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30 December 2003, Volume 15 Issue 4 Previous Issue    Next Issue
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BACTERIAL PRODUCTIVITY IN PRYDZ BAY AND ITS ADJACENT WATERS, ANTARCTICA 2003, 15 (4):  239-248.  Abstract ( 1489 )   PDF (167KB) ( 1752 )   Bacterial productivity were estimated by 3H thymidine uptake in the Prydz Bay and its adjacent waters during the 16th Chinese National Antarctic Research Expedition (CHINARE) in the austral summer of 1999/2000. The bacterial productivity ranged from 4.5 to 191 ngC·dm -3 ·h -1 , with an average of 50.4 ngC·dm -3 ·h -1 in waters studied, which was relatively low and similar to those in the Ross Sea. The mean ratio of BP to PP was 0.41 in our study area. The maximum value of bacterial productivity occurred in the subsurface of water column which may be a typical feature of BP profiles. The distribution of BP in the surface water was inversely correlative to that of DOC. The relationship among BP , PP and DOC suggested that bacterial activities was influenced mostly by phytoplankton activities and hydrologic factors in the Prydz Bay and its adjacent waters. Related Articles | Metrics

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IRON ENRICHMENT INCUBATION EXPERIMENTS IN PRYDZ BAY, ANTARCTICA 2003, 15 (4):  249-260.  Abstract ( 1697 )   PDF (235KB) ( 1591 )   Three shipboard iron enrichment phytoplankton incubations were carried out in the Prydz Bay, Antarctica, from January to March of 2002. Waters for the incubations (Exp. 1, 2 and 3) were collected from 20 m depth in 3 stations (St. Ⅰ 1, Ⅶ 1 and Ⅶ 5), respectively. Although the nutrient concentrations in the surface waters of the three stations were consistently high, the chlorophyll a concentrations varied much. Chlorophyll a concentrations in the 20 m depth of St. Ⅰ 1 and Ⅶ 1 were 0.13-0.17 μg·L -1 and 0.20-0.26 μg·L -1 , respectively, while this figure was 2.35-2.65 for St. Ⅶ 5. There were six levels of enriched iron concentrations (control, 5, 10, 20, 40 and 80 nM) in Exp. 1 while three enriched iron levels (control, 10 and 40 nM) were arranged in Exp. 2 and 3. The iron enrichments stimulated the phytoplankton growth and nutrient drawdown in Exp. 1 (6-26th, January) and Exp. 2 (20th February-4th March). In Exp. 3, phytoplankton growth and nutrient drawdown were at nearly the same rate in the control and iron enriched bottles. In Exp. 1, the chlorophyll a concentrations in the bottles with 20, 40 and 80 nM iron enrichments grew exponentially to 40-43 μg·L -1 on the 17 th day, with a growth rate of 0.36-0.38 d -1 . Chlorophyll a concentration in the bottle enriched with 10 nM iron reached its peak (19.35 μg L -1 ) on the 23 rd day (growth rate 0.27 d -1 ). Phytoplankton in the control bottle and the bottle enriched with 5 nM iron grew at the rates of 0.13 and 0.16 d -1 , respectively. In Exp. 2, the chlorophyll a growth rates were 0.13, 0.32 and 0.40 d -1 in the control bottle and bottles with 10 and 40 nM iron enrichments, respectively. It seems that 10 nM iron enrichment was not enough to stimulate the phytoplankton to reach their maximum growth rate. Related Articles | Metrics

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ZINC-COIL SHAPES AND ITS AREAS IN SEAWATER NITRATE MEASUREMENT OF ZINC CADIUM METHOD 2003, 15 (4):  261-266.  Abstract ( 1503 )   PDF (113KB) ( 1742 )   According to the zinc cadmium reduction method in China Specification for Oceanographic Survey, surface area of circular zinc coil of 1.5 cm diameter is 30 cm 2 for the 50 mL sample. We improved the circular coil to the Archimedes′ spiral coil of the interval 2πa greater than 10 mm, the nitrate concentrations with the spiral coil are 11% higher than that with the circular coil. In the area tests of the spiral coil and for 4 μM concentrations of standard nitrate solution, the concentration value becomes saturated beyond 35 cm 2. As for 14 μM concentration, the concentration value approaches saturated until at 45 cm 2. So the 30 cm 2 area of the circular coil in the Specification is not enough. In the range between 1 and 17 μM, the relative errors of nitrate concentrations with the spiral coils of the F98072 and 931210 serial numbers (Shanghai Chemical Reagent Co.) are about 19%-23%. Related Articles | Metrics

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BUILDING OF CHINESE POLAR CRYOSPHERE NETWORK DATABASE SYSTEM 2003, 15 (4):  267-273.  Abstract ( 1548 )   PDF (294KB) ( 1699 )   Based on Microsoft Windows 2000 Server operating system, the CIPCDS was established by database management system SQL Server 7.0. It is made up of six sub databases: glacier physics, glacier chemistry, sea ice, meteorology, remote sensing and GIS map. All those basic information and observational data of ice sheets, glaciers, frozen earth, snow, sea ice, topography are stored in 150 tables. The former four sub databases mainly include: glacier movement, radar survey, glacier temperature, snow/ice crystal, density, rigidity, mass balance; pH value, conductivity rate, main ions, isotopes, organic substances, gas of surface snow, snow pit and ice core; sea ice extent and areas, sea ice thickness and salinity; all kinds of weather elements on the ground and upper air. The last two sub databases mainly include: remote sensing images for the polar regions, topographic data. The homepage and web pages of CIPCDS were made by Sybase Power Dynamo, Internet Information Server 5.0 and Front Page 2000. Two protocols in data translation in CIPCDS: HTTP and FTP was established for internet users, while for intranet users, a CIPCDS data management software by Power Builder 7.0 was manufactured independently. Users admitted by CIPCDS can query, download, manage, and export all information they concerned. Related Articles | Metrics

