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30 June 2014, Volume 26 Issue 2 Previous Issue    Next Issue

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CRUSTAL THICKNESSES ALONG THE TRAVERSE FROM ZHONGSHAN TO DOME A IN EAST ANTARCTICA Feng Mei，An Meijian，An Chunlei，Shi Guitao，Zhao Yue，Li Yuansheng，Douglas Wiens 2014, 26 (2):  177-185.  DOI: 10.13679/j.jdyj.2014.2.177 Abstract ( 1800 )   PDF (4826KB) ( 1186 )   From the 4th International Polar Year in 2007/2008 to 2013, Chinese Antarctic inland icecap expeditions deployed cold-mode very-broadband seismic stations along the path from Zhongshan to Kunlun (Dome A). Using the observations recorded by the stations, we retrieved S-receiver functions of 7 stations from seismic waveform observations, and inverted for crustal thicknesses beneath the seismic stations using the receiver functions. The result shows, with the increasing of latitude of the seismic stations, crustal thicknesses increase from 38 km beneath Zhongshan station to ~58 km beneath EAGLE and CHNB; then decrease to 47 km beneath CHNA; and finally increase to 62 km beneath the highest point of the Antarctica, Kunlun station (Dome A). This thickness variation is consistent with the bedrock surface variation along the path. The thickness variation indicates that the tectonics between Zhongshan and CHNB is relatively homogeneous. The crustal thickness beneath Kunlun station is not only the largest in Antarctica but also is very large comparing with cratons in other continents. The crust beneath CHNA is ~10 km thinner than neighboring stations, which may be resulted by short-time observation for the station and also may indicate that the crustal structure lateral variation is very large. Related Articles | Metrics

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BIODIVERSITY OF AIRBORNE BACTERIA AT THE GREAT WALL STATION, ANTARCTICA Xia Xiaomin, Wang Jianjun, Chen liqi, Yan Jinpei, Zhang Rui 2014, 26 (2):  186-192.  DOI: 10.13679/j.jdyj.2014.2.186 Abstract ( 1632 )   PDF (2078KB) ( 1747 )   Bacteria are an important component of the aerosol, which is closely related with the human beings. This study analyzed the community structure of air-borne bacteria at The Great Wall Station, Antarctica, based on 16S rRNA gene clone library analysis. High diversity of air-borne bacteria was observed in the aerosol samples collected at The Great Wall Station. Ninety three sequences from the clone library can be classified into 53 OTUs (operation taxonomic unit) based on 97% sequence similarity. Shannon and Simpson index of the clone library are 3.58 and 0.04, respectively. Phylogenetic analysis showed the sequences can be affiliated into seven phylum: Actinobacteria、Cyanobacteria/Chloroplast、Bacteroidetes、Firmicutes、Planctomycetes、Proteobacteria and Verrucomicrobia. Proteobacterial sequences accounted for 65.6% of the clone library. There were same amount of sequences (30.1%) seemed to be derived from marine and terrestrial environments, suggesting a strong atmosphere exchange of the land and sea near The Great Wall Station. In addition, there were 15 sequences related with human activities, which indicated that human activities had already affected the airborne microbial community structure of The Great Wall Station. References | Related Articles | Metrics

