2008 Vol. 27, No. 1

Display Method:
Simulation of arctic surface radiation and energy budget during the summertime using the single-column model
LI Xiang, WANG Hui, ZHANG Zhanhai, WU Huiding
2008, (1): 1-12.
The surface heat budget of the Arctic Ocean (SHEBA) project has shown that the study of the surface heat budget characteristics is crucial to understanding the interface process and environmental change in the polar region. An arctic single-column model (ARCSCM) of Colorado University is used to simulate the arctic surface radiation and energy budget during the summertime. The simulation results are analyzed and compared with the SHEBA measurements. Sensitivity analyses are performed to test microphysical and radiative parameterizations in this model. The results show that the ARCSCM model is able to simulate the surface radiation and energy budget in the arctic during the summertime, and the different parameterizations have a significant influence on the results. The combination of cloud microphysics and RRTM parameterizations can fairly derive the surface solar shortwave radiation and downwelling longwave radiation flux. But this cloud microphysics parameterization scheme deviates notably from the simulation of surface sensible and latent heat flux. Further improvement for the parameterization scheme applied to the Arctic Regions is necessary.
Evolution and breaking of a propagating internal wave in stratified ocean
LI Bingrui, FAN Haimei, TIAN Jiwei, SUN Bo, ZHANG Zhanhai
2008, (1): 13-22.
The evolution and breaking of a propagating internal wave are directly numerically simulated using a pseudo-spectral method. The mechanism of PSI (parametric subharmonic instability) involved in the evolution is testified clearly. It dominates gradually in nonlinear resonant interactions. As a consequence, the energy cascades to a second plant wave packet which has lower frequencies and higher wavenumbers than that of the primary wave. With the growth of this wave packet, wave breaking occurs and causes strongly nonlinear regime, i.e. stratified turbulence. The strong mixing and intermittent of the turbulence can be learned from the evolution of the total energy and kurtosis of vorticity vs. time. Some statistic properties of the stratified turbulence are also analyzed, including the spectra of KE (kinetic energy) and PE (potential energy). The results show that the PE spectra display a wavenumber range scaling as 0.2N4ky-3 (N is the Brunt-Väisälä frequency, ky is the vertical wavenumber), which is called buoyancy subrange. However, the KE spectra cannot satisfy the negative cubic law of vertical wavenumber, which have a much larger downtrend than that of the PE spectra, for the potential energy is transferred more efficiently toward small scales than the kinetic energy. The Cox number of diapycnal diffusivity is also calculated, and it shows a good consistency with the observations and deductions in the ocean interior, during the stage of the stratified turbulence maintaining a fairly active level.
Resistance of the diffusive boundary layer to salt release from saline sediments to freshwater
GAO Zengwen, ZHENG Xilai, XU Qinxuan
2008, (1): 23-28.
The diffusive boundary layer (DBL) is the zone for matter exchange between surface water and aquatic sediments. To elucidate the influence of DBL on salt release from saline sediments to freshwater, two experiments with or without wind blowing were conducted. According to the experiments, a 3.5 cm DBL is formed above the smoothed sediments at a steady wind field and this thickness is greater than other studies. The observed flux of salt through the DBL is 6% larger than the calculated value from Fick's first law. The results indicate that molecular diffusion is the dominant mechanism for salt transport through the DBL. The presence of DBL suppresses the hydrodynamic enhancement for matter exchange between sediments and overlying water. Therefore, salts in the sediments of a polder reservoir may influence the water quality chronically.
Size-fractionated uranium isotopes in surface waters in the Jiulong Estuary in China
LÜ E, ZHANG Lei, CHEN Min, QIU Yusheng, XING Na, YANG Weifeng, LI Yanping, HUANG Yipu
2008, (1): 29-41.
