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    30 September 2010, Volume 22 Issue 3 Previous Issue    Next Issue

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    ADCP data technical processing of the CHINAREs and its multidisciplinary application
    2010, 22 (3):  211-230.  DOI: 10.3724/SP.J.1084.2010.00211
    Abstract ( 1651 )   PDF (3461KB) ( 2007 )  
    Twelve cruises underway data of Acoustic Doppler Current Profiler (ADCP) installed on board Xuelong Vessel between China and the Antarctic have been obtained by the Chinese National Antarctic Research Expeditions (the CHINAREs) since 1995. However, most of them is still stored in the database as original. This paper presents a basic flow chart of the ADCP data processing based on analysis of relative records by navigation and positioning equipments on board, and our knowledge on the oceanographic status along the transects of the ship. The flow chart includes data scanning, time correction, loading data into databases, editing, calibration and rotation, navigation calculation, and lastly computing absolute current velocities and making vector plots at different layer along parts of the ship tracks for the CHINARE-12th (1995/1996), -13th (1996/1997), -14th (1997/1998), and -15th (1998/1999) (in austral summers). Absolute current vector plots were obtained for this processed data set. Such technical processing flow chart may facilitate for ADCP data processing, analysis of the other cruises in the future. We made technical advice on how more accurate ADCP data would be obtained according to our processing experience. We also described farther ADCP data analysis and multidisciplinary applications.
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    SHOCK METAMORPHISM OF H-CHONDRITES FROM THE GROVE MOUNTAINS, ANTARCTICA
    Jiang Wang
    2010, 22 (3):  231-243.  DOI: 10.3724/SP.J.1084.2010.00231
    Abstract ( 1496 )   PDF (13550KB) ( 1138 )  

    Shock metamorphism of 47 H-Chondrites from Grove Mountains(GRV), Antarctica, were studied. Silicate and opaque minerals were observed under optical microscope for shock metamorphism features, such as undulatory extinction, planar fractures, mosaic extinction, shock-induced melting, and metal-sulfide dendritic eutectic. Shock-induced regions of 10 H-Chondrites were observed. Wadsleyite was found in GRV022469. Petrologic and mineralogical characteristics support that wadsleyite was formed by solid-state transformation. Based on shock effects, especially low-pressure phase mineral components and chemical characteristic, shock metamorphism stage of H-Chondrites is relatively low (lower than the S5). Shock-induced melt veins are thinner compared to those in L-Chondrites.

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    Variability of Marine Hydrological Features at Northern Margin of Amery Ice Shelf
    2010, 22 (3):  244-253.  DOI: 10.3724/SP.J.1084.2010.00244
    Abstract ( 1552 )   PDF (6063KB) ( 1337 )  
    CTD data observed by the 24th CHINARE (2007/2008) team are used to analyze the spatial distribution of temperature, salinity, and density at the northern margin of Amery Ice-shelf and to compare it with that of the 22nd CHINARE (2005/2006) team. It is discovered from the comparison that the new variation at the northern margin of Amery Ice Shelf is the thermocline deepening, there exists the subsurface warm water in the oceanic upper layer in the east part of the northern margin of Amery Ice Shelf, and the warm water is limited in a small area at the east end of the Ice-shelf and its adjacent locations. Therefore it is obviously a local feature. In addition, the temperature, salinity, and density have their east-west gradients in the surface layer, which might be closely related to the floe concentration in the sea surface. These local features result from ocean-ice-atmosphere interaction.
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    Decomposition of Organic Carbon and Inorganic Carbon beneath Euphotic Zone in Prydz Bay, Antarctica
    2010, 22 (3):  254-261.  DOI: 10.3724/SP.J.1084.2010.00254
    Abstract ( 1788 )   PDF (794KB) ( 1674 )  

    As the most important carbon pool in the ocean, particulate organic carbon (POC) plays an important role in marine carbon cycling. During the 25th Chinese National Antarctic Research Expedition (CHINARE-25), the decomposition ratio of organic carbon and inorganic carbon of Prydz Bay was calculated with a simple mathematical model. In the mean time, the re-mineralization efficiency of POC during sedimentation over the continental shelf of Prydz Bay was estimated according to the ratio of OC/N in the surface sediment. The results showed that the POC concentration of Prydz Bay ranged from 24.38 to 446.40μg?dm-3, with an average of 118.16μg?dm-3. Based on the observed data (dissolved inorganic carbon, dissolved O2 and nutrients), calculated remineralization ratios of elements were 164.1, 135.2 and 19.29 for O/P, C/P and N/P, respectively. At the P2 section on the continental shelf of Prydz Bay, the ratio of the decompositions of the organic carbon and inorganic carbon during their burial processes was 1.27 (mole ratio), and 81% of the POC in upper water was remineralized and re-involved in the marine carbon cycling, when it was buried to the seabed.

