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1.
悬浮颗粒物及粒径是水质重要参数,其分布特征研究有助于加深对海洋生态环境的了解。利用2013年6月和2013年11月LISST-100观测数据,研究了黄、渤海区域悬浮物粒径和浓度的分布情况,浓度分布整体上呈现近岸高远岸低的状况,粒径分布呈现近岸细远岸粗的特征,季节分布特征明显;通过典型断面分析,悬浮物粒径和浓度随着水深变化明显,连续站数据分析结果表明大风对底层颗粒物的再悬浮作用显著,潮流对悬浮物的时空分布有着重要影响;水体衰减系数随着体积浓度变化明显;此外,还研究了悬浮颗粒物粒径Junge分布在黄、渤海区域的适用性。 相似文献
2.
悬浮颗粒物及粒径是水质重要参数,研究其分布特征有助于加深对海洋生态环境的了解。利用2013年6月和2013年11月LISST-100观测数据,研究了黄、渤海区域悬浮物粒径和浓度的分布情况,浓度分布整体上近岸高远岸低,粒径分布呈现近岸细远岸粗的特征,季节分布特征明显。通过典型断面分析发现,悬浮物粒径和浓度随着水深变化明显,连续站数据分析结果表明,大风对底层颗粒物的再悬浮作用显著,潮流对悬浮物的时空分布有着重要影响;水体衰减系数随着体积浓度变化明显。此外,还研究了悬浮颗粒物粒径Junge分布在黄、渤海区域的适用性。 相似文献
3.
利用ADCP和LISST-100仪观测悬浮物浓度的研究 总被引：3，自引：0，他引：3
利用黄河口海床基声学多普勒流速剖面仪(ADCP)的周日观测资料对悬浮物浓度进行了反演,反演过程中综合考虑了球面扩散、声学近场的非球面扩散、海水和悬浮颗粒的吸收衰减以及其他因素对回声信号的影响,结果表明在粒径保持相对稳定的情况下,利用ADCP仪回声强度反演悬浮物浓度具有较高的精度.结合现场激光粒度仪(LISST-100)测得的粒径分布信息在反演过程中考虑了粒径修正,重点讨论了观测区域粒径变化对结果的影响,结果表明粒径的剧烈变化会降低体积后向散射强度与悬浮物浓度之间的相关性.大颗粒物质的存在使计算得到的悬浮物浓度偏高,粒径修正虽然在一定程度上消除了这种影响,但线性拟合的相关性并未提高. 相似文献
4.
《海洋与湖沼》编辑部 《海洋科学》2011,35(10):128-129
黄、东海悬浮细颗粒物浓度和粒径分布变化研究
分析了2006年6月和2007年1月用LISST-100对黄、东海悬浮物的观测数据,研究了黄、东海的悬浮物粒径和体积浓度分布情况,并从动力学角度对其进行解释。 相似文献
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海南近海海域浊度与悬浮颗粒物粒径的分布特征 总被引：1，自引：0，他引：1
利用2005年8-9月在海南西部近海海域底质调查获得的水体浊度、悬浮颗粒物粒径的数据和资料,探讨了该区浊度和悬浮颗粒物粒径的分布规律,结果表明:(1)研究区表层水体浊度与悬浮颗粒物的总体积浓度由岸向外海方向逐渐减小,底部水体浊度与悬浮颗粒物的体积浓度高值区呈斑状分布;(2)研究区的水体浊度和悬浮颗粒物体积浓度随着水深增大而增大,部分调查站位出现异常现象;(3)研究区表层和底部水体浊度与悬浮颗粒物各粒级的体积浓度相关性较好,相关系数在0.85以上。 相似文献
7.
应用LISST-100现场激光粒度仪于2006年8月在北部湾首次进行了悬浮颗粒剖面测量，获得了整个垂直剖面的悬浮颗粒现场粒径分布、体积比和光衰减系数，并计算得到了垂直剖面的总浓度和各层的粒度参数及粒级组成。结果表明，悬浮颗粒自上而下均为双峰分布，只是表层的双峰位于5．57μm和34．4μm，中间层和底层的双峰位于34．4μm和129．4μm。悬浮颗粒体积比自上而下逐渐增大，到达底层时达到最大。光衰减系数的变化趋势与颗粒体积比非常相似，且二者存在很好的相关性，相关系数高达0．98。整个垂直剖面上，表层粒度较细，随着深度增加粒度逐渐变粗，到达底层时粒度最粗。悬浮体总体上正偏，峰态值较小，分选较差。粒度以砂为主，粉砂含量次之，不舍黏土。 相似文献
8.