Surface water was collected from the Jiulong Estuary for determination of activity concentrations of uranium isotopes in different size fractions, namely, greater than 53, 10~53, 2~10, 0.4~2 μm, 10 000 u~0.4 μm and less than 10 000 u fractions by microfiltration and cross-flow ultrafiltration technologies. Results indicated that most of the dissolved uranium (<0.4 μm) existed in the low molecular mass fraction (<10 000 u), and the colloidal uranium-238 (10 000 u~0.4 μm) only contributed less than 1% of the dissolved uranium-238. The fractions of colloidal uranium in the dissolved phases decreased with the increasing salinity. A positive linear relationship between uranium-238 activities and salinities was observed for the dissolved, colloidal and low molecular mass fractions, indicating a conservative behavior of uranium in the Jiulong Estuary. In the particulate phases (>0.4 μm), the partitioning of uranium isotopes among different size fractions was controlled by the partitioning of particle concentrations. In the regions with salinities below 20, the partitioning of uranium-238 among different size fractions was as follows:10~53 μm > 2~10 μm > 0.4~2 μm greater than above 53 μm. However, the order at the offshore station with salinities above 30 changed as follows:0.4~2 μm > 10~53 μm > 2~10 μm greater than above 53 μm. The fraction of the 0.4~2 μm particles increased at the offshore station, suggesting the increased contribution of the authigenic uranium. The activity ratio of uranium-234 to uranium-238 in the dissolved phases, including the low molecular mass fraction and the colloidal fraction, was larger than unity, showing the occurrence of excess uranium-234. In contrast, the activity ratio of uranium-234 to uranium-238 in all size fractions of the particulate phase was close to the equilibrium value (1.0). The observed different values of the activity ratio of uranium-234 to uranium-238 in the dissolved phase and the particulate phase were ascribed to the preferential leaching of uranium-234 and the small amount of the leaching particulate uranium. The mass ratio of thorium-232 to uranium-238 also showed different values between the dissolved phase and the particulate phase. Mass ratio of thorium-232 to uranium-238 in the dissolved, colloidal and low molecular mass fractions was less than unity, while those in the different size fractions of particulate phases were larger than unity, reflecting a different behavior between uranium and thorium during their transport into the ocean.
Heavy metals,polycyclic aromatic hydrocarbons and organochlorine pesticides in the surface sediments of mangrove swamps from coastal sites along the Leizhou Peninsula, South China
TANG Yijie, FANG Zhanqiang, YU Shixiao
2008, (1): 42-53.
Contents of heavy metals, polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorcyclohexanes (HCHs) in surface sediments from mangrove areas of the Leizhou Peninsula were analyzed in July and November 2005. Risk assessment criteria applied by Long E R et al. (1995) and Long E D et al. (1998) (effects range low, ERL; effects range mean, ERM) of chemicals in sediments from the gulf or estuary were used to assess the potential ecological risks of heavy metals, PAHs, DDTs and HCHs to aquatic organisms in the studied area. The results indicated that the average contents of zinc, nickel, chromium, lead, copper, arsenic and mercury were (61.97±55.87), (59.99±39.01), (47.93±28.37), (26.64±13.00), (23.45±41.96), (9.32±3.62), (0.14±0.18) mg/kg in dry weight in the sediment samples collected from five studied sites in the Leizhou Peninsula, respectively. Cadmium was not calculated due to its content being below the detection limit (< 0.3 mg/kg). The average levels of Cr, Cu, Ni, Pb, Zn and Hg exceed their background values. The average contents of Ni were higher than ERM. The contents of PAHs in the sediments from the five studied sites were (79.78±43.70) ng/g in dry weight, far lower than ERL(4 022 ng/g). The contents of DDE, DDD and DDTs in the sediments from five studied sites were (2.60±4.68), (17.52±27.25), (27.78±46.64) ng/g in dry weight respectively, clearly higher than ERL, and the average contents of DDT were (7.66±15.93) ng/g in dry weight, much higher than ERM. HCHs could be detected in the sediments only from Gaoqiao sampling site, with the average contents (0.07±0.08) ng/g in dry weight.
Downward continuation of aeromagnetic data to the marine surface
XU Shizhe, WANG Rui, ZHOU Jianxin, XIAO Pengfei, CHEN Shengchang
2008, (1): 54-60.
