• Ocean and Polar Research
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• v.33 no.3
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• pp.303-308
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• 2011

Polar psychrophiles which thrive under extreme conditions such as cold temperature, high salinity, and high dose ultraviolet light, emerge as novel targets for biotechnology. To prevent genetic drift and the possibility of contamination by subculturing, cryopreservation was employed for two psychrophilic microalgae, Porosira sp. (KOPRI AnM0008) and Pyramimonas sp. (KOPRI AnM0046), which have anti-freeze activities. Five cryoprotectants (dimethyl sulphoxide, ethylene glycol, glycerol, methanol and propylene glycol) showed toxicity at 20-30% (v/v). The optimal cryoprotectant concentration and equilibration time were less than 20% and 10 min, respectively. Cryopreservation was carried out in the presence of cryoprotectants either by direct freezing in liquid nitrogen ($LN_2$) or controlled freezing using a controlled rate freezer followed by storage in the $LN_2$ tank. As a result, Pyramimonas sp. (KOPRI AnM0046), a psychrophilic chlorophyta was revived. Cryopreserved Porosira sp. was not revived from either freezing protocols probably due to the silicic cell wall and its relatively large cell size. In the case of Pyramimonas sp. (KOPRI AnM0046), the controlled freezing method showed higher revival yield than the direct freezing method.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.501-503
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• 2007

오호츠크해 사할린 북동 해저사면지역은 세계적인 가스수화물 산출지역으로 알려져있다. 이미 2005년 탐사에서 50 cm 두께의 순수 가스수화물 시료를 해저면에서 채취한 지역이다. 2006년 탐사에서는 다양한 주파수대역의 고해상도 지구불리장비를 사용하여 탐사를 실시하였다. Side-scan Sonal와 3.5 kHz SBP 탐사, 수중음향 탐사를 통해 대규모 하도구조가 가스수화물지역의 북쪽 경계를 형성하고 있음을 밝혔다. 가스수화물의 BSR은 수심에 얕아짐에 따라 계속해서 심도가 감소하여 수심 약 300 m에서 해저면에 다다름. 이는 연구지역에서의 가스수화물 안정대의 상부경계가 약 300 m임을 시사한다 가스수화물 분출구조들은 약 1000m 수심을 경계로 천부에 분포하고, 해저면에는 원형의 가스분출구조들이 특징적으로 나타난다. 반면에 1000 m 수심보다 깊은 지역에서는 mud-dirpir의 상승구조로 판단되는 상승구조들이 해저면에 굴곡지형을 형성하고 있다. 해수중으로 분출하는 가스기둥들은 수심 111.2 m에서 1226.4 m 지점까지 다양한 수심에서 분포하며, 상승높이는 최대 750 m에 이르며, 약 150 m 수심까지 도달한다. 이는 해저에서 분출되는 메탄가스가 해수에 흡수되지 않고 해수면까지 이동하여 대기중으로 발출될 수 있음을 시사한다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.47-49
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• 2006

The Sea of Okhotsk is the unique area providing the highest methane production rate of the northern hemisphere. The area of focused fluid venting offshore the NE Sakhalin continental slope was investigated during the CHAOS (Hydro-Carbon Hydrate Accumulations in the Okhotsk Sea) expeditions onboard of RV "Akademik Lavrentyev" In 2003, 2005 and 2006. The International Research Project CHAOS (Russia-Korea-Japan) aimed at the study of gas hydrate formation processes associated with the fluid venting in the Sea of Okhotsk. Several new gas hydrate accumulations were discovered during the cruise. Hydrate-associated structures have been named as KOPRI, VNIIOKeangeologia, POI and KIT (the names of cruise participant institutes) Some of hydrate-bearing cores contain big amount of gas hydrates: massive gas hydrate layers (up to 35cm thick) were recovered. The shallowest submarine gas hydrate accumulations in the world (at the depth less then 400m) were discovered during the cruise.

