Archive

30 September 2016, Volume 28 Issue 3 Previous Issue    Next Issue

---

For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Select

Effects of Antarctic Dome A Hypoxia and an Extreme Cold Environment on Catecholamines and Myocardial Enzymes of Chinese Expeditioners 2016, 28 (3):  311-316.  DOI: 10.13679/j.jdyj.2016.3.31 Abstract ( 815 )   PDF (2101KB) ( 891 )   Antarctic Dome A is characterized by a multitude of environmental stressors. The effects of the extreme cold and hypoxic environment of Dome A on the catecholamines and myocardial enzyme of expeditioners were investigated. Blood samples from 25 male members of the 29th Chinese Antarctic inland expedition were collected upon departure from Shanghai, during an 18-day stay at Dome A, and upon return to Shanghai. Plasma levels of norepinephrine, epinephrine, dopamine, and high-sensitivity C-responsive protein (hsCRP), as well as serum levels of creatine kinase MB (CK-MB) and cardiac troponin I (cTnI), were measured. Compared with departure, epinephrine and CK-MB levels displayed an increasing trend at Dome A, but did not differ significantly, while dopamine levels increased significantly (P＜0.05). Epinephrine levels decreased significantly (P＜0.01), while dopamine levels increased significantly (P＜0.05), upon return to Shanghai. Compared with the departure (P＜0.01) and Dome A levels (P＜0.01), CK-MB levels decreased significantly upon return to Shanghai. cTnI, hsCRP, and norepinephrine levels did not change significantly at different time points. Pearson’s correlation analysis showed that the CK-MB and epinephrine levels were significantly positively correlated (r=0.285*, P<0.05). These data suggest that there might be adaptive compensatory changes in the myocardium of Chinese Antarctic inland expeditioners, although no pathological injury was found upon their return to Shanghai. Serum levels of myocardial enzymes were closely related to the neuroendocrine regulation of catecholamines. Studies of future expeditions are needed to explore the underlying mechanism. Related Articles | Metrics

Select

Rapid Analysis on Contents of Chemical Elements in Pond Sediments from East Antarctica Using Near-infrared Spectroscopy 2016, 28 (3):  317-323.  DOI: 10.13679/j.jdyj.2016.3.317 Abstract ( 869 )   PDF (3445KB) ( 1099 )   Spectra of three pond sediment profiles collected from Ross Island in East Antarctica were measured by an ultraviolet–visible–near-infrared reflectance spectrophotometer. Specific peaks and troughs were observed in the spectra, and their distribution patterns correlated well with lithology. All sediment subsamples were separated into a modeling set and a test set to establish the relationship between the spectra and the element contents using a partial least squares method. The difference between the predicted and test values showed that the contents of all 20 measured elements strongly correlated with the spectral data. Among them, the N, C, H, Mn, Ba, P, Al, Fe, K, Se, As, and Hg contents were predicted accurately (the correlation coefficients between the predicted and tested values (r2) were >0. 90). Thus, we conclude that the element contents in sediments from East Antarctic can be determined rapidly using near-infrared reflectance spectroscopy. Related Articles | Metrics

Select

Upstream Velocity of the Amery Ice Shelf Derived from Satellite Radar Feature Tracking 2016, 28 (3):  324-330.  DOI: 10.13679/j.jdyj.2016.3.324 Abstract ( 719 )   PDF (2132KB) ( 924 )   The flow rates of glaciers hold special significance in the analysis of the mass balance of the Antarctic ice sheet and its effect on sea-level rise and global climate change. In this study, ALOS/PALSAR imagery was combined with a digital elevation model, and the synthetic aperture radar intensity feature tracking method was used to obtain the upstream glacier velocity of the Amery Ice Shelf. The results showed that the flow rate of the main streamline ranged from 540 to 720 m·a-1 in the upstream region of the Amery Ice Shelf, and gradually decreased with decreasing elevation. Under the influence of bedrock and highlands on the two sides of the shelf, the flow rate of the main streamline was negatively correlated to the distance from the surrounding highlands. This result is in accord with the flow rate that was measured by NASA in 2000 using the radar repeat track interferometry method. Our analysis using bare rocks as reference points indicates that the associated error is relatively small and the ice flow rate obtained by this approach is reliable. Related Articles | Metrics

