Chinese Journal of Polar Research

SPATIAL DISTRIBUTION OF GE IN THE SEDIMENTS OF PRYDZ BAY, SOUTHERN OCEAN

Shen Chen，Hu Chuanyu，Sun Weiping，Zhang Haisheng

2013, 25 (2): 105-112. DOI: 10.3724/SP.J.1084.2013.00105

Abstract ( 2017 )

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The spatial distribution and concentration of Germanium (Ge) was investigated in sediments from the Southern Ocean (Prydz Bay). The content of Ge_total in surface sediments ranged from 1.14×10^-6—2.35×10^-6, with a mean of 1.71×10^-6. The highest Ge_total content was found in P3-9 station, which was in the deeper open sea area out of the Prydz Bay. The lowest Ge_totalwas recorded at the P4-13 station, which was near the edge of the Amery ice shelf. In the surface sediments, Ge_bio accounted for 16%—68% of Ge_total.Spatially,Ge_bio and Ge_totalhad similar distribution patterns, with higher values recorded outside, and lower contents in the south area of 67°S. The vertical distribution of Ge decreased with depth in the core sediments. In the surface sediments outside of the Polynyas, there was a positive correlation between Ge_bioand biogenic silica（BSiO₂）. Specifically, the depth profiles of Ge_bio and BSiO₂were similar in the sediments from the P3-16 station.

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DIVERSITY AND COMMUNITY COMPOSITION OF BACTERIOPLANKTON IN THE BERING SEA DURING SUMMER 2010

LIU Ying，ZHANG Fang，LING Yun，Tao Yan，HE Peimin，HE Jianfeng

2013, 25 (2): 113-123. DOI: 10.3724/SP.J.1084.2013.00113

Abstract ( 1897 )

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Marine bacterioplankton play a key biogeochemical role in the marine ecosystem. To investigate the diversity and community composition of bacterioplankton in the Bering Sea (Arctic Ocean), we collected samples from different depths during the Fourth Chinese National Arctic Research Expedition (2010 summer). Samples were analyzed using DGGE and clone libraries were constructed. In the basin area of the Bering Sea, the Shannon diversity index of bacterioplankton was highest (2.61) from B07-50 m, and lowest (1.99) from B07-3 m. There was greater variability in bacterial diversity within the basin than on the shelf of the Bering Sea, possibly related to complex changes in the marine environment. Through cloning and sequencing, the bacterioplankton was divided into four main phylogenetic groups: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Bacteroidetes. Gammaproteobacteria dominated the samples, accounting for 53% of all bacteria, with another 37% identified as Bacteroides. The four groups varied in their spatial distribution, Gammaproteobacteria and Bacteroidetes were found at three sites(B07, B13 and B15), Alphaproteobacteria only existed in samples from 50 m and 100 m at B07, and Betaproteobacteria was found in all three sites, except for surface waters of B13. Temperature decreased and salinity increased with depth at the three stations in the B section of the Bering Sea. Generally, nitrate, phosphate and silicate concentrations were greater in the basin area (B07 station) than in the shelf area (B15 and B13 station). Conversely, ammonia concentration was greater in the shelf area than in the basin.

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ARCHAEAL ABUNDANCE AND DIVERSITY WITHIN DIFFERENT SECTIONS OF SUMMER SEA-ICE AND SEA WATER IN PRYDZ BAY, ANTARCTICA

Ma Jifei，Du Zongjun，Luo Wei 1，Yu Yong，Zeng Yixin，Chen Bo，Li Huirong

2013, 25 (2): 124-131. DOI: 10.3724/SP.J.1084.2013.00124

Abstract ( 1817 )

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To determine the abundance and diversity of archaea in Prydz Bay, Antarctica, summer sea-ice and seawater samples were collected during the 26th Chinese National Antarctic Research Expedition. Fluorescence in situ hybridization (FISH) was applied to determine the proportions of different archaea. Community composition was analyzed by constructing a 16S rRNA gene clone library. Finally, correlation analyses were performed to assess links between physicochemical parameters and archaeal diversity and abundance within the sea-ice. The FISH found that archaea was abundant in the top section of sea-ice, with the concentration of NH₄⁺identified as a major driver of this distribution pattern. Using 16S rRNA gene libraries, archaea were not detected in the top and middle sections of the sea-ice. Overall, the diversity of archaea in sea-ice was low; all archaeal clones obtained from the bottom section of the sea-ice were grouped into the Marine Group I Crenarchaeota, while the archaeal clones from seawater were grouped into Marine Group I Crenarchaeota, Marine Group II and III of Euryarchaeote.

