2008 Vol. 27, No. 6

Display Method:
A Lagrangian mean theory on coastal sea circulation with inter-tidal transports I. Fundamentals
FENG Shizuo, JU Lian, JIANG Wensheng
2008, (6): 1-16.
A brief review is made on the theory of the Lagrangian residual circulation and inter-tidal transports in a convectively weakly nonlinear system. In the review the emphasis is put on the systematical development of the theory and its weakness of convectively weakly nonlinear approximation. The fundamentals of a Lagrangian tidally-averaged theory on circulation with inter-tidal transport processes have been proposed for a general nonlinear coastal/estuarine system. The Lagrangian residual velocity is strictly defined, and it has been verified to be able to embody the velocity field of circulation. A new concept of the concentration for intertidal transport processes is presented. The concentration describing the inter-tidal transport processes should be a "Lagrangian inter-tidal concentration" defined and named, but not the Eulerian tidally-averaged concentration used traditionally. The circulation described here contains a set of infinite temporal-spatial fields of velocity/concentration, each of which corresponds to a specific value of tidal phases varying continuously over one tidal cycle. When the convectively weakly nonlinear condition(with a smaller order of eddy diffusion and sources) is approximately satisfied, a set of infinite temporal-spatial fields of velocity/concentration can be reduced to a single one:the mass transport velocity/the Eulerian tidally averaged concentration as exhibited traditionally.
Seasonal and spatial distributions of phytoplankton biomass associated with monsoon and oceanic environments in the South China Sea
GAO Shan, WANG Hui
2008, (6): 17-32.
Seasonal variations of phytoplankton/chlorophyll-a (Chl-a) distribution, sea surface wind, sea height anomaly, sea surface temperature and other oceanic environments for long periods are analyzed in the South China Sea (SCS), especially in the two typical regions off the east coast of Vietnam and off the northwest coast of Luzon, using remote sensing data and other oceanographic data. The results show that seasonal and spatial distributions of phytoplankton biomass in the SCS are primarily influenced by the monsoon winds and oceanic environments. Off the east coast of Vietnam, Chl-a concentration is a peak in August, a jet shape extending into the interior SCS, which is associated with strong southwesterly monsoon winds, the coastal upwelling induced by offshore Ekman transport and the strong offshore current in the western SCS. In December, high Chl-a concentration appears in the upwelling region off the northwest coast of Luzon and spreads southwestward. Strong mixing by the strong northeasterly monsoon winds, the cyclonic circulation, southwestward coastal currents and river discharge have impacts on distribution of phytoplankton, so that the high phytoplankton biomass extends from the coastal areas over the northern SCS to the entire SCS in winter. These research activities could be important for revealing spatial and temporal patterns of phytoplankton and their interactions with physical environments in the SCS.
A unified C-band and Ku-band geophysical model function determined by neural network approach
ZOU Juhong, LIN Mingsen, PAN Delu, CHEN Zhenghua, YANG Le
2008, (6): 33-39.
The geophysical model function (GMF) describes the relationship between backscattering and sea surface wind, so that wind vectors can be retrieved from backscattering measurement. The GMF plays an important role in ocean wind vector retrievals, its performance will directly influence the accuracy of the retrieved wind vector. Neural network (NN) approach is used to develop a unified GMF for C-band and Ku-band (NN-GMF). Empirical GMF CMOD4 and QSCAT-1 are used to generate the simulated training data-set, and Gaussian noise at a signal noise ratio of 30 dB is added to the data-set to simulate the noise in the backscattering measurement. The NN-GMF employs radio frequency as an additional parameter, so it can be applied for both C-band and Ku-band. Analyses show that the σ0 predicted by the NN-GMF is comparable with the σ0predicted by CMOD4 and QSCAT-1. Also the wind vectors retrieved from the NN-GMF and empirical GMF CMOD4 and QSCAT-1 are comparable, indicating that the NN-GMF is as effective as the empirical GMF, and has the advantages of the universal form.
Integration technology research on marine geographical information system
XUE Cunjin, SU Fenzhen, DU Yunyan, YANG Xiaomei
2008, (6): 40-48.
It is urgent and necessary to integrate a marine geographical information system (MGIS) with marine remote sensing detection modules. On the basis of the current technology and features of applications, an open three-layer integration framework is designed. At the data layer, a two-level three-base integration mechanism based on the plug-in technology is applied; At the function layer, an integration mode based on API, DLL, EXE and COM is discussed; and at the application layer, a sharing mechanism based on the clients/service is adopted. As an example, the remote sensing integrated application information system of China's coastal zone and offshore (MaXplorer1.0) with multiecology remote sensing fusion and assimilation module, surge detection module as well as eight other thematic application modules is integrated, and the key technology of integration is discussed at different layers and in different modules. The result shows that it is possible to realize the conformity of technology and resources and to provide the incorporate technology platform for marine information operational functioning after applying the integration framework.
