• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.2
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• pp.78-91
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• 2015

Macrobenthic community was studied at 87 stations including intertidal and subtidal area in Yoja Bay, south coast of Korea in summer season of July 2001. Duplicate sediment samples were taken using a van Veen grab ($0.1m^2$) in each station. Mud facies of the sediments were widly distributed in the bay. And relatively high content of sand was shown in the Bulgyo-cheon stream estuary. A total of 274 species was occurred with a mean density of $2,346ind./m^2$ and a mean biomass of $78.2g/m^2$. The polychaetes were species- and density-dominant faunal group with a total of 122 species (44.5% of the total number of species), and mean density of $1,543ind./m^2$ (65.8% of the mean density). Meanwhile, molluscs were biomass-dominant faunal group with $44.4g/m^2$. Bio-Env. analysis showed that the combination of bottom salinity and sand content of the surface sediments was highly correlated to the major macrobenthic communities. The macrobenthic species number, decreasing toward inner bay from mouth of the bay, was significantly correlated to the sediment environmental variables and bottom water salinity. The spatial distribution of abundance showed significant correlation to the sand and mud contents and mean grain size of the surface sediments. Major dominant species were Minuspio japonica (polychaete) with a mean density of $1,167ind./m^2$ at upper part of the bay where salinity was low and Eriopisella sechellensis (amphipod) with $152ind./m^2$ in central part of the bay. Species diversity (H') was $3.0{\leq}$ in the mouth part of the bay and ranged 2.0-3.0 in the inner part of the bay, which showed a significant positive correlation to bottom salinity. Total number of species also showed significant correlations to the sediment composition and bottom salinity. Based on the cluster analysis the macrobenthic community of the bay was classified into five station groups from the bay mouth toward the inner part of the bay depending on the species composition. From the SIMPER analysis Minuspio japonica, Eriopisella sechellensis and Sternaspis scutata mainly contributed to the classification of station group. These results suggested that the macrobenthic communities of the bay were mainly influenced by bottom salinity together with sediment composition, and that the studies of spatial distributions of major dominant species and benthic communities should be conducted continuously to monitor the Yeoja Bay benthic environment.

• 한국해양학회지
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• v.11 no.2
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• pp.89-95
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• 1976

Some factors of seawater such as water temperature, salinity, pH, dissolved oxygen and asturation of dissolved oxygen were determined in 5 meters intervals from surface to bottom at 11 stations in Yeongil Bay of Korea during late October 1973. Distribution pattern of water masses in Yeongil Bay during the period seemed to be heterogeneous as dividing into two parts of surface and bottom. Water temperature, pH, dissolved oxygen and saturation of dissolved oxygen of surface water mass showed higher values and salinity of the mass showed lower values than those factors of bottom water mass. Surface water mass might be originated from Tsushima current during summer season and bottom water mass from cold body of East Sea of Korea which seemed to extend to coastal zone during winter season. Land water discharge from Hyeongsan River into the Bay is considered as a minor factor playing slight role in the water mass composition of the area.

• Ocean and Polar Research
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• v.33 no.spc3
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• pp.325-336
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• 2011

Seasonal to inter-annual variations of water properties in the western channel of the Korea Strait are investigated using quasi-monthly hydrographic observations collected during 2006-2010. Weak vertical temperature and salinity gradients are observed during the winter months and these remain until May. At the upper layer, temperature increases from March and reaches a maximum in August, while salinity decreases during the same period. Near-bottom water shows low temperatures during late winter and fall with a minimum peak in September. Korea Strait Bottom Cold Water produces thick layers (>20 m) in 2006 and 2010, while it is observed very near the bottom with relatively high temperature in 2008 and 2009.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.301-306
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• 2011

This study was determined to analysis the characteristics of water mass in the Bottol Bada, Yeosu in August, 2010 based on the data from the distribution of water temperature and salinity. Sampling was carried out a total of three times (i.e. July 29, August 13, and August 30, 2010) and performed at three stations. Observation was done during the period of time 10:00-15:00, indicating the decreasing tidal height and turn of tide. In July 29, thermocline was found at 4 m in St. 1, but the stratification did not observe in August 13 and August 30. The remarkable water temperature between surface and bottom was found in St. 2 and St. 3, whereas St. 1 did not find. A particular finding during this study showed a cold water mass at bottom layer from St. 2 and St. 3, which was first occurred in July 29 and persisted in August 30 without any of destruction. Water temperature had a remarkable fluctuation between surface and bottom, whereas salinity had a unique in St. 1. St. 2 and St. 3 showed the increasing salinity according to water depth in August 13 and August 30. Transparency had considerable fluctuations in St. 1 and St. 3 depending to sampling date, but St. 2 did not fluctuate. Consequently, the Bottol Bada had a significantly different water mass between inner and outer waters. Furthermore, strong irradiance and weak wind play an important role in developing the stratification between surface and bottom, in particular the introduction of offshore waters contribute to highly developing the stratification in the Bottol Bada during the period of August in 2010.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.330-342
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• 1998