Select

Antimycin A and Vulgamycin Derivatives from the Arctic Marine Actinomycete Streptomyces sp. 604F 2016, 28 (3):  331-335.  DOI: 10.13679/j.jdyj.2016.3.33 Abstract ( 762 )   PDF (978KB) ( 937 )   Various types of constituents, including aromatic nitro compounds, peptides, and terpenoids, have been reported from different polar microorganisms. In our investigation of secondary metabolites of Arctic actinomycete with new structures or potent bioactivity, five antimycin A derivatives, Antimycin A1b (1), Antimycin A4a (2), Antimycin A2a (3), Antimycin A3a (4), Antimycin A1a (5), together with Vulgamycin (6) and its derivative 8-deoxyenterocin (7), were obtained from Streptomyces sp. 604F. The compounds were purified by Sephadex LH-20 column chromatography and semi-preparative high-performance liquid chromatography, and their structures were determined by comparing their liquid chromatograph-mass spectrometry and 1H- and 13C-NMR data with those of previously reported compounds. This is the first report of compounds 1—7 from microbes derived from Arctic sediment, and it is the first time that antimycin and vulgamycin compounds were identified as metabolites from the same source. Related Articles | Metrics

Select

A Mooring System Based Study on the Multi-Year Variations of Intermediate Atlantic Water in the Canada Basin of the Arctic Ocean 2016, 28 (3):  336-345.  DOI: 10.13679/j.jdyj.2016.3.336 Abstract ( 874 )   PDF (5175KB) ( 940 )   Since the 1990s, the Arctic marine environment has entered a period of rapid change characterized by a significant reduction of sea ice. Here, we examined changes in the upper ocean of the Canada Basin during this period. Temperature and salinity profile data were obtained from four mooring systems of the Beaufort Gyre Exploration Project, which were deployed in the Canada Basin from 2003 to 2011. These data were used to analyze the characteristics of intermediate Atlantic Water in the Canada Basin. During the period of observation, the Atlantic Water core temperature remained steady in the central Canada Basin, decreased significantly on the Chukchi Plateau, and increased continuously to the north of the central basin region and the Canadian Archipelago slope break. The corresponding Atlantic Water core depths increased to different extents, and was primarily influenced by different surface fresh water contents and changes of wind stress due to melting sea ice. The surface heat content (75—200 m depth) of the four stations increased significantly in ice-free areas, while remaining stable in sea ice areas. Heat content changes at 200—400 m and 400—800 m depths are consistent with the changes of the Atlantic water core depth. When the Atlantic water core depth reached 400 m or greater, the heat content decreased between 200—400 m and increased between 400—800 m. Although the four stations are all located in the Canada Basin, the mechanisms responsible for the changes of the intermediate Atlantic Water differ to each other. Related Articles | Metrics

