1928 research outputs found
Sort by
Complete genome analysis of bacteriochlorophyll acontaining Roseicitreum antarcticum ZS2-28T reveals its adaptation to Antarctic intertidal environment
Full text linkAerobic anoxygenic phototrophic bacteria (AAPB) are photoheterotrophic prokaryotes able to use both light and dissolved organic matter as energy sources. Roseicitreum antarcticum ZS2-28T was isolated from intertidal sediment in the Larsemann Hills, Princess Elizabeth Land, Antarctica, and was able to produce bacteriochlorophyll a. It is the type strain of the sole species within the genus Roseicitreum. The complete genome sequence of the bacterium was determined using Illumina HiSeq X and PacBio RSII systems. The genome of R. antarcticum ZS2-28T was 4253095 bp and consisted of one chromosome and four plasmids. A number of genes related to the bacteriochlorophyll a production, photosynthetic reaction, cold adaptation, salt adaptation, ultra-violet resistance and DNA damage repairing were found in the genome. In addition to genomic islands and type IV secretion systems, genes related to gene transfer agents were detected in the genome of R. antarcticum ZS2-28T, suggesting that this bacterium can adapt to its environment by acquiring exogenous nucleic acids. The annotated complete genome sequence provides genetic insights into the environmental adaptation and ecological function of R. antarcticum ZS2-28T in Antarctic coastal area
Assessment on India’s involvement and capacity-building in Arctic Science
Full text linkIndia became an observer in Arctic Council in 2013 and has three research stations operational in the poles, including “Maitri” commissioned in 1989 and “Bharati” commissioned in 2012 at Antarctic and “Himadri” at Arctic. Though the Government of India has consistently been extending full support to the research endeavours yet the same is bogged by inadequate research output, lack of dedicated polar research vessel and other bureaucratic bottlenecks. A massive void in the Indian scientific pursuits is that India does not possess a polar research vessel or an icebreaker and has to rely on chartered vessels, seriously limiting its research timeframe as well as huge economic drain and thus compromising the scientific research. This cleft in the professed research narrative despite having a physical presence for over 3 decades in the polar regions and the proposal for acquisition of a polar research vessel having been approved in June 2010 yet the same is yet to be operationalised which is seriously impinging the scientific research as well as the professed commitment to Arctic research. Recently, India has released its draft Arctic Policy and had sought public comments thereon till 26 January 21 before its finalisation. India’s draft policy reiterates the oft stated goals of scientific research, connectivity, global governance and international cooperation, and human development with emphasis on Indian human resource pool. The inspiration of a delayed Indian policy on the High North appears to be the Chinese white paper of 2018. The scientific pursuits can propel the strategic engagement in the region to greater levels by extensive collaboration and cooperation with several other nations present there. Indian attempts so far have remained acutely short of the promise and India should build on its strengths for obtaining a leadership position in this strategically vital and economically lucrative region
The marine environmental evolution in the northern Norwegian Sea revealed by foraminifera during the last 60 ka
Full text linkBoth planktonic and benthic foraminifera were identified in a sediment core collected from the northern Norwegian Sea to reconstruct the paleoceanographic evolution since the last glaciation. The assemblages and distribution patterns of dominant foraminiferal species with special habitat preferences indicated that three marine environments occurred in the northern Norwegian Sea since 62 ka BP: (1) an environment controlled by the circulation of the North Atlantic Current (NAC); (2) by polynya-related sinking of brines and upwelling of intermediate water surrounding the polynya; (3) by melt-water from Barents Sea Ice Sheet (BSIS). At 62–52.5 ka BP, a period with the highest summer insolation during the last glaciatial