• The Safety technology
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• no.179
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• pp.15-17
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• 2012

극지(極地), 그곳은 말 그대로 '맨 끝에 있는 땅'이다. 흔히 남 북 양극지방을 통칭하는 말이기도 하다. 극지에 대한 일반 국민들의 관심은 2009년에 진수된 우리나라 최초의 쇄빙선 아라온호의 명성으로 극대화됐다. 거기에 얼마 전 TV 다큐멘터리 '남극의 눈물' 방영도 일반인들에게 극지에 대한 친숙함과 이해를 높이는 데 한몫 했다. 얼음과 눈, 그리고 살을 에는 추위뿐인 동토의 땅에서 대한민국 태극기를 펄럭이며 극지의 모든 것에 대해 연구하는 과학기지가 있다. 바로 남극 세종과학기지와 2014년 완공되는 장보고과학기지, 그리고 북극의 다산과학기지다. 인천광역시 연수구 송도동에 자리 잡은 극지연구소(KOPRI, Korea Polar Research Institute)는 극지와 그 관련지역에서의 기초 및 첨단 응용과학 연구, 남 북극 과학기지 운영 등을 지원하는 극지 전문기관으로, 국토해양부 한국해양과학기술원 부설기관이다. 이곳은 우리나라 유일의 극지연구전문기관으로, 미래의 기후 변화와 무한한 생물종을 연구하는 과학자들의 열의가 대단하다. 그 뜨거운 열기의 중심에는 바로 안전이 자리 잡고 있다. '극지'라는 특수지역을 무대로 삼아 국가적인 연구를 수행하고 있는 만큼 '안전'은 연구 활동을 뒷받침 하는 주춧돌이자 왕성한 연구활동을 이어나갈 수 있게 하는 원동력이 되고 있다. 안전을 위시해 전문적인 극지 연구를 하고 있는 이곳, 극지연구소만의 특별한 안전관리 현장을 찾아가봤다.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2410-2412
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• 2010

• Journal of Microbiology
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• v.45 no.6
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• pp.541-546
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• 2007

Red algae are distributed globally, and the group contains several commercially important species. Griffithsia okiensis is one of the most extensively studied red algal species. In this study, we conducted expressed sequence tag (ESTs) analysis and synonymous codon usage analysis using cultured G. okiensis samples. A total of 1,104 cDNA clones were sequenced using a cDNA library made from samples collected from Dolsan Island, on the southern coast of Korea. The clustering analysis of these sequences allowed for the identification of 1,048 unigene clusters consisting of 36 consensus and 1,012 singleton sequences. BLASTX searches generated 532 significant hits (E-value <$10^{-4}$) and via further Gene Ontology analysis, we constructed a functional classification of 434 unigenes. Our codon usage analysis showed that unigene clusters with more than three ESTs had higher GC contents (76.5%) at the third position of the codons than the singletons. Also, the majority of the optimal codons of G. okiensis and Chondrus crispus belonging to Bangiophycidae were G-ending, whereas those of Porphyra yezoensis belonging to Florideophycidae were G-ending. An orthologous gene search for the P. yezoensis EST database resulted in the identification of 39 unigenes commonly expressed in two rhodophytes, which have putative functions for structural proteins, protein degradation, signal transduction, stress response, and physiological processes. Although experiments have been conducted on a limited scale, this study provides a material basis for the development of microarrays useful for gene expression studies, as well as useful information for the comparative genomic analysis of red algae.

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1621-1629
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• 2008

Harmful algal blooms (HABs), commonly called red tides, are caused by some toxic phytoplanktons, and have made massive economic losses as well as marine environmental disturbances. As an effective and environment-friendly strategy to control HAB outbreaks, biological methods using marine bacteria capable of killing the harmful algae or algicidal extracellular compounds from them have been given attention. A new member of the $\gamma$-Proteobacteria, Hahella chejuensis KCTC 2396, was originally isolated from the Korean seashore for its ability to secrete industrially useful polysaccharides, and was characterized to produce a red pigment. This pigment later was identified as an alkaloid compound, prodigiosin. During the past several decades, prodigiosin has been extensively studied for its medical potential as immunosuppressants and antitumor agents, owing to its antibiotic and cytotoxic activities. The lytic activity of this marvelous molecule against Cochlodinium polykrikoides cells at very low concentrations ($\sim$l ppb) was serendipitously detected, making H. chejuensis a strong candidate among the biological agents for HAB control. This review provides a brief overview of algicidal marine bacteria and their products, and describes in detail the algicidal characteristics, biosynthetic process, and genetic regulation of prodigiosin as a model among the compounds active against red-tide organisms from the biochemical and genetic viewpoints.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.380-388
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• 2012

