2002 Vol. 21, No. 1

Physical Oceanography,Marine Meteorology and Marine Physics
Circulation and its seasonal variability in region around the Kerguelen Plateau
Shi Jiuxin, Le Kentang, Byung Ho Choi
2002, (1): 1-17.
A coupled ice-ocean isopycnal numerical model of the Southern Ocean is established to study the circulation and its seasonal variability in the region around the Kerguelen Plateau.An analysis of the simulated results shows significant stripe-like structure and non-zonal feature of the Antarctic Circumpolar Current (ACC) in this region.ACC begins to bifurcate and to turn its direction before meeting the plateau.The southernmost branch of ACC is near to the Antarctic coast and displays its strong interaction with the westward Antarctic Slope Current.The northern branch of ACC has a tendency of annual variations while the southern one varies in a semiannual cycle.The variation phases of both branches are coincident with that of the wind stress in this region.
Implementation and application of a nested numerical storm surge forecast model in the East China Sea
Yu Fujiang, Zhang Zhanhai
2002, (1): 19-31.
A nested numerical storm surge forecast model for the East China Sea is developed.A one-way relaxing nest method is used to exchange the information between coarse grid and fine grid.In the inner boundary of the fine grid model a transition area is set up to relax the forecast variables.This ensures that the forecast variables of the coarse model may transit to those of fine grid gradually,which enhances the model stability.By using this model,a number of hindcasts and forecast are performed for six severe storm surges caused by tropical cyclones in the East China Sea.The results show good agreement with the observations.
Tidal harmonic analysis of TOPEX/POSEIDON data in the Northwest Pacific by introducing difference-ratio relations
Liu Kexiu, Majirui, Han Guijun, Fan Zhenhua, Xu Chongjin
2002, (1): 33-44.
The difference-ratio relations are introduced to separate tidal constituents that are aliased due to the sampling interval and sampling span of the TOPEX/POSEIDON altimeter.It is found that some tidal constituents such as K1 and SSA,though aliased at along track points,are not aliased at crossover points Ixrausf the data at crossover points are double those at along track points.So the harmonic analysis method can be employed directly for the analysis of time series at crossover points.Then the difference-ratio relations from crossover points are introduced to analyze the time series at along track points.The TOPEX/POSEIDON data in the Northwest Pacific are analyzed with this method.The results from this method agree well with tidal constants from tidal gauges.
Marine Meteorology
Cyclone formation and development in the Antarctic Prydz Bay
Xie Simei, Mei Shan, Liu Kewei, Wei Lixin
2002, (1): 45-54.
Using meteorological data of field observation in 1990-2000,especially polar orbit highresolution NOAA satellite cloud maps received from the Antarctic expedition vessel since 1997,the formation and development of the Prydz Bay cyclone are studied in this paper.Some new viewpoints are suggested such as:when surround-polar cyclone enters the Prydz Bay,it can also intensify and develop in summer; cyclone can also develop in the easterlies in this bay.These view points revise old uncomplete view point that the Prydz Bay is a burial ground of cyclone,and also further consummate formation-development theory of surround-cyclone in the Antarctic westerlies and cyclone in the Antarctic easterlies.In this paper,the mechanism of ice-air-sea interaction in the Prydz Bay is studied,and the physical process of cyclone formation-development is explained.By use of wholly dynamic transportation method,an energy exchange case of a cyclone,which explosively developed after entering the Prydz Bay,is calcu caculated.In the open water area,momentum flux is-2.205 N/m2.sensible heat flux is 486.69 W/m2,and latent heat flux is 261.84 W/m2.It is larger than values of westerlies burst over the Pacific.The heat transferred from ocean to atmosphere in form of sensible and latent heat promotes cyclone development rapidly.In this case wind force was as strong as 12 grade,with 10 minutes average wind speed of 38 m/s,and instantaneous wind speed of 100 m/s which broke the wind speed record of 96 m/s in the Antarctic (Wendler and Kodama).
Marine Physics
Estimation of chlorophyll-a concentration in the Zhujiang Estuary from SeaWiFS data
Chen Chuqun, Shi Ping, Magnus Larson, Lennart Jönsson
2002, (1): 55-65.
The chlorophyll-a concentration is generally overestimated for the southern China coastal waters if the default algorithm of the SeaDAS is employed.An algorithm is developed for retrieval of chlorophyll-a concentration in the Zhujiang Estuary,Guangdong Province,China,by using simulated reflectance data.The simulated reflectance is calculated corresponding to the SeaWiFS wavelength bands,via a general model by inputting measured water components,i.e.,the suspended sediment,chlorophyll-a,and yellow substance (DOC) concentration data of 130 samples.Empirical relationships of the chlorophyll-a concentration to 240 different band combinations are investigated based on the simulated reflectance data,and the band combination,R5R6/R3R4,is found to be the optimum one for the development of an algorithm valid for the Zhujiang Estuary.This algorithm is then employed to determine the chlorophyll-a concentration from SeaWiFS data.The estimated concentrations have a better accuracy than those obtai obtained from the SeaDAS default algorithm when compared with sea truth data.The new algorithm is d}on_strated to work well and is used to derive a series of image maps of the chlorophyll-a concentration distribution for the Zhujiang Estuary and adjacent coastal areas.
