2007 Vol. 26, No. 5

Display Method:
Seasonal variability of turbulent heat fluxes in the tropical Atlantic Ocean based on WHOI flux product
JIANG Hua, WANG Hui, WU Dexing
2007, (5): 1-11.
The mean seasonal variability of turbulent heat fluxes in the tropical Atlantic Ocean is examined using the Woods Hole Oceanographic Institution (WHOI) flux product.The most turbulent heat fluxes occur during winter seasons in the two hemispheres, whose centers are located at 10°~20°N and 5°~15°S respectively.In climatological ITCZ, the turbulent heat fluxes are the greatest from June to August, and in equatorial cold tongue the turbulent heat fluxes are the greatest from March to May.Seasonal variability of sensible heat flux is smaller than that of latent heat flux and mainly is dominated by the variations of air-sea temperature difference.In the region with larger climatological mean wind speed (air-sea humidity difference), the variations of air-sea humidity difference (wind speed) dominate the variability of latent heat flux.The characteristics of turbulent heat flux yielded from theory analysis and WHOI dataset is consistent in physics which turns out that WHOI's flux data are pretty reliable in the tropical Atlantic Ocean.
A hybrid Lagrangian-Eulerian numerical model for sea-ice dynamics
JI Shunying, LI Hai, SHEN Hung Tao, WANG Ruixue, YUE Qianjin
2007, (5): 12-24.
A hybrid Lagrangian-Eulerian (HLE) method is developed for sea ice dynamics, which combines the high computational efficiency of finite difference method (FDM) with the high numerical accuracy of smoothed particle hydrodynamics (SPH).In this HLE model, the sea ice cover is represented by a group of Lagrangian ice particles with their own thicknesses and concentrations.These ice variables are interpolated to the Eularian gird nodes using the Gaussian interpolation function.The FDM is used to determine the ice velocities at Eulerian grid nodes, and the velocities of Lagrangian ice particles are interpolated from these grid velocities with the Gaussian function also.The thicknesses and concentrations of ice particles are determined based on their new locations.With the HLE numerical model, the ice ridging process in a rectangular basin is simulated, and the simulated results are validated with the analytical solution.This method is also applied to the simulation of sea ice dynamics in a vortex wind field.At last, this HLE model is applied to the Bohai Sea, and the simulated concentration, thickness and velocity match the satellite images and the field observed data well.
The algorithms of chlorophyll-a concentration for CMODIS
MAO Zhihua, ZHU Qiankun, GONG Fang, PAN Delu
2007, (5): 25-33.
The algorithms of extracting chlorophyll-a (Chl-a) concentration have been established for Chinese moderate resolution imaging spectrometer (CMODIS) mounted on Shenzhou-3 spaceship launched on 25 March 2002.The CMODIS is an ocean color sensor with 30 visible channels and 4 infrared channels, much different from other ocean color satellites and needs new algorithms to process data.Three models of Chl-a concentration were established based on Chl-a data retrieved from sea-viewing wide field-of-view sensor (SeaWiFS), with the average relative errors of 26.6%, 24%.0% and 33.5%, respectively.This practical and economic approach can be used for developing the algorithms of Chinese ocean color and temperature sensor (COCTS) on the satellite Haiyang-1 to derive the Chl-a concentration concentration distribution.The applicability of the algorithms was analyzed using some in situ measurements.Suspended sediment is the main factor influencing the accuracy of the spectral ratio algorithms of Chl-a concentration.The algorithms are suitable to using in the regions where suspended sediment concentrations (SSC) are less than 5 g/m3 under the condition of relative error of Chl-a concentration retrieval within 35%.High concentration of suspended sediment leads to the overestimate remote sensing retrieval of concentration of Chl-a, while low-middle SSCs lead to the low Chl-a concentration values using the spectral ratio algorithms.Since the accuracy of Chl-a concentration by the spectral ratio algorithms is limited to waters of Case 2, it is necessary to develop semi-analytical models to improve the performance of satellite ocean color remote sensing in turbid coastal waters.
Photochemical oxidation of dimethylsulfide in seawater
YANG Guipeng, LI Chengxuan, QI Jialin, HU Lige, HOU Haijun
2007, (5): 34-42.
