东海南部暗鳍兔头鲀渔场环境因子初探

根据舟山海洋渔业公司近3年在东海南部暗鳍兔头鲀钓作业记载的日志和生产统计资料,初步分析了东海南部暗鳍兔头鲀渔场的环境因子,结果表明:暗鳍兔头鲀渔场的变动和渔获量与水温环境因子的关系较为密切.当水温在17～23℃时,暗鳍兔头鲀渔获量随着温度的升高大致增加;当水温高于23℃时,暗鳍兔头鲀渔获量随着温度的升高反而降低;黑潮、台湾暖流、冷水团等海流的变化影响着暗鳍兔头鲀渔场范围大小及其移动,近3年渔场基本稳定在26°0'～28°30'N,122°30'～126°00'E的海域;浮游生物的分布与垂直移动影响暗鳍兔头鲀栖息集群及鲀钓渔法,暗鳍兔头鲀作业渔场的浮游生物量为25~50 mg/m3.     

星载激光测高仪海面回波的仿真与分析

星载激光测高仪发射的1 064 nm波长激光被波动海洋表面反射,系统接收的时间波形与瞬时海面波浪分布相关。而海面波浪又直接受海面风速影响,因此可以通过观测激光测高仪回波变化监测不同风速下海态变化。本文依据激光雷达方程,利用蒙特卡洛法模拟不同风速下的海面波浪分布,通过光线追击建立海面回波波形仿真器;以地球科学激光测高系统(geo-science laser altimeter system,GLAS)参数为输入,仿真得到不同风速下的海面回波:发现当海面风速在3~10 m/s之间时,回波呈单峰高斯波形,与GLAS发布的实际回波相符;且回波脉宽,以及有效能量反射率(即有效回波能量与发射能量之比)与实测参数误差小于10%。进一步分析可知,回波特征参数与海面风速之间存在显著关联,为利用激光测高仪大规模精确反演海洋表面风速奠定了基础。     

Species of Symplectoscyphus Marktanner-Turneretscher, 1890 (Cnidaria: Hydrozoa,Sertulariidae) from recent Antarctic expeditions with R.V. Polarstern,with the description of four new species

Fifteen species of the genus Symplectoscyphus Marktanner-Turneretscher have been studied, four of which are new to science (Symplectoscyphus anae sp. nov., S. frigidus sp. nov., S. sofiae sp. nov. and S. weddelli sp. nov.). The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R.V. Polarstern. Each species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The type material of five poorly known species of Symplectoscyphus, S. aggregatus (Jäderholm), S. cumberlandicus (Jäderholm), S. glacialis (Jäderholm), S. hero Blanco and S. plectilis (Hickson and Gravely), has been re-examined, re-described and figured. Finally, a general survey of the bathymetrical and biogeographical distribution of the known Antarctic species is given.     

Cleavage pattern in Oscarella species (Porifera,Demospongiae, Homoscleromorpha): transmission of maternal cells and symbiotic bacteria

The cleavage and the first stages of development of larvae in five Oscarella species, from the north-west Mediterranean, O. lobularis, O. tuberculata, O. imperialis, O. microlobata and Oscarella sp., are investigated. Eggs are isolecithal, and rich in yolk inclusions. The cleavage is holoblastic, equal and asynchronous. During cleavage, there is no central cavity (blastocoel). The result of cleavage is the formation of a solid morula constituted by equal blastomeres. The polarity of the blastomeres is not expressed prior to the beginning of larva differentiation, i.e. approximately up to 64-cell stage. The superficial membrane of the blastomeres shows numerous filopodia which form blastomere contact. Symbiotic bacteria and cells with inclusions of the maternal mesohyl are present in the intercellular spaces of the embryo from the beginning of cleavage. Whereas maternal symbiotic bacteria are present in the embryo of the five species studied, maternal cells with inclusions are absent from two species (O. tuberculata and O. microlobata). The most original feature of early development in the genus Oscarella is the formation of a coeloblastula larva from a morula due to the progressive migration of the internal cells to the periphery.     

约翰·亚当斯海权思想研究

约翰·亚当斯是美国早期的外交家和美国第二任总统，也是最早关注美国海权建设的政治家之一。约翰·亚当斯海权思想的形成深受美国的繁荣和安全对海洋严重依赖的现实，他的职业背景特别是他参与美国政治活动的经历，以及关于中立国自由航行的国际法和国际惯例的影响。其海权思想主要包括坚持中立权利和海上航行自由、海军对维护国家独立和海洋权益的作用以及对发展强大海权的信念。约翰·亚当斯的海权思想十分理性，极具现实主义色彩，对美国海军政策和海洋战略的发展有重要影响。     

基于HYCOM模拟的南海西北部环流

为研究北部湾在内的南海西北部海域环流结构的时空特征,本文基于Hybrid Coordinate Ocean Model(HYCOM)模式和气象强迫数据,通过三重嵌套模拟研究南海西北部环流在风力强迫下的结构及其时空分布特征,结果表明:(1)南海西北部流场受季风影响较大,冬季基本为西南向流,夏季基本为东向流,流场结构复杂,外海涡旋众多,Ekman运动特征较为明显;(2)北部湾流场呈现出较强的密度流特征,冬季基本为气旋式环流,夏季同时存在较小尺度的气旋式和反气旋式环流; 7月湾口表层的气旋式环流结构向下直接影响到海底;(3)北部湾的海表面盐度受蒸发降雨影响较大,盐度分布西低东高,这与湾口和琼州海峡入侵的南海高盐海水有关;(4)在热盐作用和季风驱动下,琼州海峡的表、底层流冬季为西向流,夏季为东向流,冬季广东沿海地区的富营养化海水可能通过琼州海峡影响广西近海海域环境质量。     