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    Adaptation Problems and Coping Strategies in Antarctic Expeditioners’ winter-over Life
    2010, 22 (3):  262-270.  DOI: 10.3724/SP.J.1084.2010.00262
    Abstract ( 1856 )   PDF (404KB) ( 1636 )  

    Antarctica is the coldest, the driest and the windiest continent on the earth. The severe natural and social environment in Antarctica challenges the limit of physical and psychological adaptation. Psychological researches on Antarctic expeditioners’ winter-over life could enhance our understanding on how human beings adapting to isolated, confined and extreme environments. Nine people who worked at Great Wall station and Zhongshan Station from 2003 to 2006 were interviewed with the in-depth semi-structured interview method. The transcriptions were analyzed by computer-aided qualitative analysis software. It was found that the adaptation problems could be categorized into four types, physical, emotional, interpersonal and task-related. Two main factors which effect on the quality of work and life in Antarctica were identified. Internal factors are personality, attitude, age and previous experiences, while external factors include natural environments, conditions of stations and key persons, especially the chef and the station master. A theoretical framework of coping strategies including organizational and individual aspects was developed. Among the seven ways of coping, energy transferring(such as taking part in sports entertainment or learning)plays the most important role. All results do not only provide a strong theoretical base for future research of Polar Psychology, but also provide an empirical base for more application on Antarctic expeditions, flight and space missions.

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    The structure and tectonic revolution of Arctic Ocean
    2010, 22 (3):  271-285.  DOI: 10.3724/SP.J.1084.2010.00271
    Abstract ( 1656 )   PDF (26678KB) ( 1151 )  

    There are very abundant natural resources, especially the oil, gas and coal in the Arctic Ocean and surrounding shelf seas. But a very few geological and geophysical survey has been finished in the area, due to the rigorous natural conditions. Many issues are still controversial. The main knowledge for the tectonics in the area is based on the aeromagnetic survey. It is tried to review for the tectonic features of Arctic Ocean in this paper. The first, the tectonic features of Eurasian Basin and its evolution is most uncontroverted due to the typical linear magnetic anomalies. The Basin opened from the period of linear magnetic anomaly 25, about 58Ma, and after linear magnetic anomaly 13, about 35Ma, Yermak Plateau broke from Morris Jesup Rise and it makes the Arctic Ocean linking to the North Atlantic. The secondly, the crust beneath Alpha Ridge and Mendeleev Ridge should be continental, similar with the Lomonosov Ridge, according to their crustal structure and thickness. It is possible that both of the Ridges broke from the Eurasian shelf. The thirdly, the crust beneath Makarov Basin is typical oceanic, but its revolution is fewer constrained. One of the main opinions about it is that it was formed by spread from Cenomanian to early Eocene, and declined by development of Gakkel spread center. The fourthly, as oldest basin in Arctic Ocean, the forming of Canadian Basin is poorly understood. But it is presumed that the basin was forming in a period between 140~135Ma to 95~80Ma, as New Siberian-Chukchi-Alaska microplate rifting from Canadian Margin in “wind screen wiper” fashion. The fifthly, the tectonic revolution of Arctic and adjacent area includes 3 phases: Late Jurassic-Early Cretaceous, Late Cretaceous-Early Cenozoic, and Cenozoic. Phase Ⅰ is determined by the formation, evolution, and extinction of the spreading center in the Canada Basin, while Phase Ⅱis connected to the development of the Labrador-Bafin-Makarov centers branch and phase Ⅲ pertains to the formation of the spreading system of ultraslow Mohna, Knipovich, and Gakkel mid-ocean ridges that has functioned until now in the Norwegian-Greenland and Eurasia basins.

