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At Admiralty Bay of central King George Island, Keller Peninsula, Ullman Spur and Point Hennequin are main Tertiary volcanic terranes. Field investigation and isotopic datings indicate that, there occurred three periods of eruptions (three volcanic cycles) and accompanying N-toward migration of the volcanic center on Keller Peninsula. After the second period of eruptions, the crater collapsed and a caldera was formed, then later eruptions were limited at the northern end of the peninsula and finally migrated to Ullman Spur. Thus Keller Peninsula is a revived caldera, and its volcanism migrated toward E with time. Point Hennequin volcanism happened more or less simultaneously with the above two areas, but has no clear relation in chemical evolution with them, frequently it belongs to another independent volcanic center.
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One of sea ice core samples was taken from Arctic by the First Chinese National Arctic Research Expedition Team in 1999. 20 vertical and 2 horizontal ice sections were cut out of the ice core sampie 2.22 min length, which covered the ice sheet from surface to bottom except losses for during sampling and section cutting. From the observation and analysis of the fabrics and crystals along the depth of the ice core sample, followings were found. Whole ice sheet consists of columnar, refrozen clastic pieces, granular, columnar, refrozen clastic pieces, granular, columnar and refrozen clastic pieces. This indicates that the ice core sample was 3-year old, and the ice sheet surface thawed and the melt water flowed into ice sheet during summer. Hence, the annual energy balance in Arctic can be determined by the ice sheet surface thawing in summer, and bottom growth in winter. The thickness of the ice sheet is kept constantly at a certain position based on the corresponding climate and ocean conditions ; A new kind of hydrodynamic-effected ice crystal was found in the analysis and was defined as refrozen clastic pieces. The newly refrozen clastic pieces are ex-plained as that they belong to the ocean dynamic broken ice pieces that come into con-tact with ice sheet due to buoyancy and move with the whole ice sheet. While these pieces moved to a colder zone, they were refrozen. Tlierefore, its structure is different from that of first-year ice and also can explain why there are typical Arctic sea ice mi-cro-algae in the ice core sample. Tlie age of the ice sheet is determined to be from 1997 winter to 1999 summer.
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In order to study the element contents and distribution of various mosses collected in the Antarctica, we analyzed the heavy elements of 3 species of Polytrichum in the Fildes Peninsula,
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During the first Chinese Scientific Expedition to the Arctic in July-September 1999, cyanobacteria in the Bering Sea were measured by epifluorescence microscopy. Cyanobacterial abundance varied from 0 to 7.93 ×103 cell/ml and decreased along a northerly directed latitudinal gradient in horizontal distribution. Cyanobacteria did not occur at station B1-12 (north of 60 °N). Vertically, high cya-nobacterial abundance appeared in the upper 25-50 m and decreased rapidly below 50 m. Tliere were no cyanobacteria at the 150 m. Seawater temperature and NH4+ - N are suggested to affect the distribution of cyanobacteria.
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Lake core sampled from Xihu in Fildes Peninsula of King Gorge Island, Antarctica could reveal the environmental change of the district. The lake corc(GA7) ,9.28 meters long ,was sectioned at an interval of 2 cm. Hirough measuring the organic carbon, magnetic susceptibility, granularity and organic carbon isotope of CA7, by use of 14 C age it was estimated that there were four periods of high temperature in Fildes Peninsula: 4800-4400 aB.P. , 3600-3350 aB. P.,2100-1800 aB.P. and 900 aB.P.-present. Meanwhile, results showed that there was a strikingly positive correlation between the content of organic carbon and that of organic carbon isotope (δCorg13) which could be the substitute indicators of environmental temperature.
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The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [O2] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. TTie [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In≥150 m the [O2] decreases, which is related with both [P] and [N] increasing closely. Seawater [N] : [P] ratios are 6-12 in≤50 m, 10.5-14.3 in 100-150 ra and 11.7-15.8 from 300 m to the bottom.
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icroorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the biotechnological applications. A psychrotrophic bacterium (strain Ar/w/h/75°/10/5) , producing cellulase at low temperatures during late-exponential and early-stationary phases of cell growth was isolated from sea ice-covered surface water in Chuckchi Sea, Arctic. This bacterium, with rod cells, was Cram-negative, slightly halophilic. Colony growing on agar plate was in black. Optimum growth temperature was 15℃. No cell growth was observed at 35℃ or above. Optimum 6alt concentration for cell growth was between 2 and 3 % of sodium chloride in media. Maximal cellulase activity was detected at a temperature of 35℃ and pH8. Cellulase was irreversibly inactivated when incubated at 55℃ within 30 min. Enzyme can be kept stable at the temperature no higher than 25℃. Of special interest was that this bacterium produced various extraccUalar enzymes including cellulase, amylase, agar hydrolase and protease, at low or moderate temperature conditions, which is certainly of it potential value for applications.
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