Rock-weathering by lichens in Antarctic: patterns and mechanisms

Saxicolous species of lichens are able to induce and accelerate weathering of their rock substrate, and effects of lichens on substrate can be attributed to both physical and chemical causes. This paper is focused on biotic weathering actions of epilithic and endolithic species on the different rock types (sandstones and volcanogenic rocks) in Antarctica. The patterns, mechanisms, processes and neoformations of rock-weathering resulting from lichen colonization are expounded in detail. Furthermore, it is pointed out that, for a better understanding of the impacts of lichens on environments, the studies on the rate of biotic weathering and the comprehensive involvement of the lichen effects on weathering of natural rocks remain to be carried out in Antarctica.     

南极石生地衣主要生物风化作用研究进展与展望

地衣以物理、化学方式参与矿质基质的风化作用 ,诱导和加速岩石的风化过程。本文对南极地区表生和内生型地衣的生物风化作用进行了综合论述 ,详细阐述了不同地衣种类诱导和参与几种主要岩石类型 (砂岩类和火成岩类 )风化作用的模式、机制、过程以及产物。同时指出 ,地衣等其他生物因素间接参与的风化过程 ,地衣导致的岩石抗风化效应以及生物风化速率等方面的研究工作是目前南极生物风化作用研究方面的新领域。     

韩国南极国家行动:动因、举措及策略

南极地区位于地球的最南端,其独特的地理位置和自然环境一方面推迟了人类对其争夺和改造,另一方面也积累和形成了特殊的资源储量和战略价值。在物质资源日益匮乏的今天,南极作为尚待开发的新边疆,其战略意义日渐突显。韩国在南极有着广泛而特殊的利益,为了实现这些利益,改变后发参与的不利局面,韩国在南极科研、政治、经济等领域采取了诸多积极举措,并且形成了一套灵活务实的策略。随着国内外形势的发展,韩国未来将制定正式的南极政策文件,在原有实践基础上加大参与力度,并充分发挥企业的支援作用,实现国内优势向国家能力的转换,从而更好地推进其南极战略。     

Investigation of Arctic and Antarctic spatial and depth patterns of sea water in CTD profiles using chemometric data analysis

In this paper we examine 2- and 3-way chemometric methods for analysis of Arctic and Antarctic water samples. Standard CTD (conductivity–temperature–depth) sensor devices were used during two oceanographic expeditions (July 2007 in the Arctic; February 2009 in the Antarctic) covering a total of 174 locations. The output from these devices can be arranged in a 3-way data structure (according to sea water depth, measured variables, and geographical location). We used and compared 2- and 3-way statistical tools including PCA, PARAFAC, PLS, and N-PLS for exploratory analysis, spatial patterns discovery and calibration. Particular importance was given to the correlation and possible prediction of fluorescence from other physical variables. MATLAB's mapping toolbox was used for geo-referencing and visualization of the results. We conclude that: 1) PCA and PARAFAC models were able to describe data in a satisfactory way, but PARAFAC results were easier to interpret; 2) applying a 2-way model to 3-way data raises the risk of flattening the covariance structure of the data and losing information; 3) the distinction between Arctic and Antarctic seas was revealed mostly by PC1, relating to the physico-chemical properties of the water samples; and 4) we confirm the ability to predict fluorescence values from physical measurements when the 3-way data structure is used in N-way PLS regression.     

Effects of coal dust on species composition of mosses and lichens in an arid environment

A wind-borne plume of coal dust has been deposited on the soil and vegetation next to a coal storage area at a power generation plant in Oregon (U.S.A.). Correlated with the deposition of coal dust were significantly increased soil temperatures, decreased pH, and increased moisture-holding properties. Some heavy metal concentrations were also higher on the plume. These differences are possibly responsible for the lower frequencies and diversity of lichen species on the plume. Moss diversity, frequency and percent cover are similar on and off the plume with the exception of Ceratodon purpureus. The increased cover of C. purpureus may be attributed to heavy metal tolerance on the plume.     

