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30 September 2012, Volume 24 Issue 3 Previous Issue    Next Issue

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BIOMARKERS RECORDS FROM LACUSTRINE SEDIMENT, LASEMANN HILLS, EAST ANTARCTICA Liu Yi，Luo Yuhan，Sun Song，He Yuxin，Liu Zhonghui，Sun Liguang 2012, 24 (3):  205-214.  DOI: 10.3724/SP.J.1084.2012.00205 Abstract ( 2312 )   PDF (3148KB) ( 1451 )   Biomarker records from Mochou lake sediments, Larsemann Hills (69°22.3′S, 76°22.0′E), East Antarctica, reveals mid-late Holocene climate history in the region. . As biomarkers for a limited number of certain haptophytes, the long chain alkenones (LCAs) were found from bottom to 76 cm of the sediment core (6500-5100 cal. yr. BP), a period with high relative sea level. Trace amounts of LCAs were also found at 36-30 cm (3700-3500 cal. yr. BP), which reflected change of lake salinity caused by cold climate with fewer ice melt water and higher evaporation. The absence of LCAs above 76cm (about 5100 cal. yr. BP) was consistent with the climate switching from cold to warm and gradually dropping of relative sea level, resulting in more glacial melting water and less intrusion of sea water. The evolution of n-alkanes (C19-C33) reflected the same history of hygrophyte population. References | Related Articles | Metrics

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EXPERIMENTAL STUDIES ON THE STABLE ISOTOPES OF N2O EMITTED FROM SEA ANIMAL COLONY SOILS IN COASTAL ANTARCTICA Bai Bo，Zhu Renbin，Xu Hua，Liu Yashu 2012, 24 (3):  215-225.  DOI: 10.3724/SP.J.1084.2012.00215 Abstract ( 2409 )   PDF (3867KB) ( 1280 )   Nitrous oxide (N2O) is an important greenhouse gas, mainly emitted from soils during the nitrification and denitrification processes. Measurement of the natural abundance of N2O stable isotopes is an effective method to distinguish the N2O sources from nitrification and denitrification. In this paper, we studied the soils from Fildes Peninsula (HS and GS), Ardley Island (AB and AF) and Emperor penguin colony (DQ and DQT) in Antarctic, and examined the isotopic compositions ofN2O through laboratory incubation experiments under N2 and under ambient air conditions, respectively. Results showed that much more N2O was formed under N2 incubation than that under ambient air incubation. For most treatments the soil emitted N2O was 15N-depleted compared to local ambient air N2O. The N2O concentration often leveled off or even decreased, accompanied by increases in δ15N and δ18O of the remaining N2O. The soil water content and pH also affect the δ15N and δ18O values. References | Related Articles | Metrics

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CHANGING CHARACTERISTICS OF BACTERIAL COMMUNITIES IN SOILS IMPACTED BY PENGUIN AND SEAL EXCRETA, EAST ANTARCTICA Ma Dawei，Zhu Renbin，Ding Wei，Chu Haiyan，Shen Congcong 2012, 24 (3):  226-237.  DOI: 10.3724/SP.J.1084.2012.00226 Abstract ( 2494 )   PDF (3078KB) ( 1388 )   Antarctic tundra soils impacted by sea animal excreta are an important source of nutrients in terrestrial ecosystem. The bacterial community in the Antarctic tundra soils plays an important role in carbon and nitrogen cycles, but at present changing characteristics of bacterial community in the soils influenced by sea animal excreta have received little attention. In this paper, we investigated four penguin and seal colony soil profiles (DA1, DMG and DS, HS) from east Antarctica. Soil enzyme activity, microbial biomass C, microbial quotient, soil respiration, metabolic quotient and DNA concentration were measured from all the soil horizons and the composition of bacterial communities were simultaneously assessed through 16 S r DNA-DGGE. The objectives were to study changing characteristics of soils bacterial community and their relationships with environmental factors. Soil invertase, urease, phosphatase activities, microbial biomass, soil respiration and microbial quotient decreased with depths, however, metabolic quotient increased, indicating that the microbial environment became worse, which caused bacteria species, quantity, enzyme secretion decreases, and the energy required by the microbial community for its growth and maintenance increased from the surface to the deeper horizons. Soil DNA concentrations were highly relevant with pH, moisture content, TOC, TN, microbial biomass C, soil respiration and enzyme activity, indicating that those environmental factors greatly affects bacteria abundance. DGGE analysis reflected the high bacterial community structure in East Antarctic tundra soils, lane numbers and type brightness decreased with depths. Clustering analysis showed that the differences between lane types were significant in four profiles with the depth, bacteria genetic similarity was 46%, and bacterial community in penguins, seals colony soil showed a significant difference.Penguins and seals excreta play an important role in the change of soil bacteria community diversity in east Antarctica. References | Related Articles | Metrics