The existing methods of downward continuation of potential field cannot be used to continue the aeromagnetic data to the marine surface because of the limited continuation distance. An iteration method for the downward continuation of potential field with a much larger continuation distance has been developed, which can continue the aeromagnetic data to the marine surface and get the marine-magnetic chart with the same scale as the aeromagnetic data.This downward continuation method will greatly raise the efficiency of marine-magnetic investigation. The principle of the iteration method is presented. The method is demonstrated on synthetic models and real aeromagnetic data. Also, the error brought by continuation is discussed. The efficiency of the iteration method for the downward continuation of potential field is compared with the fast fourier transform (FFT) method, the former is much better than the latter.
Two new species of Eirenidae from the coast of southeast China
GUO Donghui, XU Zhenzu, HUANG Jiaqi
2008, (1): 61-66.
Through the examination of 377 samples collected from the Taiwan Straits, two new species of Eirenidae, i. e., Eirene octonemalis n. sp. and Eutima krampi n. sp. are described. All type specimens are deposited at the Department of Oceanography, Xiamen University.
Potential impacts of Three Gorges Dam in China on the ecosystem of East China Sea
2008, (1): 67-76.
The Changjiang River in China was dammed in 2003. The possible changes in matters fluxes from the river downstream after the completion of Three Gorges Dam and their potential impacts on the ecosystem of the East China Sea are discussed.The estuarine and coastal waters in the East China Sea were heavily fertilized by the inflow of nutrient-rich freshwater from the Changjiang River, which has led to severe eutrophication and frequent harmful algal blooms, thus worsening the ecosystem health in this area. Analysis showed that the nutrient loadings are very likely to be reduced in the lower Changjiang River due to the construction of Three Gorges Dam. Especially for the total phosphorus, the discharges to the East China Sea will be reduced by one-third, which would relieve the severe eutrophication in this area. However, the expected decrease in the riverine silicate discharge would lead the ratio of silicon to nitrogen to be much less than 1 in the estuarine and coastal waters and thus may cause an elevation of flagellate growth. The changes in the annual water discharges and their seasonal distributions below the dam will be minor. Reduction of suspended particulate matter loading, due to the sedimentation behind the dam, will reduce the nutrient loadings of the particulate form especially for phosphorus, and decrease the turbidity of estuarine and coastal waters. On the other hand, this may enhance the erosion of the delta and the coasts as well as modifythe benthic ecosystem.
Chlorophyll a and primary production in the northeastern Pacific Ocean
CHEN Xingqun, LIN Rongcheng
2008, (1): 77-84.
The primary production and chlorophyll a concentration of picoplankton (0.2~2 μm), nanoplankton (2~20 μm) and microplankton (20~200 μm) are described in the northeastern Pacific Ocean near the Hawaii Islands during the six survey cruises from 1996 to 2003:DY85-4, DY95-7, DY95-8, DY95-10, DY105-11 and DY105-12.14. The primary production of carbon was in range from 76.8 to 191.9 mg/(m2·d) with an average of 116.1 mg/(m2·d) in the east region, and from 73.1 to 222.5 mg/(m2·d) with an average of 127.1 mg/(m2·d) in the west region, similar to the other oligotrophic regions of the Pacific Ocean investigated. The chlorophyll a concentration was about 0.1 mg/m3 from the surface to the 50 m depth, about 0.2~0.4 mg/m3 from 50 to 100 m, and gradually decreased below the 100 m depth. The picoplankton accounted for more than 70% of the total chlorophyll a in the upper layer (surface to 125 m), but it decreased to less than 50% in depth below 125 m. The nanoplankton and microplankton combined only accounted for less than 30% of the total chlorophyll a in the upper layer, but showed a more even vertical distribution.
Analysis on promoter elements of cpc operon from Arthrospira platensis
LU Yongzhong, ZHANG Xuecheng
2008, (1): 85-91.
