• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.38-39
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• 2005

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.209-212
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• 2006

황해와 동중국해의 해황 변동에 관한 연구는 현장관측을 중심으로 체계적으로 많이 수행되어 왔지만, 인공위성자료를 이용한 황해와 동중국해의 해황 변동 연구는 미비한 실정이다. 이것은 인공위성자료를 통해 얻을 수 있는 관측항목이 표층수온자료에 국한되어 있었기 때문이다. 그러나 SeaWiFS 해색위성과 같은 인공위성자료들을 이용하여 부유물 농도, 엽록소 농도 등이 원활하게 생산되고 있으며 최근 연구결과에 의해 염분과 유향성분 동도 추정 및 추출이 가능케 되었으므로 이들 인공위성자료를 이용한 황해와 동중국해의 해황 변동에 관한 연구를 수행하게 되었다. 특히 2004 년도는 계절변동에 있어서 이상기후의 해라고 점철되고 있다. 2004년 봄철의 폭설과 일시적인 고온현상, 여름철에는 10년만의 무더위, 겨울철에는 36년만에 가장 포근한 날씨가 지속되었다. 이러한 이상기후의 발생은 해양과 대기의 상호작용에 의해서 기인했을 것이라고 생각되어 한반도 주변 해역에서 황해와 동중국해의 해황변동이 연안해역의 해황변동과 어떠한 연관성이 존재하고, 이러한 요인들은 2004년도에 발생한 이상기후와 어떤 상관관계를 갖는지 연구하기 위한 기초연구를 진행하였다. 2003년 12월 - 2004년 2월과 2004년 12월 2005년 2월에 통일한 시기에 관측된 NOAA 표층수온 분포 영상자료들을 황해와 동중국해 해역을 중심으로 월별로 비교해보면 2003년 12월 - 2004년 1월에 관측된 표층수온 분포값보다 2004년 12월 - 2005년 1월에 관측된 표층수온 분포값이 상대적으로 높은 분포 특성을 나타내고 있었다. 이와 같은 현상은 국립수산과학원의 2004년 10월과 12월의 정선관측자료에서도 나타나고 있었다. 그러나 이와는 반대로 2004년 2 월에 관측된 표층수온 분포값보다 2005년 2월에 관측된 표층수온 분포값이 상대적으로 낮은 분포 특성을 나타내고 있었다. 따라서 인공위성자료를 이용한 황해의 2004년 해황 분석 결과는 이상수온 상승의 원인이 쿠로시오 해류의 변통과 관련성이 높다고 판단되며 이에 대한 지속적인 연구가 현재 진행중에 있다.

• Journal of Aquaculture
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• v.17 no.2
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• pp.103-108
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• 2004

Effects of temperature and salinity were investigated on physiological responses of Mytilus coruscus seedlings. Temperature tolerance and survival of M. coruscus, were examined at temperature 20, 25, 28, 30 and 35$^{\circ}C$ for 9 das. Survival of M. coruscus was 90% at temperature 2$0^{\circ}C$ and $25^{\circ}C$. LT$_{50}$ (lethal temperature) of 9 days was at 27.1$^{\circ}C$. The respiration and filtration rates of M. coruscus were increased with temperature up to $25^{\circ}C$, and decreased with temperature ranged from $25^{\circ}C$ to 3$0^{\circ}C$. LS$_{50}$ (lethal salinity, psu) of 9 days at 1$0^{\circ}C$, 15$^{\circ}C$ and $25^{\circ}C$ were 17.01 psu, 19.95 psu and 21.79 psu respectively. Salinity affected survival of M. coruscus with higher temperature. However the respiration and filtration rates were reduced with lower salinity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.145-149
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• 1988

The effects of temperatures, salinities and diets on the larvae of the fresh water prawn, Macrobrchium koreana were studied. Survival rates were decreased with increasing salinity concentrations, and the second larval stages were almost died in 48 hours in over $40\%$ sea weter$(13.7\%)$. The intermolt duration of the each stage were shortend with increasing water temperature, and the optimum temperatures of the larvae were from $22^{\circ}C\~26^{\circ}C$ The larvae fed with the meat of Tapes japonicus showed the highest survival rate. When the larvae were fed with the eggyolk powder, all the lauvae died before fourth zoea. Under starved condition moltings were continued up to third zoea.

