• 환경위생공학
• /
• 제23권3호
• /
• pp.31-38
• /
• 2008

This study was conducted to investigate the effects of environmental factor such as temperature, salinity, turbidity, pH and dissolved oxygen on the growth of Vibrio spp.. In this survey, total 56 seawater samples were obtained from 8 different sites of the Incheon coastal area during the periods from april 2008 to october 2008. Enumeration of Vibrio spp. was determined by using the most probable number(MPN) procedure. Isolation rates of V. parahaemolyticus, V. vulnificus, V. cholerae in all samples tested were 44.0%, 21.4% and 13.1%, respectively. The enumeration of Vibrio spp. was very low correlated with water temperature and pH and negatively correlated with salinity, dissolved oxygen and turbidity. We found salinity to be the parameter most highly correlated with the enumeration of Vibrio spp. The highest rate of antibiotic resistance of V.vulnificus and V.parahaemolyticus was Cefazolin(11.5%), Ampicillin(70.8%), respectively.

• 한국물환경학회지
• /
• 제28권3호
• /
• pp.384-393
• /
• 2012

Saemangeum lake is an artificial lake created by reclamation works and an estuary embankment since 2006. The sea water flows into the lake by the operation of two sluice gates, and the freshwater enters into the lake by the upper streams. For the reflection of hydrology and hydrodynamics effects in Saemangeum area, a hydrodynamics model was developed by connecting Hydrological Simulation Program with Fortran (HSPF) and Environmental Fluid Dynamic Code (EFDC). The HSPF was applied to simulate the freshwater discharge from the upper steam watershed, and the EFDC was performed to compute water flow, water temperature, and salinity based on time series from 2008 to 2009. The calibration and validation are performed to analyze horizontal and vertical gradients. The horizontal trend of model simulation results is reflected in the trend of observed data tolerably. The vertical trend is conducted an analysis of seasonal comparisons because of the limitation of vertically observed data. Water temperature reflects on the seasonal changes. Salinity has an effect on the near river input spots. The impact area of salinity is depending on the sea water distribution by gate operation, mainly.

• Ocean and Polar Research
• /
• 제29권1호
• /
• pp.33-42
• /
• 2007

To obtain the overall distribution patterns and characteristics of the East Sea Intermediate Water (ESIW), the historical data obtained by the Japan Maizuru Marine Observatory (MMO) and the Korea Ocean Research and Development Institute (KORDI) were analyzed. To obtain water characteristics of the ESIW on isopycnal surfaces, temperature, salinity and dissolved oxygen were interpolated at every 0.01 interval of potential density. And then the interpolated values were averaged at the same potential density. This potential density average method preserved the salinity minimum layer more clearly compared to the depth average method. The potential density(${\sigma}_{\theta}$) range of the ESIW was $26.9{\sim}27.3$. The representative potential density of the ESIW was found to be 27.2, because the characteristics of the ESIW was clear at this density. From the horizontal distributions of physical properties on the isopycnal surface of $27.2{\sigma}_{\theta}$ it is suggested that the low salinity ESIW circulates anticlockwise over the whole basin with the high salinity intermediate water. The low salinity intermediate water extended from the northwestern part to the east along the sub-polar front and to the Ulleung Basin along the east coast of Korea.

• 한국환경생태학회지
• /
• 제32권6호
• /
• pp.591-602
• /
• 2018

기수갈고둥(Clithon retropictus)은 염분농도, 물흐름, 지반조건 등 환경의 질을 판단할 수 있는 생물학적 지표종으로서의 가치가 높아 멸종위기야생생물 2급으로 지정되었으나 생리생태적인 특성에 대한 기초 연구는 여전히 부족한 실정이다. 이에 본 연구는 연초천 기수역을 대상으로 염분농도, 하상 토양입도 등의 환경조건이 개체크기, 밀도 등에 미치는 영향을 파악하고자 하였다. 기수역에서 생물의 분포에 영향을 미치는 핵심 변수인 염분농도를 조사한 결과 민물에서부터 기수에 해당하는 0~25‰ 범위를 나타내었다. 하상 입도는 연초보와 가까울수록 거친 자갈이 많아진 반면, 하류로 갈수록 모래보다 작은 입자의 비율이 증가했다. 개체수와 개체크기는 연초보를 중심으로 물이 정체되는 담수인 상류와 해수가 만나는 하류에서 급격히 감소한 것으로 미루어 염분농도에 대한 내성은 넓은 것으로 확인되었다. 하지만 양극단으로 갈수록 개체수와 개체크기가 줄어드는 것으로 나타나 적응성은 약해지는 것으로 분석되었다. 개체수 및 개체크기와 환경요인과의 상관관계를 분석한 결과, 염분농도와 하상입도 모두에 영향을 받는 것으로 나타났다. 염분농도와는 높을수록, 하상입도와는 모래보다 작은 입자가 많을수록 개체수는 감소하는 경향이었다. 개체크기와의 관계에서도 염분농도가 높은 하류로 갈수록 크기는 줄어들었다. 하상입도는 입자크기 19mm 이상인 자갈이 많아질수록 개체가 커지는 것으로 분석되었다.

