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1.
海洋中不产氧光合细菌的研究进展   总被引:1,自引:0,他引:1  
李云  李道季 《海洋通报》2004,23(4):86-92
介绍了海洋中需氧的不产氧光养菌(aerobic anoxygenic phototrophic bacteria,简称AAP细菌)在全球海域的分布和丰度、光合作用能力、系统发生、多样性,以及与光合自养生物的关系、在海洋碳循环中的贡献等方面的研究进展,阐述了海洋中不产氧光合细菌在碳、氮、硫、铁等物质循环过程中的重要性和一些新种的发现及其应用,指出了目前海洋中不产氧光合细菌研究中存在的问题。  相似文献   

2.
This paper discusses the impact of local and national policies in the Philippines on the participation of indigenous peoples in relation to fisheries management. Specifically, this research focuses on the Tagbanua, an indigenous group in Coron Island, Palawan, on the western side of the Philippines. The struggle of the Tagbanua in reclaiming their ancestral title to the land and sea reflects broader moves toward self-determination, which is critical not only to their ancestral lands and waters, but also to their survival. Indigenous rights are essential in addressing social justice and in giving a greater voice that encourages indigenous peoples towards self-governing institutions and common management of resources. Significantly, the fundamental development of indigenous peoples lies in the recognition of their rights in their ancestral domain and the preservation of their culture, tradition, system, practices and their natural resources. This paper examines the Tagbanua experience, through a critical exploration of institutions and property rights, with attention to corresponding effects in reducing conflict with other stakeholders in the area, and in affecting the sustainability of fishery resources.  相似文献   

3.
In 2015 and 2016, 1,200,000 migrants crossed the Mediterranean into Europe. At least 6000 went missing at sea. In response to states’ failure to provide adequate search and rescue (SAR), several non-governmental organisations (NGOs) have launched their own rescue operations in both the Central Mediterranean and Aegean. This article provides the first empirical analysis of SAR NGOs, outlining their structure and operating models, investigating the reasons underlying their proliferation and assessing their contribution to mitigating the loss of life at sea  相似文献   

4.
采用组织切片和显微观察方法,对孵化后1~30d的真鲷(Pagrusmajor)仔稚鱼鳔的发育与分化发育进行了研究。结果表明:孵化后1~2d的仔鱼,开始在消化道的前端背部出现鳔原基,接着出现导气管、鳔腔、气腺和迷网,而后鳔囊开始充气。到孵化后20~30d,鱼鳔分化发育基本稳定。真鲷仔鱼鳔器官的分化发育早期大致可以分为两个阶段:一是鳔腔扩大阶段,约在仔鱼孵化后的3~4d,此阶段的发育是非功能性的;二是鳔囊充气阶段,大约在孵化后9~10d左右出现,形成一个缓慢向前方伸展的椭圆形鳔囊,此阶段鳔的发育是功能性的。此时鳔器官的发育好坏对真鲷仔鱼的生理、生态影响很大,反映在成活率的高低方面显得非常明显。真鲷鳔器官的分化发育在仔稚鱼期基本完成。  相似文献   

5.
An electronic databank on the seismostratigraphic units based on seismic studies in the northeastern Indian Ocean is created and schematics of the sediment thickness distribution over its area are compiled. For each unit, the interface boundaries are dated, the matter composition is identified, and the sedimentation rates are estimated. An integrated map of the total thickness of the sediments and rates of their sedimentation are constructed. The lower limit of the parameters of the sedimentation process for the sedimentary layers after their compaction caused by the weight of the overlying layers is characterized.  相似文献   