Dimethylsulfide (DMS) is generally thought to be lost from the surface oceans by evasion into the atmosphere as well as consumption by microbe.However, photochemical process might be important in the removal of DMS in the oceanic photic zone.A kinetic investigation into the photochemical oxidation of DMS in seawater was performed.The photo-oxidation rates of DMS were influenced by various factors including the medium, dissolved oxygen, photosensitizers, and heavy metal ions.The photo-oxidation rates of DMS were higher in seawater than in distilled water, presumably due to the effect of salinity existing in seawater.Three usual photosensitizers (humic acid, fulvic acid and anthroquinone), especially in the presence of oxygen, were able to enhance the photo-oxidation rate of DMS, with the fastest rate observed with anthroquinone.Photo-oxidation of DMS followed first order reaction kinetics with the rate constant ranging from 2.5×10-5 to 34.3×10-5 s-1.Quantitative analysis showed that approximately 32% of the photochemically removed DMS was converted to dimethylsulfoxide.One of the important findings was that the presence of Hg2+ could markedly accelerate the photo-oxidation rate of DMS in seawater.The mechanism of mercuric catalysis for DMS photolysis was suggested according to the way of CTTM (charge transfer to metal) of DMS-Hg2+ complex.
Resources calculation of cobalt-rich crusts with the grid subdivision and integral method
WU Ziyin, CHU Fengyou, MA Weilin, LI Shoujun, SHANG Jihong
2007, (5): 43-53.
On the basis of three geological models and several orebody boundaries, a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the central Pacific Ocean.The formulas of this method are deduced and the interface of program module is designed.The method is carried out in the software "Auto mapping system of submarine topography and geomorphology MBChart".This method and program will possibly become a potential tool to calculate the resources of seamounts and determine the target diggings for China's next Five-year Plan.
Rock magnetic property of gravity core CSH1 from the northern Okinawa Trough and the effect of early diagenesis
GE Shulan, SHI Xuefa, WU Yonghua, LEE Tehquei, XIONG Yingqian, SAITO Yoshiki
2007, (5): 54-65.
Detailed rock magnetic investigations were undertaken at 2~4 cm interval for the gravity core CSH1 (with a length of 17.36 m) from the northern Okinawa Trough.Time-scale of the core was constructed by two characteristic tephras and foraminferal assemblages, indicating an age of 50 ka for the bottom of the core.Except for three tephras and abrupt decrease in surface, there are little changes in all kinds of rock magnetic parameters that can be correlated to the climate change for the last 50 ka.Different from the common sediments, most S-ratios (S equals the negative ratio of IRM-0.3T to SIRM, which is an indicator of low coercivity content)of the sediments are smaller than 0.9, which implies a substantial amount of magnetic minerals with high coercivity.The existence of iron sulphide (greigite or pyrrhotite) is revealed by representative susceptibility-temperature curves showing 200~350℃ Curie temperature in addition to 580℃ of magnetite, and also by awful smell during heating and dark heating products.Both the occurrence of authigenic iron sulphide and quick decrease of magnetic parameters near the surface clearly show that sediments from Core CSH1 have undergone early diagenesis.The featureless magnetic changes of the whole core except for three tephras mean that the post-depositonal alteration is so strong that most original signals have been destroyed.For the same reason, the organic matter in sediment and sulphate in pore water must have been consumed along with dissolution, precipitation of iron and manganese happening sequencially during the redox reaction series.Great caution must be taken when using these altered chemical parameters for the interpretation of climatic changes.
A survey on Hydroidomedusae from the upwelling region of southern part of the Taiwan Strait of ChinaⅠ.On new species and records of Anthomedusae
XU Zhenzu, HUANG Jiaqi, GUO Donghui
2007, (5): 66-75.
Through the examination of 377 samples of the Anthomedusae, eight new species and one new record are described.
Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers
DOU Shuozeng, TSUKAMOTO Katsumi
2007, (5): 76-89.
Under artificial LD cycles (6, 12, 18 L), the elvers of Japanese eel, Anguilla japonica, showed a 24 h cycle of locomotor activity rhythm being most active at light transitions:the eels' activity rose to a primary peak after lights-off, followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time, and then reached a secondary peak before lights-on.Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d.Moreover, their activity level at dark phase significantly increased as the light period was prolonged:higher activity levels during shorter dark period.However, the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions.The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system.In all the LD cycles, over 99% of the activity occurred in the dark phase, indicating that the eels were always nocturnally active no matter what time of day it might be.Under 12 L conditions, the eels' activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10~15 to 20~25℃.The activity rhythm pattern (i.e., two peaks occurring around light transitions) did not apparently change among temperatures.However, in contrast with the primary activity peaks immediately after lights-off at 20 and 25℃, the timing of the primary peaks at 10 and 15℃ showed a latency of a few hours following lights-off, indicating the inhibiting effect of low temperature on the eels' activity.
Genetic parameter estimates for growth traits at early stage of Pacific abalone,Haliotis discus hannai Ino
DENG Yuewen, LIU Xiao, ZHANG Guofan, ZHAO Hongen
2007, (5): 90-95.