Marine Geology and Geomorphology
Foraminifera in surface sediments of the Bering and Chukchi Seas and their sedimentary environment
Meng Yi, Chen Ronghua, Zheng Yulong
2002, (1): 67-76.
Based on a quantitative analysis of foraminifera in 39 surface samples of the Bering and Chukchi Seas,the nearly absence of planktonic foraminifera in the surface sediments can be related to the low surface primary productivity and strong carbonate dissolution in the study area.It has been revealed that the surface primary productivity,and carbonate dissolution and properties of water masses related to the water depth mainly control the distribution of benthic foraminifera.The shelf of the Chukchi Sea is dominated by the Elphidium spp.assemblage and Nonionella robusta assemblage with low foraminiferal abundance and diversity,which is controlled by the coastal water mass of the Arctic Ocean.The slope of the Bering Sea is dominated by the Uvigerina peregrina-Globobulimina affinis assemblage with abundant N.robusta,and relatively high foraminiferal abundance and diversity,which is controlled by the intermediate and deep water masses of the Pacific Ocean.However,the Bering Sea has relatively shallow carbonate lysocline and compensation depth (CCD),at about 2 000 and 3 800 m,respectively.In addition,there exists Stetsonia arctica in the surface sediments of the upper slope in the Bering Sea,which is a typical deep-sea benthic foraminiferal species of the slope in the Arctic Ocean.This indicates that the deep water of the two seas beside the Bering Strait had ever exchanged.
Rifting characteristics of eastern subbasin of South China Sea and its spreading pattern
Li Jiabiao, Jin Xiangiong, Gaojinyao
2002, (1): 77-85.
With processing and interpretation of 25 000 km full-coverage multibeam swath data from the eastern South China Sea,it is found that NE-trending and NW-trending linear morphological features such as scarps,horsts and grabens,govern the central part (14°-17° N) of eastern subbasin.Compared with reflection seismic profiles,these NE-trending linear morpho-structures are considered to be the representation of basement structures on seabed and can be divided into three linear structural zones.The trend of the central zone is NE45°-50° occurring around extinct spreading center,the trend of the second zone is NE70°-78° on both sides of the central one and the trend of the third zone is about NE60° just on the north of the second one.These three NE-trending linear zones are formed in late-stage NW-SE-trending seafloor spreading of the eastern subbasin along NW-trending linear faults,and respectively correspond to three spreading episodes:17.0-19.0 Ma (5d-5e),19.0-21.0 Ma (5e-6a) and 21.0~24.2 Ma (6a-6c) based on the contrast of morpho-structures to magnetic lineation anomalies.
Discovery and features of vertical zonations of tidal salt-marsh foraminifera in Jianchuan, North Jiangsu Province, China
You Kunyuan, Zhang Zhaogan, Wu Xiaogen, Shi Bingwen
2002, (1): 87-94.
Through densified surface sampling of foraminifera and accurate elevation measurement along three transect lines in open-coast tidal salt-marsh of Jianchuan,particular salt-marsh foraminifera assemblages were found.The salt-marsh foraminifera assemblages are distributed in well-defined vertical zonations with respect to elevation and closely parallel marsh floral zonations.At the top of the vertical zonation all foraminifera disappear abruptly which are accurately located at the highest high water datum.This distribution pattern can be used to relocate former sea levels accurately (to an accuracy of within ±5 cm).A modern regional criterion of foraminifera for relocating the former sea levels in high resolution in our country is provided,and deficiencies of studying the vertical zonation only in sheltered coast salt-marsh abroad are filled up.
Behaviors of 210Pb and 210Po around hydrothermal vents in the Okinawa Trough
Yang Yongliang, Masashi Kusakabe, Yoshiyuki Yamamoto
2002, (1): 95-114.
Vertical profiles for the uranium-series radioisotopes 210Pb and 210Po were obtained at the two hydrothermal vent sites,the Iheya Ridge and the Minami-Ensei Knoll,in the Mid-Okinawa Trough in 1993 and 1994,respectively.In 1995,both radioisotopes were measured at the Minami-Ensei Knoll again.At the Iheya Ridge,where the hydrothermal activity is not active as reflected by the CH4,and 222Rn data,both the total 210Pb and 210Po activities show deficiency relative to their parents,and the mean residence time of 210Pb and 210Po is approximately equal to 20 and 2-5 a,respectively.At the Minami-Ensei Knoll,which is characterized by black smokers,the total 210Pb(0.167×10-3-2.5×10-3 Bq/kg) around the plumes is deficient relative to 226Ra but the total 210Po activities (1.83×10 -3-2.83×10-3 Bq/kg) are in excess relative to 210Pb.The 210Po activities are higher than those in the East China Sea and the Okinawa Trough and excess 210Po has been found.The 210Pb/226Ra and 210Po/210Pb activity ratios are 0.1-0.4 and 1.1-7.8,respectively.210Pb is preferentially scavend in the hydrothemial plumes.The possible mechanisms governing the concentration of 210Pb in the Minami-Ensei Knoll involve a lateral transport of 210Pb via diffusion.The high 210Po/210Pb activity ratios in the hydrothermal plumes suggest a depletion of 210Pb and addition of 210Po in the hydrothermal vent area.
