• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.254-258
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• 2014

Field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. To correctly estimate ice load and ice resistance on ship's hull, It is essential to understand the material properties of sea ice during ice field trials and to perform the proper experimental procedure by gathering sea ice data. A measurement of sea ice properties was conducted during February and March of 2012 with the Korean Icebreaking research vessel "ARAON" in the Amundsen Sea, Antarctica. This paper describes a test procedure to obtain sea ice data which provide basic information to estimate ice loads and icebreaking performance of the ship. The data gathered from sea ice field trials during the 2012 Antarctic voyage of the ARAON includes ice temperature/salinity/density and the compressive/flexural strength of sea ice. This paper analyses the gathered Antarctic sea ice material properties comparing with the previous data obtained during ARAON's Arctic and Antarctic voyages in 2010.

• ALGAE
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• v.35 no.1
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• pp.17-32
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• 2020

Asterochloris is one of the most common genera of lichen phycobionts in Trebouxiophyceae. Asterochloris phycobionts associated with the lichenized fungi Cladonia and Stereocaulon in King George Island (Antarctica) and Morro Chico (Chile), were isolated and then used to establish clonal cultures. To understand the phylogenetic relationships and species diversity of Antarctic Asterochloris species, molecular and morphological data were analyzed by using three microscopy techniques (light, confocal laser and transmission electron) and a multi-locus phylogeny with data from the nuclear-encoded internal transcribed spacer (ITS) rDNA and the actin and plastid-encoded ribulose bisphosphate carboxylase large chain (rbcL) coding genes. Morphological data of three Antarctic strains showed significant species-specific features in chloroplast while molecular data segregated the taxa into distinct three clades as well. Each species had unique molecular signatures that could be found in secondary structures of the ITS1 and ITS2. The species diversity of Antarctic Asterochloris was represented by six taxa, namely, A. glomerata, A. italiana, A. sejongensis, and three new species (A. antarctica, A. pseudoirregularis, A. stereocaulonicola).

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.215-219
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• 2007

Long-tenn variation in krill (Euphausia superba) and salp (mainly Salpa thompsoni) stocks was compared to environmental changes in the Atlantic and Indian sectors of the Antarctic. Environmental conditions examined were air temperature, water temperature, salinity, and sea-ice extent from 1926 to 1938 and from 1982 to 2000. The long-term pattern of krill was opposite to that of salp: krill stock decreased while salp stock increased concurrently. Krill stock was about three-fold higher from 1926 to 1938 than from 1982 to 2000, but salp was about four -fold lower in 1926-1938 than in 1982-2000. A wanning trend was observed in the environmental data, and the long-term variation in krill and salp stocks was affected by this trend.

• Ocean and Polar Research
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• v.25 no.4
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• pp.617-623
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• 2003

Organisms living in the Arctic and Antarctic regions are exposed to strong constraints, of which temperature is a driving factor. Evolution has led to special adaptations, some with important implications at the biochemical, physiological, and molecular levels. The northern and southern polar oceans have very different characteristics. Tectonic and oceanographic events have played a key role in delimiting the two polar ecosystems and influencing evolution. Antarctica has been isolated and cold longer than the Arctic; its ice sheet developed at least 10 million years earlier. As an intermediate system, the Arctic is a connection between the more extreme, simpler Antarctic system and the very complex temperate and tropical systems. By studying the molecular bases of cold adaptation in polar fish, and taking advantage of the information available on hemoglobin structure and function, we analysed the evolutionary history of the ${\alpha}\;and\;{\beta}globins$ of Antarctic and Arctic hemoglobin using the molecular clock hypothesis as a basis for reconstructing the phylogenetic relationships among species.

• Ocean and Polar Research
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• v.26 no.2
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• pp.155-163
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• 2004