• Korean Journal of Environmental Biology
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• v.32 no.3
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• pp.216-224
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• 2014

Decrease in dissolved oxygen concentrations associated with temperature fluctuation is an important criteria to evaluate the mortality rate of the species. Based on this parameter, we investigated the survival rate, physiological response and histological change of warty sea squirt. It was found that the survival rate of the warty sea squirt species was 63.3% at $23^{\circ}C$ and 56.6% at $26^{\circ}C$ respectively. However, exposure of six days at $29^{\circ}C$ caused deaths among species, which indicated the 6day-$LT^{50}$ of the tested species to be $24.58^{\circ}C$ ($19.48{\sim}35.48^{\circ}C$). Further, after 11 day of exposure, the dissolved oxygen concentration has been found to decrease, with the survival rate of 20% at $4.0mg\;L^{-1}$ and deaths at $2.0mg\;L^{-1}$, thus 11day-$LC^{50}$ calculated to be $3.88mg\;L^{-1}$ ($3.29{\sim}4.57mg\;L^{-1}$). In addition, decrease in rate of oxygen consumption and excretion of ammonia was also noted at this critical water temperature and dissolve doxygen concentration. Moreover, there has been common histopathological changes were observed in warty sea squirt's gill pouch, digestive tract, and tunic as follows such as: proliferation of epithelial cells, condensation and necrosis, permeation of phagocyte and blood cell, loss of cilium and muscular fiber degeneration. Based on our study results, we suggest that these parameters can also be useful to evaluate the survival rate and physiological response in other species.

• 한국해양학회지
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• v.30 no.5
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• pp.512-521
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• 1995

To investigate a short-term (from 2 hours to 24 hours) variability of a mixed layer, oceanographical data (water temperature, salinity, current) and meteorological data (wind, air temperature, solar radiation) were collected at a site in the Korea Strait at the interval of one hour for 48 hours from October 12 to 14, 1993. The average rates of temporal variations of the mixed layer depth (MLD) and temperature of the mixed layer (MLT), which are very weakly correlated with the wind stress and buoyancy flux at the sea surface, are about 5.2 m/hour and 0.2$^{\circ}C$/hour, respectively. The mixed layer is relatively shallow when both MLT and MLS (salinity of the mixed layer) are low, while MLD is relatively deep when they are high. MLT shows a sudden decrease or increase. Analysis of satellite infrared images and XBT data shows that sudden increase of MLT is caused by advection of warm water. These results suggest that the short-term variation of the mixed layer in the Korea Strait in autumn, in which surface current is relatively strong and different water masses exist, is mainly determined by advection rather than air0sea interaction such as wind stress or buoyancy flux.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.243-252
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• 1985

The mechanism of reproductive cycle of longchin goby Chasmichthys dolichognathus was investigated for the annual variations of gonadosomatic index(GSI), histological changes of gonad, reproductive cycle, and initiating and terminating factors of the breeding season. The experimental fish were captured in the tide pool of Tongbaeksom, Pusan, Korea from February 1983 to September 1984. Experimental fish for the study of initiating and terminating factors of the breeding season were maintained in filtered recirculating aquariums and exposed to various temperature and photoperiod regimes. The ovary is a pair of sac-shaped organ, and the testicular structure is tubular and it is connected to the seminal vesicle which is located at the posterior end of the testis. GSI began to increase from February when the water temperature began to increase and reached peak in April. It began to decrease from August, the top water temperature season, and maintained relatively low values until January. The annual reproductive cycle includes successive six developmental stages : early growing from December to February, late growing from January to March, early mature from February to May, late mature and ripe from March to August, spawning from April to July, degeneration and resting stage from May to December. An experimental study based on the reproductive cycle of this species indicated that rising temperature under long photoperiod during spring stimulated gonadal maturation, whereas terminating factor of the breeding season with recrudescence of the gonads was demonstrated as high water temperature during summer regardless of photoperiod.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.394-406
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• 1991