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RESEARCH ON MICROPARTICLES IMPLICATING POLLUTION IN POLAR REGION 2003, 15 (4):  274-282.  Abstract ( 1444 )   PDF (138KB) ( 1672 )   Environmental problems and global changes are the hot spots that nowadays people pay attention to. Polar region is special from geographical point of view. The microparticle in polar atmosphere and ice core contains information of volcano, dust storm and human activity, etc. Based on the previous research, this article discussed the sulphide, the nitrate, organic pollution heavy metal and volcanic dust, etc., which tie up to the human activity. The composition of microparticles in the ice core and atmosphere of the two polar regions indicates that despite the remoteness, these two places have been influenced by human activity especially the Arctic region. There are still a lot of difficulties in the research of microparticle and other impurities in the polar region, such as the analysis method, the sampling and the observation, etc. Advanced works are needed to solve these problems. Related Articles | Metrics

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STUDY ON KEY PROCESSES AFFECTING RAPID CHANGES IN THE ARCTIC 2003, 15 (4):  283-302.  Abstract ( 1755 )   PDF (669KB) ( 3231 )   Recent evidences show that a rapid change has occurred in the Arctic since the last half century. Temperature increased 2-3 °C in some regions of the Arctic continents. Coverage of sea ice decreased 5% in the Arctic Ocean, thickness of sea ice shrunk in the center of the Arctic Ocean, the surface and intermediate water layers are freshening and warming, absorption of the atmospheric CO 2 increased in the marginal sea ice zone, and depletion of ozone appeared and ultraviolet radiation increased. To understand processes of air sea ice interaction and their impacts to global change, First Chinese National Arctic Research Expedition was conducted from July 1 to September 9 of 1999 to implement a multidisciplinary survey in the Chukchi Sea, the Canada Abyssal Plain, and the Bering Sea. Advancement has achieved to understand regional characteristics of the Arctic and the sub Arctic as well as their effective processes on global change. A phenomenon of persistent warming has been observed in the medial layer waters in the Canada Abyssal Plain where has also been found as a major sink of fresh water from rivers to the Arctic Ocean. Exchange of water masses between the western Arctic Ocean and the Bering Sea as well as warm water structure in secondary surface layers were studied. Using data from multidisciplinary investigations on a floating packed ice, the atmospheric boundary layer was characterized, variations of energy balance on the underlying surface were modeled, and as air sea and ice air turbulent fluxes were calculated respectively, as well as differences of their parameters in the boundary layer were discussed. Fluxes of air sea CO 2 showed that most of the surveyed waters would play as a sink of the atmospheric CO 2. Higher biological pump operations presented in the western Arctic Ocean with an effective organic carbon sink in the Chukchi Sea. Microbiological activities didn′t find remarkably suppressed even in the cold waters. Biological processes of iodine in the surveyed sediment cores indicated a trend of concentration distribution increases from low to high latitude, suggesting a potential sink of iodine in the Arctic region and implying iodine as a significant indicator for variations of paleooceanic geochemical elements in the polar regions. There was a diversity of community and a variety of ecological structure in the Chukchi Sea or the Bering Sea, but a higher nutrient and low chlorophyll (HNLC) appeared in the Bering Abyssal Basin and lower levels of primary production and particle organic matters occurred in summer sea ice melting season in the Chukchi Sea. Pb in marine aerosols over the Chukchi Sea showed a high concentration. Ozone concentrations in the surface air or their daily change magnitude decreased with increase of latitude, which could be attributed to impacts from climate system such as from a warm high passed or a change of the tropopause height. Related Articles | Metrics

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A PRIMARY STUDY ON EXTRACELLULAR ENZYME PRODUCTION OF ARCTIC SEA-ICE BACTERIA AND THE EFFECT OF LEADING ENVIRONMENT FACTORS 2003, 15 (4):  303-309.  Abstract ( 1481 )   PDF (116KB) ( 1662 )   Sea ice covering Arctic sea provides a unique habitat with lower temperature and higher salinity, containing a complex microbial community. Numerous sea ice bacteria could produce extracellular enzymes, and the property of enzymes hydrolyzing proteins or lipids was much higher than that hydrolyzing polysaccharids. Temperature and salinity were two leading environment factors directly affecting the survival and activity of sea ice bacteria. This paper showed, with a high growth temperature limit at 35 °C , 76% of sea ice bacteria producing protease was cold adapted. However, 98% of those proteases had an optimum temperature higher than 35°C , and 62% of them even higher than 45 °C . Nearly all sea ice bacteria producing protease were halophilous or salt adapted. Related Articles | Metrics

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SATELLITE REMOTE SENSING VALIDATION EXPERIMENT AT SEA ICE ZONE, EAST ANTARCTICA 2003, 15 (4):  310-317.  Abstract ( 1460 )   PDF (143KB) ( 1867 )   Antarctic sea ice area is one of key regions, which affect the global climate and environment. Satellite remote sensing is a key polar research tool. During Sept.-Oct. 2003, Australian Antarctic Division organized the program "Satellite Remote Sensing Validation Experiment", which involved considerable international collaboration, to conduct a field campaign onboard the Australian icebreaker R/V Aurora Australis in the East Antarctic seasonal sea ice zone to validate routine AMSR E sea ice geophysical features i.e. concentration, snow cover thickness, and sea ice physical temperature, in the late austral winter to early spring period. The field work is introduced in this paper. Related Articles | Metrics