period, intensification of the NAC led to higher absolute abundances and higher diversity of foraminiferal faunas. The higher abundance of benthic species Cibicidoides wuellerstorfi indicates bottom water conditions that were well-ventilated with an adequate food supply; however, higher abundances of polar planktonic foraminiferal species Neogloboquadrina pachyderma (sin.) indicate that the near-surface temperatures were still low. During mid-late Marine Isotope Stage (MIS) 3 (52.5–29 ka BP), the marine environment of the northern Norwegian Sea alternately changed among the above mentioned three environments. At 29–17 ka BP during the last glacial maximum, the dominant benthic species Bolivina arctica from the Arctic Ocean indicates an extreme cold bottom environment. The BSIS expanded to its maximum extent during this period, and vast polynya formed at the edge of the ice sheet. The sinking of brines from the formation of sea ice in the polynyas caused upwelling, indicated by the upwelling adapted planktonic species Globigerinita glutinata. At 17–10 ka BP, the northern Norwegian Sea was controlled by melt-water. With the ablation of BSIS, massive amounts of melt water discharged into the Norwegian Sea, resulting in strong water column stratification, poor ventilation, and an oligotrophic bottom condition, which led to a drastic decline in the abundance and diversity of foraminifera. At 10–0 ka BP, the marine environment was transformed again by the control of the NAC, which continues to modern day. The abrupt decrease in relative abundance of Neogloboquadrina pachyderma (sin.) indicates a rise in near-surface temperature with the strengthening of the NAC and without the influence of the BSIS
Variation of Antarctic marginal ice zone extent (1989–2019)
Full text linkThe Antarctic marginal ice zone (MIZ) is the transition region between open water and consolidated pack ice, which is defined as an area with 15%–80% sea ice concentration. The MIZ represents the outer circle of Antarctic sea ice and the biological activity circle of Antarctic organisms, which provides a direct indication of the extent of Antarctic sea ice. In this study, the joint total variation and nonnegative constrained least square algorithm are applied to retrieve the Antarctic MIZ extent based on passive microwave data sets from 1989 to 2019. The spatial and temporal variations of the Antarctic MIZ extent and five regions are analyzed. The results show that the Antarctic MIZ extent follows a strong monthly variation pattern, decreasing from November to February and increasing from March to October. The annual MIZ extent is largest in the Weddell Sea and smallest in the Western Pacific Ocean. The edge of the sea ice begins to form a closed ring in May, which eventually closes near the Antarctic Peninsula. The ring width variation is large in summer, but generally stabilizes between 350 and 370 km in winter. The average latitude of the Antarctic MIZ is relatively stable in summer, but changes substantially in winter with a difference of approximately 3°. In October, the lowest mean latitude of the MIZ can reach 64.35°S. The sea surface pressure, 2-m temperature, and 10-m wind speed are negatively correlated with the MIZ extent variation, among which the second-order partial correlation coefficient of the sea surface pressure and MIZ extent is −0.8773 in the Western Pacific Ocean
Russia’s Chairmanship Programme for the Arctic Council 2021-2023
Full text linkRussia builds its chairmanship of the Arctic Council on the principle of responsible governance for the sustainable development of the polar region. As a country that accounts for almost a third of the Arctic with a population of over 2.5 million people, Russia implements an integrated comprehensive development programme in the high latitudes and therefore prioritizes the balanced promotion of the region’s sustainable development in the social, economic and environmental dimensions during its 2021-2023 Arctic Council Chairmanship
Pan-Arctic Report, Gender Equality in the Arctic, Phase 3
Full text linkGender equality in the Arctic is highly relevant to the agenda and role of the Arctic Council (the Council) and its Sustainable Development Working Group (SDWG), which have emphasised gender equality in previous projects and initiatives.
