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1.
Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G+C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter. 相似文献
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Development of Arctic sea-ice organisms under graded snow cover 总被引:5,自引:0,他引:5
In 1988, the short-term response of sea-ice organisms to manipulated changes in snow cover (no snow cover, natural snow cover, natural snow cover + black foil) was investigated in one ice floe located in the East Greenland Current northwest of Svalbard over a period of three weeks. Autotrophic organisms (flagellates and diatoms) were concentrated in the lowermost 30 cm of the floe. In the field without snow cover, the highest diatom concentrations were observed, consisting nearly entirely of pennate forms, together with a maximum bacterial abundance. The community of larger protozoa and smaller metazoa was dominated by ciliates. Under natural conditions the flora consisted of both flagellates and diatoms, while turbellaria were the dominating animals. In the darkened field, the organism concentrations decreased with time. The results indicate that brine drainage, induced by changes in ice temperature, can reduce concentrations of ice organisms over short time scales. 相似文献
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Using the monthly 1°×1°sea-ice concentration data of Hadley center and the monthly NCEP geopotential height data from January 1953 to February 2003,temporal and spatial changing characters of sea-ice are examined.The results show almost all of the sea-ice of eight regions was decreasing,especially all s easons in Europe.But in Asia part,those display some increasing trends in spri ng and winter.Abrupt times of sea-ice in Europe were at end of 1970's and in Asia the times in summer/fall(spring/winter)were at end of 1980's. 相似文献
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Yusuke Kawaguchi Jennifer K. Hutchings Takashi Kikuchi James H. Morison Richard A. Krishfield 《Polar Science》2012,6(1):39-53
During the summer of 2010 ice concentration in the Eurasian Basin, Arctic Ocean was unusually low. This study examines the sea-ice reduction in the Eurasian Basin using ice-based autonomous buoy systems that collect temperature and salinity of seawater under the ice along the course of buoy drift. An array of GPS drifters was deployed with 10 miles radius around an ice-based profiler, enabling the quantitative discussion for mechanical ice divergence/convergence and its contribution to the sea-ice reduction. Oceanic heat fluxes to the ice estimated using buoy motion and mixed-layer (ML) temperature suggest significant spatial difference between fluxes under first-year and multi-year ice. In the former, the ML temperature reached 0.6 K above freezing temperature, providing >60–70 W m?2 of heat flux to the overlying ice, equivalent to about 1.5 m of ice melt over three months. In contrast, the multiyear ice region indicates nearly 40 W m?2 at most and cumulatively produced 0.8 m ice melt. The ice concentration was found to be reduced in association with an extensive low pressure system that persisted over the central Eurasian Basin. SSM/I indicates that ice concentration was reduced by 30–40% while the low pressure persisted. The low ice concentration persisted for 30 days even after the low dissipated. It appears that the wind-forced ice divergence led to enhanced absorption of incident solar energy in the expanded areas of open water and thus to increased ice melt. 相似文献
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采用Hadley中心1953—2012年海冰密集度资料、NCEP/NCAR逐月再分析资料和1977—2011年日本气象厅台风资料,对冬春季北极海冰变化的主要特征进行了分析,并对冬春季北极海冰变化与西北太平洋台风活动之间的关系进行了初步探讨。结果表明,冬春季北极海冰表现为明显的年代际变化,且在1965—2004年间具有3—4 a的低频振荡周期。在20世纪60年代后期和70年代初期,海冰变化最为显著。冬春季海冰变化与西北太平洋热带气旋生成频次、强度频次的相关性在9月份明显高于其他月份,且为正相关,而与热带气旋强度等级有较显著的负相关性。冬春季北极海冰变化与夏季西太平洋副高强度、副高面积均有很好的负相关关系。冬春季海冰面积偏多(少)时,夏季北美东部、冰岛附近地区、北太平洋以及中低纬度大部地区500 h Pa高度场为负(正)距平分布。冬春季北极海冰面积异常对北半球大气环流的持续性影响,在随后到来的台风盛期有较明显的体现。 相似文献
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