2006 Vol. 25, No. 4

Display Method:
Response of the cold water mass in the western South China Sea to the wind stress curl associated with the summer monsoon
ZHUANG Wei, WANG Dongxiao, HU Jianyu, NI Wensheng
2006, (4): 1-13.
Analys is of clmiatological observation temperature data reveals that during the southw esterly monsoon, there exists a low tem perature zone east of Vietnam.It cools down from June to August and warms up in September.Mean while, during this period, the cold watermass spreads easwtard to the deep bas in.Num erical experiments validate the results of data analysis and further verify that there are two basic factors that induce the Vietnam cold water.The major one is the strong local positive wind stress curl, which leads to the divergence of sea surface water and the upward supplement of lower layer water in the deep basin.Anotherminor one is the alongshore component of south westerly monsoon, which drives the offshore Ekman transport and coastal upwelling in the shallowregion along the Vietnam coast. In add ition, the negative wind stress curl in the southern South China Sea inputs negative vorticity to the ocean and drives a strong anticyclonic gyre, which affects the spatial distribution of the cold water evidently.
Impact of GCP distribution on the rectification accuracy of Landsat TM imagery in a coastal zone
ZHANG Ying, ZHANG Dong, GU Yan, TAO Fei
2006, (4): 14-22.
The purpose is to explore the effect of the spatial distribution of ground control points (GCPs) on the accuracy of imagery rectification. Both area-distributed and linearly distributed GCPs were used to rectify a Landsat TM image of a coastal zone. Rectification accuracy was checked against 99 independent points over the intertidal mudflats with no ground control. Results indicate that the root-mean-square error of residuals over these areas is several times larger than its GCPs-measured counterpart. If the GCPs are spatially dispersed over an area, residuals fluctuate but increase steadily with distance to the source of control in easting (R2=0.827). In northing they fluctuate around 150 m until 15 km, beyond which they rise steadily at a small range of fluctuation. These residuals are less predictable from distance to the source of control than in easting (R2=0.517). If the GCPs are distributed along a control line, residuals rise with distance to it linearly and predictably (R2=0.877) in the direction perpendicular to it. In a direction parallel to it, the distance has little impact on rectification residuals.
Geometries and mechanism of folds in sediments on the southern Huanghai Sea shelf
LI Xishuang, LIU Baohua, ZHAO Yuexia, LI Sanzhong
2006, (4): 23-31.
Most descriptions and studies about folds have been associated with consolidated strata; fold deformation in loosely-consolidated sediments, however, has been rarely discussed. Since the Pleistocene, tectonic activities have been intensive over the South Huanghai Sea (SHS) shelf, resulting in fold deformation features that are preserved in thick sediment layers. Four types of folds with different geometries have been identified on the basis of an analysis of single-channel seismic profiles from the SHS shelf region:(1) fault-propagation fold; (2) fault-drag fold; (3) transversal bending fold; and (4) multi-action-folding fold. Studies on the geometry and mechanism of the folds indicate that base faults and fault blocks control the folding patterns in loosely-consolidated sediments on the SHS shelf and a large quantity of pore water in sediments plays an important role in cansing the deformation of sediment layers. The continuity of deformations of fault-propagation fold and fault-drag fold indicates that there is a genetic relationship between these fold types. The potential of earthquakes induced by fault-propagation folding in the deformation zone should be taken into account in the assessment of the marine engineering geology conditions of the SHS shelf.
Impact of the cord-grass Spartina alterniflora on sedimentary and morphological evolution of tidal salt marshes on the Jiangsu coast, China
WANG Aijun, GAO Shu, JIA Jianjun
2006, (4): 32-42.
The tidal flats of the Wanggang area, on the Jiangsu coast, represent the largest continuously distributed coastal wetland in terms of area coverage in China, and the dynamics of tidal flat accretion and erosion is highly complicated. The cord-grass Spartina alterniflora, which was introduced artificially into the Jiangsu coast, has significant influences on the regional tidal flat evolution in terms of deposition rate, spacial sediment distribution patterns and tidal creek morphology. On the basis of the data set of bed elevation and accumulation rate for different periods of time, the applicability of the Pethick-Allen model to the Jiangsu tidal salt marshes is discussed. In addition, caesium-137 dating was carried out for sediment samples collected from the salt marsh of the Wangang area. In combination with the caesium-137 analysis and the data collected from literature, the Pethick-Allen model was used to derive the accumulation rate in the Wanggang tidal flat for the various periods. The results show that the pattern of tidal flat accretion has been modified, due to more rapid accretion following the introduction of S.alterniflora to the region. Surficial sediment samples were collected from representative profiles and analyzed for grain size with a laser particle analyzer. The result shows that fine-grained sediment has been trapped by the plant, with most of the sediment deposited on the Suaeda salsa and Spartina angelica flats being derived from drainage creeks rather than the from gently sloping tidal flats. Remote sensing analysis and in situ observations indicate that the creeks formed in the S.alterniflora flat have a relatively small ratio of width to depth, a relatively high density, and are more stable than the other tidal flat creek systems in the study area.