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SPATIAL DISTRIBUTION OF PICO- AND NANO- PHYTOPLANKTON AND BACTERIA IN THE CHUKCHI SEA IN RALATION TO WATER MASSES Zhang Fang，He Jianfeng，Guo Chaoying，Lin Ling，Ma Yuxin 2012, 24 (3):  238-246.  DOI: 10.3724/SP.J.1084.2012.00238 Abstract ( 2500 )   PDF (3251KB) ( 1324 )   Based on the Third Chinese Arctic Expedition cruise in the summer of 2008, the distribution patterns of pico-, nano-plankton and bacteria abundance in the Chukchi Sea were studied. Pico- and nano-phytoplankton abundances ranged from 0.01×103 to 5.51×103 cells/mL and from 0.01×103 to 5.51×103 cells/mL, respectively. The lowest numbers of bacteria in the entire water column was recorded at station R17 at 100 m depth (0.21×106 cells/mL), and the highest concentration was observed at station R09 at 10 m depth (9.61×106 cells/mL). Our results demonstrated that melting sea ice is affecting affects the physical characteristics of the Chukchi Sea by causing reductions in the salinity of the surface mixed layer, which in turn results in greater hydrodynamic stability of the water column. These changes were accompanied by increasing bacterial concentrations. The Pacific warm water brought high nutrients into the Chukchi Sea, which led to higher abundance of bacteria and nano-phytoplankton in the Chukchi Sea comparing to other regions of the Arctic Ocean. However, the number of picophytoplankton in the Anadyr Water with notably relation to chlorophyll a was larger than the other two water masses. The structure of pico- and nanoplankton communities coupled with the water masses in the Chukchi Sea was can be considered to act as asindicators of the variability the inflow of Pacific warm water into the Chukchi Sea. References | Related Articles | Metrics

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THE DISTRIBUTION AND CONTENT OF PARTICULATE BIOGENIC SILICA IN SURFACE WATERS OF PRYDZ BAY,SOUTHERN OCEAN, DURING THE AUSTRAL SUMMER OF 2011 Hu Chuanyu，Han Zhengbing，Shen Chen，Zhang Haisheng 2012, 24 (3):  247-253.  DOI: 10.3724/SP.J.1084.2012.00247 Abstract ( 2286 )   PDF (3413KB) ( 1502 )   To characterize the correlation among PBSi and plankton, nutrients and POC, the contents and distributions of PBSi in the upper surface waters of Prydz Bay, Southern Ocean, were investigated during the CHINARE-27 cruises. Results show that the contents of PBSi ranged between 0.76—19.72 μmol/dm3, the average content of PBSi was 6.06 μmol/dm3, and the distribution of surface PBSi had significant regional characteristics. The concentrations were higher in the southern area of 67°S than in the northern area. The distribution of PBSi and Chl a and POC show similar patterns, and PBSi had a negative correlation with silicate. In the vertical direction, the mole ratio of Si/C decreased with increasing depth. This trend indicated a higher rate of PBSi dissolution, or lower rate of organic matter remineralization rate in the upper 200 m. References | Related Articles | Metrics

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EFFECTS OF SEABIRD ACTIVITY ON CARBON DIOXIDE EXCHANGE BETWEEN TUNDRA AND ATMOSPHERE IN NY-ÅLESUND, ARCTIC Chen Qingqing，Zhu Renbin，Ding Wei，Xu Hua 2012, 24 (3):  254-265.  DOI: 10.3724/SP.J.1084.2012.00254 Abstract ( 2135 )   PDF (5982KB) ( 1319 )   The high altitude area in Arctic is one of important global seabird active regions. Seabird guano provides rich nutrients for tundra soils, thus affects carbon cycle in tundra ecosystem. However, effects of seabird activity on CO2 fluxes from Arctic tundra have not been reported. During the summertime of 2009, CO2 fluxes were investigated in the bird sanctuary and non-bird region from Ny-?lesund using a static chamber technique. To evaluate temporal variations and daily variations of CO2 fluxes from the bird sanctuary, bird-intensive areas (HB), fewer activities area (MB) and the edge region with little seabirds activities（LB）were investigated. Net CO2 fluxes and photosynthetic rates were (-107.6±19.2),（21.7±9.7）and（67.5±12.4）mg/(m2.h) and（-243.6±25.5）,（-105.5±7.6）and（-45.6±12.0）mg/(m2.h ), respectively. They were both significantly different between the observation sites, and photosynthetic rates reduced in order, indicating bird activities significantly increased atmosphere CO2 uptake. The respiratory rates were（136.0±16.5）,（127.2±15.6）and（113.0±6.8）mg/(m2.h) had no significant differences between the observation sites, indicating the effect of bird activities may be insignificant. The average NEE of non-bird region (seaside and mining tundra) were (6.91±4.8）and（17.5±41.6）mg/(m2.h), respectively. The data suggested the non-bird tundra was the CO2 sink. Temporal variations of CO2 fluxes during summertime in the non-bird region showed it was a source for atmospheric CO2. The CO2 fluxes were positively related to air temperature and ground temperature, with no significant correlation with precipitation and air humidity. Our results from 23 observation sites in three types of tundra indicated seabird activity had a major impact on carbon fluxes and significantly enhanced the sink of carbon in Arctic tundra. Related Articles | Metrics