南极水域一种章鱼的形态特征及分类

本文对我国“雪龙号”船第22次南极考察(2005/2006)时采集的一尾章鱼的形态特征进行描述与鉴定。鉴定认为,系无须亚目、蛸科(章鱼科)、爱尔斗蛸亚科Pareledone属的Parele-done turqueti种。皮肤柔软光滑,无疣突。漏斗器官VV型。中腕型,腕式为Ⅱ=Ⅲ.Ⅰ=Ⅳ。腕吸盘单列,无扩大的吸盘。腕间膜较深,腕间膜式为c=d.e.b.a。雄性右侧第三腕茎化,茎化部分(端器)具独特的舌叶和交接基结构,舌叶勺状,凹槽无横脊,交接基短。具前后唾液腺、嗉囊和墨囊。齿舌发达,由7列异形小齿组成。半鳃内外侧各具鳃小片7个。     

Improved magnetic anomalies of the Antarctic lithosphere from satellite and near-surface data

The Antarctic magnetic anomaly map compiled marine and airborne surveys collected south of 60°S through 1999 and used Magsat data to help fill in the regional gaps between the surveys. Ørsted and CHAMP satellite magnetic observations with greatly improved measurement accuracies and temporal and spatial coverage of the Antarctic, have now supplanted the Magsat data. We combined the new satellite observations with the near-surface survey data for an improved magnetic anomaly map of the Antarctic lithosphere. Specifically, we separated the crustal from the core and external field components in the satellite data using crustal thickness variations estimated from the terrain and the satellite-derived free-air gravity observations. Regional gaps in the near-surface surveys were then filled with predictions from crustal magnetization models that jointly satisfied the near-surface and satellite crustal anomalies. Comparisons in some of the regional gaps that also considered newly acquired aeromagnetic data demonstrated the enhanced anomaly estimation capabilities of the predictions over those from conventional minimum curvature and spherical harmonic geomagnetic field models. We also noted that the growing number of regional and world magnetic survey compilations involve coverage gaps where these procedures can contribute effective near-surface crustal anomaly estimates.     

论南极条约体系的法律实施与执行

以1959年《南极条约》为核心的南极条约体系为缔约国确立了非军事化、南极环境保护、南极海洋生物资源养护等宽泛的国际法义务。随着南极条约体系的不断发展,南极人类活动的形式也从早期单一的政府组织的科学考察活动,朝着南极旅游、南极渔业以及南极生物资源勘探等多元化的商业活动方向发展。南极条约体系主要通过国际法层面的视察机制,以及敦促缔约国采取必要的国内立法或其他适当措施的形式具体实施和执行其所确立的原则与规则。不过因视察机制缺乏必要的救济措施、属人管辖限制而造成的对非缔约国执法真空,以及因地理位置遥远、气候环境严酷而导致的法律执行不能等问题依然困扰整个南极机制。面对挑战,南极条约体系应通过强化国际执法合作、完善南极视察机制以及加强公民极地教育等综合执法手段加以积极应对。     

南极欺骗岛土壤细菌群落结构和多样性分析

采用基于16S r DNA克隆文库的非培养方法和传统培养方法相结合的手段,对南极欺骗岛土壤细菌群落结构及多样性进行了初步分析。对来自16S r DNA克隆文库的118个阳性克隆进行测序和序列比对,结果显示细菌来自放线菌门(Actinobacteria)、变形杆菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)3大门的39个操作分离单元(OTU),其中优势菌群为放线菌门和变形杆菌门,分别占65.25%和28.81%。放线菌门的主要优势属为鱼孢菌属(Sporichthya)、类诺卡式氏菌属(Nocardioides)、束缚菌属(Conexibacter)、Gaiella和节杆菌属(Arthrobacter)。变形杆菌门的主要优势属为鞘氨醇单胞菌属(Sphingomonas)、硫杆菌属(Thiobacillus)、寡养单胞菌属(Stenotrophomonas)和热单胞菌属(Thermomonas)。采用6种培养基对细菌进行培养和分离,共得到57株菌,来自放线菌门、变形杆菌门、拟杆菌门和厚壁菌门4大门的13个OTU,其中优势菌群为放线菌门和变形杆菌门,分别占57.89%和31.58%。优势属是放线菌门的节杆菌属(Arthrobacter)、雷夫松氏菌属(Leifsonia)和变形杆菌门的假单胞菌属(Pseudomonas)。本论文为研究欺骗岛土壤细菌多样性以及有益菌种资源的开发和利用奠定了基础。     

