• Ocean and Polar Research
• /
• 제25권4호
• /
• pp.645-652
• /
• 2003

The coastal environment of King George Island is potentially subject to contamination by pollutants arising from station operations, such as emissions from fossil fuel burning, oil spills, waste disposal, etc. As a preparatory step to assess such impacts on the marine environment and living organisms of this island, two molluscan species (the bivalve Laternula elliptica and the gastropod Nacella concinna) were selected as biomonitors for metal pollution monitoring, and their baseline levels have been investigated for the past several years at King Sejong Station. In this review, variability of the baseline levels is discussed in relation to body size, tissue type, and sex. Natural elevations of some metals are also discussed with respect to the environmental characteristics of this region.

• Ocean and Polar Research
• /
• 제31권4호
• /
• pp.297-304
• /
• 2009

We investigated the response of the westerly winds over the Southern Ocean (SO) to glacial boundary conditions for the Last Glacial Maximum using the CCM3 atmospheric general circulation model. In response to glacial boundary conditions, the zonally averaged maximum SO westerly winds weakened 20-35% and were displaced toward the equator by 3-4 degrees. This weakening of the SO westerly winds arose from a substantial increase in mean sea level pressure (MSLP) in the southern part of the SO around Antarctica relative to the northern part. The increase in MSLP around Antarctica is associated with a marked temperature reduction caused by an increase in sea ice cover and ice albedo feedback during the glacial time. The weakened westerly winds in the SO and their equator-ward displacement might play a role in reducing the atmospheric $CO_2$ concentration by reducing upwelling of the carbon rich deep water during the glacial time.

• Ocean and Polar Research
• /
• 제44권1호
• /
• pp.83-97
• /
• 2022

The Amundsen Sea in West Antarctica is one of the most affected regions by climate change, but it is one of the least studied realms due to difficulties in access. Korea Polar Research Institute (KOPRI) launched a research project in the Amundsen Sea in 2010 using the icebreaker research vessel (IBRV) Araon and has been conducting various research initiatives. In this paper, previous researches derived from the Amundsen Sea Embayment by Korean researchers are introduced. Through previous studies, researchers have been able to interpret the environmental and biogeochemical changes according to the inflow Circumpolar Deep Water (CDW) and provide information for climate models. In particular, researches using radiocarbon isotopes (¹⁴C) were introduced to understand the physical and biogeochemical mechanisms of the carbon cycle in the Amundsen Sea. Opportunely, with the construction of a second icebreaker research vessel, the direction for systematic and long-term polar data acquisition can be presented.

• 천문학회보
• /
• 제29권2호
• /
• pp.28.1-28.1
• /
• 2004

• KSBB Journal
• /
• 제23권5호
• /
• pp.445-448
• /
• 2008

생명공학분야에서 매우 중요한 효소 중에 하나인 lipase는 여러 산업에 유용하게 사용되고 있다. lipase를 선별하기 위해서는 최적화된 발현 시스템이 필요하다. 많은 발현 시스템중에 E.coli 발현 시스템은 바람직한 특성을 갖는 효소를 스크리닝하거나, 선별된 변이체들의 특성을 확인하는 데에 소요되는 시간과 비용을 단축시켜 줄 것이다. 본 연구에서는 그 중에 BL21와 OrigamiB에서 CalB를 발현하였다. 그 결과 BL21 균주에서 발현된 CalB는 대부분이 불용성의 inclusion body를 형성하고, 전혀 활성을 나타내지 않았다. 이전의 타 연구와 더불어 이 결과에서 E.coli 균주에서 CalB의 기능적 발현이 상당히 어렵다는 것을 알 수 있다. 특히 불용성의 inclusion body형성과 lipase의 세포에 대한 유독성이 원인이 될 수 있다. 그러나 BL21와 비교해보면, OrigamiB에서 발현된 CalB 또한 많은 양의 inclusion body를 형성하지만, lipase의 주요 특성중의 하나인 가수분해 활성이 상당하게 나타나는 것을 알 수 있다. lipase의 구조 형성을 도와주는 변형된 OrigamiB와 저온유도시스템인 pCold 플라스미드를 사용했기 때문이다. 이처럼 균주나 플라스미드의 선택, 유도조건의 변경 등의 여러 연구를 통하여 유용한 효소를 선별할 수 있다.

• 대한원격탐사학회지
• /
• 제28권1호
• /
• pp.21-28
• /
• 2012

본 논문에서는 서남극해에 위치한 Wilkinson 빙하주변에 존재하는 다양한 산란특징을 보이는 빙산을 고해상도 C-밴드RADARSAT-2의 다중편파 합성구경레이더 (SAR) 자료를 이용하여 탐지할 수 있는 기법을 연구 하였다. 다중편파 SAR 자료에 적용할 수 있는 다양한 기법 들 중 전자기파 산란 특성을 파악할 수 있는 Freeman-Durden decomposition, H/A/$\bar{\alpha}$ decomposition, 그리고 entropy (H)와 anisotropy(A) 기법 들과, 다중편파 SAR자료의 분류를 위해 Wishart 무감독 분류법을 연구지역 SAR 자료에 적용 하였다. 그 결과, Freeman Durden, H/A/$\bar{\alpha}$ decomposition을 이용한 기법들은 대부분의 빙산들을 잘 분류 하였지만 해빙과 비슷한 표면 산란과 체적 산란을 가지고 있는 빙산은 구분되지 않았다. 반면, H와 A의 조합 변수 중 하나인 [1-H][1-A] 변수를 이용한 무감독 분류법은 이러한 빙산들을 잘 구분하였다.