Benthic environmental parameters were analysed at 40 stations during the period from April 1995 to February 1996. such as water temperature, salinity, and dissolved oxygen (DO)-concentration in the surface and bottom water layers, grain size, chemical oxygen demand (COD), ignition loss, particulate organic carbon (POC) in the sediment of Youngsan River estuary. The water temperature ranged from 4.1 to $29.8^{\circ}C$ in the surface and 4.0 to $20.7^{\circ}C$ in the bottom layers. Salinity ranged from 15.1 to $33.6\%_{\circ}$ in the surface and 31.5 to $33.2\%_{\circ}$ in the bottom layer. The salinity in the outer pan of the study area was higher than that of inner area from autumn to spring, whereas they remained lower in summer. Dissolved oxygen concentration ranged from 5,1 to 11.2 $mg/\ell$ in the surface, and 0.79 to 10,2 $mg/{\ell}$ in the bottom layers. Hypoxic condition ($\le2.0mg/\ell$) was developed in the bottom water layer from Youngsan dike to Mokpo Harhour in summer due to the summer stratification. The surface sediment type was silty clay with a mean grain size of $9.12{\pm}0.45\phi$. The range of COD was from 6.15 to $15.49mgO_2/g$ with a mean of $10.59{\pm}12.64mgO_2/g$. The COD in the inner stations was relatively higher than that of outer stations, and decreased toward the outer part of the study area. Ignition loss (IL) ranged from 3.35 to $15.45\%$ with a mean of $5.96{\pm}1.91\%$. Principal component analysis was carried out from the following five environmental parameters: water temperature, dissolved oxygen in the bottom layer and mean grain size, clay content and COD in the sediment. The forty stations in the study area were classified into three stational groups. Group I was located in the inner part of the estuary characterised by relatively low surface salinity and bottom water temperature, fine sedimemt texture, high organic matter and low dissolved oxygen concentration during the summer. Meanwhile, Group III showing relatively high bottom salinity and water temperature was located in the outer part of the estuary characterising coarse sediment and low organic content in sediment. Group II was between Group I and Group III. The division of the areal groups had high correlations to the DO in the bottom layer and clay content in the sediment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.103-111
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• 2013

In this study, field measurements were conducted in the section about 7 km from sea dike to westward. The observations of along channel current were carried out, and water temperature and salinity were measured simultaneously at 10 stations during one tidal cycle, and sampling interval is 1 hour. The maximum ebb current is about 1.5 m/s at the surface layer but flood current is 0.4 m/s at the bottom layer during discharge period. Residual current during river discharge shows two layer structures which is typical characteristic of the estuary system. On the other hand, residual current during a period with no discharge has shown multi-layer structure different from general estuarine systems. The distribution of high salinity can be seen at the bottom layer as the effect of discharge does not reach down to the bottom layer during discharge. As a result, freshwater is not effected at the bottom layer during observation, and mixing of surface layer to bottom layer is reduced by stratification.

• Ocean and Polar Research
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• v.30 no.4
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• pp.379-399
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• 2008

