真鲷饵料生物褶皱臂尾轮虫和眼点拟微绿藻的大量培养     

刘新富  雷霁霖  刘忠强  柳学周 《海洋科学》2000,24(5):47-51

于1992～1994年 ,在中国水科院黄海水产研究所小麦岛试验基地(青岛)进行的“中日合作真鲷增殖放流项目”执行期间 ,对真鲷饵料生物———眼点拟微绿藻 (Nannochloropsisoculata)和L型褶皱臂尾轮虫 (Branchionus plicatilis)进行了大量培养。眼点拟微绿藻的平均接种密度为1211.3×104个/ml,经5～6d的室内或室外露天培养即可达到平均为2341.0×104 个/ml的收获密度 ;采用眼点拟微绿藻和新鲜面包酵母作为混合饵料 ;褶皱臂尾轮虫 (L型 )培养3～4d即可由接种时平均密度148.0个/ml,增长至平均216.8个/ml的采收密度。眼点拟微绿藻和轮虫的日间增殖密度分别是12.8 %和26.6 %。每生产108个褶皱臂尾轮虫需要消耗0.73m3眼点拟微绿藻 (密度为2000×104/ml)和790.8g 鲜面包酵母。采用此法 ,作者连续3a成功地为每年百万尾以上真鲷苗种提供了足够的生物饵料。总结3a苗种培育和生物饵料培养之间的关系 ,作者认为 ,大规模稳定生产海水鱼类苗种时,育苗与饵料生物培养 (褶皱臂尾轮虫和眼点拟微绿藻 )水体的合理比例应为1∶1～1.5∶3。  相似文献   

Short-term temperature and salinity variations in the Tsushima Strait in 2004: Behavior of the surface low-salinity water in the strait     

Kosuke Mori  Takeshi Matsuno  Tomoharu Senjyu  Naoki Hirose  In-Seong Han 《Journal of Oceanography》2009,65(3):301-310

Temporal variations in temperature and salinity observed in 2004 were investigated on a short time scale in the Tsushima Strait. The data were obtained by long-term in situ measurements at Mitsushima and Futaoi Island using an instrument equipped with a piston-type wiper to avoid biofouling. In addition, the temperature and salinity values of the surface layer obtained by a commercial ferryboat between Hakata and Busan were used to investigate their spatiotemporal variations. Temperature and salinity variations with a time scale of several days had a negative correlation in the summer. This evidence suggests that a warm and less saline water mass, which is considered to be mainly the Changjiang Diluted Water (CDW), flowed intermittently through the Tsushima Strait in summer. In late July 2004, a large low-salinity water mass was detected in the Tsushima Strait. At that time, the freshwater transport through the Tsushima Strait transiently reached about 12 × 10⁴ m³s⁻¹, which is estimated from observed acoustic Doppler current profiler (ADCP) data along a ferryboat line and inferred salinity profiles. This estimated value is more than double the maximum of the climatological monthly mean of the Changjiang discharge. Furthermore, salinity and surface current data obtained by high frequency ocean radar (HF radar) indicate that water properties at Mitsushima may occasionally represent part of the water flowing through the western channel via a countercurrent, although Mitsushima is geographically located in the eastern channel.  相似文献   

Changes in the abundance and composition of picophytoplankton in relation to the occurrence of a Kyucho and a bottom intrusion in the Bungo Channel,Japan     

Miho Hirose  Toshiya Katano  Yuichi Hayami  Atsushi Kaneda  Takeshi Kohama  Hidetaka Takeoka  Shin-ichi Nakano 《Estuarine, Coastal and Shelf Science》2008