• 한국지구과학회지
• /
• 제36권4호
• /
• pp.367-389
• /
• 2015

본 연구에서는 Ocean Data View (ODV)를 이용하여 한반도 주변 해역의 수온 염분 분포도를 작성하는 실험 프로그램을 개발하였다. 정선 해양 관측 자료는 본 연구를 위해 새롭게 개발된 별도의 프로그램을 이용하여 ODV 호환형식으로 변환된 후 분석되었다. 새로운 실험 프로그램을 65명의 예비 교사들에게 적용하였을 때, 기존 프로그램을 사용한 같은 집단에 비해 과제 수행 완성도가 매우 향상되었다. 새로운 프로그램에 대한 실험 참가자들의 만족도를 살펴보기 위해 설문지 분석을 실시하였다. 분석 결과 정확하고 빠른 등치선 작성 분야에서 가장 높은 만족도를 나타내었으며, 새로운 실험 프로그램의 이해 및 적용에 관한 긍정적인 반응을 확인하였다.

• 한국해안·해양공학회논문집
• /
• 제26권3호
• /
• pp.184-195
• /
• 2014

낙동강 하구역은 하구둑이 건설된 이후, 담수는 갑문 개폐에 의해서 인위적으로 방출되고 해수유입은 하구둑에 의해 억제되어왔다. 이로 인해 인위적인 수문 개방에 의한 해수와 담수의 수렴 및 혼합은 낙동강 하구역의 해수순환에 큰 영향을 미치는 것으로 나타났다. 홍수기 방류 중 낙동강 하구역의 수로별 유동 환경과 하구 흐름 특성을 조사하기 위해 유속 및 염분 관측을 수행하였다. 분석 결과 지형적 특징 및 방류의 영향에 의해 수로별 유속 및 염분 분포 특징이 상이하게 나타났다. 낙동강 하구역의 홍수기 방류에 의한 영향은 각 수로별 잔차유속 및 염분 수직분포에 다르게 작용하며, 지형적 특징은 염분침투 범위에 영향을 미침으로써 상대적으로 고염의 물이 정체되는 구간이 존재한다.

• Ocean and Polar Research
• /
• 제30권4호
• /
• pp.509-518
• /
• 2008

Distribution of bacterial abundance and production was investigated in seawater around Saemangeum dike 7 times during March, $2007{\sim}July$, 2008. In the inner area of the dike, salinity variation was great due to river runoff from Mangyung and Dongjin Rivers and high chlorophyll a (chl a) concentrations up to $124.3{\mu}g\;l^{-1}$ was found. In the outer area of the dike, salinity was higher than in the inner area of the dike, and chl a was lower up to 10 times than in the inner area of the dike. Thus, the area of Saemangeum showed meso- to hypereutrophic conditions. Bacterial abundance and production ranged from 0.3 to $4.3{\times}10^9\;cells\;l^{-1}$ and from 5.2 to $570 pmol\;l^{-1}h^{-1}$ in outer area of the dike, respectively, while in the inner area of the dike bacterial abundance and production was 3 to 4 times higher ($0.4{\sim}12.7{\times}10^9\;cells\;l^{-1}$ and $12.3{\sim}1309\;pmol\;l^{-1}h^{-1}$, respectively) than those in the outer area. In both areas, bacterial abudance and production was highest in summer and lowest in winter. However, the variations of bacterial parameters was very large in each season. These large variations seemed to be related with the supply of organic matter. Bacterial abundance and production showed significant negative correlations with salinity in the inner area, suggesting that allochthonous organic matter input by river runoff could be an important factor in regulating the distribution of bacterial abundance and production. In addition, bacterial production also correlated positively with chl a in the inner area, suggesting that autochthonous substrate might be another regulating factor of bacterial growth in the area. These results suggest that the supply of both allochthonous organic substrates introduced by river runoff and autochthonous substrates produced by phytoplankon could be important in regulating bacterial growth and utilization of organic matter in the area. Thus, to manage water quality in the inner area of dike, it seems to be important to lower the load of both organic and inorganic nutrients from adjacent rivers.