Spatial-temporal variations in physiochemical water qualities (temperature, salinity, DO, SPM, POC and nutrients) of surface and bottom waters were investigated along the mid-western coastal area (Taean Peninsula to Gomso Bay) of Korea. Spatial distribution patterns of temperature and salinity were mostly controlled by the physical mixing process of freshwater from Geum River and/or Gyunggi Bay with nearby coastal water. A strong tidal front is formed off Taean Peninsula during spring and summer. Seasonal variations in nutrient concentrations, lower in spring and summer and higher in fall and winter, are primarily regulated by magnitude of phytoplankton occurrence rather than freshwater loadings into the bay. Based on seasonal and spatial variability of physicochemical parameters, water quality of the study area can be divided into four water masses; Gyunggi Bay-influenced Water Mass (GBWM), Geum River-influenced Water Mass (GRWM), Yellow Sea Bottom Cold Water Mass (YSBCWM) and Cheonsu Bay Water Mass (CBWM). Water quality of the GBWM (Taean Peninsula coastal area), which has relatively low salinity and high concentrations of nutrients, is strongly controlled by the Gyunggi Bay coastal water, which is under influence of the Han River freshwater. In this water mass, the mixed layer is always developed by strong tidal mixing. As a result, a tidal front is formed along the offshore boundary of the mixed layer. Such tidal fronts probably play an important role in the distribution of phytoplankton communities, SPM and nutrients. The GRWM, with low salinity and high nutrients, especially during the flood summer season, is closely related to physiochemical properties of the Geum River. During the flood season, nutrient-enriched Geum River water mass extends up to 60 km away from the river mouth, potentially causing serious environmental problems such as eutrophication and unusual and/or noxious algal blooms. Offshore (<$30{\sim}40m$ in water depth) of the study area, YSBCWM coupled with a strong thermocline can be identified in spring-summer periods, exhibiting abundant nutrients in association with low temperature and limited biological activity. During spring and summer, a tidal front is formed in a transition zone between the coastal water mass and bottom cold water mass in the Yellow Sea, resulting in intensified upwelling and thereby supplying abundant nutrients to the GBWM and GRWM. Such cold bottom water mass and tidal front formation seems to play an important role in controlling water quality and further regulating physical ecosystem processes along mid-western Korean coastal area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.67-73
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• 1998

In order to find out the environmental factors influencing the catch of anchovy lift nets in kamakbay, the three oceanographic factors, i. e., the water temperature, the salinity, the amount of chlorophyll-a were observed respectively from August 1 to 12, 1995 and from September 20 to 26, 1995, and each of them was compared with the catch of anchovy by the lift net. The results obtained are summerized as follow : 1) The water temperature was ranged from 17.3 to 29.6$^{\circ}C$ and its difference between the surface and bottom was 1 to 3$^{\circ}C$. In the three areas, A, B and C, the area A was the hightest in temperature, the area B being a second, and the area C being the lowest. 2) The salinity was ranged from 32.20 to 33.47$\textperthousand$ and its difference between the surface and bottom was not significant. In the three areas, the area A was the highest in salinity, the area B being a second, and the area C being the lowest. 3) The amount of chlorophyll-a was ranged from 0.19 to 5.30mg/m supper(3) and its difference among the three areas was not significant. Daily variation of the amount was very irregulated because the position operated was changed daily. 4) A comparison of the water temperature, the salinity and the amount of chlorophyll-a with the catch gave that the water temperature and the amount of chlorophyll-a had large influence on the catch and the salinity did not so. However, the influence of the amount of chlorophyll-a was larger than that of the water temperature. 5) The catch of anchovy was large respectively during two hours after sun set and during two hours before sun rise.

• Journal of Food Hygiene and Safety
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• v.10 no.2
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• pp.53-59
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• 1995

Vibrio unlnificus, a normal inhabitant in estuaries, is of great concern because it is a potent human pathogen causing septicemia, wound infection and gastrointestinal disease in Kum river, sampling was undertaken in five station from March, 26, 1993 to February, 22, 1994. Samples of 54 and 49 were collected from seawater and bottom deposit. The total detection rate of V. unlnificus was 11.7%. The detection rates of V. unlnificus in the seawater and the bottom deposit were 9.3% and 14.3% respectively. V. unlnificus was mainly detected in estuary water when temperature was above 23$^{\circ}C$ and salinity was below 15%. We suppose that water when temperature, salinity, pH and COD affect growth of V. unlnificus.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.2
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• pp.132-140
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• 1997

The basic experiment on the telemetry system of temperature and salinity, which is a study for the effective management of costal fishing-ground nowadays, was carried of 8 days from April 5, 6, 26, 27 , 1996 to May 31 and June 1, 21, 22, 1996 at the fish farm of Yooksam at Samyang-Myun, tongyongkun(34。45.02'N, 128。24.79'E). The results obtained were as follows : 1. The average temperature and salinity of STD of telemetry system was coincided with that of ICTD system calibration precisely. 2. A daily variation of temperature in fish cage which was measured by the telemetry system was influenced mainly by sunrise and sunset. 3. A daily variation of salinity in fish cage which was measured by the telemetry system was influenced mainly by tidal current. 4. The fish school in fish cage was distributed mainly 2~7 m layer during daylight and was arisen to the surface at sunset, was settled down to the bottom at sunrise.