The Bungo Channel in southwestern Japan receives both warm, called Kyucho, and cold deep-water intrusions (bottom intrusion) from the Pacific Ocean. Abundances of Prochlorococcus, Synechococcus, and eukaryotic picophytoplankton were monitored from 18 July to 17 August 2001 to clarify whether advected picophytoplankton from the Pacific Ocean can grow in the channel or not. Synechococcus cells were further discriminated into low- and high-PUB types according to their fluorescence property in flow cytometry. From 18 to 25 July, the water temperature decreased by 3 °C at a 5-m depth at all stations, indicating the occurrence of a bottom intrusion. From 25 July to 4 August, a Kyucho occurred and the water temperature rapidly increased. From 4 to 17 August, a bottom intrusion and a Kyucho both occurred twice, although the intensities were smaller than those occurring until 4 August. From 18 to 30 July, the abundance of both Prochlorococcus and a high-PUB type of Synechococcus drastically decreased because of a bottom intrusion; however, the abundances rapidly increased due to the advection by a Kyucho. These advected cells increased from 4 to 17 August in the channel and Kitanada Bay. Changes in the abundance of low-PUB type of Synechococcus and eukaryotic picophytoplankton were less noticeable than those in the abundance of Prochlorococcus and high-PUB type. The present study demonstrated that oceanic picophytoplankton advected by the Kyucho could grow in the channel. However, abundances of low-PUB type and eukaryotic picophytoplankton increased higher than those of Prochlorococcus and high-PUB type did. Thus, these oceanic phytoplankters will be excluded when Kyucho does not occur for a long time. The co-occurrence of various types of picophytoplankton found in the channel is probably achieved by both Kyucho event and their growth capability in the channel.  相似文献   

沙虫干呈味及功能性成分研究     

章超桦  铃木健  吉江由美子 《广东海洋大学学报》2000,20(2):24-27

对沙虫干抽提物成分的组成进行的研究结果表明 :游离氨基酸含量 w为 10 .3% ,占抽提物含氮物质的 77.9%。抽提物组成中 ,呈甘味的 Gly(3.2 % )、Ala(2 .5% )和呈鲜味的 IMP(0 .2 7% )、Glu(0 .2 5% )、琥珀酸 (0 .35% )等成分同沙虫干独特的风味有关 ,Na 、Cl-等无机离子也同其呈味相关。此外 ,牛磺酸含量 w高达 3.2 % ,是富含牛磺酸的一种海洋生物 ;精氨酸的含量 w亦较高 ,为 1.2 %。  相似文献   

Correction to: El Niño-related sea surface elevation and ocean bottom pressure enhancement associated with the retreat of the Oyashio southeast of Hokkaido,Japan     

Hasegawa  Takuya  Nagano  Akira  Matsumoto  Hiroyuki  Ariyoshi  Keisuke  Wakita  Masahide 《Marine Geophysical Researches》2019,40(4):513-514

Marine Geophysical Research - In the original publication, the Fig. 2 was published incorrectly. The correct version (Fig. 2) is given in this correction. The original article has been...  相似文献   

ANALYSIS OF Cu, Cd, Co AND Ni IN SURFACE WATER OF THE KUROSHIO AREA IN THE EAST CHINA SEA     

王正方  龚敏  卢勇  阮正  邱华英  王虹  Takeshi Sagi 《中国海洋湖沼学报》1992,10(3):223-230

Study of 1986 and 1987 heavy metal distribution in surface water of the Kuroshio area in the East China Sea showed regional and slight seasonal variations in distribution and concentration . Heavy metal levels in Taiwan Strait, the sea area north of Taiwan and the continental shelf are higher than those in the main axis of the Kuroshio . Dissolved Cu in summer and winter decreases with the increase of salinity , but dissolved Cd has no obvious change with salinity .  相似文献   

Motion of iron sulfide inclusions inside a shock‐melted chondrule     

Masayuki UESUGI  Takeshi AKAKI  Minoru SEKIYA  Tomoki NAKAMURA 《Meteoritics & planetary science》2005,40(7):1103-1114

Abstract— We calculated the trajectories of molten spheres of iron sulfide inclusions inside a melted chondrule during the nebular shock wave heating. Our calculations included the effects of high‐velocity internal flow in the melted chondrule and apparent gravitational force caused by the drag force of nebular gas flow. The calculated results show that large iron sulfide inclusions, which have radii 0.23 times larger than those of the parent chondrules, must reach the surface of the melted chondrule within a short period of time (<<1 s). This effect will provide us with very important information about chondrule formation by nebular shock wave heating.  相似文献   