Mawson and Mirnyy Stations: the spatiality of the Australian Antarctic Territory, 1954–61

This article focuses on the spatiality of the Australian Antarctic Territory in the important 1954–61 period. Attending particularly to three key components of polar spatiality—geopolitics, international territorial law, and the built environment—the article analyses the development of the Territory as a unique Australian space. The 1954–61 period is particularly significant: during this period, the International Geophysical Year brought an unprecedented number of people to Antarctica; the continent's first permanent colonies were constructed; and, despite Cold War tensions, the 1961 Antarctic Treaty established the spatial configurations and rules which continue to govern the continent today. The article focuses particularly on two key stations in the Territory constructed during this period: Australia's Mawson Station and the Soviet Mirnyy Station. Mawson is a legal colony, designed to cement Australia's claim to 42 per cent of the Antarctic continent; Mirnyy, in contrast, is an anti-colony, designed to reject Australia's claim. How the individual spatialities of these two stations articulate to the broader politics of Antarctic territoriality—and particularly Australia's claim to the Australian Antarctic Territory—is the focus of this article.     

Role of Antarctic ice mass balance in present-day sea-level change

The Antarctic ice sheet is arguably the most critical in terms of future sea-level rise, primarily because it contains 70% of the world's fresh water. While there exists evidence of accelerated ice-sheet ablation during the past decade, the possibility that the ice sheets contributed little to 20th century sea-level rise could result in Antarctica becoming the largest contributor to sea-level rise during the 21st century. Here we review the findings of studies published following the 2007 Intergovernmental Panel for Climate Change (IPCC) study, focusing on the role of Antarctica in present-day (1992–2006) sea-level rise. We show that the choice of glacial isostatic adjustment (GIA) model significantly affects GRACE-estimated Antarctic mass loss, adding 0.25–0.45 mm/yr to the estimate of sea-level rise. The current estimate of Antarctica's contribution to sea-level rise has a wide range: from −0.12 to +0.52 mm/yr. The discrepancy between observed sea-level trend of 1.8 mm/yr and those estimated from various geophysical sources (2.10 ± 0.99 mm/yr) is 0.30 mm/yr. The role of Antarctica in sea-level rise might be better constrained by lengthening satellite observations, using long-term GPS data to discriminate subglacial vertical motion from ice mass balance, and detecting the sea-level signal due to elastic loading from the melting ice-sheets.     

两株南极枝孢霉属真菌Cladosporium sp.NJF4和NJF6的次级代谢产物研究

南极因其独特的自然环境成为潜在、重要的微生物资源库,是产生新型生物活性物质和先导化合物菌株的潜在种源地,南极微生物正在成为创新药物研究新的重要资源。虽然近年来对南极微生物次级代谢产物的研究逐渐增加,但与温带和热带微生物研究相比仍处于初级阶段。对从南极普里兹湾海洋沉积物中获得的两株枝孢霉属真菌Cladosporium sp. NJF4和NJF6进行次级代谢产物分离及结构鉴定,获得20个化合物。化合物结构类型包括甾醇(1)、倍半萜类(7—8)、生物碱类(9—14)、二酮哌嗪(2—5、15—17)、芳香酸(6、18—19)等,其中倍半萜类(7—8)为首次从枝孢霉属真菌中分离得到,以上研究将为丰富南极微生物次级代谢产物库奠定一定的研究基础。     

The spatial and seasonal distributions of air-transport origins to the Antarctic based on 5-day backward trajectory analysis

Transport of moisture-bearing air to the Antarctic is one of the important factors that control the mass balance of the ice sheet. Here, we investigate the distribution of air-parcel transport using a backward trajectory analysis over the entire Antarctic ice sheet, based on whether the air parcel was located inside or outside of Antarctica at 5 days before arrival. At this time, we considered the air from outside Antarctica to be moisture rich. Oceanic air was found to dominate in West Antarctica throughout the year, whereas air from inland was more prominently distributed around East Antarctica, especially in summer. In East Antarctica, there was a significant seasonal variation: air from inland dominated in summer, while air of oceanic origin dominated in winter. The distribution of air parcels that came from oceanic/inland sources was similar to the accumulation map (based on satellite data), which indicates that oceanic air parcels could be a substitute for moisture transport to the Antarctic. To determine the future impacts of climate change (e.g., sea level rise), more precise predictions of the variations in the surface mass balance will be required. Our results contribute towards the improved understanding of the spatial distributions of accumulation and aerosols found in Antarctic snow and ice cores.     