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ESTIMATION ON CARBON FLUX IN THE SOUTHERN OCEAN DURING THE 26TH CHINARE Xu Suqing, Chen Liqi,Chen Haiying 2014, 26 (2):  193-200.  DOI: 10.13679/j.jdyj.2014.2.193 Abstract ( 1630 )   PDF (4433KB) ( 1385 )   The Southern Ocean is an important sink of atmospheric CO2 and the magnitude of the CO2 sink is heavily disputed because its ability to absorb CO2 changes significantly in the decades. An empirical relationship was deduced based on the in-situ pCO2 in the surface sea water and its main controls including Chla and SST obtained during the 26th CHINARE. An extrapolation model was found combining the empirical relationship and relative remote sensing data to compute the air-sea carbon fluxes and carbon uptake in the Southern Ocean (south of 50°S). Results of the extrapolation model show that it was a weak source of atmospheric CO2 in the area from 90°E to 90°W (clockwise), 50°S to 75°S in November, 2009 with an average flux 9.482mol/m2*mon, and carbon release was 0.0017795*1015gC. While in December, 2009, the study area from 90°E to 90°W (clockwise), 50°S to 75°S turned to be a weak sink with an average flux -12.451mol/m2*mon and carbon uptake was 0.026656*1015gC. When the empirical relationship was applied to the whole area from 50°S to 75°S, the results show in November 2009 the Southern Ocean was a source of 0.0027896*1015gC and in December 2009 it was a sink of -0.0035035*1015gC. Compared to the research results before, we found that the ability of carbon uptake decline obviously. References | Related Articles | Metrics

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GEOCHEMISTRY OF PENGUIN ORNITHOGENIC SEDIMENT FROM BYERS PENINSULA, ANTARCTIC Ma Xiaorong, Nie Yaguang, Liu Xiaodong, Sun Liguang 2014, 26 (2):  201-211.  DOI: 10.13679/j.jdyj.2014.2.201 Abstract ( 1395 )   PDF (3039KB) ( 1239 )   Abstract Byers Peninsula, which is located at the western end of Livingston Island, is the largest ice-free area among South Shetland Islands. We collected a 55cm long sediment core (named P1) influenced by penguin droppings, and carried out deep analyses including the chemical element contents and isotopic geochemical characteristics for this sediment profile. According to the analysis on C/N, sources of organic matter, and δ15N in the sediment profile, we found that the organic matter in P1 sediments mainly originated from the input of penguin guano. Using enrichment factors, correlation analysis, PCA component analysis and other Statistical analysis methods, the P, F, Cu, Hg, As, S were identified to have the common source from the penguin droppings. The contents of these elements in the sediment profile of P1 have significant positive correlation with TOC and δ15N, reflecting that they were controlled by the relative change of penguin guano’s input level in the sediments. Our results were compared with the bio-element assemblage in the ornithogenic sediments from the Ardley Island around Great Wall Station, and the Gardner Island around Davis Station, East Antarctic, and we found that the bio-element assemblage of these three different areas are basically consistent, indicating that the biomarkers of elements in the penguin ornithogenic sediment might be almost identical throughout the entire Antarctic area, but there were also some slight differences, this may be related to the differences of bedrock and weathered soil background, the degree of weathering, as well as the types of penguin food. Our results provide the foundation for reconstructing the historical penguin population changes in this region and its possible response to climate change. References | Related Articles | Metrics

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DNA BARCODING OF ANTARCTIC MARINE ZOOPLANKTON FOR SPECIES IDENTIFICATION AND RECOGNITION Cheng Fangping, Wang Minxiao, Li Chaolun, Zhang Yongshan, Sun Song 2014, 26 (2):  212-221.  DOI: 10.13679/j.jdyj.2014.2.212 Abstract ( 1398 )   PDF (2092KB) ( 1463 )   Polar zooplanktons are particularly sensitive to climate change, and have been applied as ‘rapid-responders’ of climate-induced changes in this fragile ecosystem. DNA barcoding provides an alternative approach for rapid species identification of zooplanktons in southern oceans, which will accelerate the routine monitoring of zooplankton community structure. 94 specimens belonging to 32 Antarctic zooplanktons were barcoded to afford a more comprehensive reference library. An 830 to 1050 base-pair region of the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene was obtained as DNA barcodes. The intraspecific variation of the gene ranged from 0 to 2.6% (p-distance), with the average of 0.67% (SD=0.67%). Meanwhile, the counterpart between species within the same genera ranged from 0.1% (Calanus) to 29.3% , with the average of 15.3% (SD=8.4%). The morphological and genetic similarities between C. propinquus and C. simillimus raise new questions about the status of C. simillimus as a different species. Except for the two Calanus species (C. propinquus and C. simillimus), the intraspecific genetic divergence was much smaller than interspecific divergence among congenus species, confirming the existence of barcode gap for Antarctic zooplanktons. In addition, species rather than Calanus species all grouped monophyly. Hence, DNA barcoding were confirmed as an accurate and efficient approach for zooplankton identification in the southern ocean (Species belonging to jellyfish and doliolum were not tested). Confirming evidences were also given by indicator vector analysis. The new primer sets issued here will undoubtedly facilitate the study on the species composition of Antarctic marine zooplankton by single-gene based environmental metagenomic analysis. Related Articles | Metrics