Sedimentary records of eutrophication in the Changjiang Estuary upwelling area over last 100 a
FENG Xuwen, JING Xianglong, YU Xiaoguo, LI Hongliang, CHEN Jianfang, QIAN Jiangchu
2008, (6): 49-61.
The upwelling area in the Changjiang Estuary was selected to collect the core, where the red tide occurred frequently and hypoxic existed. The total organic carbon (TOC), total nitrogen (TN), biogenic silica (BSi) and stable organic carbon isotopic ratios(δ13 Corg) were determined on the 210Pb-dated sediment core. The concentrations of TOC, TN, BSi as well as their sedimentation fluxes have increased to some extent since the 1970s. TOC and TN fluxes increased about 45%, 36% respectively. The average δ13 Corg value in the core was -23.67×10-3 which remained nearly constant before the 20 century. The δ13 Corg values increased after the 1900s, two marked increases were observed from the 1950s and the 1970s. A simple δ13 Corg model was used to estimate the contribution of terrigenous and marine organic matter inputs for the sediment, which indicated the increase in accumulation since the 1970s has been almost exclusively marine. The increasing of marine organic matter accumulation (TOC, TN and BSi) was corresponding with the increasing of fertilizer consumption and the NO3-N budgets from the Changjiang River. The riverine runoff of fertilizers and nutrients stimulated the algae blooming. Enhanced primary production resulted in an enrichment of organic matter in the sediment. These data support the hypothesis that anthropogenic nutrient loading has been a significant factor on the eutrophication in the Changjiang Estuary.
The evidence for the existence of methane seepages in the northern South China Sea: abnormal high methane concentrations in bottom waters
YIN Xijie, ZHOU Huaiyang, YANG Qunhui, WANG Hu, CHEN Jian
2008, (6): 62-70.
The methane concentration of water samples at five stations collected by the CTD rosette water sampler in the areas of southwest Dongsha Islands and the Xisha Trough was analyzed by the gas-stripping method on aboard ship. It shows abnormal high methane concentrations in near bottom water samples at three stations. In the southwest Dongsha Islands area, the methane concentration of 4.25 and 10.64 nmol/dm3 occurs in near bottom water samples at Stas E105A and E106, respectively. In the Xisha Trough area, the high methane concentrations of 5.17, 8.48 and 8.70 nmol/dm3 in water depths of 1 750, 1 900 and 2 050 m, respectively, have been observed at Sta. E413. It is believed that the abnormal high methane concentrations are generated from the leakage of methane from sediments. Combining with previous geophysical and geochemical data from these two areas, this was probably related to the submarine gas hydrates decomposition and cold seep system. In May 2007, gas hydrate samples were successfully obtained by the drilling in the Shenhu Sea area located in the southwest Dongsha Islands area. It is called for further drilling surveys to confirm the existence of gas hydrate and cold seep system in the Xisha Trough as early as possible.
The distribution of phenylalkanes in the modern sediment associated with gas hydrate from the Gulf of Mexico
WANG Cuiping, SUN Hongwen, SONG Zhiguang, ZHANG Tao
2008, (6): 71-82.
Phenylalkanes with carbon numbers between 16 and 19, characterized by the main carbon-18, have been identified in the modern sediments collected from gas hydrate area from the Gulf of Mexico. The structure of phenylalkanes with four isomers for every carbon number was determined by means of their mass spectra and previous studies. The distribution of the series characterized by a low molecular mass was similar to the distribution of n-alkane, alkylcyclohexanes and alkylbenzenes in each sample. There were differences in the distribution of the phenylalkane series between the S-1, S-4, S-7, S-9 samples and the S-8, S-10 and S-11 samples. The phenylalkanes might be derived from Archaea associated with anaerobic oxidation of methane (AOM) processes in S-1, S-4, S-7 and S-9 samples according to their distribution resembled with the distribution of the extract from a type of Archaea. The distribution of alkylcyclohexanes and alkylbenzenes in S-1, S-4, S-7 and S-9 sample was found to be similar to each other. The odd-over-even predominance of alkylcyclohexanes was seen as the input of some bacterial.
Analysis on the indicator species and ecological groups of pelagic ostracods in the East China Sea
XU Zhaoli
2008, (6): 83-93.