The phorbol ester TPA induces metamorphosis in Red Sea coral planulae (Cnidaria: Anthozoa)

Controlled experiments on the metamorphosis of marine invertebrate larvae require artificial inducers. These inducers can be used for studying the involvement of known signal transduction pathways in settlement and metamorphosis. The ability of the tumor-promoting phorbol ester TPA (12-O-tetradecanoylphorbol-13-acetate) to induce metamorphosis in planulae of the Red Sea soft coral speciesHeteroxenia fuscescens, Xenia umbellata, Dendronephthya hemprichii, Litophyton arboreum andParerythropodium fulvum fulvum, and the stony coralStylophora pistillata, was examined by using various concentrations of TPA. The chemical induced metamorphosis in all six species. The effect was unspecific and concentration-related. For all the corals except forX. umbellata the highest mean percentages of metamorphosis were obtained with 8.1×10^–7–10^–9 M TPA. ForX. umbellata, the percentage of metamorphosis was lower, and was obtained within a wider TPA concentration range. The present results, along with previous studies on Hydrozoa and Scyphozoa, demonstrate that TPA is the first common artificial inducer for these classes of Cnidaria. TPA is known to activate the enzyme protein kinase C (PKC) and therefore plays an important role in studying the phosphatidylinositol signal transduction system. Evidence for the involvement of this pathway in triggering metamorphosis has already been reported for Hydrozoa and Scyphozoa. Our results suggest that PKC is also involved in initiating metamorphosis in Anthozoa.     

海面杂波的仿真

海浪引起的雷达反射信号即海面杂波对于欲探测目标的雷达图像造成干扰,此种干扰无法建立精确的数学模型。在舰船指控系统的陆基演练中,要求模拟海上战术环境,本文提出海情仿真的工程近似仿真方法。     

Deep crustal structure of Baiyun Sag,northern South China Sea revealed from deep seismic reflection profile

This paper discusses deep crustal architecture of the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea based on velocity analysis, time-depth conversion and seismic interpretation of the deep seismic reflection profile DSRP-2002. The profile was acquired and processed to 14 S TWT by the China National Offshore Oil Corp. (CNOOC) in 2002. It extends across the Baiyun Sag of the Pearl River Mouth Basin, from the northern continental shelf of the SCS to the deepwater province. As the first deep seismic reflection profile in the Pearl River Mouth Basin, this profile reveals seismic phases from basement down to upper most mantle. The Moho surface appears in the profile as an undulating layer of varying thickness of 1-3 km. It is not a single reflector interface, but a velocity gradient or interconversion layer. The crust thins stepwisely from the shelf to the continental slope and the abyssal plain (from north to south), and also thins under depocenters. The crustal thickness is only 7 km in the depocenter of the main Baiyun Sag, which corresponds to a Moho upwelling mirroring the basement topography. In the lower slope and the ocean-continental transition zone of the southernmost portion of the profile, three sub-parallel, NW-dipping strong reflectors found at depths around 10--21 km are interpreted as indications of a subducted Mesozoic oceanic crust. Crustal faults exist in the northern and southern boundaries of the Baiyun Sag. The intense and persistent subsidence of the Baiyun Sag might be related to the long-term activity of the crustal faults.     

Opening and evolution of the South China Sea constrained by studies on volcanic rocks: Preliminary results and a research design

The South China Sea (SCS) is characterized by abundant seamounts, which provide important information about the evolution of the SCS and related deep processes. Cenozoic volcanism in the SCS and its surroundings comprises three stages relative to the spreading of the SCS:prespreading (>32 Ma), syn-spreading (32-16 Ma), and post-spreading (<16 Ma). The pre-spreading magmatism predominantly occurs on the northern margin of the SCS and in South China coastal areas and shows a bi-modal affinity. The syn-spreading magmatic activity was very limited on the periphery of the SCS, but may be concentrated in the SCS. However, seafloor samples of this stage are not available yet because of overlying thick sedimentary deposits. Post-spreading magmatism is widespread in the central and southwest sub-basins of the SCS, Hainan Island, Leizhou Peninsula, Thailand, and Vietnam. These are mainly alkali basalts with subordinate tholeiites, and display OIB-type geochemical characteristics. The Dupal isotope anomaly and presence of high-magnesian olivine phenocrysts suggests their possible derivation from the Hainan mantle plume. The temporal and spatial distribution of Cenozoic volcanism in the SCS and its surroundings may be accounted for either by plate stress re-organization before and after SCS spreading, or by ridge suction of plume flow during opening of the SCS. If the latter is the case, the volcanic rocks within the SCS basin may not be typical mid-ocean ridge basalts (MORB). It remains puz-zling, however, that the transition between the South China continental margin and the SCS basin does not have features typical of a volcanic rifted margin. Clearly, the relationship between mantle plume and SCS opening needs further evaluation. A better un-derstanding of the link between deep processes and opening of the SCS not only requires enhanced studies on igneous petrogene-sis, but also is heavily dependent on systematic sampling of seafloor rocks.