共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
3.
九龙江口磷的界面分配和转移 总被引：5，自引：0，他引：5
１９９２年８月航次调查结果表明，九龙江口水体中磷的迁移呈保守行为，ＴＰ和ＰＰ含量随着海水盐度的降低呈增加趋势，ＤＰ含量刚好相反；Ｓ〈１５的低盐区，盐度对磷迁移的影响比较显著。 相似文献
4.
对海南岛南岸古珊瑚后报海温研究的几点看法 总被引：1，自引：0，他引：1
海南岛南是研究古珊瑚后报古海温的理想场所之一。根据近海现今海温与珊瑚生长率季节变化的特点，指出开展古珊瑚地化指标后报海面温度（ＳＳＴ）研究时，应尽可能采用先进取样技术进行小样品取样，应开展珊瑚生长模式研究，注意ＳＳＴ变化中数年平均值与气候平均值的差值范围，建议重视近数在年冬季ＳＳＴ后报工作。 相似文献
5.
河口及近岸海区营养盐含量较丰富,是海洋生物繁殖的良好环境,因此调查研究这些区域水体中的营养盐有重要的现实意义。AsTon指出,近年来河口区磷酸盐、硅酸盐、硝酸盐及其它无机形式氮行为的研究已引起了许多研究人员的注意。一方面是由于这些物质对生物过程包括对控制生产力的过程具有重要作用;另一方面是由于对排入河口富营养污水(例如生活污水等)影响的关注。 关于河口及近岸区营养盐含量变化及行为的研究情况曾进行了大量的研究工作。当河水与海水混合时,河流带入营养盐的行为,如活性磷酸盐、活性硅酸盐及硝酸盐是否有转移,保守性如何,是近年来较为关心的问题之一,也是一个十分复杂的过程。且影响 相似文献
6.
九龙江口本中1995年有机物的转移 总被引：1，自引：0，他引：1
１９９５年３个航次调查研究结果表明，九龙江口水体总有机物的含量受悬浮物含量控制。在Ｓ〈５的低盐度区，悬浮泥沙和有机物产生明显的絮凝；在Ｓ〉５的广阔海域，它们的行移接近于理想混合。估算得出九龙江河流的入海一约；悬浮泥沙为９．８＊１０＾５ｔ／ａ；总ＣＯＤ为３．２＊１０＾ｔ／ａ，其中溶解态ＣＯＤ为２．１＊１０＾４ｔ／ａ约占２／３，为水体有机物的主要开矿如换算为溶解有机碳，则ＤＯＣ的平均通量为３．２＊１０ 相似文献
7.
九龙江口生物可利用磷的行为与人海通量 总被引：1，自引：1，他引：0
于１９９５年３、５月在九江口进行两个航次的现场调查，研究不同形态磷的河口行为，并估算生物可利用磷的入海通量。结果表明，在Ｓ〈２０区域内，溶解活性磷（ＤＲＰ）的行为受控于“缓冲机制”，其含量在８－１０μｇ／ｄｍ＾３水平上下波动。颗粒磷中ＭｇＣｌ２可提取磷（ＭｇＣｌ２－Ｐ）含量随盐度增大而增大，并与叶绿素ａ以及悬浮物Ｆｅ、Ｍｎ、Ａｌ含量呈正相关关系。ＮａＯＨ／ＮａＣｌ可提取磷（ＮａＯＨ／ＮａＣｌ－Ｐ） 相似文献
8.
海蛇乙醇浸出物对小鼠学习记忆的影响 总被引：2，自引：0，他引：2
本研究采用学习记忆行为训练和生化测定的方法,观察了我国４种常见海蛇的乙醇浸出物（ＡＥＢＳＳ）对小鼠的正常学习记忆、东莨菪碱（Ｓｃｏｐ）所致记忆障碍、脑不同部位蛋白质含量的影响。结果表明,ＡＥＢＳＳ（剂量５．００ｍｇ浸出蛋白／ｋｇ体重以上）对正常小鼠的学习记忆能力及脑内蛋白质合成有明显的促进作用;ＡＥＢＳＳ还能极显著地改善Ｓｃｏｐ所致的学习记忆障碍,使Ｓｃｏｐ组大脑皮层和小脑的蛋白质含量显著增加,海 相似文献
9.
本研究采用学习记忆行为训练和生化测定的方法,观察了我国４种常见海蛇的乙醇浸出物（ＡｌｃｏｈｏｌｉｃＥｘｔｒａｃｔｓｏｆＢｏｄｉｅｓｏｆＳｅａ Ｓｎａｋｅ．ＡＥＢＳＳ）对小鼠的正常学习记忆、东莨菪碱（Ｓｃｏｐｏｌａｍｉｎｅ,Ｓｃｏｐ）所致记忆障碍、脑不同部位蛋白质含量的影响。结果表明,ＡＥＢＳＳ（剂量５００ｍｇ浸出蛋白／ｋｇ体重以上）对正常小鼠的学习记忆能力及脑内蛋白质合成有明显的促进作用;ＡＥＢＳＳ还能极显著地改善Ｓｃｏｐ所致的学习记忆障碍,使Ｓｃｏｐ组大脑皮层和小脑的蛋白质含量显著增加,海马脑区的蛋白质含量增加极显著。结果提示,ＡＥＢＳＳ对小鼠学习记忆的作用机制可能与中枢胆碱能递质系统的蛋白质合成有关。 相似文献
10.
１２５Ｍａ后陆－陆碰撞造成的碳储存的讨论ＤｅｒｒｉｌｌＫｅｒｒｉｃｋ等评论：Ｓｅｌｖｅｒｓｔｏｎｅ和Ｇｕｔｚｌｅｒ（１９９３）认为，在特提斯陆－陆碰撞期间，碳从大气转移到深成变质储集层可能导致了１２５Ｍａ后的全球变冷。但是，由于大气ＣＯ＿２含量长期由... 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
14.
15.
《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
17.
18.
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