Ecological adaptation and ecological groups of pelagic ostracods were examined in the East China Sea (23° 30'~33° 00'N, 118°30'~128°00'E), in relation to temperature and salinity. The data were collected in four surveys conducted from 1997 to 2000. The density, yield density, or negative exponent models were used to determine the optimal temperature and salinity of water for the thriving growth of pelagic ostracods. Thereafter,ecological groups and potential distribution patterns of pelagic ostracods were determined based on the predicted parameters such as optimal temperature and salinity, consulting the geographic distribution. The analytical results indicate that, among the numerical dominant pelagic ostracods in the East China Sea (ECS), Euconchoecia aculeata, E. elongata, E. chierchiae, E. maimai, and Cypridina dentata, etc. are offshore subtropical water species. These species are widely distributed in the area, and they can be brought by the warm current to north offshore during spring and winter. The predicated optimal temperature (OT) and optimal salinity (OS) for Paraconchoecia decipiens, P. echinata, P. spinifera, P. oblonga, Conchoecia magna and Porroecia porrecta are all greater than 25℃ and 34 separately. These species are mainly distributed in the waters of the Kuroshio, the Taiwan Warm Current, and the Taiwan Strait, and therefore are designated as oceanic tropical water species. On the other hand, Pseudoconchoecia concentrica is considered as offshore subtropical water species based on its geographical distribution although its OT is 19℃. The other species, though their OSs are approximately 34 and with OTs ranging from 20° to 25℃, are considered as offshore subtropical water species because they were found to be widely distributed from the South China Sea to the East China Sea.
Zoospores of Undaria pinnatifida: their efficiency to attach under different water velocities and conjugation behavior during attachment
PANG Shaojun, SHAN Tifeng
2008, (6): 94-101.
In the invading course of Undaria pinnatifida, zoospore attachment in a dynamically changed subtidal water environment is crucial for the establishment of a potential population in alien waters. Among many abiotic factors that may interfere with the attachment process, water velocity is the most important one. In this investigation, the effect of water velocity on zoospore attachment of U. pinnatifida was investigated in an artificially designed system. It was found that freshly released zoospores that were transported by water flowing at 0~16 cm/s showed no difficulty in attaching the smooth surface. Zoospore attachment decreased at elevated water flowing rates. At 70 cm/s no spore attachment occurred. Spores that have settled on glass slide for up to 1 h could not be stripped away by flowing water at a rate of 129 cm/s, the same was true of the 20 d old filamentous gametophytes. It was found that more than 70% of free-swimming zoospores tended to settle down adjacent to the settled spores and formed conjugated clusters from two up to a few hundred cells in still culture.
Research Notes
Influence analysis of gaseous absorption on “HY-1A” CZI data processing Simulation and correction for Rayleigh scattering
SUN Ling, ZHANG Jie, GUO Maohua
2008, (6): 102-114.
Besides ozone, oxygen and water vapour should be considered for their absorptive effects on " HY-1A" CZI data processing. First,gaseous transmittances under various conditions are computed and analyzed for the band settings of this sensor. Second, transmittances under six standard atmospheres are approximated as functions of zenith angle, the water vapour transmittance is approximated as a function of water vapour content and zenith angle, and the ozone transmittance is approximated as a function of ozone content and zenith angle. Finally, taking Rayleigh scattering as an example, the influence of ignoring gaseous absorption when calculating TOA reflectance is analyzed, and the effect of applying the presented transmittance approximations to gaseous absorption correction for Rayleigh scattering in "HY-1A" CZI data processing is evaluated.
Potassium-argon/argon-40-argon-39 geochronology of Cenozoic alkali basalts from the South China Sea
YAN Quanshu, SHI Xuefa, YANG Yaomin, WANG Kunshan
2008, (6): 115-123.
Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activity of the South China Sea after spreading were studied. The potassium-argon ages of eight alkali basalt samples from the South China Sea, and the argon-argon ages of two samples among them are reported. Apparent ages of the whole rock are 3.80 to 7.91 Ma with an average value of 5.43 Ma (potassium-argon, whole rock), and there is little difference among samples at the same location, e.g., 4.76~5.78 Ma for location S04-12. The argon-argon ages for the two samples are 6.06 and 4.71 Ma, which lie within the age scope of potassium-argon method. The dating results indicate that rock-forming age is from late Miocene to Pliocene, which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea. Volcanic activities occur after the cessation of spreading of the South China Sea, which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea. These dating results, combined with geochemical characteristics of these basalts, the published chronological data for the South China Sea and its adjacent regions, and the updated geophysical data near Hainan Island, suggest that after the cessation of spreading of the South China Sea, there occur widely distributing magmatic activities which primarily is alkali basalt, and the volcanic activity continues to Quaternary. The activity may be relative to Hainan mantle plume originated from core/mantle boundary.