Select

Potential Ecological Risk Assessment of Heavy Metals in Bering Sea, the Chukchi Sea, and the Canada Basin 2016, 28 (3):  346-352.  DOI: 10.13679/j.jdyj.2016.3.34 Abstract ( 881 )   PDF (2963KB) ( 1079 )   The concentrations of eight heavy metals in sediment in Arctic and subarctic areas of the Bering Sea, the Chukchi Sea, and the Canada Basin were determined using an inductively coupled plasma mass spectrometer. Then, the geochemical and spatial distributions, as well as the correlations, of the eight elements were studied. The results showed that the Zn, Bi, Pb, Cu, Ni, Co, and Cr concentrations were strongly correlated, which indicated they had similar sources and spatial distribution characteristics. The concentrations of the above seven elements in sediments in the Bering Sea and the Chukchi Sea were lower than those in the Canada Basin. However, the spatial distribution of Cd obviously differed from that of the other seven elements. Finally, the Hakanson Potential Ecological Risk Index and the Nemerow Comprehensive Pollution Index were used to evaluate the potential ecological risk of the eight metals. The results showed that the Hakanson Index of the Arctic area reached 43.1, which indicated that this area has a slight risk of ecological damage. Co posed the greatest ecological risk. The results of both methods showed the same distribution trend of the ecological risk of the heavy metals. The Bering Sea had the lowest ecological risk, while most of the Chukchi Sea was relatively risk-free and the Canada Basin had the highest ecological risk. The degree of heavy metal pollution showed a gradually decreasing trend from high to low latitudes, and the degree of pollution of the Western Hemisphere was greater than that of the Eastern Hemisphere. Related Articles | Metrics

Select

A Study of Clustering All-sky Images Based on Auroral Appearance 2016, 28 (3):  353-360.  DOI: 10.13679/j.jdyj.2016.3.353 Abstract ( 783 )   PDF (4495KB) ( 818 )   Auroral appearance forms provide remarkable visual and distinguishable features for the study of solar-terrestrial physics. Proper classification is meaningful for studying the relationship between various types of auroral phenomena and the dynamics of the magnetosphere. The selection of auroral classification schemes has been criticized in supervised classification experiments, which require large amounts of labor. Additionally, the accuracy of manual labeling has been questioned. More importantly, the results of supervised classifications cannot be used to verify the correctness of classification schemes. Thus, we should investigate whether existing classification schemes are accurate, as well as identify better classification schemes. To address these issues, a clustering method was used to explore the feature space of aurora data based on an available auroral image characterization method. Nine cluster validation indices were used to select the optimal number of clusters. Six thousand all-sky images, which were randomly selected from observations acquired in the Arctic Yellow River Station in 2003—2004, were clustered using the Ncut algorithm. The results showed that schemes consisting of two and four classes were the most accurate. The two-class schemes had well-separated auroral types, and the distribution of pre-noon and post-noon occurrence peaks can be used to determine whether an aurora may be an arc. In the four-class schemes, although the naked eye failed to find a typical image that can represent all images in this class, the temporal distribution characteristics of these classes were very distinct, which proves that the auroral appearance is identifiable using an unsupervised method. Related Articles | Metrics

Select

A Polar Science Linked Data Method and Its Research Application 2016, 28 (3):  361-369.  DOI: 10.13679/j.jdyj.2016.3.361 Abstract ( 788 )   PDF (3716KB) ( 1047 )   To accurately and intelligently find data and information among massive polar science datasets, this paper proposes a linked data method for polar science data searching. Firstly, a systematic study of the characteristics of polar science data was conducted to discover the implied semantic information of these datasets. Secondly, a polar science linked data index system containing three aspects and four-level indices was built. Thirdly, a linked calculation method of the essential characteristics of polar science data was discussed in detail. In general, essential data characteristics include temporal, spatial and content elements. Finally, we designed and implemented a prototype system for polar science linked data discovery based on the Polar Science Data Center of the National Earth System Science Data Sharing Platform, which is one of the 23 platforms of the National Science and Technology Infrastructure. In an experimental environment, it uses the metadata of polar science datasets to abstract the corresponding index value, and then it calculates the degree of correlation among different datasets. Thus, a polar science linked data network can be built automatically. The results showed that by using the polar science linked data method, the prototype system can retrieve not only needed data, but also potential linked data. Such linked data method research can be further used to integrate, fuse, and share polar science data. Related Articles | Metrics

