般高于长江口以南的海域,在南黄海,除夏季外,其他季节均有出现高值.在东海高密集区一般出现在不同水系交汇区,尤其在长江冲淡水、沿岸水和外海高温高盐水交汇的锋面最为密集.这对于不同水系在研究区内运动和消长有一定的指示意义. 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.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
13.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
14.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
15.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
16.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献
17.
Andrzej Chybicki 《Marine Geodesy》2018,41(1):1-23
Current trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favorable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment in the water and other factors. In this paper, a novel 3-dimensional geographical weighted regression (3GWR) SDB technique is presented, it binds together methods already presented in other studies, the geographically weighted local regression (GWR) model, with depth dependent inverse optimization. The proposed SDB model was calibrated and verified on a relatively difficult test site of the South Baltic near-shore areas with the use of multispectral observations acquired by a recently launched Sentinel-2 satellite observation system. By conducted experiments, it was shown that the proposed SDB model is capable of obtaining satisfactory results of RMSE ranging from 0.88 to 1.23[m] depending on the observation and can derive bathymetry for depths up to 12m. It was also shown, that the proposed approach may be used operationally, for instance, in the continuous assessment of temporal bathymetry changes, for areas important in the context of ensuring local maritime safety. 相似文献
18.
N. H. Khadge 《Marine Georesources & Geotechnology》2000,18(3):251-258
As a part of the environmental impact assessment studies, geotechnical properties of sediments were determined in the Central Indian Basin. The undrained shear strength and index properties of the siliceous sediments were determined on 20 box cores of uniform dimension collected from various locations in five preselected sites. The maximum core length encountered was 41 cm and most of the sediments were siliceous oozes consisting of radiolarian or diatomaceous tests. The shear strength measurements revealed that surface sediments deposited in recent times (0-10 cm) have a shear strength of 0-1 kPa; this value increases with depth, reaching 10 kPa at 40 cm deep. Older sediments have greater strength because of compaction. Water content varies in the wide range of 312-577% and decreases with depth. The clay minerals such as smectite and illite are dominant and show some control over water content. Wet density, specific gravity, and porosity do not indicate any notable variation with depth, thereby indicating a uniform, slow rate of sedimentation. The average porosity of sediments is 90.2%, specific gravity 2.18, and wet bulk density 1.12 g/cm 3 . Sediments exhibit medium to high plasticity characteristics, with the average plasticity index varying between 105% and 136%. Preliminary studies on postdisturbance samples showed an increase in natural water content and a decrease in undrained shear strength of sediments in the top 10- to 15-cm layer. 相似文献
19.
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
20.
An Improved Calibration of Satellite Altimetric Heights Using Tide Gauge Sea Levels with Adjustment for Land Motion 总被引：2，自引：0，他引：2
Gary T. Mitchum 《Marine Geodesy》2000,23(3):145-166
Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data. 相似文献