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31.
印度洋东部金枪鱼延绳钓渔业研究--大眼金枪鱼(Thunnus obesus)的生物学特征 总被引:4,自引:0,他引:4
根据作者在印度洋东部海域的延绳钓生产实践,对渔获的大眼金枪鱼群体的群体构成、摄食、繁殖等基本生物学特征进行了初步探讨.结果表明,渔获群体由纯重10~115kg、叉长80~195cm个体组成,纯重与叉长关系式w=2.000×10-5×L2.969;渔获物以3~5龄个体为主,雄性个体所占比例明显高于雌性个体,且随年龄增长雄性个体所占比例逐步提高.鱼群在该海域产卵期较长,不同年龄组性腺发育节律有明显差异. 相似文献
32.
Takuya Itaki Masashi Ito Hisashi Narita Naokazu Ahagon Hideo Sakai 《Deep Sea Research Part I: Oceanographic Research Papers》2003,50(12):1507
The depth distributions of the radiolarian fauna in the Chukchi and Beaufort Seas, marginal seas of the western Arctic Ocean, were examined quantitatively in depth-stratified plankton tows from 4 or 5 intervals above 500 m and in surface sediments from various depths between 163 and 2907 m. The radiolarian assemblage from the water column in September 2000 was dominated by Amphimelissa setosa and followed by the Actinomma boreale/leptoderma group, Pseudodictyophimus gracilipes and Spongotrochus glacialis. These species are related to the Arctic Surface Water shallower than 150 m. This assemblage is similar to that in the Greenland Sea relating to the ice edge, but did not contain typical Pacific radiolarians in spite of the flow of water of Pacific origin in this region. The living depth of Ceratocyrtis historicosa was restricted to the relatively warm water between 300 and 500 m corresponding to the upper Arctic Intermediate Water (AIW) originating from the Atlantic Ocean. Radiolarian assemblages in the surface sediments are similar to those in the plankton tows, except for common Cycladophora davisiana in sediment samples below 500 m. C. davisiana is probably a deep-water species adapted to the lower AIW or the Canadian Basin Deep Water ventilated from the shelves. 相似文献
33.
Ocean Color Satellite Imagery and Shipboard Measurements of Chlorophyll a and Suspended Particulate Matter Distribution in the East China Sea 总被引:1,自引:0,他引:1
Satellite-derived ocean color data of Coastal Zone Color Scanner (CZCS) on board the Nimbus-7 and Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS) are jointly used with historical in situ data to examine seasonal and spatial distributions of chlorophyll a (Chl-a) and suspended particulate matter (SPM) concentrations in the East China Sea. Ocean color imagery showed that Chl-a concentrations on the continental shelf were higher than those of the Kuroshio area throughout the year. Satellite-derived Chl-a concentrations are generally in good accordance with historical in situ values during spring through autumn (although no shipboard in situ measurement was conducted at nearshore areas). In contrast, ocean color imagery in winter indicated high Chl-a concentrations (4–10 mg m–3) on the continental shelf where bottom depth was less than 50 m when surface water was turbid (2–72 g m–3 of SPM at surface), while historical in situ values were usually less than 1 mg m–3. This suggests that resuspended bottom sediment due to wind-driven mixing and winter cooling is responsible for the noticeable overestimation of satellite-derived Chl-a concentrations. The algorithm for ocean color needs to be improved urgently for turbid water. 相似文献
34.
Qian Fenlan Yu Hongjian Lan Youchang Chen Zhi Zhou Mingyu Farn Parungo Wu Peiming 《海洋学报(英文版)》1996,15(1):69-84
AtmosphericinputoftraceelementstothewesternPacificOceanandtheKuroshiooceanarea¥QianFenlan;YuHongjian;LanYouchang;ChenZhi;Zhou... 相似文献
35.
Kern E. Kenyon 《Journal of Oceanography》1997,53(1):89-92
The effects of the gravity torques acting on the angular momentum of surface gravity waves are calculated theoretically. For
short crested waves the gravity torque is caused by the force of gravity on the orbiting fluid particles acting down the slopes
of the crests and troughs and in the direction parallel to the crests and troughs. The gravity torque tries to rotate the
angular momentum vectors, and thus the waves themselves, counterclockwise in the horizontal plane, as viewed from above, in
both hemispheres. The amount of rotation per unit time is computed to be significant assuming reasonable values for the along-crest
and trough slopes for waves in a storm area. The gravity torque has a frequency which is double the frequency of the waves.
