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81.
海洋浮游单胞藻在海产动物育苗中生产性培养新方法的试验研究 总被引:1,自引:0,他引:1
本文提出了一种在中继培养以后.以1∶1接种不施肥培养的新方法.此法能在两天内培养出育苗生产所要求的高浓度饵料液,饵料液的氨氮含量及三态氮总量较常规培养分别降低约70倍及10倍.可节省营养盐用量50%.此法适用于目前北方常用的几种海洋浮游单胞藻。 相似文献
82.
Summary 4,6-Dibromoindole and 4,6-dibromo-2-methylindole have been isolated from the acorn wormGlossobalanus sp. The biosynthetic implications of this finding are discussed.We wish to thank Prof. Paul J. Scheuer, University of Hawaii for his encouragement and for use of his facilities during spectroscopic work. T.H. gratefully acknowledges the giving of a travel grant by the University of the Ryukyus Foundation for International Exchange. 相似文献
83.
刘晓飞 《温州大学学报(自然科学版)》2012,(5):36-41
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。 相似文献
84.
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。 相似文献
85.
G. Henning D. K. Hofmann Y. Benayahu 《Cellular and molecular life sciences : CMLS》1996,52(7):744-749
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. 相似文献
86.
87.
利用气相色谱质谱(GC MS)、胶束电动毛细管色谱(MECC)分析技术对渤海中部凹陷油气地球化学进行了勘查。结果表明,渤海中部凹陷2m深沉积物中苯和甲苯的平均体积分数分别为0.107×10-6和0.130×10-6;返浆脱气样中的苯和甲苯的平均体积分数为0.844×10-6和0.195×10-6;利用激光频率调制吸收光谱测量技术测得井中返浆气样甲烷碳同位素比δ13C1为-21‰~-72‰。钻探结果证实,调查区内8口油气井中的6口井位于沉积物甲苯异常范围内,5口井位于苯异常范围内。苯和甲苯异常呈顶端聚集模式。返浆脱气样中的苯和甲苯浓度在油气层上方300m左右明显升高。研究区内天然气以油型气和煤成气为主,含少量生物成因气和深部气。 相似文献
88.
Deep crustal structure of Baiyun Sag,northern South China Sea revealed from deep seismic reflection profile 总被引:15,自引:0,他引:15
HUANGChunju ZHOUDi SUNZhen CHENChangmin HAOHujun 《科学通报(英文版)》2005,50(11):1131-1138
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. 相似文献
89.
Opening and evolution of the South China Sea constrained by studies on volcanic rocks: Preliminary results and a research design 总被引:8,自引:0,他引:8
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. 相似文献
90.
本文在分析了轴系校中计算方法的基础上,通过实例介绍推进轴系的一种简易校中计算方法及其力学模式的确立,为船上的轴系对中提供对中数据。 相似文献