Marine Chemistry
Effects of chemical ecological adjustment and control experiment on phytoplankton community in the Aoshan Bay
Chen Bijuan, Zhao Jun, Xin Fuyan, Cui Yi, Guo Feng
2002, (1): 115-123.
There is a low nutrient level in the Aoshan Bay.In June 1999,the chemical adjustment and control experiment was made in the Aoshan Bay.Following tracts investigation was carried out before the experiment and on the 1st,2nd,4th,5th,6th and 45th day/after the experiment.While the variance of amount of phytoplankton,the replacement of superior species and the species composition of phytoplankton were researched.The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment.Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment,its dominant index was 37.7%.Six days after the experiment,its dominant index dropped to 17.6%.Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1% to 39.2%,it became the first dominant species.Forty-five days after the experiment,the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997.
Nitrogen forms and decomposition of organic carbon in the southern Bohai Sea core sediments
Song Jinming, Ma Hongbo, Lü Xiaoxia
2002, (1): 125-133.
Study on form characteristics of nitrogen in marine sediments is the primary method to research its biogeochemical cycling and nitrogen form characteristics in core sediments can reflect the process and results of early diagenesis in a certain degree.In this paper,Sequential extraction process in natural grain size was used for studying the existent forms of nitrogen in five core sediments of the southern Bohai Sea for the first time.Nitrogen was divided into two parts-transferable and fixed based on whether it could be extracted by the reagent.Distributions and early diagenesis of transferable nitrogen forms in the southern Bohai Sea were researched integratedly.Results indicate that IEF-N and OSF-N are predominant forms in transferable part in the studied core sediments.Contents of different nitrogen forms vary differently with depth,and have different diagenesis process.Decomposition constant of organic nitrogen (ON) and OC are about 15.51×10-3a-1 and 4.79×10-3a-1 respective and the decomposition content of biogenic elements C,N,P,Si has the sequence N > P > C > Si.OC/TN (simplified as C/N in the following) ratio is much lower than OC/ON,which indicates that sediment preserves plenty of inorganic nitrogen(IN) and/or fixed nitrogen,and the decrease of OC/ON ratio with depth is due to ON reservation in sediments.Generally,transferable nitrogen acvrounts for more proportion of TN in the surface layer than in the deep layer of core sediments,whereas,some stable forms of nitrogen can activate and become transferable under appropriate environment,which induces the proportion of transferable nitrogen in TN in the deep layer to be almost the same as that in the surface layer.
Marine Biology and Fishery
Distribution characteristics of size-fractionated chlorophyll a, primary production and new production in the Laizhou Bay, July 1997
Cai Yuming, Ning Xiuren, LiuZilin, Liu Chenggang
2002, (1): 135-146.
The distributions of chlorophyll a concentration,primary production and new production were observed in the Laizhou Bay of the Bohai Sea in both spring and neap tides during July 1997.The results showed that there were marked features of spatial zonation in the surveyed area,due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a,primary production and new production were all higher in spring tides than that in neap tides in the Laizhou Bay.The highest values of these parameters were encountered in the central regions of the bay.At most stations,chlorophyll a concentrations at the bottom were higher than that at the surface.The results of size-fractionated chlorophyll a and primary production showed that contributions of nano-combining pi-coplankton (>20 μm) to total chlorophyll a and primary production were dominant in phytoplankton community biomass and production of the Laizhou Bay.The environmental factors,primary production and new production in the Laizhou Bay are compared with other sea areas.
Studies on filtration rate in four species of suspension feeding bivalves
Lin Yuanshao, Luo Wenxin, Cao Wenqing, Guo Donghui, Zheng Airong, Huang Changjiang
2002, (1): 147-155.
The filtration rates of four kinds of bivalves that were cultivated dominantly around Xiamen sea area were measured by using a laboratory flowing system.The experimental results were shown below:(1) Filtration rates were measured in the range of 54-74.8 ml/(g·min) among the four bivalves,sequencing descently Saccostrea cucullata > Sinonovacula constricta > Mytilus viridis > Ruditapes philippinarum.(2) The relationship between filtration rates on individual size showed a negative exponential function (FR=aWb,FR'=aWb-1),with b-1=-0.435 6 and-0.392.(3) Filtration rates on Skeletonema costatum were much higher than on Alexandrium tamarensis and Scripp-silla trochoidea in S.cucullata and R.philippinarum.(4)FR'on algal densities was also shown a negative function (FR'=aDb-1),with b-1=-0.143 and-0.215 2 in S.cucullata and R.philippinarum,respectively.