6.
Anchovy and sardine in the Mediterranean are known to share the same habitat and, consequently, to interact with one another. These two sympatric pelagic species are planktivorous and consume a wide range of planktonic prey items during all their developmental stages, potentially overlapping their ecological niches, although the feeding interactions between these species have been poorly investigated. Here we compare the dietary habits of the juvenile phases of anchovy and sardine during different seasons in the northwestern Mediterranean Sea, through analysis of their stomach contents and of their feeding-related anatomical characteristics. In this study we show that juveniles of anchovy and sardine do not compete for food, and we describe significant dietary differences between anchovy and sardine due to their different alimentary tract morphology.  相似文献   

7.
A method is proposed for identifying seamounts in the northwest sector of the Pacific based on the following criteria: a closed, close to isometric contour of the isobaths at the base of a structure, its quasi-conical shape, and angles of slope exceeding 5° within the limits of the closed contour. A catalog of the mountains has been compiled, consisting of 1995 objects and their quantitative characteristics. The catalog data were statistically processed, and the following was calculated: the correlation between the number of seamounts from the radius of their base and volume, the distribution of the number of mountains, and the total volume within the study area. It is shown that seamounts are characterized as multiscale, and they are located very unevenly: areas with and without their accumulation are distinguished, and the composition of volcanic rocks is typically isotopically and geochemically heterogeneous. It is concluded that currently there is no single geodynamic model that can explain the revealed phenomena in their entirety. At the same time, the data suggest that the nature of some magma chambers that feed intraplate volcanoes is caused by transformation of energy in the lithosphere as a nonlinear open system.  相似文献   

8.
A detailed investigation of microstructures of the phosphorites from Christmas Island under a scanning electron microscope coupled with an analysis of their chemical composition revealed that both their structure and composition are quite similar to those of the granular and microgranular phosphorites on present-day continents, as well as those of the phosphorites on some of the Pacific guyots. Their composition, together with their geological position and interrelationships with the surrounding rocks, proves that the ornitogenic hypothesis based on the presumed guano accumulation followed by its transformation into phosphatic rock is not compatible with the field observations. Meanwhile, the problem of the source of the Fe and Mn impregnation in the phosphorites remains unresolved and needs further investigations.  相似文献   

9.
Petrological-geochemical data were obtained for intrusive rocks (gabbroids) recovered on the eastern flank of the Knipovich Ridge by deep-sea site 344 (DSDP, Leg 238). It was found that these rocks are similar to basalts and basaltic glasses studied in the adjacent sections of the ridge rift zone [7, 8]. This indicates that the intrusive rocks and erupted lavas are comagmatic. The gabbroids, basalts, and their quenched glasses were derived by differentiation in different-depth chambers and feeder channels. The petrochemical features of the gabbros and basalts (low Fe content, oxidized magnetic minerals) caused their weak magnetic properties. Owing to the multidirectional movements of the oceanic blocks, the bodies of the intrusive and effusive rocks their lost strict linearity and produced the mosaic anomalous magnetic field of the Knipovich Ridge.  相似文献   

10.
虾池养殖环境有机污染物降解细菌的筛选   总被引:2,自引:0,他引:2  
在实验室条件下通过富集培养共分离出 1 2 1株菌进行筛选。利用需氧性、BOD2 / COD0 、胞外酶等指标进行筛选 ,最后筛选到 7株对富营养有机物具有较高降解能力的细菌 ,它们均能产生酪蛋白酶、明胶酶、脂酶 (Tween- 80 )、淀粉酶其中 4株细菌还能产生卵磷脂酶。通过测定 BOD5及 COD来衡量 7株细菌利用对虾饵料的能力 ,5d内对虾饵料培养基的 CODMn去除率达到 59.6%~ 79.2 %。用常规生理生化方法将细菌鉴定到属 ,其中 1株为弧菌属细菌 (Vibrio spp.) ,6株为芽孢杆菌属细菌(Bacillusspp.)。  相似文献   

11.
The results of investigations of internal waves carried out in three test ranges located in the north part of the Aegean Sea and characterized by different dynamics of wave motions and water masses are used to study the electromagnetic waves induced by wave motions. We analyze their dependence on the period of waves and wavelength, reveal specific features of the behavior of the electric and magnetic fields and their phases as functions of depth, and compare the intensities of electromagnetic fields obtained under different hydrological conditions.  相似文献   