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THE SPATIOTEMPORAL DISTRIBUTION OF FISHING GROUNDS FOR ANTARCTIC KRILL(EUPHAUSIA SUPERBA) AROUND THE SOUTH ORKNEY ISLANDS IN AUSTRAL SUMMER-AUTUMN AND ITS RELATION TO ENVIRONMENTAL FACTORS BASED ON A GENERALIZED ADDITIVE MODEL Zhu Guoping，Zhu Xiaoyan，Xu Yiying，Xia Hui，Li Yingchun，Xu Pengxiang，Xu Liuxiong 2012, 24 (3):  266-273.  DOI: 10.3724/SP.J.1084.2012.00266 Abstract ( 2612 )   PDF (2608KB) ( 1938 )   The present study analyze the spatial-temporal distribution of Antarctic krill (Euphausia superba) fishery in the South Orkney Islands in the austral summer-autumn during 2009-2010 season and 2010-2011 season using the generalized additive model (GAM) based on the data collected from the scientific observers of Chinese Antarctic krill fishery, the relationship between the spatial-temporal distribution of Antarctic krill fishery and sea surface temperature (SST) and sea state are also analyzed. The results show that the rate of deviance explained about CPUE (catch per unit effort) is 41.78 %, the factor that provides the largest contribution is month and the contribution rate is 15.53 %. Significant difference can be found for the distribution pattern on CPUE in different months. The average CPUE value attain the lowest in January and reach the highest in April; significant difference can also be occurred in average CPUE value among months. The main fishing ground is concentrated in 60°12′S to 60°30′S, 45°30′W to 47°30′W. The suitable SST range is 0.1 to 1.8 ℃ and the most suitable range of SST is 0.5 to 1.5 ℃. The average CPUE values have remarkably difference among sea states and vessels. The results of stepwise GAM show that the relative importance of the six variables affecting CPUE of Antarctic krill fishery in the South Orkney Islands can be described as the following order: month, vessel, longitude, SST, latitude, and sea state. References | Related Articles | Metrics

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DAYSIDE DIFFUSE AURORA RESPONSE TO AN INCREASE OF SOLAR WIND DYNAMIC PRESSURE Chen Xiangcai，Han Desheng，Hu Zejun，Liu Janjun，Hu Hongqiao，Xing Zanyang，Liu Junming，Liu Ruiyuan 2012, 24 (3):  274-283.  DOI: 10.3724/SP.J.1084.2012.00274 Abstract ( 1962 )   PDF (4643KB) ( 1531 )   The sudden enhancement of solar wind dynamic pressure can result in the disturbance on the flux of energetic particles precipitating into the ionosphere and the current intensity in magnetosphere-ionospheric current system. The diffuse aurora, which is excited by high-energy particles of magnetosphere precipitating into the upper atmosphere and impacting with the neutral gas, can respond to the disturbance. Because of the location of Yellow River Station (YRS) in Ny-?lesund, Svalbard is good for the optical observation of dayside aurora. A case of the dayside diffuse aurora was observed by the all-sky imager (ASI) in YRS, which intensively responds to a variety of solar wind dynamic pressure. With the enhancement of the solar wind dynamic pressure, the diffuse aurora on the equatorward of ASI’s field-of-view showed the intensity enhance and the poleward extension on latitude, the geomagnetic environment also showed a corresponding disturbance at the same time. We suggested that the dayside magnetopause is compressed because of the enhancement of the solar wind dynamic pressure. It can result in the enhancement of pitch-angle scatter by wave particle interaction in the magnetosphere. Consequently, the number flux of the high-energy particle scattering the loss-cone and precipitating into the equatorward ionosphere of auroral oval is enhanced, and led the emission increase of dayside diffuse aurora. References | Related Articles | Metrics

