Loading...

Archive

    30 December 2001, Volume 13 Issue 4 Previous Issue    Next Issue

    Contents
    For Selected: Toggle Thumbnails
    Contents
    DISTRIBUTION,ABUNDANCE AND GROWING CONDITION OF THE ANTARCTIC KRILL(EUPHAUSIA SUPERBA) IN 1999/2000 IN THE PRYDZ BAY REGION,ANTARCTICA
    2001, 13 (4):  231-244. 
    Abstract ( 1591 )   PDF (339KB) ( 1396 )  

    Antarctic Krill ( Euphausia superba ) were collected from the Prydz Bay region during the austral summer of 1999/2000. Three longitudinal transects,with 15 sites,were sampled. Although krill were encountered in 14 sites,the densities were comparatively low in general. The main component of the krill population was post larval stages. The mean numerical density and weight density integrated for the whole survey region were 16.17 ind./1000 m 3 and 12.02 g/1000 m 3,respectively. The abundance of krill was relatively high and they distributed more evenly in slope area than the open sea area,except that the highest value was found in open sea area. No krill occurred in the only station of the shelf area. The krill were growing better in the slope area than in the open sea area,but as for the whole study area,Antarctic krill were under normal growing state. The results of the analyses of the environmental factors indicate the presence of the three large sample stations were to some extent related to the cold water mass at 75 m depth,as well as the confluence area between the high and low Chl a centers at 25 m depth.

    Related Articles | Metrics
    null
    2001, 13 (4):  245-252. 
    Abstract ( 1405 )   PDF (239KB) ( 1336 )  

    It is the first time that the palaeogoe sediments kept in good condition were discovered on the Great Wall area,which is located in the Fildes Peninsula,west Antarctic. According to the research on the surface textures of the quartz grains, the grain size features of the sediments and elemental geochemistry such as the ratios of Sr/Ba and B/Ga,we can conclude that the palaeogoe sediments deposit under glaciofluvial lacustrin sedimental environment, and the sedimental environment records the history of the gemorphy evolution ,ice sheet advance and recession and palaeoclimate variability of this area dated from 4600 aBP. The discovery of the palaeogoe sediments is very significant for the palaeoenvironment study on the ice-free area of the Antarctic, because the sediment sections offer a new carrier recording the palaeoenvironment information,except for lake sediments,ocean sediments ,ice core and loess.

    Related Articles | Metrics
    THE SIPHONOPHORES AND ITS DISTRIBUTION IN SOUTHERN EDGE WATERS OF CANADA BASIN, ARCTIC OCEAN
    2001, 13 (4):  253-263. 
    Abstract ( 1596 )   PDF (496KB) ( 1501 )  

    The composition, abundance and vertical distribution of planktonic Siphonophores, collected in Chukchi Sea and adjacent southern edge waters of Canada Basin, Arctic Ocean during the summer 1999 by first Chinese National Arctic Scientific Expedition, have been analysed. Totally, only two species of Siphonophores were identified in southern edge waters of Canada Basin, and they are absent in the Chukchi Sea. The principal morphological characteristics of the polygastric (asexual) and eudoxid (sexual) stages of Muggiaea bargmannae Totton and Dimophyes arctica Chun are fully described and illustrated. Besides, their morphological forms and ecological habits are discussed. The abundance of Dimophyes arctica , with a mean value of 42×10 -3 ind/m 3, is higher than that of Muggiaea bargmannae (24×10 -3 ind/m 3) in southern edge waters of Canada Basin. These two species of Siphonophoras were found in water layers of 100-800m and were the most abundant in 300-200m, in and above which a sharp halocline occurred .

    Related Articles | Metrics
    VERTICAL FEATURES OF NUTRIENT AND DISSOLVED OXYGEN OF THE BERING BASIN IN JULY 1999
    2001, 13 (4):  264-272. 
    Abstract ( 1616 )   PDF (249KB) ( 1299 )  

    From July 20 to 30,1999, China R/V Xuelong occupied 22 stations in the Bering Basin on the cruise of China First Arctic Science Expedition. The chemical samplings are sum of 271. For vertical distributions of silicate , phosphate , and dissolved inorganic nitrogen (nitrate plus ammonium plus nitrite), the similar point is that there are three layers with two nutriclines. The first layer is in 25m; the followings are obvious nutriclines; the second layer is between 50m and 200m; then there are plain nutriclines; and the third layer is from 500m to bottom (~3900 m). The difference is in the third layer, where slowly increases with depth, but and slowly decrease or remain the same with depth. Vertical oxygen and and and profiles indicate the sea waters within the potential temperature (θ) minimum layer (0.5-2.7°C, salinity of 33.01-33.17,depth of 81-157 m) are active layer of atmospheric oceanic exchange and main layer of biological action. The decreases relate with both and increase in ≥150 m. The : ratios (=9+ and =135+) of the sea waters of the Bering Basin are uniformly 0.786-1.029, indicating that nutrient features of the northern and central Bering Basin seawaters are rather conservative.