Impact of the exceptionally high flood from the Changjiang River on the aquatic chemical distributions on the Huanghai Sea and East China Sea shelves in the summer of 1998
WANG Baodong, WANG Xiulin
2006, (4): 43-52.
On the basis of the field observation in the Huanghai Sea and East China Sea in the summer of 1998, a rare event of exceptionally high discharge from the Changjiang River was described and how this high discharge altered water masses as well as chemical distributions on the shelves of the Huanghai Sea and East China Sea. The maximal extending ranges of the Changjiang diluted water and the nutrients in the freshwater from the Changjiang River were recorded for the first time. It was also found that there was a closed area with high oxygen and pH values in the offshore area of the southern Huanghai Sea and the northern East China Sea, indicating that the extensive spreading of nutrients due to the high discharge led to photosynthesis of phytoplankton mostly taking place in the offshore area far from the river mouth. The presence of "excess nitrogen" in almost all the northern East China Sea and the south of the Huanghai Sea suggests that these areas are potentially phosphorus-limited rather than nitrogen-limited, manifesting more like an estuarine ecosystem rather than a common marine ecosystem.
Iron and inorganic carbon in Liaodong Gulf sediments of Bohai Sea in China
NIU Lifeng, LI Xuegang, SONG Jinming, YUAN Huamao, LI Ning, DAI Jicui
2006, (4): 53-64.
Iron in seawater is an essential trace metal for phytoplankton that plays an important role in the marine carbon cycle. But most studies focused on oceanic iron fertilization in high nutrient low chlorophyll (HNLC) seawaters. A study of inorganic carbon (IC) forms and its influencing factors was presented in Liaodong Gulf sediments, and especially the influence of iron was discussed in detail. Inorganic carbon in Liaodong Gulf sediments was divided into five forms:NaCl, NH3·H2O, NaOH, NH2OH·HCl and HCl. The concentration of NaCl and NaOH forms were similar and they only occupied the minority of total inorganic carbon (TIC). However, NH3·H2O, NH2OH·HCl and HCl forms were the principal forms of TIC and accounted for more than 80% of TIC. Especially, the percentage of NH3·H2O form was much higher than that in the Changjiang River Estuary and Jiaozhou Bay sediments. All forms of inorganic carbon were influenced by organic carbon, pore water, iron, pH, redox potential (Eh) and sulfur potential (Es) in sediments, moreover, the influences had different characteristics for different IC forms. However, the redox reactions of iron affected mainly active IC forms. Iron had little effect on NH2OH·HCl and HCl forms of IC which were influenced mainly by pH. Iron had a stronger influence on NaCl, NaOH and NH3·H2O forms of IC; the influence of Fe2+ was higher than Fe3+ and its effect on NH3·H2O form was stronger than on NaCl and NaOH forms.
Identification and characterization of adult alpha-and beta-globin genes and their genomic arrangement in Pseudosciaena crocea
CHU Wuying, QIAN Ronghua, WANG Lianshen, YU Xiameng, YOU Zhenqiang, YU Lian
2006, (4): 65-76.
The α-and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3'-end (3'-RACE). The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA stop codon at Position 469 and the AATAAA polyadenylation signal at Position 560, which codifies 145 amino acids. The entire open reading frame of the β-globin gene is 447 bp long, which encodes 148 amino acids. Amino acid identity of the α-globin or β-globin gene compared with those reported in other fish species, ranged from 31.9% to 76.4%. When comparing with human α-and β-globins, three important alterations in the structural regions can be noted:α39 Thr→Gln, α113 His→Tyr and β117 His→Lys. The α-globin has a unique inserted amino acid residue in the 47th position. To understand the process of globin gene duplication and identify the regulatory elements present in the intergenic and intragenic regions of globin genes, the genomic arrangement of α-and β-globin genes was investigated. The results showed that the orientation of the two genes was head-to-head relative to each other. The intergenic region between the translation initiation codons of the linked α-and β-globin genes contains classical promoter elements and the length of it is much shorter than that reported in other fish.
Model study on Bohai ecosystem 1. Model description and primary productivity
LIU Hao, YIN Baoshu
2006, (4): 77-90.
