25 February 2011, Volume 22 Issue 1
    

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  • Editorial Office of Advances in Polar Science
    Advances in Polar Science. 2011, 22(1): 0-0.
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  • Reviews
  • LU Longhua, BIAN Lingen
    Advances in Polar Science. 2011, 22(1): 1-9. https://doi.org/10.3724/SP.J.1085.2011.00001
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    The Antarctic and Arctic are sensitive to global climate change; therefore, they are key regions of global climate change research. This paper, the progress in scientific investigations and research regarding the atmosphere in the polar regions over the last 30 years by Chinese scientists is summarized. Primary understanding of the relationship between the polar regions and global change, especially, the variations in time and space in the Antarctic and Arctic regions with respect to climate change is indicated. Operational weather forecasts for investigation of the polar regions have also been established. Moreover, changes in sea ice and their impact on the atmosphere of polar regions have been diagnosed and simulated. Parameterization of the atmospheric boundary layer of different underlying layers and changes in the atmospheric ozone in the polar region has also been experimented. Overall, there has been great progress in studies of the possible impact of changes in the atmospheric environment of polar regions on circulation in East Asia and the climate of China.

  • Articles
  • LEI RuiBo, LI ZhiJun, CHENG Bin, YANG QingHua, LI Na
    Advances in Polar Science. 2011, 22(1): 10-16. https://doi.org/10.3724/SP.J.1085.2011.00010
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    Thermodynamic processes of a system involving a floe and a small lead in the central Arctic were investigated during the ice-camp period of the third Chinese National Arctic Research Expedition from 20 to 28 August,2008. The measurements included surface air temperatures above the floe,spectral albedo of the lead,seawater temperatures in the lead and under the ice cover,and the lateral and bottom mass balance of the floe. The surface air temperature at 1.15 m remained below 0℃throughout the observation period and sea ice had commenced its annual cycle of growth in response to autumn cooling during the study.The surface of the lead was frozen by 23 August,after which the spectral albedo of the thin-ice-covered lead in the band of 320-950 nm was 0.46 ±0.03,the seawater temperatures both in the lead and under the ice cover,as well as the vertical seawater-temperature gradient in the lead decreased gradually,and the oceanic heat under the ice was maintained at a low level approaching 0 W/m2. By the end of the measurement,the thickness of the investigated floe had reached its annual minimum,while the lateral of the floe was still in the melting phase,with a mean melting rate of 1.0 ±0.3 cm/d during the measurement,responding to an equivalent latent heat flux of 21 ±6 W/m2. The lateral melting of the floe had made a more significant contribution to the sea-ice mass balance than the surface and bottom melting in the end of August.

  • MA YongFeng, BIAN LinGen, XIAO CunDe,
    Advances in Polar Science. 2011, 22(1): 17-24. https://doi.org/10.3724/SP.J.1085.2011.00017
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    The heights of automatic weather station (AWS) sensors over the Antarctic ice sheet are nominal and change with snow accumulation or ablation. Therefore, the measured data may not be used directly. In this study, we analyzed the impact of snow accumulation on AWS observations using continuous measurements from three AWS that were deployed on the traverse route from the Zhongshan Station to Dome A over East Antarctica. We then corrected the measured air temperature to account for changes in the sensor height relative to the snow surface to improve the authenticity and representativeness of the observation data from the AWS. The results show that (i) the annual mean snow accumulations at Dome A, Eagle and LGB69 were approximately 0.11 m, 0.30 m and 0.49 m, respectively, and the corresponding annual mean air temperature differences between the corrected and measured values at 1 m in height were 0.34℃, 0.29℃ and 0.35℃; (ii) the impact on air temperature from accumulation decreases with height from the surface; (iii) the air temperature difference between the corrected and measured values was not directly proportional to the snow accumulation but was related to the seasonal air temperature variations and the intensity of the local surface inversion; and (iv) the averaged corrected air temperature was higher than the measured values except during the summer when there were days without temperature inversion. The magnitude of the temperature difference between the corrected and measured was mainly determined by snow accumulation and the intensity of the local surface inversion.