Collapse and fragmentation of rotating magnetized clouds – I. Magnetic flux–spin relation     

Masahiro N. Machida  Tomoaki Matsumoto  Kohji Tomisaka  Tomoyuki Hanawa 《Monthly notices of the Royal Astronomical Society》2005,362(2):369-381

We discuss the evolution of the magnetic flux density and angular velocity in a molecular cloud core, on the basis of three-dimensional numerical simulations, in which a rotating magnetized cloud fragments and collapses to form a very dense optically thick core of  >5 × 10¹⁰ cm⁻³  . As the density increases towards the formation of the optically thick core, the magnetic flux density and angular velocity converge towards a single relationship between the two quantities. If the core is magnetically dominated its magnetic flux density approaches  1.5( n /5 × 10¹⁰ cm⁻³)^1/2 mG  , while if the core is rotationally dominated the angular velocity approaches  2.57 × 10⁻³ ( n /5 × 10¹⁰ cm⁻³)^1/2 yr⁻¹  , where n is the density of the gas. We also find that the ratio of the angular velocity to the magnetic flux density remains nearly constant until the density exceeds  5 × 10¹⁰ cm⁻³  . Fragmentation of the very dense core and emergence of outflows from fragments will be shown in the subsequent paper.  相似文献   

Relationship between atmospheric conditions at Dhaka, Bangladesh, and rainfall at Cherrapunjee, India     

Fumie Murata  Toru Terao  Taiichi Hayashi  Haruhisa Asada  Jun Matsumoto 《Natural Hazards》2008,44(3):399-410

To improve flood forecasting, the understanding of the atmospheric conditions associated with severe rainfall is crucial. We analysed the atmospheric conditions at Dhaka, Bangladesh, using upper-air soundings. We then compared these conditions with daily rainfall variations at Cherrapunjee, India, which is a main source of floodwater to Bangladesh, and a representative sample of exceptionally heavy rainfall events. The analysis focussed on June and July 2004. June and July are the heaviest rainfall months of the year at Cherrapunjee. July 2004 had the fourth-heaviest monthly rainfall of the past 31 years, and severe floods occurred in Bangladesh. Active rainfall periods at Cherrapunjee corresponded to “breaks” in the Indian monsoon. The monsoon trough was located over the Himalayan foothills, and strong westerly winds dominated up to 7 km at Dhaka. Near-surface wind below 1 km had southerly components, and the wind profile had an Ekman spiral structure. The results suggest that rainfall at Cherrapunjee strongly depends on the near-surface wind speed and wind direction at Dhaka. Lifting of the near-surface southerly airflow by the Meghalaya Plateau is considered to be the main contributor to severe rainfall at Cherrapunjee. High convective available potential energy (CAPE) also contributes to intense rainfall.  相似文献   

The development of Fe-nodules surrounding biological material mediated by microorganisms     

Hidekazu Yoshida  Koshi Yamamoto  Yuki Murakami  Nagayoshi Katsuta  Toru Hayashi  Takeshi Naganuma 《Environmental Geology》2008,55(6):1363-1374

Takashikozo is a phenomenon of Quaternary sediments in Japan. They are cylindrical Fe-oxyhydroxide nodules that form as plaques round plant roots, where Fe is preferentially concentrated to develop a solid wall. Structural features suggest that after the roots have decayed, the central space where the roots were situated acts as a flow path for oxidized water. Analysis of microbial 16S rDNA extracted from the nodules identified iron-oxidizing bacteria encrusted round the roots where they are the likely initiators of nodule formation. Direct microscopic observation revealed an accumulation of Fe-oxyhydroxides that fill the pore spaces and is also likely to be linked with the encrusting microbial colonies. Geological history and nanofossil evidence suggest that these Fe-nodules may have been buried at a depth of up to several tens of meters for at least 10⁵ years in reducing Quaternary sediments. Thus Fe-oxyhydroxide nodules that have formed in a geological environment at the interfaces between water and rock by microbial mediation can persist under reducing conditions. If this is the case, the phenomenon is significant as an analogue of post-closure conditions in radioactive waste repositories, since it could influence nuclide migration.  相似文献