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CHARACTERISTICS OF THE E-LAYER DOMINATED IONOSPHERE IN THE POLAR REGIONS DURING POLAR NIGHTS

Wu Yewen，Liu Ruiyuan，Zhang Beichen，Wu Zhensen，Xu Sheng，Liu Junming

2013, 25 (2): 132-141. DOI: 10.3724/SP.J.1084.2013.00132

Abstract ( 1780 )

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The E-Layer Dominated Ionosphere (ELDI) is defined as the ionosphere where the maximum electron density in the E-Layer is larger than that of the F-Layer. The characteristics of the ELDI in the polar region during polar nights were investigated in 2007—2010 in the Corrected Geomagnetic Latitude and Magnetic Local Time Coordinates, using the measurements of COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate satellite). The ELDI is marked in the polar region during polar nights, with a similar distribution to the auroral oval. The ELDI occurred more during the night than the day, especially after midnight. Maximum occurrence probability was about 70% and 90% in the Arctic and Antarctic, respectively. The ELDI appears slightly wider in the Antarctic than in the Arctic. In the area where the occurrence probability of ELDI is higher, the ionospheric maximum electron density (N_mI) is larger than outside this area, especially during the night. The N_mI before midnight is close to, and even slightly larger than, the N_mI at mid-day, a phenomenon which was more obvious in the Antarctic. Additionally, the electron content in the E-Layer (TECE), the ionospheric total electron content (TECI) and the ratio of TECE accounting for TECI were also greater in the area where the occurrence of ELDI is larger, compared with outside the area. The values of TECE and TECI were largest in the Arctic, while the values of TECEI were largest in the Antarctic. These patterns were mainly caused by the precipitation of high-energy particles, which increases the ionization rate in the bottom of the ionosphere. Meanwhile, differences in ELDI features between the Arctic and Antarctic are attributed to differences in the departure of the geomagnetic pole from the geographic pole in each hemisphere; this causes a greater electron density in the Arctic than Antarctic, especially in the F-layer, during polar night.

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THE EFFECT OF SOLAR ACTIVITY ON THE N_mF2 AT ZHONGSHAN STATION

Xu Sheng，Zhang Beichen，Guo Lixin，Liu Ruiyuan，Liu Junming，Wu Yewen，Hu Hongqiao，Huang Dehong

2013, 25 (2): 142-149. DOI: 10.3724/SP.J.1084.2013.00142

Abstract ( 1498 )

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We investigated the solar activity dependence of the ionospheric F2 peak electron density (N_mF2) at Zhongshan Station from 1995 to 2006. We found that N_mF2 increased linearly with solar activity indices. There were also correlations between N_mF2, local time and seasonal changes. Diurnally, N_mF2 was maximal at magnetic noon, larger than other time obviously. There was a weak relationship between N_mF2 and solar activity during the night, with almost no change over time. Annually, the maximum correlation appeared during the equinoxes. There were double peak values in the equinoxes, which were even greater than in the summer of the southern hemisphere. The changes in the slope were relatively smooth in the summer of the southern hemisphere. In the southern hemisphere winter, there was only a change in the slope near the magnetic noon, with almost no changes at other times. At Zhongshan Station, there was usually a strong linear relationship between N_mF2 and P. There was no obvious saturation or amplification effect at Zhongshan compared with middle and low latitudes. We analyzed possible reasons for the N_mF2 variations, linked to the special geographic latitude of the Zhongshan Station.

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SPATIAL AND TEMPORAL VARIATIONS IN CO₂, CH₄ AND N₂O CONCENTRATION IN NY-ÅLESUND, SVALBARD

Chen Qingqing，Zhu Renbin，Xu Hua

2013, 25 (2): 150-160. DOI: 10.3724/SP.J.1084.2013.00150

Abstract ( 1930 )

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During the summers of 2008 and 2009, total 239 gas samples were collected using vacuum flask from the sites in different tundra areas, including bird sanctuary, beach tundra, mining area, human activity area, etc. in Ny-Ålesund, Svalbard, Norway. The concentrations of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) in these gas samples were determined by gas chromatography in the laboratory, the spatial and temporal variations of their concentrations were analyzed, and the factors affecting their concentrations were also analyzed in this study. The diurnal mean CO₂ and N₂O concentrations in summer 2008 were about 30 ppm and 25 ppb higher than those in summer 2009 at the sites in the bird sanctuary. The mean CO₂ concentration at the sites in beach tundra were 30 ppm higher in summer 2008 than in summer 2009 while the mean N₂O concentration was 11 ppb lower in summer 2008 than in summer 2009. The CH₄ concentration in summer 2008 was 0.7 ppm lower than that in summer 2009 at the bird sanctuary, vice versus for the sites in the beach tundra. These interannual variation of greenhouse gases concentrations might be related to environmental conditions. High seabird activity sites (HB) showed lower CO₂ concentrations than medium and low seabird activity sites (MB and LB) in bird sanctuary. Overall the mean concentration of CO₂ in the bird sanctuary was lower than that in the beach tundra, but higher N₂O concentration occurred there, indicating that CO₂ uptake and N₂O emission might be associated with seabird activities. The deposition of seabird guano supplied much organic carbon, nitrogen into local soils, and further stimulated tundra vegetation growth, which might increase tundra CO₂ sink and N₂O emission. Overall the mean concentrations of CO₂ and CH₄ in Ny-Ålesund were higher than the averages monitored in ZEP (Zeppelin Station), whereas the mean N₂O concentration was lower than the average in ZEP. In addition, the mining area and human activity areas around the base and airport did not show evidently higher atmospheric concentrations of CO₂, CH₄ and N₂O concentration.

