2002 Vol. 21, No. 4

Physical Oceanography,Marine Meteorology and Marine Physics
Study on circulation and meso-scale eddies in the South China Sea in summer of 1998
Xu Jianping, Xue Huijie, Shi Maochong, Liu Zenghong
2002, (4): 469-481.
Abstract:
By using wide scope ADCP data which were got during SCSMEX (South China Sea Monsoon Experiment) period in the summer of 1998, and comparing these data with numerical modelling result, the distribution and variation characteristics of the circulation and meso-scale eddies in the South China Sea (SCS) were studied. The results show that:(1) in the SCS, 18 different scale eddies or motion systems with characteristics similar to meso-scale eddy were found during the investigation; (2) a strong westward current was found in the south of the Taiwan Shoal; (3) the energy of those eddies west of 114°E was much stronger than that of the east; and (4) there exist many powerful meso-scale eddies in the Nansha region south of 12°N. The distributions of numerous eddies reflect the complexity of the circulation in the SCS. It seems that the formation of those eddies should be caused by joint work of wind, coast feature, bottom topography, water density, inertial force and continental shelf waves.
Marine Physics
A new model to extract environmental pattern for fishing ground
Su Fenzhen, Zhou Chenghu, Liu Baoyin, Du Yunyan, Shao Quanqin
2002, (4): 483-493.
Abstract:
The relationship between the forming of fishing ground and the oceanic spatio-temporal field is nonlinear. In order to analyse the relationship between variables with spatio-temporal structures,a spatio-temporal pattern extracting model is provided to find the reason for the forming of fishing ground. In the model, the spatio-temporal structure of the oceanic factors is expressed as neighbour.The elements in the neighbour are filled in the table of decision-making system. After a recursion processing the spatio-temporal rule will be extracted with the spatio-temporal structure. And a experiment is given to show how to find the temperature pattern for the forming of the fishing grounds in Dasha area.It shows that the model is active and it should be the research front for the marine fishery.
A study on quality and availability of COCTS images of HY-1 satellite by simulation
Li Shujing, Mao Tianming, Pan Delu
2002, (4): 495-504.
Abstract:
Hy-1 is a first China's ocean color satellite which will be launched as a piggyback satellite on FY-1 satellite using Long March rocket. On the satellite there are two sensors:one is the China's ocean color and temperature scanner (COCTS), the other is CCD coastal zone imager (CZI).The COCTS is considered to be a main sensor to play a key role. In order to understand the characteristics of future ocean color images observed, a simulation and evaluation study on the quality and availability of the COCTS image has been done. First, the simulation models are introduced briefly, and typical simulated cases of radiance images at visible bands are introduced, in which the radiance distribution is based on geographic location, the satellite orbital parameters and sensor properties, the simulated method to evaluate the image quality and availability is developed by using the characteristics of image called the complex signal noise ratio (CSNR). Meanwhile, a series of the CSNR images are generated from the simulated radiance components for different cases, which can be used to evaluate the quality and availability of the COCTS images before the HY-1 is placed in orbit. Finally, the quality and availability of the COCTS images are quantitatively analyzed with the simulated CSNR data. The results will be beneficial to all scientists who are in charge of the COCTS mission and to those who plan to use the data from the COCTS.
Marine Chemistry
Measurement of nuclides of uranium and thorium series of disequilibrium using γ-spectroscopy
Liu Guangshan, Huang Yipu, Li Jing, Ye Lin
2002, (4): 505-517.
Abstract:
The decay dynamic equations of two daughters were resolved as initial activities of daughters are not zero, and gave calculation formula of activities for measuring uranium and thorium series of disequilibrium using γ-spectroscopy. 238U, 234Th, 226Ra, 222Rn, 228Ra, 228Th, 224Ra, 212pb, 210pb and 40K in two sediment samples were determined as application.
Marine Geology and Geomorphology
Sulfur isotopic composition of modern seafloor hydrothermal sediment and its geological significance
Zeng Zhigang, Li Jun, Jiang Fuqing, Qin Yunshan, Zhai Shikui
2002, (4): 519-528.