    Related Articles | Metrics
    ESTIMATION OF THE GRAVITY IN QOMOLANGMA PEAK ──ON THE BASIC PRINCIPLE OF ESTIMATE METHOD
    2001, 13 (4):  273-282. 
    Abstract ( 1362 )   PDF (280KB) ( 1389 )  

    In this paper, we investigate the research approaches for estimating the gravity at the point, to which it is difficult for mankind to climb, and for the instrument to be carried, in the mountain area from the observed gravity and height of the nearby observation. The research results are as follows. When the wave length for the topographic load λ≤50km,The crustal strength is strong enough to keep the crust not deformed. Therefore, it is improper to use Airy Heiskanen or Pratt Hayford local compensation model to estimate the gravity. Because the free air gravity anomaly is affected by the topographic undulation, we may use the height of nearby point of known gravity to estimate the gravity. Based on this idea, utilizing four kinds of formulas, we give the gravity of Everest (976970±7)×10 -5 ms -2 , which is beneficial to the research for geoid and orthometric height, according to the view of isostasy, the deviation from result mentioned above approaches 100×10 -5 ms -2 .

    Related Articles | Metrics
    EXISTING CONDITIONS OF COLLINS ICE CAP ON KING GEORGE ISLAND,ANTARCTICA
    2001, 13 (4):  283-293. 
    Abstract ( 1445 )   PDF (314KB) ( 1246 )  

    The climate in the King George Island is dominated by the frequent succession of low pressure systems which leads to a highly maritime climate. On the basis of meteorological observation,it is obtained that the surface temperature lapses in summer and winter are nearly the same,about 0 65℃/100m on the ice cap,and temperature jump is around 0.3℃. The mean annual temperature of the ice cap is relatively high,and at equilibrium-line altitude(ELA) is -3.5℃. However,since the annual temperature difference is small,the summer temperature is lower,average temperature from December to February is 0℃ at ELA. In addition,the ice cap is highly cloudy,foggy and humid that the snow surface received low amount of radiation. This heat condition is favorable to ice cap existing since it results in weak summer melt. There is relatively plentiful precipitation on Collins Ice Cap. The precipitation is 800mm at ELA,and increases rapidly with elevation,at the summit of the main dome,may over 2000mm. Most annual precipitation is solid on the ice cap,which is the mass base of glacier existing.

    Related Articles | Metrics
    CHANGES OF SERUM THYROID HORMONE AND PLASMA CATECHOLAMINE OF EXPEDITION MEMBERS IN ANTARCTIC ENVIRONMENT
    2001, 13 (4):  294-300. 
    Abstract ( 1321 )   PDF (373KB) ( 1317 )  

    The changes of serum thyroid hormone total thyroxine (TT4), triodothyronine (TT3), thyroid stimulating hormone (TSH) and plasma catecholamine,including norepinephrine (NE), epinephrine (E), dopemine (DA) were investigated in 10 male Antarctic expedition members (in Great Wall Station) under extreme environmental condition by CLIA and HPLC ECD. Samples were taken at different time: (1) before leaving to Antarctica (2) returned to China after living 1 year and 2 weeks in Antarctica. Comparing of before leaving and returned, results showed that there was a significant decrease in the contents of TT4 (P<0.01), with no significant change in the content of TT3. It was also found that the content of TSH increased significantly (P<0.01); No significant changes of plasma NE and DA were found,but the content of E decreased significantly (P<0.05). The results indicated that the special Antarctic environment led to a restrain effect on the thyroid function and the level of plasma E in Antarctic expedition members. Both the thyroid and adrenal system were associated in response to the Antarctic systemic stress to maintain the balance between human bodies and environments.

    Related Articles | Metrics
    THE APPLICATION OF POST-PROCESSING DIFFERENTIAL GPS IN PLOTTING AT ANTARCTIC GROVE MOUNTAINS
    2001, 13 (4):  301-306. 
    Abstract ( 1511 )   PDF (380KB) ( 1394 )  

    Considering the abominable condition in polar region, a new method of surveyingDifferential GPS was put forward in this paper. The practice of author in Antarctic Grove Mountains during CHINARE 16 (Chinese National Antarctic Research Expedition 16) shows that the method of post processing GPS assisted with Total Station is generally applicable and efficient. It is completely satisfied with the acquirement of a topographical map in 1∶10000 or smaller scale. And the method of GPS is a convenient means to collect considerable topographical data in polar region.

    Related Articles | Metrics