• Journal of Korean Society for Atmospheric Environment
• /
• 제16권E2호
• /
• pp.85-96
• /
• 2000

The concentrations of Pb, Mn, Al and Na were measured from a total of 26 snow samples collected from a 1.5-m deep snow pit in Livingston Island, South Shetland Islands, at the northern tip of the Antarctic Peninsula. Ore sampling location is great concern, because of its proximity to the southern extremity of south America, a candidate for the source regions of pollutant aerosols entering Antarctica. The mean concentrations of Pb and Mn were found to be 4.97 pg g(sup)-1 and 20.6 pgg(sup)-1, respectively. These concentrations levels are similar to those reported for recent snow at other Antarctic sites with pronounced spring maxima for both metals. Contributions form natural sources are estimated to be minor (∼16%) for Pb. For Mn, on the other hand, contribution from rock and soil dusts is found to be very important. Excess Pb over Pb from natural sources is likely to be anthropogenic, especially from South Americal. Our results show that yearly Pb fallout flux is much greater in Antarctic coastal areas than at other Antarctic locations far from the coast , indicating that the transport and deposition patterns of pollutant aerosols are not simple is Antarctica. It is also suggested that the recycling of anthropogenic Pb in seawater to the atmosphere could significantly contribute to the Pb fallout flux in the Antarctic coastal regions.

• Ocean and Polar Research
• /
• 제26권2호
• /
• pp.155-163
• /
• 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.

• Ocean and Polar Research
• /
• 제37권1호
• /
• pp.23-35
• /
• 2015

A 450 m-long sediment section was recovered from Hole U1359D located at the eastern levee of the Jussieau submarine channel on the Wilkes Land continental rise (East Antarctica) during IODP Expedition 318. The age model for Hole U1359D was established by paleomagnetic stratigraphy and biostratigraphy, and the ages of core-top and core-bottom were estimated to be about 5 Ma and 13 Ma, respectively. Biogenic opal content during this period varied between 3% and 60%. In the Southern Ocean, high biogenic opal content generally represents warm climate characterized by the increased light availability due to the decrease of sea-ice distribution. The surface water productivity change in terms of biogenic opal content at about 10.2 Ma in the Wilkes Land continental rise was related to the development of Northern Component Water. After about 10.2 Ma, more production of Northern Component Water in the North Atlantic caused to increase heat transport to the Southern Ocean, resulting in the enhanced diatom production. Miocene isotope events (Mi4~Mi7), which are intermittent cooling intervals during the Miocene, appeared to be correlated to the low biogenic opal contents, but further refinement was required for precise correlation. Biogenic opal content decreased abruptly during 6 Ma to 5.5 Ma, which most likely corresponds to the Messinian salinity crisis. Short-term variation of biogenic opal content was related to the extent of sea-ice distribution associated with the location of Antarctic Polar Front that was controlled by glacial-interglacial paleoclimate change, although more precise dating and correlation will be necessary. Diatom production in the Wilkes Land continental rise increased during the interglacial periods because of the reduced sea-ice distribution and the southward movement of Antarctic Polar Front.

• 대한원격탐사학회지
• /
• 제27권5호
• /
• pp.535-542
• /
• 2011

본 연구에서는 서남극 Canisteo 반도와 그 주변 지역이 촬영된 2쌍의 ERS-1/2 tandem pair에 4-pass DInSAR 기법을 적용하여 표면 변위도를 생성하였고, 빙하와 해빙의 표면 변위를 해석하였다. 표면 변위도에서 빙하는 매우 빠른 움직임을 나타냈으며 인접해 있는 정착빙을 밀어내어 정착빙 표면에서는 빙하와 같은 방향의 변위가 관찰되었다. Cosgrove 빙붕도 큰 변위를 나타냈으며, 인접해 있는 정착빙을 밀어내는 것이 관찰되었다. 일부 해빙은 정착빙과 반대 방향의 움직임을 보였다. 이는 해빙이 해류에 영향을 받는 유빙이기 때문이며, 이로부터 정착빙과 유빙의 경계를 확인할 수 있었다. 빙붕과 빙상의 표면은 SAR영상에서 유사한 밝기를 보이며, 간섭도에서도 비슷한 정도의 간섭띠 변화율을 나타내 두 빙체를 쉽게 구분 할 수 없었다. 그러나 움직임이 큰 빙붕과 변위가 거의 없이 안정적인 빙상의 경계를 절대위상복원 후 생성한 변위도를 통해서 쉽게 확인할 수 있었다.