A total of 5 different polar microorganisms were isolated from Arctic lichens and their bioactive compounds were extracted from cell culture using different solvents including acetone, water, chloroform, diethylether, ethanol, ethyl acetate, methanol, and petroleum ether. The antibacterial properties of the extracts were evaluated by disk diffusion tests and minimal inhibitory concentration tests against 6 bacterial pathogens; Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterobacter cloacae, Pseudomonas aeruginosa and Escherichia coli. Among the extraction samples, ethyl acetate extracts of Burkholderia sordidicola S5-$B^T$ (KOPRI 26644) showed the highest activity (inhibition zone, 7-10 mm; MIC value, 57.5-1000 ug/ml) against targeted bacteria. Among the various solvents used for extraction, chloroform extract exhibited the weakest, but still obvious, activity.

• Geosciences Journal
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• v.22 no.6
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• pp.939-953
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• 2018

We examined the microfabrics of omphacite and garnet in foliated eclogite to determine the influence of the layered structure on seismic observations in subduction zone. The analyzed eclogite, from the Lanterman Range, northern Victoria Land, Antarctica, is characterized by layering in which the modal abundances of garnet and omphacite vary. For garnet, the low aspect ratios, similar angular distribution of long axes relative to the foliation in both layers, uniform grain size distribution, near-random crystallographic preferred orientations (CPOs), and misorientation angle distributions are indicative of passive behavior during deformation. In contrast, omphacite shows relatively high aspect ratios, a low angle between the long axes of crystals and the foliation, a wide grain-size distribution, and distinctive CPOs, suggesting dislocation creep as the main deformation mechanism. The results of fabric analyses are consistent with strain localization into omphacite or omphacite-rich layers rather than garnet or garnet-rich layers. The single-crystal seismic anisotropy of garnet is very weak ($AV_P=0.2%$, $AV_S=0.5-0.6%$), whereas that of omphacite is much stronger ($AV_P=3.7-5.9%$ and $AV_S=2.9-3.8%$). Seismic anisotropy of the omphacite-rich layers shows an increase of 329% for $AV_P$ and 146% for $AV_S$ relative to the garnet-rich layers. Our results demonstrate the importance of the layered structure in strain localization and in the development of the seismic anisotropies of subducting oceanic crust.

• Ocean and Polar Research
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• v.25 no.3
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• pp.315-329
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• 2003

During the 1st Korea-Russia Arctic Expedition from 3 to 26 August, 2000 phytoplankton biomass and nutrient concentration were measured in the Barents and Kara Seas. Total of 57 surface samples were collected f3r the phytoplankton related measurements. Chlorophyll a (chi a) concentraitons were measured to investigate the relations between physico-chemical factors and phytoplankton biomass distribution. Chl a values ranged from 0.14 to $2.34mg\;m^{-3}$ (mean of $0.65{\pm}0.42mg\;m^{-3}$) over the surface stations. The elevated values of the chi a concentrations $(1.49{\sim}2.34mg\;m^{-3})$ were found in the southeastern Barents Sea near the Pechora River. Nanoplanktonic $(<20{\mu}m)$ phytoflagellates were the important contributors for the increase of the chi a. The nano-sized phytoflagellates accounted for more than 80% of the total chi a biomass in the study area. Mean chi a concentration in the Barents Sea $(0.72{\pm}0.57 mg\;m^{-3})$ was higher than in the Kan Sea $(0.52{\pm}0.45mg\;m^{-3})$, but there was no big difference between two areas. Surface temperatures and salinities ranged from 4.1 to $11.7^{\circ}C$ (mean of $8.8{\pm}1.9^{\circ}C$) and from 23.8 to 32.5psu (mean of $30.3{\pm}1.9^{\circ}C$ psu), respectively. The physical factors were not highly correlated with phytoplankton distribution. It is speculated that the insignificant correlation between phytoplankton biomass and physical factor was due to the same current which introduced similar water mass with higher water temperature and lower salinity into the study area. The mean values of major nutrients such as ammonia, nitrite, nitrate, phosphate, and silicate were $0.42{\pm}0.31{\mu}M,\;0.10{\pm}0.03{\mu}M,\;1.44{\pm}1.03{\mu}M,\;0.35{\pm}0.12{\mu}M,\;10.99{\pm}3.45{\pm}M$, respectively. The relations between phytoplankton biomass and nutrient concentration were not close, indicating that the surface nutrient concentrations during the study seem to be controlled by other physical factors such as input of fresh water (i.e. dilution effects).