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During CH IN ARE-15 (Dec. 1998-Mar. 1999), a lake core 67. 5 cm in length, was sampled in Y2 lake, which is located on the Ardley Island, Antarctica. The concentrations of some chemical elements in Y2 lake sediments were analyzed. According to compaiative research on elementary characters of sediments in Antarctic West Lake, fresh penguin dropping as well as guano soil on the Ardley Island and Pacific Island in South China Sea, it presents that the Y2 lake sediments were ameliorated by penguin dropping. The result of element cluster analysis shows that the type elements in the sediment impacted by penguin dropping include Sr, F, S, P, Ca, Se, Cu, Zn and Ba. This can provide a base for further interpreting the climatic and environmental event recorded in the sediment.
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Ecological and palaeoecological studies were carried out in a series of lakes in the Vestfold Hills (68°38' S, 78°06' E) on eastern Antarctic continent. Dynamics types of the lakes in environmental geomorphology and physic-chemistry, as well as features of biological community structures in different lakes were analyzed. Marine macro-and micro-fossils collected from the terraces and beaches surrounding these lakes and determined in 14C radiocarbon ages to be the Late Pleistocene, were used as evidences to show the evolutionary processes of the lakes after sea level changes and transgressions since 18000 a B. P.. Basic modals of evolution for the lakes given in the paper could be regarded as not only explaining the history of environmental and ecological changes in VH lakes, and also reflecting of local environmental evolution in Antarctic region and global climate changes from past to present time.
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Geochemical characteristics of rare-earth elements (REE) and sedimentary features were studied in the borehole 96-7-1 from Elson Lagoon in Barrow, Arctic Alaska. The results show that total contents of REE (ΣREE) are lower, suggesting that physical weathering is dominate, therefore, concentrations of rarer earth elements are lower in the paleosediment environment. The chondrite-normalized distribution patterns of REEs are characterized by light REE (LREE) enrichment and Eu-depletion with the terrestrial sedimentary rock as the parent materials. In comparison with the borecore AB-67 in Elson Lagoon, the main conclusions for climatic and environmental changes are similar: before 1740 A. D., it was cold and dry with terrestrial properties, but the comparatively warming around 1400 A. D. and 1550 A. D.; after 1740 A. D., it became warming, or markedly after 1821 A. D.; but it was cold around 1890 A. D. From 1904 A. D., it got warm again, but it was relatively cold around 1971 A. D..
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Abstract During the summers of 1999 and 2000, sampling was carried out in Mt. Yulong, for the investigation of the spatial distribution of oxygen stable isotope in the atmospheric-glacial-hydro system and similar results obtained in the two years have confirmed our conclusion. There is an evident negative correlation between stable isotopic composition and air temperature-precipitation amount, suggesting that there exits a strong " precipitation amount effect" in this typical monsoon temperate-glacier region. There are marked differences between the δ18O values in winter accumulated snow, glacial meltwater, summer precipitation and glacier feeding stream. Under the control of varied climatic conditions, spatial and temporal variations of above glacial-hydro mediums are apparent. Isotopic depletion or fractionation and ionic changes had occurred during the phase-change and transformation processes of snow ice, ice-melt water, flowing of runoff and contact with bedrock. The variation of stable isotope in a runoff can reflect not only its own flowing process but also its different feeding sources.
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Permafrost temperatures from the surface down to about 9 m from 3 boreholes distributed around Kangiqsualujjuaq village on the coast of Hudson Strait were recorded and analyzed for the period 1989-1998. The results indicate that the permafrost is getting warm along the southern shore of Hudson Strait from 1993 to 1998 though it became cooling for the past 40 a or more. The observed trend in the order of 0. 098°C/ a at the 9 m depth is consistent with the long-term regional warming observed in air temperatures. It also coincides with that all the global circulation models predict an enhanced warming in polar regions associated with the increase in concentration of greenhouse gases in the atmosphere.
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The main sources of nssSO42- and NO3- were summarized in this paper. By analyzing the spatial distribution features of major ions in Antarctic ice sheet and studying on the different time of the same volcanic event recorded by different ice cores from different regions in Antarctica, this paper intends to study the transmission path of nssSO42- and NO3-. Results show that nssSO42- and NO3- are transmitted to the ice sheet through long distance and high altitude. The procedure of the transmission is that nssSO42- and NO3- are transmitted to the level between the top of troposphere and the bottom of stratosphere, then subsided to the ice sheet surface and spread to other regions.
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The investigation of phytoplankton standing stock, euphotic layer and photosynthesis rate were carried out in 19-27 of January, 2000 at three longitudinal sections (70°30' E, 73°00' E and 75°30' E). The results showed that the high value of chlorophyll a concentration was in inshore bay, polynya and the continental slope of the investigated sea area. At various investigated stations, average chlorophyll a concentration at sub-surface layer (25 m) was higher than that at surface layer; its concentration at the deeper layers of over 50 m decreased with increasing depth. At anchor station, the maximum chlorophyll a concentration appeared at surface layer in Antarctic summer's afternoon while the minimum value appeared in the morning; chlorophyll a concentration at water layer of 0-25 m was obviously higher than that at deep water layer, being related to the releasing of ice-algae. High productivity was in inshore bay and polynya of continental shelf. Chlorophyll a concentration at surface layer is closely correlated to the dissolved oxygen concentration in seawater. The sea area with chlorophyll a concentration of over 1.0 μg/ dm3 may be the convergence of CO2 and that of below 1.0 μg/ dm3 may be the source of CO2.
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During the CHINARE-
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A Gram negative bacterium Ar/W/b/75°25' N/ 1 producing extracellular alkaline protease was isolated from surface water of latitude 75°25' N, and longitude 162°25' W in Chukchi sea, Arctic. The strain can grow at the temperature range from 7 ℃ to 30 ℃, and grow better at 30 ℃. It can not grow at 40 ℃. Keeping certain salinity concentration in medium is necessary for cell growth. It grows well in medium containing salinity concentration from 0. 5% to 10% sodium chloride. Glucose, sucrose and soluble starch can be utilized by the strain, among which glucose is the optimal carbon source. Peptone is the optimal organic nitrogen source for cell growth and protease producing, and ammonium ni~ trate is the optimal inorganic nitrogen source. About 75. 7% of total protease of the strain are extracellular enzyme. Optimal temperature for proteolytic activity is at 40 ℃. Protease of the strain keens stable below 40 ℃. and shows high proteolvtic activity within the pH range from 7 to 11.
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As a structure linking the ecosystem and population, community plays an important role in the marine ecology. Abundance of different species and development-stages were used in our classification to the sampling stations with clustering-analysis and multr dimension scaling, through which three geographic communities were marked out, respectively as following: the Salp community characterized by presence of
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