• 한국수산과학회지
• /
• 제38권5호
• /
• pp.331-341
• /
• 2005

Distribution of anchovy (Engraulis japonica) eggs and larvae was studied in the southwestern sea of Korea in July and November, 2001. Anchovy eggs were found mainly in the oceanic fronts of the northern sea area which were formed in the offshore area of Chuja Is. Bogil Is. and Chungsan Is. from west to east. Anchovy eggs were also found in the surrounding sea of Cheju Is. in the southern sea front area. The waters were highly heterogeneous and the water masses were bordered based on temperature $(10.8-26.4^{\circ}C)$ and salinity (28.9-33.7 psu). The anchovy eggs were mostly found outside of the China Coastal Water, where salinity was below 31 psu. The anchovy eggs were not found in November. Abundance of the anchovy larvae were higher in July than November. Temperature ranged from $10.8^{\circ}C\;to\;25.9^{\circ}C\;and\;15.9^{\circ}C\;to\;20.5^{\circ}C$, and salinity ranged from 28.9psu to 34.1psu and 33.2psu to 34.1psu in July and November, respectively. Non-swimmable larvae were found throughout the whole area of the southwestern sea of Korea. The area beyond the oceanic front had anchovy eggs dispersed from the spawning grounds to offshore. Dispersion pattern showed that the eggs were transported from the spawning grounds with a process of advection and diffusion based on the flow pattern which were caused by winds. Distribution pattern of the anchovy eggs and larvae may be used for the prediction of oceanic currents in each area.

• Ocean and Polar Research
• /
• 제34권1호
• /
• pp.37-51
• /
• 2012

We investigated the distribution and species composition of zooplankton in relation to hydrographical characteristics in the Korea Strait during the winter (February) and summer (July) of 2009. Satellite images of sea surface temperatures and in situ CTD data showed that the southeastern water zone (St3-5) off Jeju Island was strongly influenced by the Tsushima Current during both the winter and summer, whereas the Changjiang Diluted Water, characterized as water with relatively low salinity, was evident in the coastal waters of Jeju Island during the summer. During winter, zooplankton abundance was significantly higher than in the summer, with dominance by copepods, ostracods, siphonophorans, appendicularians, and nauplii. In both seasons, copepods represented >70% of the total zooplankton population. Calanus sinicus, a large calanoid copepod, was dominant in near the coast, and that may be associated with the intrusion of low salinity water (i.e., the Changjiang Diluted Water) along the coast. The abundance of P. parvus s.l. and A. omorii, known as neritic copepods, was mainly associated with the Korea Southern Coastal Water. Foraminiferans, Ostracods, O. plumifera, and P. aculeatus were concentrated in the southeastern water off Jeju Island during both seasons; showing their association with the Tsushima Current, which is characterized warm, high salinity water. Our results suggest that the distribution, abundance, and species composition of zooplankton are highly influenced by different water masses in the Korea Strait.

• Fisheries and Aquatic Sciences
• /
• 제15권3호
• /
• pp.221-231
• /
• 2012

The marine medaka Oryzias dancena choriogenin H gene (odChgH) and its mRNA expression during estradiol-$17{\beta}$ (E2) exposure were characterized. At the amino acid level, the choriogenin H protein is predicted to possess the conserved repetitive N-terminal region, as well as zona pellucida (ZP) and Trefoil factor family (TFF) domains. At the genomic level, odChgH has an eight-exon organization with a distribution pattern of transcription factor binding sites in the 5'-upstream region, which is commonly found in other estrogen-responsive genes. The tissue distribution pattern of odChgH mRNA was found to be gender-specific, whereby females showed a higher expression level and wider tissue distribution than did males. During embryonic development, odChgH mRNA was robustly detected from the stage of visceral blood vessel formation. Experimental E2 exposure of males resulted in odChgH mRNA being induced not only in the liver, but also in other several tissues. The E2-mediated induction was fairly dose-dependent. The basal expression levels of hepatic odChgH mRNA were lower in males that were acclimated to 30 ppt salinity than in those acclimated to 0 or 15 ppt salinity. In contrast, the inducibility of odChgH mRNA during E2 exposure was greater in seawater-acclimated fish than in brackish water- or freshwater-acclimated fish.