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COMMUNITY COMPOSITION OF ANTARCTIC BACTERIOPLANKTON ISOLATED FROM THE PRYDZ BAY, ANTARCTICA Wu Yuehong, Han Zhengbing, Zhang Xinqi, Zhou Yadong, Wu Min, Xu Xuewei 2014, 26 (2):  222-229.  DOI: 10.13679/j.jdyj.2014.2.222 Abstract ( 1472 )   PDF (2457KB) ( 1395 )   Twelve sea water samples of three stations from the Antarctic Prydz Bay, near Cape Darnley, were collected. Based on the oligographic media, totally 95 strains of antarctic bacterioplankton were isolated. The 16S rRNA gene sequences were determined and analyzed. The isolates fell into three lineages: Alphaproteobactia, Gammaproteobacteria and Bacteroidetes. The sequences were assigned to 35 operational taxonomic units (OTUs) based on sequence analysis. The results revealed that the Alphaproteobactia was the dominant bacterial groups and the proportions were 52.6~62.5% in different layers. Analysis using shannon diversity index indicated that station P2-14 located in continental shelf was higher than station P2-11 and P2-8 located in Slope area. There was a positive correlation between the bacteria diversity and biomass as well as productivity of phytoplankton. Shannon diversity index of the surface is the lowest, and Shannon diversity index of 50 m layer is highest. There was no difference of Shannon diversity index between 100 and 200 m layers. Bacteria vertical distribution is correlated to the nutrient concentration and dissolved Oxygen. In addition, some strains isolated from oligographic media showed low affiliation with the sequences from the described species (less than 97 %), suggesting the presence of some novel taxa and the specific strains in antarctic euphotic layer. Therefore as it is revealed in this study, the bacterioplankton resources are rich in antarctic euphotic layer. Massive unknown microorganism deserve further studying and exploration as valuable resources． References | Related Articles | Metrics

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ADAPTATION OF PHYTOPLANKTON COMMUNITIES TO LIGHT AND SALINITY VARIATION IN KONGSFJORDEN (SPITSBERGEN), ARCTIC CUI Shikai, HE Jianfeng, HE Peimin, ZHANG Fang, LIN Ling, MA Yuxin 2014, 26 (2):  230-237.  DOI: 10.13679/j.jdyj.2014.2.230 Abstract ( 1543 )   PDF (2112KB) ( 1522 )   The basic environmental variables and adaptability of phytoplankton communities to low light and salinity were studied using incubation experiments in Kongsfjorden, a high Arctic fjord of Spitsbergen, in late summer 2006. Chlorophyll a concentrations were steady or decreased slightly in darkness after one day or one week incubation. Chlorophyll a concentrations showed an initial decline when exposed to natural light after one week incubation in darkness, and then increased significantly. In a salinity experiment, the maximal growth rate was observed at a dilution ratio of 10%, however, higher dilution ratios (≥40%) had an obvious negative effect on phytoplankton growth. We suggest that the phytoplankton communities in fjords in late summer are darkness adapted, and the inflow of glacial melt water is favorable for phytoplankton growth in the outer fjords where the influence of freshwater is limited. References | Related Articles | Metrics