Abstract:
A total of 1 264 sulfur isotopic values for modem seafloor hydrothermel sediments from different hydrothermal fidds have been collected. On this basis, combining our sulfur isotpic data for surface hydrothermal sediments from the Jade hydrohtermal field in the Okinawa Trough and the TAG hydrothermal field in the Mid-Atlantic Ridge, respectively, and comparing the sulfur isotopic compositions and analyzing their sources of sulfur in seafloor hydrothermal sediments from different geologic-tectonic setting, the results show that:(1) sulfur isotopic values of sulfides and sulfates in modern seafloor hydrothermal sediments are concentrated in a narrow range, δ34S values of sulfides vary from l×10-3 to 9×10-3, with a mean of 4.5×10-3 (n=1 042), δ34S values of sulfates vary from 19×10-3 to 24×10-3, with a mean of 21.3×10-3 (n=217); (2) comparing the sulfur isotopic compositions of hydrothermal sediments from the sediment-hosted hydrothermal fields, the range of sulfur isotopic values for hydrothermal sediments from the sediment-free hydrothermal fields is narrow relatively; (3) the differences of sulfur isotopic compositions in sulfides from different hydrothermal fields show the differences in the sources of sulfur. The sulfur of hydrothermal sulfides in the sediment-free mid-ocean ridges is mainly from mid-ocean ridge basalt, and partially from the reduced seawater sulfate, and it is the result of partially reduced seawater sulfate mixed with basaltic sulfur. In the sediment-hosted nid-ocean ridges and the back-arc basins, the volcanics, the sediments and the organic matters also can offer their sulfur for forming hydrothermal sulfides; (4) the variations of sulfur isotopic compositions and the different sources of sulfur for hydrothermal sediments may be attributed to the various physical-chemical characteristics of hydrothermal fluids, the magmatic evolution and the different geologic-tectonic settings of seafloor hydrothermal systems.
Marine Biology and Fishery
Community diversity of bacteria in digestive tract of mud snail (Bullacta exarata Philippi) and its rearing shoal
Wang Guoliang, Zheng Tianlun, Lu Tongxia, Wang Yinong, Yu Hong, Jin Shan
2002, (4): 529-534.
Abstract:
The bacterial flora in the digestive tract of B. exarata Philippi and its rearing shoal were investigated, respectively. A total of 107 strains of heterotrophic bacteria, isolated from crop, stomach and intestine, mainly belong to genera Photobacterium, Bacillus, Pseudomonas and Vibrio. Varieties of bacteria in crop were significantly more than that in stomach and in intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera are Photobacterium, Bacillus, Pseudomonas, Vibrio and some genera of Enterobacteriaceae. The number of heterotrophic bacteria and Vibrio in rearing shoal changed in line with the alteration of the temperature, and were significantly affected by the use of pesticide.
Studies on Genus Cryptomonas from China seas
Hu Hongjun, Li Yeguang, Wu Liping, Qi Yuzao
2002, (4): 535-540.
Abstract:
Six species of Genus Cryptomonas from the East and South China Seas are reported. C.varibilis H. J. Huet L. P. Wu, C. zhanjiangensis H. J. Huet L. P. Wu and C. zhejiangensis H. J. Hu et Y. G. Li are described as new. C. profunda Butcher, C. pseudobaltica Butcher and C. chrysoides Butcher are reported as new record.
Biological characteristics of marine bacterium S-9801 strain and its culture conditions of pigment production
Tian Li, He Peiqing, Wu Hongqing, Wen Zhanbo, Liu Chenlin, Li Guangyou
2002, (4): 541-545.
Abstract:
Strain of Flavobacterium sp. (S-9801), was screened from 207 strains of marine bacteria isolated from the Bohai Sea continental shelf and the Zhujiang Estuary, for its red pigment production. The biological characteristics of strain S-9801 and culture conditions of pigment production have been checked out in this study. The color of the bacterial colony on 2216E medium was from coccineus to rose bengal. Optimum culture conditions were sodium chloride concentration(g/dm3), 10~30; pH,3~8; temperature, 25~28℃; tryptone and yeast extract as nitrogen sources and gluccse as carbon source. Under optimum conditions, pigment accumulation started after 12 h, reaching a maximum rate of synthesis at 36 h.