Select

The Practice of Establishing Marine Protected Areas in the Southern Ocean and Related Legal and Political Debates 2016, 28 (3):  370-380.  DOI: 10.13679/j.jdyj.2016.3.370 Abstract ( 879 )   PDF (692KB) ( 1144 )   The practice of establishing marine protected areas (MPAs) within the Convention on the Conservation of Antarctic Marine Living Resources has attracted the attention of the international community. In 2009, the Commission for the Conservation of Antarctic Marine Living Resources established its first MPA, the South Orkney Islands southern shelf MPA. However, since 2012, no progress has been made on the Ross Sea MPA proposal and the Eastern Antarctic MPA representative system proposal. Among others, legal concerns such as the interpretation of the Antarctic Treaty System in relation to MPAs and the definition of an MPA, as well as political concerns such as the potential consideration of geopolitics and the exclusion of fishing activities, are sensitive points of debate. Here, a careful study of these legal and political concerns has been conducted. The findings are as follows. The Commission is mandated to establish an MPA to achieve the objective of conserving Antarctic marine living resources. However, the objectives of both proposals are, to some extent, beyond that competency. Both proposals are related to claimed Antarctic territories and fishing activities of proponents; thus, the political concerns were unresolvable. It is suggested that to achieve the objective of the Convention, the conservation of Antarctic marine living resources, measures must be taken to resolve the associated legal and political concerns, increase the transparency of the procedures, expand engagement, and fully implement the research and monitoring plans of established MPAs. Related Articles | Metrics

Select

South Korean National Antarctic Action: Causes, Measures and Tactics 2016, 28 (3):  381-389.  DOI: 10.13679/j.jdyj.2016.3.381 Abstract ( 781 )   PDF (743KB) ( 1096 )   The South Pole is located at the southernmost tip of the Earth, and its unique geographical location, resources, and natural environment have strategic value. Material resources are becoming increasingly scarce, and as a new frontier to be developed, the strategic significance of the South Pole is increasing. South Korea has extensive and special interest in the Antarctic. In order to realize these benefits and change the adverse situation of backwardness, it has taken many active measures in the Antarctic scientific research, politics, economy and other fields, and formed a set of flexible and practical tactics. As its international and domestic situations change in the future, South Korea will issue a formal Antarctic policy document and intensify the participation on the basis of the original practice. To better promote its Antarctic strategy, South Korea will obtain full support from the business community and society, which will enable its transformation from a developing industrialized nation to a world power. Related Articles | Metrics

Select

Increased Acidification of the Southern Ocean Surface Waters 2016, 28 (3):  390-399.  DOI: 10.13679/j.jdyj.2016.3.390 Abstract ( 1114 )   PDF (1065KB) ( 1322 )   Ocean acidification (OA) has been an important research topic for a decade. Given that 30%—40% of ocean uptake of anthropogenic CO2 occurs in the Southern Ocean (SO), and that the SO consists of high-latitude waters with low buffering capacity, a greater understanding of OA and the factors that affect it is particularly necessary. The OA-mediated decline in the seawater carbonate ion concentration and the carbonate saturation state, which dramatically impairs the ability of calcifying organisms to form calcium carbonate (including aragonite and calcite), will eventually have an adverse impact on the marine ecosystem. It is critical to understand the OA responses and predict their resulting impact on the carbonate system and ecosystem of the SO. In this article, we review studies of the acidification of SO surface waters and provide an overview of the acidification of the open ocean and representative marginal seas and bays of the SO. Additionally, we identify future trends in OA research, as well as some urgent problems. Related Articles | Metrics