On the basis of bioinformatics analysis, six putative promoters were isolated from the upstream sequence of c-phycocyanin gene of Arthrospira platensis FACHB341 through site-directed mutagenesis, and the transcriptional pattern of c-phycocyanin gene was determined by SmartRace. Results showed that each isolated promoter drived the expression of gfp in E.coli, and Promoter Ⅲ was the strongest one according to the GFP level. Only one transcript of c-phycocyanin gene was found under experimental conditions, and the transcription start site G was located at the -285 bp upstream of the start codon, from which it could be inferred that the transcript was from the promotion of Promoter Ⅰ.
Purification and characterization of lipoxygenase from Entermorpha clathrata
YANG Wenge, XUE Changhu, XU Dalun, FU Xueyan, HE Xiong
2008, (1): 92-101.
The purification and characterization of lipoxygenase (LOX, EC from the green algae Enteromorpha clathrata were studied. Two components marked LOX-1 and LOX-2 were purified and their molecular masses were estimated to be 102 and 79 ku by SDS-PAGE. Both LOX-1 and LOX-2 were stable over the pH wide range 6.0~10.0 and had the optimum pH of 10.0 and 8.6, at optimum temperature of 30 and 25℃, respectively. Substrate specificities of LOX-1 and LOX-2 were the greatest towards linoleic acid, followed by arachidonic acid and linolenic acid. The Michaelis constant values of LOX-1 and LOX-2 were 0.23 and 0.20 mmol/dm3 with the substrate of linoleic acid. The LOX activities were stimulated greatly by Ca2+ but inhibited by Hg2+ and the antioxidants such as BHA, BHT and TBHQ. The hydroperoxide products of LOX were analysed by HPLC with the substrate of methyl linoleate, and the results showed that LOX-1 formed mainly 9-hydroperoxides while LOX-2 formed both 9-and 13-hydroperoxides at a ratio of 24:76.
Response of phytoplankton to multispecies mariculture: a case study on the carrying capacity of shellfish in the Sanggou Bay in China
GE Changzi, FANG Jianguang, SONG Xiefa, MAO Yuze, YE Naihao
2008, (1): 102-112.
A multispecies model for shellfish polyculture in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamys farreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen(DIN) in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the large-scale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m3, the expandable multiple of scallop culture k and that of oyster culture y are determined as k=-0.276 5y+4.690 5 and 0.133 3k+0.006 6y ≤ 0.667 5, where, k (or y) is equal to 1, the culture scale of scallop (or oyster) is 8.8×109 individuals (or 66 ha, with a density of 59 ind./m2), and the kelp culture scale is 3 300 ha with a density of 12 ind./m2.
Genetic diversity and differentiation of three populations of Penaeus monodon Fabricus
WANG Guizhong, TAN Shuhua, LI shaojing, YE Haihui
2008, (1): 113-121.
Genetic diversity of two wild Penaeus monodon populations sampled from the coastal waters of Qinglan (Hainan Province of China, HN) and Malaysia (KD), and the F1 generation of a Thailand broodstock population (CP) were examined by vertical polyacrylamide gel electrophoresis. Of 21 loci encoded by ten enzymes, 11 were polymorphic. The mean proportions of polymorphic loci of HN, KD and CP were 36.36%, 45.45% and 50.00%, with the average heterozygosities of 0.135, 0.181 and 0.191, and the effective numbers of alleles per loci were 1.300, 1.330 and 1.329, respectively. The divergent indexes of HN, KD and CP were 0.023, 0.124, and 0.117, respectively. The genetic distance between the two wild populations was 0.005, and the gene differentiation coefficient was also very low (0.014). The results indicated that the F1 generation population had a higher genetic diversity than the two wild populations, and that the HN population had the lowest one. There was no significant differentiation between HN and KD populations and all populations existed with a slight heterozygote excess.
Numerical study of pollutant movement in waves and wave-induced long-shore currents in surf zone
TANG Jun, SHEN Yongming, QIU Dahong
2008, (1): 122-131.