Heritability and genetic and phenotypic correlations were estimated for juvenile growth traits of Pacific abalone Haliotis discus hannai Ino.The estimates were calculated from shell length and shell width measurements on progeny resulting from 12 half-sib families and 36 full-sib families obtained using artificial fertilization of mating three females to each male.The measurements were taken at 10, 20 and 30 d after fertilization.It was found that heritability estimates based on sire component ranged from 0.23 to 0.36 for shell length and 0.21 to 0.32 for shell width.Heritability estimates from dam component were larger than those from sire component at three ages, indicating presence of maternal effects, non-additive genetic effects and common environmental effects.Phenotypic correlations were significant at three ages (P<0.05), with values of 0.92, 0.93 and 0.92, respectively.Genetic correlations from the paternal half-sib correlation analysis were highly positive at three ages, with values of 0.50, 0.78 and 0.81, respectively.The results suggest that selective breeding is an effective approach to improving growth traits of Pacific abalone stocks.
Species composition,diversity and density of plagic Ostracoda in the East China Sea
XU Zhaoli, GU Xiaolian, ZHANG Fengying
2007, (5): 96-106.
On the basis of seasonal investigations at 23°30'~33°00'N, 118°30'~128°00'E of the East China Sea during 1997~2000, dynamics on the density and diversity of Ostracoda was discussed.Results showed that totally 26 species were identified.The Ostracoda diversity was opposite to the change of its density in most seasons which reflected an uneven assignment of Ostracoda density among its different species.The Ostracoda density was 0.70 ind./m3 in spring, 1.72 ind./m3 in summer, 2.57 ind./m3 in autumn and 0.90 ind./m3 in winter.Euconchoecia chierchiae in spring and winter, Euconchoecia maimai in summer and Cypridina dentata in autumn were main dominant species in each season.The Ostracoda density did not show an obvious linear relationship with the hydrologic factors in summer and autumn, but was related to the surface salinity in spring and the surface temperature in winter.Its high density areas mainly distributed in the north offshore in all the seasons while in the south offshore in winter and in spring, and the south nearshore in summer and autumn, implied the zooplankton was a typical warm water animal, whose high density distribution in autumn were located in a similar position to Todarodes pacificus, Navodon Septentrionalis, Scomber japonicus and other fishes in the sea, so as to be an important indicator for fishing ground.The main species dominating in Ostracoda now are different from the species twenty years ago probably attributes to global warming.
Influence of the concentration ratio of nitrogen to phosphorus on the growth and interspecies competition of two red tide algae
KANG Yanyu, LIANG Junrong, GAO Yahui, LIN Rongcheng, GAO Hua, XING Xiaoli, MA Jie, LUO Qiaoqi
2007, (5): 107-115.
The growth and interspecies competition of two red tide algal species Thalassiosira pseudonana Hasle et Heimdal and Gymnodinium sp.were studied under different concentration ratios of nitrogen to phosphorus, and the algal batch culture experiments were conducted.The physiological and biochemical indexes were measured periodically, including the maximum comparing growth rate, relative growth rate, average double time and chlorophyll a concentration.The results showed that when the concentration ratio of nitrogen to phosphorus was 16:1, the maximum comparing growth rate, relative growth rate and chlorophyll a concentration of Thalassiosira pseudonana all reached the highest, and average double time was the shortest.This implied that the optimal concentration ratio of nitrogen to phosphorus of Thalassiosira pseudonana is 16:1.When the concentration ratio of nitrogen to phosphorus was 6:1, the maximum comparing growth rate, relative growth rate and the chlorophyll a concentration of Gymnodinium sp.reached the highest, and average double time was the shortest, so the optimal concentration ratio of nitrogen to phosphorus of Gymnodinium sp.is 6:1.From the growth curves as indicated both in the cell density and the chlorophyll a concentration, it is suggested that the influence of concentration ratio of nitrogen to phosphorus on the chlorophyll a concentration and the cell density are almost the same.Different concentration ratios of nitrogen to phosphorus had weak influence on community succession and the competition between the two algae.Gymnodinium sp.may use the phosphorus in vivo for growth, so it is important to pay attention to the concealment of phosphorus, in order to avoid the outbreak of red tide.On the basis of the importance of nitrogen and phosphorus and the ratio of their concentration, the possible outbreak mechanism of red tide of the two algae was also discussed.
Numerical simulation and mechanism analysis of freak waves
ZHANG Yunqiu, ZHANG Ningchuan, HU Jinpeng
2007, (5): 116-124.