For long crested waves the gravity torque acts in the vertical plane of the orbit and tries to decelerate the particles when
they rise and accelerate them when they fall. By disrupting the horizontal cyclostrophic balance of forces on the fluid particles
(centrifugal force versus pressure force) the gravity torque accounts qualitatively for the three characteristics of breaking
waves: that they break at the surface, that they break at the crest, and that the crest breaks in the direction of wave propagation. 相似文献
36.
Noriaki Kimura 《Journal of Oceanography》2007,63(4):685-694
This paper examines the mechanism controlling the short time-scale variation of sea ice cover over the Southern Ocean. Sea
ice concentration and ice velocity datasets derived from images of the Defense Meteorological Satellite Program (DMSP) Special
Sensor Microwave Imager (SSM/I) are employed to reveal this mechanism. The contribution of both dynamic and thermodynamic
processes to the change in ice edge location is examined by comparing the meridional velocity of ice edge displacement and
sea ice drift. In the winter expansion phase, the thermodynamic process of new ice production off the ice edge plays an important
role in daily advances of ice cover, whereas daily retreats are mostly due to southward ice drift. On the other hand, both
advance and retreat of ice edges in the spring contraction phase are mostly caused by the dynamic process of the ice drift.
Based on the above mechanism and the linear relation between the degree of ice production at the ice edge and northward wind
speed, the seasonal advance of ice cover can be roughly reproduced using the meridional velocity of ice drift at the ice edge. 相似文献
37.
The EU Green Paper on Maritime Policy is the European response to the new generation of ocean strategies based on science, technology and innovation aimed at new objectives, such as the strengthening of security and access to new resources. The European character of the proposal is found in the presence of social, cultural and historical elements, what is called the “European vision”. The viability of a European vision of the oceans and the idea of maritime empire as an extension of the current concept of empire within the general context of emerging ocean strategies are the elements offered up for debate on this European Union initiative. 相似文献
38.
C.G. Castro M. Nieto-Cid X.A. lvarez-Salgado F.F. Prez 《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(12):1925-1940
The short-time-scale variability of the remineralization patterns in the domain of Eastern North Atlantic Central Waters (ENACW) off the NW Iberian Peninsula is studied based on biogeochemical data (oxygen, nutrient salts, total alkalinity, pH, dissolved organic matter and fluorescence of dissolved humic substances) collected weekly between May 2001 and April 2002. The temporal variability of inorganic variables points to an intensification of remineralization during the summer and autumn, with an increase of nutrients, total inorganic carbon and fluorescence and a decrease of oxygen. During the subsequent winter mixing, there is a biogeochemical reset of the system, with lower nutrients, total inorganic carbon and fluorescence and higher oxygen. In contrast to inorganic variables, the levels of dissolved organic matter in the ENACW seem to respond to short-term events probably associated with fast sinking particles, where solubilisation of organic matter prevails over remineralization. Applying a previously published stoichiometric model, we observed a vertical fractionation of organic-matter remineralization. Although there is a preferential remineralization of proteins and P compounds in the entire domain of ENACW, the percentage was higher in the upper ENACW (σ<27.10 kg/m3) than in the lower; the percentage of N and P compounds in the oxidised organic matter was >80% for the upper ENACW and 63% for the lower. Likewise, the redissolution of calcareous structures contributes about 6% and 13% to the carbon regenerated in the upper and lower layers of ENACW, respectively. 相似文献
39.
40.
富钴结壳分布的分形特征 总被引:8,自引:0,他引:8
何高文 《海洋地质与第四纪地质》2001,21(1):89-92
利用我国在西太平洋国际海底两个海山获得的富钴结壳资料进行分形研究后发现,富钴结壳的分布具有变维分形分布的特点,结壳丰度呈二阶累计和分形分布,结壳厚度呈多阶不定累计和分形分布,通过计算得到了它们各自的分维数,进而对两个海山的结壳资源进行了初步评价。 相似文献