12.
This article discusses the possible socioeconomic impact of Taiwan Strait Tunnel from the perspective of the relationship between the construction of Taiwan Strait Tunnel and the socioeconomic development of the two sides of the Taiwan Strait and the surrounding areas. First of all, the construction of Taiwan Strait Tunnel in its conceptual stage depends on the socioeconomic development of the two sides of the Strait. Important basic conditions—such as the mainland's and Taiwan's future sustainable economic growth above what has already been achieved; their further development of economic, trade, and social ties; their political dialogue based on “the principle of one China”; and the progress of the peaceful reunification of the motherland—will decide the construction of the Taiwan Strait Tunnel. Under such conditions, once the Taiwan Strait Tunnel is operable, it will create a huge demand pull on the two sides of the Taiwan Strait and their surrounding areas for a long period and, thus, will bring about a sustainable increasing economic upsurge in the two sides. Secondly, once the Taiwan Strait Tunnel is open to traffic, its transport ability will be tremendous and will greatly influence the economic development of the two sides of the Strait and enhance their economic and trade ties and their personnel exchange. At the same time, the tunnel will not only form a new traffic pattern of the two sides of the Taiwan Strait, but it will also improve their traffic structure and expand their traffic scale to a large extent. It is certain that the construction of Taiwan Strait Tunnel will be a highly complex project of an all-time grand scale to be constructed over quite a long period. It will encounter a lot more restrictive factors than have ever been met in the fields of design, programming, techniques, equipment, organization of construction, and the operation and maintenance of the tunnel and line. Moreover, it will also encounter many important restrictive factors as a result of its socioeconomic impact.  相似文献   

13.
The study of foraminifers from sediments accumulated during the last 30 ky revealed their similar distribution in the central and marginal parts of the Deryugin Basin, which implies similar environmental changes throughout this morphological structure. The lack or extreme taxonomical impoverishment of the benthic foraminiferal assemblages during the Last Glacial Maximum indicates a combination of several factors: the significant deterioration of the parameters controlling their bioproductivity in response to the general cooling; the development of anoxic bottom conditions; and, probably, the unfavorable influence of cold barite-methane seeps on the geochemical parameters of the bottom waters. The weaker activity of these seeps in the central part of the basin during the Holocene is evident from some deviations in the structure of the benthic foraminiferal assemblages against the background of their general taxonomic similarity.  相似文献   

14.
吴德辉  连东英 《台湾海峡》2005,24(3):377-382
本文应用准地转正压无辐散模式对双涡的相互作用进行了数值模拟试验。试验结果表明:(1)只考虑相对涡度平流的情况下双涡以互旋为主,而且随着初始间距的缩小,互旋越来越明显。双涡的相互作用与它们的初始间距以及它们的强度和结构有密切的关系。(2)双涡的移动加速和减速都是出现在它们移动方向改变的时刻,当移动方向向逆时针方向变化时移速减慢,否则加快。  相似文献   

15.
分析了三种不同多波束测深系统回波强度的记录方式及数据结构,基于各自生成声纳图像的特点规律的差异,按其声纳图像不同用途对多波束测深系统进行了归类,其结果可为用户结合自身需求,正确购置多波束测深系统及合理应用声纳图像提供参考.  相似文献   

16.
E. D. Golubeva 《Oceanology》2006,46(5):672-682
Based on the summarized geological and petrogeochemical information on the basaltic magmatism on the Pacific Ocean floor, the formation-geochemical rock types, their associations in the oceanic morpho-structures, and petrological provinces were distinguished. The features of the composition variations of the rocks presented mainly by magno-and ferrotholeiites in mid-oceanic ridges and by their petrological analogues at the plates (Fenner trend) were examined. The increase in the silica acidity and alkalinity of the rocks (Bowen trend) is moderately manifested in the eastern provinces of the ocean and is much more pronounced in the western areas (including the formation of complexes constituted by significant volumes of alkaline rocks).  相似文献   