A numerical wave model based on the modified fourth-order nonlinear Schroe dinger equation (mNLSE) in deep water was developed to simulate the formation of freak waves and a standard split-step, pseudo-spectral method was used to solve the equation.The validation of the model is firstly verified, then the simulation of freak waves was performed by changing sideband conditions, and the variation of wave energy was also analyzed in the evolution.The results indicate that Benjamin-Feir instability (sideband instability) is an important mechanism for freak wave formation.
Experimental investigation on the wave-induced pore pressure around shallowly embedded pipelines
PAN Dongzi, WANG Lizhong, PAN Cunhong, HU Jinchun
2007, (5): 125-135.
A series of regular wave experiments have been done in a large-scale wave flume to investigate the wave-induced pore pressure around the submarine shallowly embedded pipelines.The model pipelines are buried in three kinds of soils, including gravel, sand and silt with different burial depth.The input waves change with height and period.The results show that the amplitudes of wave-induced pore pressure increase as the wave period increase, and decay from the surface to the bottom of seabed.Higher pore pressures are recorded at the pipeline top and the lower pore pressures at the bottom, especially in the sand seabed.The normalized pressure around pipeline decreases as the relative water depth, burial depth or scattering parameters increase.For the silt seabed, the wavelet transform has been successfully used to analyze the signals of wave-induced pore pressure, and the oscillatory and residual pore pressure can be extracted by wavelet analysis.Higher oscillatory pressures are recorded at the bottom and the lower pressures at the top of the pipeline.However, higher residual pressures are recorded at the top and the lower pressures at the bottom of the pipeline.
Research Notes
Laurencia nanhaiense sp.nov.,a new species of the genus Laurencia(Rhodomelaceae,Rhodophyta) from China
DING Lanping, HUANG Bingxin, XIA Bangmei, TSENG C K
2007, (5): 136-143.
Laurencia nanhaiense sp.nov. (Rhodomelaceae, Rhodophyta) is described from Hainan and Guangdong Provinces, China.The new species clearly displays one of the defining features of the genus, viz.four periaxial cells per vegetative axial segment.It differs from other closely related species in having a combination of features such as terete axes from a basal system composed of a primary discoid holdfast and a secondary attachment to give rise to many short rhizoids, branching oppositely and alternately, irregularly tristichous or subverticillately polystichous, having more curve branches with very sparse, adventitious ultimate branchlets, non-projecting superficial cortical cells at the apices of ultimate branchlets, presence of longitudinally oriented secondary pit-connections between contiguous superficial cortical cells, absence of lenticular thickenings in the walls of medullary cells, parallel arrangement of tetrasporangia along the axis of stichidia, and presence of intercellular spaces between medullary cells.
The point of no return and pectoral angle of Japanese anchovy(Engraulis japonicus) larvae during growth and starvation
WAN Ruijing, LI Xiansen, ZHUANG Zhimeng, JOHANNESSEN Arne
2007, (5): 144-152.
At a temperature of 23.0~24.8℃, the mixed feeding of Japanese anchovy larvae was initiated 24 h before the yolk-sac was exhausted.The point of no return (PNR) was reached on the 6th day after hatching.On the 4th day after hatching, the pectoral angle appeared in both fed and unfed anchovy larvae although it was more evident and sharper in the starved and the PNR stage larvae than in the fed ones.According to observations of larvae collected in the sea, the pectoral angles were evident not only in the larvae of 3.62~7.44 mm in standard length, but also in the larvae of 2.70 mm in standard length with remnants of yolk.The pectoral angles became diffuse when the larvae reached 7.84 mm and vanished at 9.86 mm.The pectoral angle cannot be used as a criterion to distinguish healthy from starving larvae.
Cytogenetic analysis in two scallops (Bivalvia: Pectinidae) by PRINS and PI banding
ZHANG Lingling, BAO Zhenmin, WANG Jue, WANG Shi, HUANG Xiaoting, HU Xiaoli, HU Jingjie
2007, (5): 153-158.
Cytogenetic analysis was performed for the bay scallop (Argopecten irradians Lamarck 1819) and the Japanese scallop (Patinopecten yessoensis Jay 1857) by primed in situ labeling (PRINS) and propidium iodide (PI) banding techniques.The PRINS analysis revealed that major rRNA genes were clustered in two loci on the telomeric regions of the short arms on two acrocentric chromosome pairs in A.irradians and on two submetacentric pairs in P.yessoensis.The histone H3 gene sites differed in number and location between these two species.The C-band-like patterns revealed by PI staining varied considerably between these two species.A.irradians displayed terminal bands at long arms on all chromosomes, centromeric bands on some pairs and interstitial bands on five pairs.P.yessoensis exhibited only centromeric bands on all chromosomes.These results would contribute to the better understanding of karyotype evolution in A.irradians and P.yessoensis.