A Nutrient-Phytoplankton-Zooplankton (NPZD) type of ecological model is developed to reflect the biochemical process, and further coupled to a primitive equation ocean model, an irradiation model as well as a river discharge model to reproduce ecosystem dynamics in the Bohai Sea. Modeled primary production shows reasonable consistency with observations quantitatively and qualitatively; in addition, f-ratio is examined in detail in the first time, which is also within the range reported in other studies and reveals some meaningful insight into the relative contributions of ammonium and nitrate to the growth of phytoplankton in the Bohai Sea.
Rates of oxygen consumption and tolerance of hypoxia and desiccation in Chinese black sleeper(Bostrichthys sinensis) and mudskipper(Boleophthalmus pectinirostris) embryos
CHEN Shixi, HONG Wanshu, ZHANG Qiyong, WU Renxie, WANG Qiong
2006, (4): 91-98.
The rates of oxygen consumption, tolerance of hypoxia and desiccation of the Chinese black sleeper (Bostrichthys sinensis) and mudskipper (Boleophthalmus pectinirostris) embryos were investigated. The pattern of oxygen consumption of the Chinese black sleeper embryos was similar to that of the mudskipper ones. The lowest rates of oxygen consumption[(1.65±0.66)nmol/(ind.·h)] of the Chinese black sleeper embryos 16 h after fertilization and the lowest rates of oxygen consumption[(0.79±0.08)nmol/(ind.·h)] of the mudskipper embryos 6 h after fertilization were recorded, respectively. Then the rates of oxygen consumption of these two species embryos increased gradually until hatching[(8.26±1.70)nmol/(ind.·h)in the Chinese black sleeper, (2.69±0.23)nmol/(ind.·h) in mudskipper]. After exposure to hypoxia water (0.16 mg/dm3), bradycardia of the embryos occurred in both the Chinese black sleeper and the mudskipper. However, the Chinese black sleeper embryos survived approximately 45 min longer than the mudskipper ones. After exposure to desiccation at a relative humidity of 58%, bradycardia of the embryos was observed in both the Chinese black sleeper and the mudskipper, and the Chinese black sleeper embryos lived approximately 9 min longer than the mudskipper ones.
Population structure of Haliotis rubra from South Australia inferred from nuclear and mtDNA analyses
LI Zhongbao, Sharon A Appleyard, Nicholas G Elliott
2006, (4): 99-112.
Microsatellite loci and mtDNA-RFLPs were surveyed in four spatially separated populations of Haliotis rubra and two populations of putative Haliotis conicorpora from South Australia. A high level of microsatellite genetic diversity was observed in all populations although several loci were characterized by homozygote excesses, probably due to null alleles. MtDNA variation was also moderate with an average of 80% haplotype variation across the six populations. Despite the high levels of genetic variation, significant pair-wise spatial differentiation is not detected among the populations. Hierarchical AMOVA analysis revealed very low levels of genetic partitioning on either a spatial or putative species level. Both molecular techniques revealed little genetic differentiation across the six populations, suggesting a panmictic population model for these South Australian abalone populations. Furthermore, no molecular evidence suggests that the putative H. conicorpora individuals sampled from South Australia belong to a separate species.
Bacterial and cyanobacterial diversities determined by T-RFLP analyses in the Jiaozhou Bay
REN Jing, DANG Hongyue, SONG Linsheng, SUN Song, AN Liguo
2006, (4): 113-123.
The methods of DAPI staining epifluorescence microscopy and T-RFLP analysis were used to analyze the microbial abundance and diversity in surface seawater sampled from 12 stations inside and outside of the Jiaozhou Bay during a survey on 12 and 13 September 2004. The abundance of total microbes is in the range of 106~107 cells/cm3, similar to those of most semi-enclosed bays in the temperate areas in the world. The highest microbial densities occur in the northeastern part of the Jiaozhou Bay, around the mouths of Loushan and Licun Rivers and the Hongdao aquacultural farming areas, suggesting that the degree and characteristics of pollutions, along with geographical and hydrological effects, may be important determinants affecting the abundance and distribution of bacteria in the Jiaozhou Bay. Bacterial communities inside and outside of the Jiaozhou Bay can be grouped into three classes based on T-RFLP patterns and cluster analyses. Stations at the water channel of the bay mouth and outside, such as D1, D3, D5, D6 and D7, are grouped together to stand for the outside bacterial community interacting with the environment outside of the Jiaozhou Bay. Stations of the innermost side of the Jiaozhou Bay, such as A3, A5, B2 and Y1, are grouped together to stand for the residential bacteria community. Stations C1, C3 and C4 are grouped together and may stand for the transitional bacterial assemblage between the residential community and the outside community. However, there is no such a defined relationship for the case of cyanobacterial diversity, indicating the fact that cyanobacteria are more flexible and adaptable to all kinds of conditions.