夏季南极固定冰单轴压缩强度及试样破碎规律研究

2012年11月—2013年4月中国第29次南极科学考察期间,针对南极夏季固定冰单轴压缩性质开展了研究。使用冰芯钻直接在平整冰层钻取力学试样,取样冰厚为149 cm,其中颗粒冰、柱状冰和片状冰分别占采样冰芯总长度的15.4%、72.5%和12.1%;单轴压缩试样只采用柱状冰部分,加工好的力学冰样尺寸为直径9 cm,长度为18 cm;共设置5个试验温度(-2、-4、-6、-8和-10℃),加载应变速率在10-6—10-2s-1。利用统计方法分析试验结果,建立了南极夏季海冰单轴压缩强度与孔隙率和应变速率的关系式,以及综合考虑应变速率和温度影响下的单轴压缩强度定量表达式;同时,基于分形理论对单轴压缩试样破碎块分布规律进行了分析,结果显示碎块长度分形维数随着温度和应变速率的降低有增大趋势。在特别低应变速率下海冰试样整体发生蠕变时,无法采用分形方法讨论海冰内部破碎程度。     

Temperature variation and its driving forces over the Antarctic coastal regions in the past 250 years

By comparing the oxygen isotopic temperatures recorded by many shallow ice cores from the coastal regions of Antarctica, this paper presents the special characteristics of the temperature variations over the Antarctic coastal regions in the past 50 years, 150 years and 250 years. In the past 50 years, the isotopic temperatures recorded in the ice cores over different sites on the Antarctic coastal regions differ greatly. For instance, although increasing isotopic temperatures have been reported for many sites studied, many sites show decreasing trends, the regional regularity in temperature variations is still insignificant. In the past 150 years, the isotopic temperature trends in the coastal regions of Antarctica show an alternate-distributing pattern. In the past 250 years, all the ice cores from the coastal regions of Antarctica have recorded the so-called Little Ice Age (LIA). The above-mentioned spatial characteristics of the temperature variations over the Antarctic coastal regions are likely to reflect the impacts of the unique Southern Hemisphere atmospheric circulation, the Antarctic Circumpolar Wave (ACW) and the special terrain (such as the large drainage basins) on the coastal regions of Antarctica. Furthermore, the impacting intensity of the unique Southern Hemisphere atmospheric circulation, the Antarctic Circumpolar Wave and the special terrain differs in terms of the temporal scale of the temperature change.     

Temperature variation and its driving forces over the Antarctic coastal regions in the past 250 years

By comparing the oxygen isotopic temperatures recorded by many shallow ice cores from the coastal regions of Antarctica, this paper presents the special characteristics of the temperature variations over the Antarctic coastal regions in the past 50 years, 150 years and 250 years. In the past 50 years, the isotopic temperatures recorded in the ice cores over different sites on the Antarctic coastal regions differ greatly. For instance, although increasing isotopic temperatures have been reported for many sites studied, many sites show decreasing trends, the regional regularity in temperature variations is still insignificant. In the past 150 years, the isotopic temperature trends in the coastal regions of Antarctica show an alternate-distributing pattern. In the past 250 years, all the ice cores from the coastal regions of Antarctica have recorded the so-called Little Ice Age (LIA). The above-mentioned spatial characteristics of the temperature variations over the Antarctic coastal regions are likely to reflect the impacts of the unique Southern Hemisphere atmospheric circulation, the Antarctic Circumpolar Wave (ACW) and the special terrain (such as the large drainage basins) on the coastal regions of Antarctica. Furthermore, the impacting intensity of the unique Southern Hemisphere atmospheric circulation, the Antarctic Circumpolar Wave and the special terrain differs in terms of the temporal scale of the temperature change.