First record of Thalassiosira curviseriata Takano (Bacillariophyta) and its bloom in the East China Sea
XIE Wenling, LI Yang, GAO Yahui
2008, (6): 124-132.
A bloom caused by a diatom, Thalassiosira curviseriata Takano (Bacillariophyta), is recorded in the East China Sea for the first time in China during a red tide investigation cruise (MC2005-2) from 27 March to 12 April 2005. This bloom was developed with the competition of Chaetoceros debilis and Skeletonema spp. The highest cell density of T. curviseriata, which has reached 1.27×106 cells/dm3, was found in the surface and middle water layers of Stas ZD, ZB in the East China Sea (27.22°~29.48°N, 121.53°~122.98°E)in early spring in 2005. During the blooming period of T. curviseriata, the population with high cell density was found in the water area with temperature of 10~15℃ and salinity of 29.0~33.5. The percentage of the predominant species, T. curviseriata, has reached 95.8% of total diatom cells at one time in the middle water layer. The morphological characteristics of T. curviseriata, were observed with light microscope (LM) and transmission electronic microscope (TEM). The cells are 5.0~12.6 μm in diameter, connecting each other by mucilaginous thread to form spiral and curved chains. Description and LM and TEM images of T. curviseriata are presented. T. curviseriata is ecologically characterized by eurythermy and euryhalinity, and its population variation is affected mainly by silicate, the ratios of phosphorus to silicon and nitrogen to silicon.
Buoyancy leads to high productivity of the Changjiang diluted water: a note
CHEN Chen-Tung Arthur
2008, (6): 133-140.
Being the mightiest river emptying into the East China Sea (ECS) and the Pacific Ocean, compounded with the large increase of nitrogen and phosphorus input due to anthropogenic activities, the Changjiang River (Yangtze River) has become a dominating source of these nutrients to the estuary. The high nutrient concentrations notwithstanding, however, outside of the estuary the high biological productivity of the Changjiang diluted water (CDW) are most probably fueled mainly by nutrient-rich subsurface waters originating from the upwelled Kuroshio waters. This is because while the buoyancy of the CDW spreads it out on the ECS continental shelf, the CDW entrains subsurface waters along with the nutrients. Nutrients thus supplied are several times more than those supplied by the Changjiang River.
Characterization and expression analysis of an allograft inflammatory factor-1 homologue in yellow grouper (Epinephelus awoara)
WANG Li, SHI Dawei, WU Xinzhong
2008, (6): 141-148.
Allograft inflammatory factor-1 (AIF-1) is a cytoplasmic calcium-binding protein involved in inflammatory response-related diseases in mammals. Previously an identified AIF-1 gene was simply reported in yellow grouper. The characterization of AIF-1 gene and its expression at the gene and protein level are further described. Yellow grouper AIF-1 is composed of 147 amino acids, and 64%~84% identical to other homologues. Basal level AIF-1 mRNA expression was noted in spleen, anterior kidney and kidney, using reverse-transcription polymerase chain reaction (RT-PCR). After stimulation of LPS, the AIF-1 mRNA expression was up-regulated in tissues examined:spleen, anterior kidney, kidney, heart and liver, but not in muscle. The recombinant AIF-1 protein was expressed in Escherichia coli, and then purified for the development of antiserum. Western blotting analysis revealed a band with a molecular mass of about 17 ku.
Estimation of growth rate of Skeletonema costatum based on relative expression amount of PCNA gene
HE Shanying, YU Zhigang
2008, (6): 149-158.
Partial sequence of Skeletonema costatum proliferating cell nuclear antigen (PCNA) gene was obtained by reverse transcriptase PCR(RT-PCR) and 3' rapid amplification of cDNA ends (3'-RACE) techniques. Based on the obtained PCNA and cytochrome b gene(Cyt b gene) sequences, a real-time fluorescent quantitative PCR (FQ-PCR) method was developed to detect the expression S. costatum PCNA gene, and this method was applied to study the relationship between the growth rate of S. costatum and the average expression amount of PCNA gene in a single cell. The expression amount of PCNA gene had large variation in cells collected at different culture phases, and the trend was well consistent with the growth rate, which suggested that the expression amount of PCNA gene correlated well with the cell division, and the PCNA could be a promising indicator for the S. costatum cell proliferation. Furthermore, using the PCNA gene as the objective gene and the Cyt b gene as the house-keeping gene, a new method for estimating the in situ growth rate of S. costatum was established by analysis of the relative expression quantity (REQ) of the PCNA gene.