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VERTICAL DEFORMATION ANALYSIS OF ANTARACTIC GNSS　STATIONS COMBINED USING GNSS AND GRACE DATA Li Weiwei, Ju Xiaolei, Shen Yunzhong, Zhang Zizhan 2014, 26 (2):  238-243.  DOI: 10.13679/j.jdyj.2014.2.238 Abstract ( 1403 )   PDF (4193KB) ( 1239 )   The GNSS monitoring time series of 12 GNSS stations in Antarctica, each of which spans no less than 3 years, are analyzed to get their vertical deformations, and the results are compared with those predicted by GIA (Glacial Isostatic Adjustment). Besides, the correlations between GNSS and GRACE (Gravity Recovery and Climate Experiment) data are also computed. The results derived from GNSS data show that the vertical deformations of most stations are on the rise, and the stations with slowly descending rate locate along the coast of East Antarctica. The vertical deformations derived respectively from GNSS and GRACE data are significantly correlated with the correlation coefficients from 0.241 to 0.663. Although the biases exist in GNSS estimated deformation trend and GIA predicted trend, they are coincide with each other overall. Related Articles | Metrics

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STUDY OF THE VARIABILITY OF POLYNYAS IN THE ARCTIC BASED ON THE AMSR-E SEA ICE CONCENTRATION Fu Hongli, Kang Jianjun, Li Xue, Han Guijun, Li Wei, Zhang Xuefeng 2014, 26 (2):  244-253.  DOI: 10.13679/j.jdyj.2014.2.244 Abstract ( 1554 )   PDF (5270KB) ( 1462 )   Arctic polynyas are significant areas for ocean–atmosphere heat exchange, high winter sea ice production with resulting brine rejection, and play a critical role in local and regional climate variability. In the study, the net water area in Arctic polynyas is obtained through the image-processing technology, and the the net heat flux and the sea ice production in the surface of the net water are also estimated. Their seasonal and interannual variabilities are analyzed. Then, the Arctic is divided into the eight domains. The difference of the variabilities in different domains is studied. The result shows that the total net water area exists two maximums at the beginning and end of freezing time, respectively, and the total ice and salinity production are manily affected by the net heat flux and have a maximum on January. It is found that the times when the net water areas arrive first maximums are related to the times when polynyas starte freezing by analyzing the seasonal variabilities of the net water areas in different polynya domains. In the interannual variability, the net heat flux has a decreading trend and the net water area has a increasing trend, as a whole. The interannual variability of total ice production is very silmilar to that of the total net water area, and has also a increasing trend. At last, the correlation of the interannual variability bewteen sea ice extent and the anuual mean net heat flux in all polynyas is discussed. References | Related Articles | Metrics

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THE ANALYSIS OF A NEW ANTARCTIC TOPOGRAPHY DATABASE: BEDMAP 2 Chen Yun, Sun Bo, Liu Chun, Cui Xiangbin, Wang Tiantian 2014, 26 (2):  254-261.  DOI: 10.13679/j.jdyj.2014.2.254 Abstract ( 1753 )   PDF (2540KB) ( 1316 )   The mass balance and stability of the Antarctic ice sheet make great contribution to the global climate change and sea level rise. Ice thickness and subglacial topography are very important to the research of Antarctic ice sheet as the basic parameters. Since the fifties of last century, people carried out a large number of ice radar , gravity and magnetic measurements for Antarctic ice sheet. These data were collected, then formed the ice thickness and subglacial topography database to render a service to ice sheet model and Earth system research. Up to now the latest achievement is BEDMAP 2. For BEDMAP 2, this paper first introduces the data sources and data processing of BEDMAP 2, then the data quality evaluation for BEDMAP 2 is discussed. The characteristics and Application of BEDMAP 2 is also analyzed. Finally, this paper makes some conclusion and outlook of the ice sheet research in China with the help of BEDMAP 2. References | Related Articles | Metrics