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APPLICATION OF SEA ICE MAP PROJECTION TRANSFORMATION AND TILE CUTTING OVER THE ANTARCTIC OCEAN Tian Lu，Ai Songtao，E Dongchen，Gong Hongqing，Shen Quan，Xu Ning，Zhang Hongyang 2012, 24 (3):  284-290.  DOI: 10.3724/SP.J.1084.2012.00284 Abstract ( 2401 )   PDF (3243KB) ( 1410 )   The distribution of sea ice over Antarctic Ocean makes a great impact on the icebreakers' navigation, which is also an important content of Antarctic research. Maps of the sea ice over polar regions released by different international organizations are mostly stereographic projection, which can not directly overlap on Google tile-maps. To transform the polar stereographic projection map into Web Mercator projection map, which is the mainstream at present, to incise, number and storage the map tiles with appropriate resampling algorithms, according to the given scale, and to finally release and share the sea ice map tiles, are the main contents of this paper. The authors compared different resampling algorithms, analyzed the advantages and weak points of Nearest Neighbor Resampling, Bilinear Interpolation, and Bicubic interpolation. Over the polar area, Bilinear Interpolation algorithm is recommended to incise map tiles. Finally the sea ice tiles are overlaid on Google Maps in “XUELONG Online” information platform, integrated with the real-time and historical locations of icebreaker “XUELONG”. This contributes to the navigation of “XUELONG” across the floating sea ice area. This study is of great significance for the icebreaker’s route selection over sea ice area both in Antarctica and Arctic. References | Related Articles | Metrics

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CONSTRUCTION OF ECO-ENVIRONMENT INFORMATION TUPU OF FILDES PENINSULA IN ANTARCTIC ICE-FREE AREAS Pang Xiaoping，Li Yanhong 2012, 24 (3):  291-298.  DOI: 10.3724/SP.J.1084.2012.00291 Abstract ( 2154 )   PDF (6618KB) ( 1385 )   Geo-information TuPu is introduced to the eco-environment study of ice-free area in Antarctica. The article has taken the Fildes Peninsula as an example for case study and determined the TuPu unit by using of vector-grid mixed data model. The classified information of the environmental elements was effectively extracted and generalized by means of data mining. The paper built series of single-factor thematic information TuPu model and the landscape pattern comprehensive information TuPu model. The thematic information TuPu includes topography, soil, vegetation and human activities. The three-dimensional visualization of the genealogical models is designed. The spatial morphology and the spatial correlation of the regional eco-environment is revealed quantitatively. All these efforts may provide a new technical approach and scientific basis for the in-depth study of Antarctic eco-environment. References | Related Articles | Metrics

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SURFACE ALBEDO MEASUREMENTS OVER SEA ICE IN THE ARCTIC OCEAN DURING SUMMER 2010 Zhang Rui，Ke Changqing，Xie Hongjie，Sun Bo 2012, 24 (3):  299-306.  DOI: 10.3724/SP.J.1084.2012.00299 Abstract ( 3083 )   PDF (2357KB) ( 1655 )   Snow and sea ice in the Arctic have the highest albedo of all surface types on the Earth, and it can reflect most of the incident radiation energy back to the sky. Variations in the surface albedo of the Arctic region have a significant effect on the radiation budget of the earth-atmosphere system and global climate. The surface albedo of different kinds of sea ice in the Arctic ocean Pacific region were measured with ASD spectrometer during the 4th Chinese National Arctic Expedition in 2010. Observation period is July 27-August 23,and the geographical range of 72 ° 18'-87 ° 20'N and 152 ° 34'-178 ° 22'W .The measurement results indicated that mean total albedo for sea ice covered by dry snow is 0.82 which is the highest one，and a certain extent decrease when melting. There are a lot of melting ponds in the Arctic Ocean summer, and ponded ice was classified into 3 types by its color. Albedo of white ice is high as 0.54, blue ice is lower as 0.31, gray ice is far lower than the other two types, generally 0.20, and albedo for melting ponds is only 0.16 by calculate. Melting pond is the main reason for the variations in albedo during the Arctic summer. References | Related Articles | Metrics

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BIBLIOMETRIC STUDY OF DISSERTATIONS ON THE THEME OF THE ARCTIC IN THE USA & CANADA Huangfu Qinghong，Hua Weina 2012, 24 (3):  307-314.  DOI: 10.3724/SP.J.1084.2012.00307 Abstract ( 2655 )   PDF (4604KB) ( 1694 )   Based on the collection of dissertations on Arctic research in USA and Canada from the database of PQDT, a bibliometric analysis has been conducted, including chronological distribution, degree-granting institutions, subjects and keywords. Some conclusions has been made that doctoral dissertations on the theme of arctic are growing steadily year by year; those institutions around Arctic are the main institutions of arctic research; geology, atmosphere, ecology and oceanography are the predominant disciplines of arctic research; oceans, islands and climate become the focus in this field. References | Related Articles | Metrics