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    Observations on the thermodynamic balance between floe and lead in the Arctic Ocean during Summer
    Ruibo Lei Qinghua Yang
    2010, 22 (3):  286-295.  DOI: 10.3724/SP.J.1084.2010.00286
    Abstract ( 2284 )   PDF (5374KB) ( 1851 )  

    Thermodynamic balance between a floe and a small lead in the Arctic Ocean has been observed during the ice-camp period in the third Chinese Arctic Research Expedition from 20 to 28 August, 2008. The field measurements include surface air temperature above the floe, albedo of the lead, seawater temperatures in the lead and under the floe, the lateral and bottom mass balance of the floe. The surface air temperature kept being sub-zero Celsius degree during the observation. Sea ice has begun its annual cycle of growth in response to autumn cooling. The surface of the lead was frozen-up by 23 August. From then onward, the albedo of the thin ice-covered lead was 0.46(±0.03), the vertical seawater-temperature gradient in the lead, as well as the seawater temperatures both in the lead and under the floe decreased gradually, while the oceanic heat under the ice approached to zero. By the end of the observation, the thickness of the investigated floe has reached its annual minimum, while the lateral of the floe was in the melt phase, with mean melt rate of 1.0(±0.3)cm/d during the measurement, responding to an equivalent latent heat flux of 19(±6) W/m2. The lateral melt of the floe showed the most significant contribution to the sea-ice mass balance when comparing with the surface and bottom mass balances of the floe for our investigated region by the end of August.

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    The Latest Research Progress on Antarctic Ice Sheet Mass Balance and Sea Level Change
    2010, 22 (3):  296-305.  DOI: 10.3724/SP.J.1084.2010.00296
    Abstract ( 1795 )   PDF (1917KB) ( 1888 )  

    On the basis of a brief introduction to the mass balance of the ice sheet and its effect on sea level, recent studies on the mass balance of Antarctic ice sheet were reviewed from two aspects, including integrated method and flux component method, and then the uncertainties affecting the mass balance were analyzed. A pattern of mass loss from Antarctica was indicated in the studies, and the mass loss near the Amundsen Sea Embayment in West Antarctic ice sheet was the most obvious. In addition, there was extensive dynamic thinning on many margins of the ice sheet. The mass loss of Antarctic ice sheet is the largest potential contributor to sea level rise. The ice shelf buttressing, the instability of the ice sheet and the function of subglacial meltwater are important to Antarctic mass balance. As observation techniques and data processing technology constantly improve in future, the mass balance estimates and the uncertainties which affect Antarctic ice sheet are expected to be further understood. Furthermore, more theoretical and technical supports will be provided to predict the range of sea level rise.

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    The Analysis of Australia’s Antarctic Politics
    2010, 22 (3):  306-312.  DOI: 10.3724/SP.J.1084.2010.00306
    Abstract ( 1534 )   PDF (314KB) ( 1928 )  

    Australia puts much emphasis on research activities on Antarctic policies. On the basis of having had a full realization of interests and challenges about Antarctic, Australia had made an excellent system of Antarctic policies and laws or acts.. Based on a brief analysis of Australia's Antarctic interests and the objectives of Australia’s Antarctic activities, combined with the performance and related activities on Australian legislation, the Antarctic management and the handling of international relations, the Australian Antarctic activities what are interest-driven have been discussed, and the important role of its Antarctic policies to maintain its Antarctic interests have been also illustrated.

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    APPLICATION OF AN ANTARCTIC BACTERIUM STRAIN FOR WATER PURIFICATION IN SIMULATED AQUACULTURE
    2010, 22 (3):  313-320.  DOI: 10.3724/SP.J.1084.2010.00313
    Abstract ( 1634 )   PDF (964KB) ( 1438 )  

    Antarctic bacterium Pseudoalteromonas sp. AN64 producing cold-active protease was used for water purification in this experiment. Effect of strain AN64 on aquaculture seawater was studied from different aspects, including dissoluble oxygen (DO), chemical oxygen demand (COD), ammonia and nitrite nitrogen and pH values. In untreated water, soluble protein content increased and reached the maximum on the 7th day with dissolution of protein. Developing with the time, DO content decreased continuously, while COD content increased and reached its maximum of 9.88 mg/L on the 11th day and sustained at a high level. In the absence of oxygen, some harmful substances, such as ammonia and nitrite nitrogen, increased and came to their maximum on the 9th and 11th day, respectively. The pH value decreased to the minimum of 5.95 on the 9th day. After treatment with Antarctic bacterium producing cold-active protease, protein content in sea water reached the maximum on the 5th day, while DO value kept fairly stable. The maximum content of COD occurred on the 7th day, earlier 4 days than the control did. At the same time, the contents of ammonia and nitrite nitrogen were only 47.7 % and 26.5 % of the control group, respectively. The change of pH was slightly and maintained between 6.85 and 7.52. It indicates that the cold-active protease produced by Antarctic bacterium can hydrolyze effectively protein in water. The low-content protein decreased the production of ammonia and nitrite nitrogen and kept the stability of pH, which provided an effective way for healthy marine aquaculture.

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