Select

A Review of Operational Weather Services for Fixed-wing Aircrafts in Antarctica 2016, 28 (3):  400-412.  DOI: 10.13679/j.jdyj.2016.3.400 Abstract ( 780 )   PDF (9805KB) ( 841 )   China has already started operating fixed-wing aircraft in Antarctica; thus, the establishment of a more comprehensive on-site meteorological observation system for Antarctic airport and aviation weather forecasting technology seems imminent. This study reviewed the status of operational fixed-wing aircraft in the Antarctic and the associated meteorological services that have been undertaken by the international community. The results showed that a number of severe weather phenomena, such as low clouds, low visibility, icing, and low-level wind shear, threaten Antarctic aviation. Based on the current weather forecasting services for China's domestic civil aviation and air force aviation, we discussed important issues regarding on-site meteorological observation equipment, numerical weather forecasting data, and aeronautical meteorological forecasting content for Antarctica fixed-wing aviation meteorological support. We believe that meteorological support for China's Antarctic fixed-wing aircraft should include: assessing the historical weather conditions at the airport location and the surrounding areas; establishing a more comprehensive meteorological observation system; focusing on the Terminal Aerodrome Forecast, as well as landing and takeoff forecasts at ZhongShan Station, by referring to the weather forecasting content for civil aviation; and paying great attention to katabatic wind, blowing snow, snow storms, low-level wind shear, and other severe weather phenomena that pose a threat to aviation. Related Articles | Metrics

Select

Comparisons on Arctic Sea Ice Concentrations Obtained by Classification of Radarsat-2 Synthetic Aperture Radar Imagery and Retrievals from Hy-2 Scanning Microwave Radiometer 2016, 28 (3):  413-423.  DOI: 10.13679/j.jdyj.2016.3.413 Abstract ( 755 )   PDF (7799KB) ( 582 )   In the region where the East Siberia Sea and the Chukchi Sea join at the Arctic Northeast Passage, four Radarsat-2 synthetic aperture radar (SAR) images were used to obtain the sea ice concentration (SIC) through image classification. The NASA TEAM algorithm was employed to retrieve the SIC in the corresponding area based on the brightness temperature data of the scanning microwave radiometer onboard the satellite HY-2. The SIC product of the Special Sensor Microwave Imager/Sounder (SSMIS) released by the Nation Snow and Ice Data Center was used for comparison. An analysis of the SIC revealed that the SIC distribution trends obtained by the SAR images and the SSMIS were in agreement. In the marginal ice zone (MIZ), the SIC derived from the SAR imagery was higher than that retrieved from HY-2 and the SSMIS, implying that SAR imagery is advantageous when observing small ice floes in the MIZ. Of the three data sources, the SIC retrievals of HY-2 were closest to the SSMIS because they had the same initial spatial resolution (25 km), and the correlation between the HY-2 and SAR results was similar to that between the SSMIS and SAR results. However, in the ice edge, the retrievals of HY-2 were lower than the SAR and SSMIS results. This was caused by the high water vapor concentration in the air at the ice edge; this issue should be addressed when improving the retrieval algorithm of the HY-2 microwave radiometer in the future. Related Articles | Metrics

Select

Pre-optimization of Fermentation Conditions for the Antarctica Fungus Penicillium sp. S-1-16 2016, 28 (3):  424-429.  DOI: 10.13679/j.jdyj.2016.3.424 Abstract ( 799 )   PDF (1290KB) ( 862 )   Culture media and fermentation conditions for cultivation of Penicillium sp. S-1-16 isolated from an Antarctic sea cucumber sample were investigated to improve the yield of secondary metabolites with modest cytotoxic activity against three cancer cell lines. The optimum fermentation conditions, including medium, temperature, and type of water, were identified based on fungal biomass, secondary metabolite production, and antitumor activity. The initial fermentation conditions were as follows: 0.3% yeast powder, 0.5% peptone, 0.3% maltose, 1% glucose, 5% sucrose, tap water, a 15% inoculum size, an initial pH of 7.0, and incubation at 18°C, with shaking at 180 r·m-1, for 15 d. Under the optimized fermentation conditions , the amount of secondary metabolites and their cytotoxic activity increased by 568.75% and 265%, respectively, compared with the initial conditions. Additionally, the secondary metabolites’ inhibition of the growth of HeLa and SGC-7901 cells increased from 0 to 48.19% and 69.18%, respectively, after the optimization. These results provide clues for subsequent separation and purification of secondary metabolites derived from the Penicillium sp. S-1-16 strain. Related Articles | Metrics