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STRATIGRAPHIC CHARACTERISTICS OF THE MESOZOIC-CENOZOIC IN THE SOUTH SHETLAND ISLANDS, ANTARCTICA

Wang Gaiyun，Deng Xiguang，Liu Jinping，Du Min

2013, 25 (2): 161-166. DOI: 10.3724/SP.J.1084.2013.00161

Abstract ( 1853 )

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South Shetland Islands is a magmatic arc formed in the subduction of the palaeo-Pacific plate beneath Antarctic Plate since late Mesozoic. Due to the subduction, the distribution of strata is rather regular in time and space. The exposing strata in southwestern South Shetland Islands is mainly the upper Jurassic- lower Cretaceous, The types of sedimentary facies are submarine fan, deep sea, marine slope apron, fan delta, and so on. The volcanism is manifested by eruption of alkaline basalt and basaltic andesite. It has recorded the evolution from fore-arc basin to volcanic islands. While the strata in northeastern South Shetland Islands is mainly upper Cretaceous to Neogene. The sedimentary environment of the upper Cretaceous-Eocene is continental basin in warm climate, which consist mainly of basaltic lava, pyroclastic debris and sedimentary rock. The volcanics are transitional from alkaline basalt to tholeiite in geochemistry. The Oligocene- Miocene has recorded the transformation from normal marine facies in interglacial stage to glacio-marine facies in glacial stage.

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A STUDY ON SCALE AND SCOPE OF MARITIME CARGOES THROUGH THE ARCTIC PASSAGES

Zhang Xia，Shou Jianmin，Zhou Haojie

2013, 25 (2): 167-175. DOI: 10.3724/SP.J.1084.2013.00167

Abstract ( 2275 )

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This paper analyzes the source of goods travelling through the Arctic passages, and examines trades generated from the Arctic area, including oil and gas exploitation. Furthermore, it assesses the present situation for maritime cargo, which travels from the Far East to both Northwestern Europe, and North America. Two main types of cargo that will go through the Arctic passages in the future are identified. First, about 10 million tons of cargo will travel from Russia and the Nordic Arctic area to the Far East in a one-way trade flow of Liquefied Natural Gas(LNG) by 2030. Second, there are the two-way trade flows of containerized cargo from the Far East to Europe and the United States through the Northeast Passage, the central Passage and the Northwest Passage. This cargo will travel through the arctic area, to relieve pressure on their present routes from the Far East to North-Western Europe and North America. Therefore, the Northwest Passage could share cargo routes from the Far East to the United States. If navigation is technically possible in all seasons, with lower cost ships as ordinary ones,and assuming to sharing traditional canal routes 50%,By 2030, the maximum amount of container freight that will go through the Arctic passages should be approximately 17.43 million TEUs, which is 85% of the traditional canal routes in 2011. The conclusion drawn from this is: in the near future gas transportation in the Northeast Passage will play a major role, and but for transit shipping,more shipping demand for Arctic sea routes will be container transpotation. The shipping costs between by using the Arctic passages and by using the traditional canal routes are also compared in the paper.

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PRELIMINARY ANALYSIS OF KEY COMPONENTS OF ARCTIC POLITICS OF RUSSIA

Wang Qi, Shi Li, Wan Fangfang

2013, 25 (2): 176-184. DOI: 10.3724/SP.J.1084.2013.00176

Abstract ( 2332 )

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The Arctic region is an internationally important area of concern, with increasing strategic significance for Russia. Through political, economic and military methods, the Russian government strives to be one of the core countries in this region. In 2008, the Russian government formulated the “Fundamentals of State Policy of the Russian Federation in the Arctic for the Period up to 2020 and Beyond”, aimed at maintaining the status of Russia as "the leading country" in the Arctic. The key elements in the Russian Arctic policy and the series of initiatives implemented by Russia in the Arctic regions, are analyzed in view of the economic, legal, military and geopolitical ramifications. Additionally, the differing attitudes from the current Russian policy in the polar regions and the earlier “Maritime Doctrine of the Russian Federation 2020” signed in 2001 are compared. Finally, the prospects of implementation of Russia's Arctic policy objectives are assessed.

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