  • Zeng YinXin, Zheng TianLing
    Advances in Polar Science. 2011, 22(1): 25-34. https://doi.org/10.3724/SP.J.1085.2011.00025
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    The evolutionary relationships and taxonomic position of two marine planktonic bacterial strains BSw20211 and BSw10014, isolated from the Canada Basin and from the Southern Ocean, respectively, were determined using a polyphasic taxonomic approach. There was a close phylogenetic relationship between the two strains and most phenotypic properties were shared. Nonetheless, they were found to belong to different species of the genus Pseudoalteromonas on the basis of genotypic analyses. Findings were consistent with the suggestion that gyrB gene sequence comparison and DNA-DNA relatedness might better define phylogenetic relationships of bacteria at the species level. However, a cut-off value of 90% gyrB gene sequence similarity was not reliable for the differentiation of species within the genus Pseudoalteromonas.

  • LUO Wei , DAI CongJie, LI HuiRong, GAO XiaoYan,
    Advances in Polar Science. 2011, 22(1): 35-41. https://doi.org/10.3724/SP.J.1085.2011.00035
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    Because of the limitations of sampling and seasonal study in polar regions, knowledge of dinoflagellate diversity, distribution and ecology are limited. Dinoflagellates have been incidentally reported from polar regions during some seasons and some populations have been reported as components of microalgae. Surveys of molecular diversity link the genotype of dinoflagellates from polar regions with environmental adaptation. In this study, 37 positive clones of dinoflagellates collected from different sites were used for genotype analysis, providing new insights into the biodiversity and distribution of these species based on 18S rRNA sequencing. Diverse genotypes were recorded for the summer season in Kongsfjorden (high Arctic) whilst a single novel genotype of dinoflagellate was recorded from winter samples from the Antarctic Ocean. Data from ice cores suggests that this single dinoflagellate genotype was adapted to extreme cold and clone library screening found that it was occasionally the only microbial eukaryotic genotype found in winter ice cores. The findings of this study could improve our understanding of the diverse dinoflagellate genotypes occurring in these perennially cold microbial ecosystems.

  • BIAN LinGen, MA YongFeng, LU ChangGui, LU LongHua
    Advances in Polar Science. 2011, 22(1): 42-48. https://doi.org/10.3724/SP.J.1085.2011.00042
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    Surface meteorological observations have been carried out at the Great Wall station (GW) and Zhongshan station (ZS) from 1984 to 2008 and from 1989 to 2008 respectively. The variation in mean air temperature and its trends are derived from the meteorological observation data recorded at both stations. The warming rate of the annual mean temperature at GW is similar to that at Bellingshausen station, which is about 3 km distant. Thus, the warming trend is representative of the King George Island region. The warming rate of ZS is less different from that at Davis station,which is about 100 km from ZS. It can be said that the meteorological data recorded at both stations are representative of the regions of the King George Island and east coast of the Antarctic.

  • YANG XiangSheng, CHEN XingLin , XU XianZhong , ZENG RunYing
    Advances in Polar Science. 2011, 22(1): 49-54. https://doi.org/10.3724/SP.J.1085.2011.00049
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    A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15℃ and 30℃, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35℃ and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride (PMSF) and hydrochloride 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), indicating that it was a serine protease. The presence of Ca2+ and Mn2+ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid (AA) residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family.

  • GUO ChaoYing, HE JianFeng, ZHANG Fang, CAI MingHong, WANG GuiZhong
    Advances in Polar Science. 2011, 22(1): 55-66. https://doi.org/10.3724/SP.J.1085.2011.00055
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    The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments (temperature, salinity, silicate, phosphate and nitrate, p <0.05) of the inner and outer basins of Kongsfjorden (Spitsbergen, Arctic) were studied using polymerase chain reaction-denaturing gradient gel electrophoresis(DGGE) fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria:Proteobacteria(Alpha, Beta and Gamma), Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m (outer fjord) was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped.