• 한국양식학회지
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• 제20권3호
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• pp.168-172
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• 2007

해산어의 종묘생산 과정에서 로티퍼 B. rotundiformis와 코페포다 T. japonicus는 매우 대표적인 동물먹이생물이다. 그리고 이 두 종의 혼합배양 방법은 대량배양과 안정배양을 목적으로 하였을 때 매우 유용한 방법으로 널리 알려져 있다. 이 연구에서는 로티퍼 B. rotundiformis와 코페포다 T. japonicus의 혼합 배양 과정에서 미칠 수 있는 배양조건으로서 광주기가 미칠 수 있는 영향을 검토하였다. 그 결과 로티퍼 B. rotundiformis와 코페포다 T. japonicus의 혼합 배양에서는 배양 환경 조건 중 광주기 조건에 따라서 혼합배양수조내 로티퍼와 코페포다의 증식 양상이 매우 달라짐을 알 수 있었다. 로티퍼의 증식율을 비교하면 반일 광주기 조건의 최고 밀도에 비하여 전일 광주기 조건하에서 로티퍼의 최고 밀도는 200% 이상 향상되는 것을 알 수 있었다. 그러나 코페포다 T. japonicus의 증식은 12L:12D<24L:0D<0L:24D의 순으로 전일 암주기 조건의 광주기 조건하에서 가장 높은 증식이 관찰되었다. 그리고 코페포다의 증식과정을 각 발생 단계별로(nauplii, copepodites 그리고 female carrying eggs) 계수한 결과, 세 가지 광주기 조건별로 각 발생단계별(nauplius, copepodid 그리고 female carrying eggs)의 증식 양상은 매우 큰 차이를 보였다.

• 한국발생생물학회지:발생과생식
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• 제24권1호
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• pp.19-30
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• 2020

The pH of water is one of the main environmental factors exerting selective pressure on marine and freshwater organisms. Here, we focus on the influence of pH on an organism's ability to maintain homeostasis and investigate the effects of acidification on immunity-related genes and osmotic pressure during early development of the olive flounder, Paralichthys olivaceus. The aim of our study was to determine the influence of various pH levels on the fertilized eggs and larvae of P. olivaceus. Gametes of P. olivaceus were artificially introduced and the resulting fertilized eggs were incubated at pH 4.0 (low), 6.0, and 8.0 (equivalent to natural sea water; control). We found that all eggs sank from the water column at pH 4.0. After 38 h, these eggs showed slow development. Hatching occurred more slowly at pH 4.0 and 6.0 and did not occur at all at pH 4.0. Result of gene expression, caspase and galectin-1 were expressed from the blastula to pre-hatch stages, with the exception of the two-cell stage. HSP 70 was also steadily expressed at all pH levels over the five days. The osmolality of fertilized eggs differed marginally at each stage and across pH levels. So, this results demonstrates that low pH level is detrimental to P. olivaceus fertilized eggs.

• 한국수산과학회지
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• 제48권4호
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• pp.542-554
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• 2015

Grain size, the content of ignition loss (IL), and the concentrations of chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Mn, Cu, Pb, Zn, Cd, Cr, As, and Hg) in surface sediments from the Taehwa River estuary, Ulsan, were measured to evaluate pollution levels and potential ecological risks of organic matter and trace metals in estuarine sediment. The mean grain size (Mz) of sediments in the study region ranged from $-0.8-7.7{\varphi}$ (mean $2.8{\pm}2.4{\varphi}$). Surface sediments in the upstream region of the Taehwa River were mainly composed of coarse sediments compared to the downstream region. The concentrations of IL, COD, AVS and trace metals in the sediment were much higher at downstream sites of Myeongchon Bridge in the vicinity of industrial complexes than at upstream sites of those in the vicinity of the residential areas due to the anthropogenic input of organic matter and trace metals by industrial activities. On the basis of several geochemical assessment techniques [sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollution load index (PLI) and ecological risk index (ERI)], the surfaces sediments in the study region are not highly polluted for trace metals, except for As. However, the higher concentrations in downstream study regions of the Taehwa River could impact benthic organisms including shellfish (i.e. Manila clam) in sediments.

• Ocean and Polar Research
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• 제37권1호
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• pp.61-71
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• 2015

Eicosapentaenoic acid (EPA) produced from marine organisms is widely used in nutraceuticals. Monodus subterraneus and Nannochloropsis oceanica, which are representative freshwater and marine Eustigmatophyceae, respectively, are known to have a high content of protein and lipid, particularly, EPA. In this study, to compare the growth and nutritional composition of M. subterraneus and N. oceanica, they were cultured in autotrophic and mixotrophic conditions with JM and f/2 medium, respectively, at $25^{\circ}C$. In addition, $80{\mu}mol\;photons\;m^{-2}s^{-1}$ with 24-hour and 12-hour light was provided, with the addition of 2% glucose to the medium for the mixotrophic culture. With regard to growth, M. subterraneus showed 10 times higher biomass in a mixotrophic culture than in an autotrophic one. However, no significant difference was observed for N. oceanica between the two culture methods. With respect to nutritional composition, M. subterraneus cultured autotrophically had a higher protein and lipid content, particularly EPA, than that cultured mixotrophically, but no significant difference was found in the two cultures of N. oceanica. Furthermore, M. subterraneus cultured autotrophically with continuous light showed higher nutritional composition, particularly EPA, than N. oceanica. In conclusion, the mass culture of freshwater M. subterraneus is much easier and more economical than marine N. oceanica. In addition, production of EPA will be economically improved if mixotrophic culturing of M. subterraneus is first conducted to maximize the biomass, and then secondary autotrophic culturing is performed.

• 한국식품위생안전성학회지
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• 제33권3호
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• pp.151-156
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• 2018

해양생물에는 육상생물자원에서는 존재하지 않는 다양한 화합물이 많이 존재하는데 이들 화합물은 새로운 치료제 및 대체 치료법을 개발하는데 유용하게 이용될 수 있다. 현재 해조류의 다양한 생리활성에 대한 연구가 진행되고 있으며 최근에는 여러 병원성 및 인체 감염균에 대한 항균효과를 나타내어 신약개발의 보고로 다양한 연구가 진행이 되고있다. 즉, 해조류는 천연물신약 또는 새로운 치료제 개발에 중요한 생물자원이다.

• 한국미생물·생명공학회지
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• 제39권3호
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• pp.218-223
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• 2011

Eicosapentaenoic acid 생산 세균을 얻기 위해 1999~2000년 하계연구 기간 중에 남극 생물 및 침적토를 사용하여 600주의 균주를 분리하였고 TLC와 GC를 사용하여 오메가-3 고도불포화 지방산 EPA를 생산하는 미생물 7 주를 성공적으로 분리하였으며, 이중 EPA 생산이 가장 높은 L93 균주를 선발하였다. 16S rDNA의 염기서열 분석을 통하여 Shewanella 속으로 조사되었으며, 이에 분리된 균주를 Shewanella sp. L93라 명명하였다. EPA를 생산 최적 배양온도 $4^{\circ}C$이며, 초기 pH 7에서 최적 EPA 함량을 보였다. 아울러 염 농도는 50 %(w/v)에서 생산이 최대였다. EPA 최적 생산 조건을 이용하여 리터당 320 mg 생산할 수 있는 생산 시스템을 확립하였다. Urea 침전법과 HPLC을 이용하여 수율 72% 이상의 97% 순도를 가진 EPA를 정제할 수 있는 분리 정제 시스템 또한 본 연구를 통하여 확립하였다.

• 한국수산과학회지
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• 제51권4호
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• pp.389-396
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• 2018

Marine pathogenic bacteria, such as Streptococcus parauberis, Edwardsiella tarda and Vibrio harveyi, can cause lethal infections in farmed fish, ozone and antibiotics, are employed to sterilize waters used for rearing fish to mitigate this threat. The most widely used method is treatment with sodium hypochlorite solution. However, the maintenance of a constant concentration of chlorine in rearing waters can be difficult. We investigated the potential of a mixed oxidant (MO) solution generated by electrolysis of sea water to improve water quality. We measured the survival rates of fish pathogenic bacteria exposed to different concentrations of MO (0.5, 1.0, 1.5 and 2.0 MO) and sodium hypochlorite (0.5, 1.0, 1.5 and 2.0 ppm) for various lengths of time (0, 5, 10, 15, 20, 25 and 30 min). We found a time-dependent decrease in the survival rates of the tested pathogenic microorganisms. The sterilization effect of the MO solution on pathogenic organisms was greater than that of sodium hypochlorite for gram-negative and gram-positive bacteria. We conclude that MO solution produced by electrolysis could be used to maintain a constant chlorine concentration in aquaculture systems.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 Asia Navigation Conference
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• pp.157-165
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• 2006

In February,2004, at International Maritime Organization (IMO), LONDON, a new international convention 'International Convention fur the Control and Management of Ship's Ballast Water and Sediment 2004' was adopted. It is called 'Ballast Water Management Convention (BWM)'. Ballast water means charged seawater or fresh water in ship's special tanks (ballast tank) to keep safety navigation and ship's maneuverability. However, from 1980, it was point out the serious problem for marine ecosystem and human life that ballast water includes harmful marine species (and small organisms) and these species are also discharged along with ballast water. These species were released with discharged ballast water in water areas, where species are different from discharged ballast water. The problem is that released species increase when released species are more powerful than native species and consequently, marine ecological system is destroyed in released water area. Authors have inspected the validity of the ballast water exchange using pumping-through method that is one of the methods of ballast water management. In this paper, the numerical simulation of the motion and density of the fluid at the time of exchange of the fluid in a 2-dimensional tank using the pumping-through method was carried out by using two different type numerical methods. One method is MPS method that is one of the particle methods. Other one is Finite Different Method (FDM). Authors were compared with result of two numerical method calculations and experiment result and reported some knowledge from these results.

• 환경생물
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• 제36권4호
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• pp.687-693
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• 2018

The active development of the global marine trade industries has been known to increase the inflows of marine invasive species and harmful organisms into the ecosystem, and the marine ecological disturbances. One of these invasive species, Ciona robusta, has now spread to the Korea Strait, the East Sea, and Jeju Island in connection with the climate change but not the Yellow Sea in Korea. Currently, the spread and distribution of C. robusta is increasingly damaging aquaculture and related facilities. Therefore, this study aims to identify the spread of C. robusta and potential habitats and to secure a data for the prevention of effective management measures due to climate change as well as damage the reduction in future through the prediction of spread. We used environmental variables in BioOracle. Also, the potential habitat and distribution of C. robusta was predicted using MaxEnt, a species distribution model. Two different RCP scenarios(4.5 and 8.5) were specified to predict the future distributions of C. robusta. The results showed that the biggest environmental factor affecting the distribution of C. robusta was the salinity as well as the highest distribution and potential habitats existent in the East Sea and around Jeju Island.

• 한국해양학회지:바다
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• 제14권1호
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• pp.63-68
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• 2009

광생물학적 수소생산 잠재력을 가진 다양한 미소생물 가운데, 남세균은 21세기의 수소경제 시대에 적합한 생물군으로 오랫동안 알려져 왔다. 광생물학적으로 수소에너지를 생산하게 될 경우, 해양 단세포성 질소고정 남세균은 남세균류의 하부 분류군들 가운데 가장이상적인 종류의 하나로 평가되고 있다. 단세포성 질소고정 남세균을 이용한 수소생산 기술을 개발하기 위해 반드시 고려해야 할 3가지 사항은 1) 자연계에 존재하는 최우수 수소생산 종주의 확립 2) 광생물학적 수소생산을 뒷받침하는 종주-특이적 최적조건의 탐색 3) 유전학적 방법을 이용한 수소생산 종주의 개량 등이다. 본고에서는 광생물학적 수소생산기술의 상업화를 향한 최근의 연구 개발 추세를 돌아보고, 해양 단세포성 남세균 종주를 이용한 광생물학적 수소생산 기술 분야에서 한국의 세계선도적 지위 확보를 위해서는 향후 10-15년간 집중적인 연구 개발이 절실함을 제안하고자 한다.