The importance of issues of gender and diversity has become increasingly evident, the latest example being Iceland’s emphasis on gender issues during its Arctic Council Chairmanship. Examples of previous work and valuable input in this field under the Council’s auspices include: the 2002 Taking Wing Conference in Inari that focused on the themes of women and work, gender and self-determination among Indigenous Peoples, and violence against women; the first edition of the Arctic Human Development Report (AHDR) in 2004, which included a chapter on gender; and the second edition of the AHDR, published in 2014, in which gender issues were mainstreamed into all chapters as appropriate
Ocean stratification and sea-ice cover in Barents and Kara seas modulate sea-air methane flux: satellite data
Full text linkThe diverse range of mechanisms driving the Arctic amplification and global climate are not completely understood and, in particular, the role of the greenhouse gas methane (CH4) in the Arctic warming remains unclear. Strong sources of methane at the ocean seabed in the Barents Sea and other polar regions are well documented. Nevertheless, some of those publications suggest that negligible amounts of methane fluxed from the seabed enter the atmosphere, with roughly 90% of the methane consumed by bacteria. Most in situ observations are taken during summer, which is favorable for collecting data but
also characterized by a stratified water column. We present perennial observations of three Thermal IR space-borne spectrometers in the Arctic between 2002 and 2020. According to estimates derived from the data synthesis ECCO (Estimating the Circulation and Climate of the Ocean), in the ice-free Barents Sea the stratification in winter weakens after the summer strong stability. The convection, storms, and turbulent diffusion mix the full-depth water column. CH4 excess over a control area in North Atlantic, measured by three sounders, and the oceanic Mixed Layer Depth (MLD) both maximize in winter. A significant seasonal increase of sea-air exchange in ice-free seas is assumed. The amplitude of the seasonal methane cycle for the Kara Sea significantly increased since the beginning of the century. This may be explained by a decline of ice concentration there. The annual CH4 emission from the Arctic seas is estimated as 2/3 of land emission. The Barents/Kara seas contribute between 1/3 and 1/2 into the Arctic seas annual emission
A case study based on ground observations of the conjugate ionospheric response to interplanetary shock in polar regions
Full text linkData acquired by imaging relative ionospheric opacity meters (riometers), ionospheric total electron content (TEC) monitors, and three-wavelength auroral imagers at the conjugate Zhongshan station (ZHS) in Antarctica and Yellow River station (YRS) in the Arctic were analyzed to investigate the response of the polar ionosphere to an interplanetary shock event induced by solar flare activity on July 12, 2012. After the arrival of the interplanetary shock wave at the magnetosphere at approximately 18:10 UT, significantly enhanced auroral activity was observed by the auroral imagers at the ZHS. Additionally, the polar conjugate observation stations in both hemispheres recorded notable evolution in the two-dimensional movement of cosmic noise absorption. Comparison of the ionospheric TEC data acquired by the conjugate pair showed that the TEC at both sites increased considerably after the interplanetary shock wave arrived, although the two stations featured different sunlight conditions (polar night in July in the Antarctic region and polar day in the Arctic region). However, the high-frequency (HF) coherent radar data demonstrated that different sources might be responsible for the electron density enhancement in the ionosphere. During the Arctic polar day period in July, the increased electron density over YRS might have been caused by anti-sunward convection of the plasma irregularity, whereas in Antarctica during the polar night, the increased electron density over ZHS might have been caused by energetic particle precipitation from the magnetotail. These different physical processes might be responsible for the different responses of the ionosphere at the two conjugate stations in response to the same interplanetary shock event
Utilization of clean energy and future trend of Antarctic research stations
Full text linkThe polar regions are rich in resources with high scientific value. Polar scientific research is of great significance to natural environment, climate, astronomy and geology. Polar scientific research is closely related to polar energy supply. Most research stations still use fossil fuels as the main source of power generation. This kind of power supply not only pollutes the environment, but also consumes a lot of manpower and material resources. As a kind of renewable energy such as solar energy and wind energy, renewable energy not only has the characteristics of sustainable development, but also has the characteristics of local power generation and transportation cost saving. At present, several countries have started the construction and application of polar renewable energy, and achieved good results in some Antarctic stations. Based on the investigation and summary of the application of renewable energy in various countries, this paper discusses the development trend of polar energy supply in the future, and provides a clear idea and direction for the development of polar renewable energy
An introduction to the riometer system deployed at China-Iceland joint Arctic observatory and its beamforming correction method based on the preliminary data
Full text linkThe China-Iceland joint Arctic observatory (CIAO) has formally been operating since October 18, 2018, and an imaging riometer system was deployed at CIAO in August 2019 for the conjunction observation purpose with the co-located ground-based all sky imager auroral observation system. The features of the riometer and antenna system are presented. The riometer’s beam-forming performance were evaluated with the analysis method introduced in detail. The analysis results showed that the mapping of beams was incorrectly ordered, and the correction has been made. The revised ordering result was reasonably verified and the analysis method was proved to be effective