Water waves, wave-induced long-shore currents and movement of pollutants in waves and currents have been numerically studied based on the hyperbolic mild-slope equation, the shallow water equation, as well as the pollutant movement equation, and the numerical results have also been validated by experimental data. It is shown that the long-shore current velocity and wave set-up increase with the increasing incident wave amplitude and slope steepness of the shore plane; the wave set-up increases with the increasing incident wave period;and the pollutant morement proceeds more quiekly with the increasing incident wave amplitude and slope steepness of the shore palane. In surf zones, the long-shore currents induced by the inclined incident waves have effectively affected the pollutant movement.
Research Notes
Two new species of Naticidae (Mollusca, Gastropoda) from the coast of China
ZHANG Suping
2008, (1): 132-136.
Two new species of Naticidae (Mollusca, Gastropoda) collected from the coast of China are described:Cryptonaitca huanghaiensis sp. nov. and Sinum vittatum sp. nov. The morphological characteristics between the new species were described and the related information was provided. The similarities and differences between the new species and related species were also compared and discussed. The new species Cryptonaitca huanghaiensis differed from Cryptonaitca hirasei and Cryptonaitca andoi in outer shape, operculum and radula. The new species Sinum vittatum is similar to Sinum japonicum (Lischke, 1869), but the shell of the former is flat-elliptical in shape, spire very small, slightly convex. While the latter is flat-globular in shape, apex light brown in color, without a brown band on the body whorl. The comparison results revealed that Cryptonaitca huanghaiensis and Sinum vittatum were two new species from the coast of China. Specimens studied were obtained from collections in the Marine Biological Museum, Chinese Academy of Sciences.
Colorimetric determination of nanomolar concentrations of silicate in natural waters after liquid-liquid extraction using methyl isobutyl ketone
REN Jingling, MI Tiezhu, DOU Weiwei, LIU Sumei, ZHANG Jing
2008, (1): 137-146.
A sensitive solvent extraction method for the determination of nonamolar concentrations of silicate in natural waters is developed. According to the traditional aqueous silicate method, silicomolybdenum blue formed by the reaction between silicate and ammonium molydate and reduced by metol-sulfite reagent is extracted by methyl isobutyl ketone. The absorbance can be enhanced substantially up to 10-folds. The detection limit of silicate is 8 nmol/dm3, which is one tenth smaller than the traditional method, with the precision of 4.0% at a silicate level of 50 nmol/dm3 and 3.2% at a silicate level of 6 μmol/dm3. Comparing the calibration curves in the distilled water and seawater, it can be seen that the salt effect also exists in the extraction method. However, the salt effect is a linear function of the salinity and can be corrected by simple calibration. The proposed method is successfully applied to the determination of silicate in natural waters. Natural concentrations of arsenate, arsenite and phosphate cause negligible interference.
Crystallographic and NMR studies on sterols from green alga Chaetomorpha basiretorsa Setchell
SHI Dayong, XU Feng, HE Juan, SHI Jiangong, FAN Xiao, HAN Lijun
2008, (1): 147-151.
Chemical investigation of the ethanol extract of the marine green alga Chaetomorpha basiretorsa Setchell led to the isolation of a new sterol stigmast-4, 28-dien-3α, 6β-diol 1 in addition to the five known sterols of β-lawsaritol 2, saringosterol 3, 24-hydroperoxy-24-vinyl-cholesterol 4, β-stigmasterol 5, 29-hydroxystigmasta-5, 24(28)-dien-3β-ol 6. Compounds were isolated by normal phase silica gel and Sephadex LH-20 gel colum chromatography, reverse phase HPLC and recrystalization. Their structures were elucidated by spectroscopic methods including MS, IR 1D/2D NMR and X-ray analysis. Cytotoxicity of compounds was screened by using the standard MTT method. All these compounds were isolated from the green alga Chaetomorpha basiretorsa Setchell for the first time and they were inactive (50% inhibitory concentration was greater than 10 μg/cm3) against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.