17.
Particular features of the distribution of the transparency and particulate matter content, their variability, and their interdependence in the surface water layer (0–5 m) over the northwestern shelf and in the adjacent abyssal part of the Black Sea in the summer were considered on the basis of long-term simultaneous optical, biological, and hydrological observations (1979–1993). In the shelf regions with different river discharges and in the waters of the open part of the sea, the distributions of the transparency, the total particulate matter, and its organic components (organic carbon, nitrogen, and chlorophyll a), as well as the relative content of particulate organic carbon in the total amount of the particulate matter and the content of chlorophyll a in the particulate organic carbon, were considered. The distributions of the transparency and particulate matter and their dependence on the water dynamics are in good agreement. It was demonstrated that extreme anthropogenic eutrophication influences the western and northern coastal shelf areas. The water transparency and particulate organic matter distributions in the central shelf area subjected to the influence of transformed river water and the water properties of the southern part of the shelf, which is influenced by the waters of the open sea, were determined according to the particular structure of the phytoplankton, its abundance, and the processes of its production and destruction.  相似文献   

18.
作者综述了南沙海域内波及细结构研究现状。首先介绍研究中所用的国际或国内首次使用的一些研究方法,它们包括最基础的CTD资料质量控制的方法,浮力频率计算方法、频散关系和波函数计算方法,细结构概率分布假设检验方法,内波检测方法,内潮计算的谱差分方法等。而后总结所得的研究成果(其中一部分是首次发表的),它们包括南沙海区浮力频率的分类及其随地域和季节的变化规律;内波频散关系和波函数;细结构特性及其与内波的关系;细结构的非高斯概率分布特性;垂向波数谱特性及其随季节、地域及水层的变化;频率特性;Cox 数及其概率分布;内潮特性等。最后对今后研究方向作了展望。  相似文献   

19.
相手蟹科的诸多种类因其形态极其相似成为方蟹总科分类中疑问较多的一个类群。通过对中国沿海相手蟹线粒体COI和16S rRNA基因序列进行分子系统发育分析,结果表明14种相手蟹COI和16S rRNA基因序列之间差异分别为5.7%~14.5%和1.5%~12.1%,均达到了种间差异水平。构建的系统发育树显示,14种相手蟹分别为独立有效物种,但分属于拟相手蟹属和近相手蟹属的4种拟相手蟹和3种近相手蟹,没有分别形成2个独立的支系,而是混合聚成一大支系。而属于螳臂相手蟹属的无齿螳臂相手蟹则首先与属于中相手蟹属的中华中相手蟹聚成一支,再与红螯螳臂相手蟹聚为一大支,表现出与形态分类的不一致。错综复杂的分子系统关系预示着相手蟹类为多系起源,也表明它们之间的种间关系乃至于属间关系尚有诸多问题有待进一步厘定。  相似文献   

20.
凡纳对虾引进亲本及其子代RFLP分析   总被引:8,自引:0,他引:8  
运用 PCR-RFLP 技术分析凡纳对虾两个引进亲本群体及其各自子一代的遗传变异情况。用一对引物对这四个群体进行 mt DNA-细胞色素氧化酶I部分片段的 PCR 扩增,扩增结果为一条约 1.25 kb的条带。用 19种限制性内切酶对该扩增条带进行酶切分析,其中 Hinf I, Sty I, Taq I 这 种酶有酶切位点。用这3种 3酶进行限制性片段长度多态性 ( RFLP )分析,共获得 种限制性类型 基因型 。而且内切酶 2 ( ) Sty I在两个不同的引进亲本群体及其各自的子一代的扩增产物的酶切中,表现出明显的差异。  相似文献   

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