The Protocol on Environmental Protection to the Antarctic Treaty was ratified in 1991. With the aim to ensure comprehensive protection of the Antarctic environment, it contains provisions on environmental protection and conservation of the Antarctic area, including provisions for Environmental Impact Assessment. Environmental Impact Assessment is a method used to predict environmental impacts at an early stage in project planning and design, and find ways to mitigate or prevent adverse impacts in order to maintain balance between development activities and environmental conservation. Internationally, the Environmental Impact Assessment (EIA) in the Antarctic is classified into three types - preliminary, Initial, and Comprehensive - based on the environmental impacts of the proposed activities. In case of the Preliminary Environmental Review (PER), proposed activity may proceed in accordance to the national procedures and drafting of an outline. However, Initial (IEE) and Comprehensive Environmental Evaluation (CEE) assess and verify the impacts of the proposed activity, and require methods or alternatives for mitigating or eliminating negative impacts on the environment. Although Korea's Act of 'Activities and Environmental Protection in Antarctica' also includes provisions on EIA for activities in Antarctica, there are obvious contrasts with the EIAs currently being conducted in Korea, in regards to deciding the level of EIA through screening and identifying key issues for assessment through scoping. In order to implement the proper EIA, more improved methods for drafting and reviewing the EIA to Antarctica in Korea are necessary.

• Journal of the Korean Geophysical Society
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• v.3 no.3
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• pp.141-152
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• 2000

In the vicinity of the Antarctic-Scotia plate boundary off Elephant Island(EI), geophysical data(multichannel seismic and gravity data) reveal rapid structural variation of the Shackleton Fracture Zone(SFZ) along its strike. The SFZ ridge terminates in front of the Antarctic Peninsula margin, whereas the transform fault of the SFZ continues farther southeast near EI and the width of the SFZ broadens toward the southeast. Accordingly, the SFZ transform fault changes its morphology along its strike as (1) a graben structure along the high Shackleton ridge in Drake Passage, (2) a half-graben structure in oceanic crust just southeast of the Antarctic-Scotia plate boundary, and (3) splay faults deforming the margin of EI. Two phases of tectonic deformation are clearly observed along the transform fault. Major extensional deformation had formed a large-scale half-graben during roughly about $10{\sim}20$ Ma when Drake Passage had opened. And then, the Shackleton fault has been reactivated with reverse sense, which has been caused by recent convergence between Antarctic and Scotia plates due to westward movement of the Scotia plate since 6 Ma.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.172-176
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• 1990

Electrocondensation method using aluminum electrodes was developed to remove excess amount of fluoride contained in Antarctic krill. Fluoride amount was reduced differently according to fluoride forms (total, ionic and bound) and sections (whole, muscle flesh and chitinous) of the Antarctic krill during electrocondensation process. Total, ionic and bound fluoride could be reduced by 56%, 35% and 60% of the initial amount contained in the whole body, respectively and reduced by 49%, 57% and 34% of the initial amount in the muscle flesh, respectively by electro condensation process for 120 min. In the case of chitinous section of the Antarctic krill, 68% of total fluoride could be decreased by this process for 120 min.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.352-358
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• 2022

We explored the frequency response of krill target strength (TS) to understand the Antarctic krill (Euphausia superba) and ice krill (Euphausia crystallorophias) using the stochastic distorted-wave Born approximation (SDWBA) model. The results showed that the distribution of orientation and the fatness factor could significantly impact on the frequency response of TS. Krill TS is clearly depended on acoustic properties, which could affect to estimate the biomass of two krill species. The results provide insight into the importance of understanding TS variation to estimate the Antarctic krill and ice krill biomass, and their ecology related to the environmental features in the Southern Ocean.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.203-207
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• 2012

The amount of fluoride removed from Antarctic krill via organic acid extraction depends on the extraction time, concentration, extraction volume, and the nature of the acid itself. The fluoride content in Euphausia superba was determined by measuring the concentration of fluoride ion in acidic extracts using an ion-selective electrode. The best results were obtained by adding 50 mL of 0.01 M citric acid to 0.3-0.5 g of krill and extracting for 5 min. Under these conditions, recoveries of fluoride from frozen whole krill and krill meat were 95.6-99.5% and 97.5-101.3%, respectively. The dry basis fluoride contents of krill by-product, krill meat and the boiled krill were 705, 298, and 575 ppm, respectively. These levels were significantly reduced by citric acid extraction.

• Journal of the Korean Solar Energy Society
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• v.25 no.3
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• pp.53-60
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• 2005

Energy resource is very important to the survival in the polar region. Wind energy, which is one of renewable energy, can guarantee the clean, inexhaustible, natural resource in the polar region. It is essential to assess the wind energy resource of the site where wind turbines will be installed. In the present study, the wind characteristics of the antarctic King Sejong station are analysed from its meteorological observation data. The wind resource of the Sejong station is also simulated and predicted using WAsP program. From the results, the Sejong station has very excellent wind resource and the site where small wind turbines will be installed is determined.