The effects of fucoidans from Laminaria japonica on AAPH mediated oxidation of human low-density lipoprotein
LI Laihao, XUE Changhu, XUE Yong, LI Zhaojie, FU Xueyan
2006, (4): 124-130.
Five fucoidan fractions from Laminaria japonica with different sulfate content and molecular weight were prepared by anion-exchange chromatography and mild acid hydrolysis. Their antioxidant effects on azo radicals 2-2'-Azobis (2-amidinopropane) dihydrochloride (AAPH) induced oxidation of human low-density lipoprotein (LDL) were evaluated by monitoring cholesteryl ester hydroperoxides (CHL-OOH) formation kinetics through reverse-phase high performance liquid chromatography (RP-HPLC) analysis. Fucoidan F-C with a low molecular mass of 2 000~8 000 and a sulfate content of 24.3% had much stronger protective antioxidant effect than other four fucoidan fractions on the hydrophilic radical AAPH induced LDL oxidation. However, the highly sulfated fucoidan fraction L-B with a molecular mass of 20 000 was completely ineffective in protecting LDL from the AAPH induced oxidation. The results suggested that both molecular mass and sulfate content of fucoidan played very important roles in their effects on the AAPH induced LDL oxidation.
Disaster prevention design criteria for the estuarine cities: New Orleans and Shanghai The lesson from Hurricane Katrina
LIU Defu, SHI Hongda, PANG Liang
2006, (4): 131-142.
The accurate prediction of the typhoon (hurricane) induced extreme sea environments is very important for the coastal structure design in areas influenced by typhoon (hurricane). In 2005 Hurricane Katrina brought a severe catastrophe in New Orleans by combined effects of hurricane induced extreme sea environments and upper flood of the Mississippi River. Like the New Orleans City, Shanghai is located at the estuarine area of the Changjiang River and the combined effect of typhoon induced extreme sea environments, flood peak runoff from the Changjiang River coupled with the spring tide is the dominate factor for disaster prevention design criteria. The Poisson-nested logistic trivariate compound extreme value distribution (PNLTCEVD) is a new type of joint probability model which is proposed by compounding a discrete distribution (typhoon occurring frequency) into a continuous multivariate joint distribution (typhoon induced extreme events). The new model gives more reasonable predicted results for New Orleans and Shanghai disaster prevention design criteria.
Research Notes
The slanting property of semi-diurnal internal tide propagation in the Pacific Ocean at 1°45'S, 156°E
BAO Xianwen, ZHANG Yijun, SUN Li, DU Tao, FANG Xinhua
2006, (4): 143-145.
By analyzing a data set collected using a moored instrument array and CTD during TOGA-COARE, it is found that there exist remarkable internal tides in the western equatorial Pacific Ocean around 1°45'S, 156°E, whose horizontal wavenumber (wavelength), vertical wavenumber, h 156° orizontal propagation speed and vertical propagation speed are 3.3×10-2km-1 (210 km), -1.6×10-3m, 2.0 m/s and -3.8 cm/s, respectively, that is, the waveform propagates downwards slantingly. Moreover, the propagating direction rotates statistically clockwise as the depth increases and its cause is unclear.
Genetic variation of Chinese and Japanese wild Pacific abalone(Haliotis discus hannai) measured by microsatellite DNA markers
LI Qi, KIJIMA Akihiro
2006, (4): 146-155.
Population differentiation and relationships among three wild populations of the Pacific abalone Haliotis discus hannai collected from coastal seas around China and Japan were estimated using microsatellite DNA analysis. The results obtained with six microsatellite loci showed a high genetic diversity for China and Japan populations. The mean number of alleles per locus ranged from 11.7 to 23.0, and the average of observed and expected heterozygosity ranged from 0.656 to 0.721, and from 0.721 to 0.793, respectively. The observed genotype frequencies at each locus were mostly in agreement with Hardy-Weinberg expectations with five exceptions. Significant differences were detected between Chinese and Japanese H. discus hannai populations[Weir and Cocker-ham's fixation index (Fst) range:0.020~0.023; Slatkin's fixation index (Rst) range:0.016~0.044], and no obvious difference was detected between the samples of Japanese H. discus hannai populations (Fst=0.002; Rst=0.007). The level of differentiation among populations is further evidenced by the nNeighbor-joining tree topology on which the Japanese samples were closely clustered, and the Chinese population formed a separate cluster. These results suggest that care should be taken in future management of different populations.