Cloning and expression of aequorin genes from jellyfish Aequorea and characterization of aequorins activities
Luo Wenxin, Zhang Jun, Li Shaowei, Cheng Tong, Chen Min, Li Shaojing, Xia Ningshao
2002, (4): 547-556.
Abstract:
Two new aequorin genes, aeqxm and aeqxxm, were isolated from jellyfish Aequorea macrodactyla and Aequorea parva respectively, which are commonly found in the warmer waters on the coastal region of the East China Sea. The DNA sequences of the two genes have no introns and each one contains an ORF of 585 bp in full-length encoding a 195-aa protein. The two genes of aeqxm and aeqxxm share nuclcotide homologies of 80.7% and 85.1% with AEVAQ440X respectively, and the corresponding proteins share amino acid homologies of 84.7% and 84.2% with AEVAQ440X. High amino acid homology was found between apoaeqxm and apoaeqxxm. The two genes were cloned into expression vector pTO-T7 respectively, and the expression yields amounted to 40% of the total protein in E. coli BL21. The activities of the two photoproteins were reconstituted by incubating the expressed apoproteins with coelenterazine f. In the presence of Ca ion, both of the regenerated aeqxm and aeqxxm exhibited an emission peak at the wave length of 470 nm.
Taxonomy and ultrastructure of five species of Tetraselmis (Prasinophyceae) isolated from China seas
Zhang Chengwu, Hu Hongjun
2002, (4): 557-579.
Abstract:
Comparative ultrastructural investigations on twenty-three isolates of Tetraselmis from the South China Sea, East China Sea and Huanghai Sea, have revealed that these isolates belong to:(1) Tetraselmis chui Butcher; (2) T. cordiformis (H. J. Carter) Stein; (3) T. helgolandica Kylin; (4) T. suecica (Kylin) Butcher; (5) T. guangdongensis sp. nov. Except T. helgolandica,the others are new records in China. T. guangdongensis sp. nov. is a new species. Its external and anatomical features closely resemble those of T. impellucida McLachlan et Parke. As in that species the pyrenoid is penetrated from many directions by cytoplasmic channels delimited by a double membrane.The protoplast withdraws from the apical portion of the theca, that portion which overlaid the trough inverts and pops out in the form of a teat. But unlike that species a starch sheath is present; pyrenoid matrix is surrounded by thylakoids which intervenes between the matrix and the starch sheath surrounding pyrenoid; the theca is stratified.
Marine Engineering
Experimental study on stability of sunken large diameter cylindrical structure on sandy seabed during construction period
Qin Chongren, Pang Hongli, Li Shisen, Zhang Wei
2002, (4): 581-595.
Abstract:
A systematic experimental research work is done for the stability of sunken large diameter cylinder during construction period. It is the first research that gives the method for assessing the stability of the larger diameter cylindrical structure, a set of values is derived also for the critical stability indices of the large diameter cylinder sunken to the sandy seabed.
Notes
Coastal geomorphic evolution at the Denglou Cape, the Leizhou Peninsula
Wang Lirong, Zhao Huanting, Song Chaojing, Yuan Jiayi, Yu Hongbing
2002, (4): 597-611.
Abstract:
The Denglou Cape, southwest of the Leizhou Peninsula, is the most typical tropical coast in the continent of China. The coastal geomorphic development basics of the geology and Quaternary environment change are discussed. Aerial photograph interpretation with fieldwork is applied to draw the outlines of geomorphic types. Based on the investigative data, the exogenic forces and marine organism conditions concerning tropical coast development in the area are expounded, and coastal dynano-deposition geomorphic bodies are analysed, mainly with sea cliff-abrasion platform, barrier-lagoon system,modern beach, coral reef and mangrove tidal flat, and the general process of coastal evolution at this area, as well as coastline changes since middle Holocene transgression.