《海洋地质与第四纪地质》2010,(3)
基于夏季渤海湾中北部312个站位的悬浮体观测资料,细致刻画了夏季该海域的悬浮体浓度的分布特征,并分析其形成原因。渤海湾中北部悬浮体水平分布表现出近岸高、远岸低,底层高、表层低的分布趋势。悬浮体体积浓度的垂直分布表现为两种类型:渤海湾的西部和中部的浅水海域,由表至底悬浮体的体积浓度逐渐增大;渤海湾湾口海域表底层附近的悬浮体体积浓度随深度变化不大,但在10~15 m深度处出现极大值。悬浮体体积浓度这种垂直分布的差异性与温跃层的存在有关。温跃层内水体层结稳定,海水垂直扩散系数小,导致颗粒物和营养盐富,生物体聚集,进而使得观测得到的悬浮体体积浓度在该层内出现峰值。 相似文献
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南黄海中部悬浮体浓度垂直分布及其季节变化对该海域泥质区的生成有重要意义,为研究黄东海物质交换、南黄海中部泥质区生成机制,利用2006年至2009年四季节的温度、盐度数据,结合水样抽滤获得的悬浮体质量浓度数据和LISST观测到的悬浮体体积浓度数据分析南黄海中部断面悬浮体浓度垂直分布及其季节变化。结果表明,悬浮体LISST体积浓度和抽滤质量浓度具有较好的相关性,并将夏冬两季悬浮体体积浓度转换为质量浓度。四季节悬浮体浓度整体上表层低于底层,潮流是控制南黄海悬浮体分布的重要动力因素,秋季大潮期悬浮体浓度高于冬季小潮期,冬春两季悬浮体浓度分布相类似;受到强台风影响,夏季悬浮体浓度高于秋冬季,以温跃层为界,底层悬浮体浓度较高,最高达26.9mg/L,以细粉砂粒级为主,上层悬浮体浓度低于2mg/L,悬浮颗粒粒径大于31.6μm。夏季,黄海冷水团西边界锋面处为粉砂为主的高悬浮体浓度区,与南黄海中部泥质区西侧厚沉积带位置对应。冬季,黄海西部沿岸流流经区域悬浮体以极细砂粒级为主,黄海暖流海域各个粒级悬浮体浓度都比较高,以粉砂粒级以上为主,整个断面中较粗颗粒的悬浮体含量较多。 相似文献
10.
LISST-100通过激光前向散射测量32个粒径的悬浮颗粒物体积分数,OBS通过接受后向散射光强测量浊度,浊度反映水体浑浊程度,可用其变化代表悬浮颗粒物浓度变化。利用LISST-100和OBS于浙江外海高生产力区对悬浮颗粒物进行周日变化的同步观测,结果表明,浮游生物高生物量水体中,LISST-100能够测量出悬浮颗粒物体积分数的变化,由于颗粒物体积与其粒径成立方关系,其对于大颗粒物质变化比较敏感;OBS只能反映部分浓度变化,OBS接收的后向散射量强度取决于颗粒物后向散射截面的影响,因此对于小颗粒悬浮物质更为敏感,对大颗粒物质变化不敏感。无机小颗粒占优水体中LISST-100和OBS对于悬浮颗粒物的测量均较为理想。在悬浮颗粒物组分复杂的水体中,采用LISST-100有其优势,它可以获得不同粒径组分的体积分数,而OBS则适用于更小粒径范围的水体,主要是因为其对大粒径的浮游生物不敏感。 相似文献
11.
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
12.
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
13.
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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《海洋学报(英文版)》2014,(9):F0003-F0003
<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, 相似文献
16.
The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
19.
Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献
20.
The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献