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GROUND-BASED REFLECTED GPS FOR SEA ICE EXPLORATION Zhang Yun, Guo Jianjing, Hong Zhonghua, Han Yanlin 2014, 26 (2):  262-267.  DOI: 10.13679/j.jdyj.2014.2.262 Abstract ( 1542 )   PDF (1863KB) ( 1348 )   This paper evaluates the potential use of reflected signals from Global Navigation Satellite Systems as a source of opportunity for sea ice permittivity and concentration research, analyses the sea ice data collected in the Greenland disco bay by the European space agency, processes the amplitudes between both polarizations of reflected signals, tracks several different satellites at the same time, and ensures the processing time and the effectiveness of the data. From the polarimetric ratio of Dual polarization of the reflected signals and the simulated complex dielectric constant, it concludes that the parametric ratio has an apparent evolution with the complex dielectric constant. References | Related Articles | Metrics

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FROM MANDATORY ICEBREAKER GUIDING TO A PERMIT REGIME: CHANGES TO THE NORTHERN SEA ROUTE  IN NEW RUSSIAN LAW Zhang Xia，Tu Jingfang，Qian Zongqi，Wang Zelin，Yang Huigen 2014, 26 (2):  268-275.  DOI: 10.13679/j.jdyj.2014.2.268 Abstract ( 1989 )   PDF (2603KB) ( 1854 )   This article focuses on two issues，which is the definition of Northern Sea Route (NSR) and rules of icebreaker guiding. Comparing the Russia legal provisions enacted in 2013 with relevant the old ones, the conclusions based on comprehensive analysis as follow: (1) In the level of legal analysis, Russia’s view on NSR being the historically emerged national transportation routes of Russia has not changed. But new law redefine the scope of NSR, which comprise and consistent with the internal waters, territorial sea, adjacent zone and exclusive economic zone of the Russia Federation. In fact, it removes ambiguity about the boundary of NSR extended to the high sea. (2) In the level of rules analysis, it develop into permit regime from mandatory Icebreaker guiding regime, especially giving the concrete, practical and predictable clause of independent navigation permissible or impermissible conditions. It is possible to foreign ships independent navigation in the N SR according with the new rules. Hence, the Russian policy of NSR appeared massive change, and it has further tendency in opening NSR to the international community. References | Related Articles | Metrics

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CHINA'S FIRST TRANS-ARCTIC VOYAGE AND RELATED EXPECTATION Wang Luo, Zhao Yue, Liu Jianmin, Guo Peiqing 2014, 26 (2):  276-284.  DOI: 10.13679/j.jdyj.2014.2.276 Abstract ( 1859 )   PDF (3009KB) ( 2160 )   According to their geographical azimuth on the Earth, the Arctic navigation routes can be divided into the Northeast Passage and the Northwest Passage; Base on their latitude ranges, the Northeast Passage can be divided into the Low Latitude Arctic Passage (Arctic coastal routes), the Mid Latitude Arctic Passage (as an international regular routes), the High Latitude Arctic Passage and the Near North Pole Passage. In the summer of 2012, Xuelong, a Chinese icebreaking research vessel, became the first ship from China that completed the entire Northeast Passage in Chinese voyage history. Xuelong started its Trans-Arctic Voyage from the Bering Strait and arrived in Iceland along the Northeast Passage, and finally returned the Bering Strait through the High Latitude Arctic Passage, completing a round-trip journey across the Arctic Ocean. This paper is base on the experience of this expedition to the Arctic Ocean. In this paper, the opinion about the classifications of the Arctic navigation routes was presented, the status of commercial utility of the Northeast Passage was summaried, the whole course and main issues of Xuelong explorering the Northeast Passage were reviewed, and finally some thinking and recommendations for China to establish its Arctic strategy on Northeast Passage were made. Related Articles | Metrics