It was proved that cold tolerance of rice plants at the young microspore stage was affected by water temperature and nitrogen application from the spikelet differentiation stage to the young microspore stage, and this mechanism could be explained in the point of view of pollen developmental physiology. The cold tolerance of rice plants at the young microspore stage was severely affected by water temperature (Previous water temperature) and nitrogen application(Previous nitrogen application) from the spikelet differentiation stage to the spikelet differentiation stage. Although the duration is only 10 days or so from the spikelet differentiation stage to the young microspore stage, these days are very important period to confirm the cold tolerance of rice plants at the young microspore stage. The higher previous water temperature up to $25^{\circ}C$ and the deeper previous water depth up to 10cm caused the more cold tolerance of rice plants. Water irrigation of 10cm before the cretical stage showed lower cool injury than that of water irrigation of 20cm during the critical stage. The preventive effect of cool injury by combined treatment of the deep water irrigation before and during the critical stage was not additive but synergistic. The cold tolerance of rice plants grown in previous heavy nitrogen level was rapidly decreased when nitrogen content of leaf blade at the young microspore stage was excessive over the critical nitrogen level. Nitrogen content of leaf blade at the changing point of cold tolerance was estimated as about 3.5% for Japonica cultivars and about 2.5% for Indica x Japonica cultuvars. It is considered that these critical nitrogen contents of leaf blade can be used as a index of the safe critical nitrogen level for the preventive practices to cool injury. It was summarized that increase of engorged pollens per anther by high previous water temperature resulted from the increase of number of differentiated microspores per anther, otherwise, the increase of engorged pollens by the decrease of previous nitrogen level was caused by the decrease of the number of aborted microspores per anther.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.313-323
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• 2016

Water temperature affects physical and biological processes in ecologies on river system and is important conditions for growth rate and spawning of fish species. The objective of this study is to compare models for water temperature during the summer season for the Fourchue River (St-Alexandre-de-Kamouraska, Quebec, Canada). For this, three different models, which are CEQUEAU, Auto-regressive Moving Average with eXogenous input and Nonlinear Autoregressive with eXogenous input, were applied and compared. Also, future water temperature in the Fourchue river were simulated and analyzed its result based on the CMIP5 climate models, RCP 2.6, 4.5, 8.5 climate change scenarios. As the result of the study, the water temperature in the Fourchue river are actually changed and median water temperature will increase $0.2{\sim}0.7^{\circ}C$ in June and could decrease by $0.2{\sim}1.1^{\circ}C$ in September. Also, the UILT ($24.9^{\circ}C$) for brook trout are also likely to occurred for several days.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.52-52
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• 2022

남조류 (cyanobacteria)의 대량증식에 의한 녹조현상은 수질 악화 및 수중 생태계에 악영향을 끼친다. 기존 연구에서는 시아노박테리아 증식에 영향을 미칠 수 있는 다양한 요인을 식별하였다. 특히, 최근 (2020)에 수행된 한 연구는 2013년부터 2018년까지 4대 강에 위치한 16개의 지점에서수집된 세 가지 환경 변수, 수온, 유속 및 인(phosphorus)농도 데이터를 사용하여 시아노박테리아 발생에 대한 예측 모델을 개발하였으며 온도가 남조류에 발생에 대한 가장 지배적인 요인임을 시사하였다. 온실가스 배출에 의한 기온의 상승으로 특징되는 기후변화는 전 지구에 급격한 환경변화를 유발하고 있으며 이는 남조류 증식에도 영향을 줄 수 있다. 이에 본 연구에서는 한국의 4대 강에서 다년간 수집된 수온(℃) 및 녹조 (cells/㎖) 데이터에 기반하여 온도-환경변수 민감도 (scaling)를 분석함으로써 기후변화와 남조류 증식의 연관성을 판단해 보고자 한다.