• Ocean and Polar Research
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• v.30 no.1
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• pp.1-10
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• 2008

In order to find the effect of intertidal sediments on nutrient cycle in coastal environment, we measured ammonia, nitrate, phosphate, and silicate concentrations every hour during at least 12 hours in the entrance of Keunso Bay during four seasons. The content of ammonia and silicate do not change considerably with season, but nitrate shows large seasonal variation. In summer, nitrate concentration was much lower than in other seasons, which resulted from large biological uptake and active denitrification in intertidal sediments during summer. Phosphate also exhibit seasonal variations, but not that large like nitrate. N/P and N/Si ratios were lower in summer than in other seasons, which was due to active denitrification in the intertidal sediments during summer. For all seasons, ammonia concentrations were higher at low tide than at high tide, but nitrate concentrations were higher at high tide. Dissolved inorganic nitrogen concentrations measured in spring, summer, and winter were higher at high tide than at low tide, but in fall, they were higher at low tide than at high tide. For spring and winter, phosphate and silicate concentrations were higher at low tide than at high tide, while in summer and fall, they were higher at high tide than at low tide. In Keunso Bay, intertidal sediments affect significantly the nutrient cycle around the coastal areas. The intertidal sediments act as a source for ammonia and silicate, but as a sink for nitrate. However, phosphate is not considerably influenced by intertidal sediments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.13 no.2
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• pp.27-32
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• 1977

The paper deals the fishing condition of the stern trawlers operated in the Atlantic coast of Africa. The datas are gathered from the Korean stern trawlers operated in the area from June, 1975 to May, 1976. The obtained results are summarized as follows: 1. The mean catch per haul are calculated as, cuttle fish 14.5kg, large size squid(more than :lOOg of body weight) 28.2kg, small size squid(less than 300g) 36.4kg, octopus 47.0kg. 2. Small size cuttle fish(less than5OOg of body weight) are caught much during after spring tide in July to September, yet, large size ClIttle fish(more than 500g) are caught much during neap tide in October to January. 3. Small size squid(less than 300g of body weight) are cBught much during after spring tide in October to December, yet, large size squid(more than 3OOg) are caught much during before spring tide in October to March. 4. Octopus are caught during neap tide in July to August.

• 한국해양학회지
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• v.10 no.2
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• pp.67-75
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• 1975

Tidal Flushing at the entrance channels of tidal bay or estuary in the central western coast of Korea; Gum River Estuary, Garorim Bay, Asan Bay, and Yeomha Estuary were studied with the recent data of current surveys measured by curret meter at three or five anchored stations along the section for one or two tidal periods at mean spring tide. Equilibrium relationship between tidal prism at mean spring tide and minimum flow area below the mean sea level of the channel in alluvial material was found as of O'Brien's (1931, 1969) study. Bed load transport in the tidal channel is balanced with the tidal flushing ability having a mean velocity of about 0.75m/sec or maximum velocity of about 1.25m/sec for a half tidal cycle over the section at mean spring tide which fairly agree with Brunn's study(1955, 1957). flushing actions for different hydraulic depth( mean depth) and bed material size in the channel were reviewed and found that it depend to a minor extent on the factors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.594-599
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• 2001

In a sandy shore surf zone of Dolsan Island, diel, tidal and seasonal effects on abundance of Acartia omorii were investigated at three sites, the bottom and surface of 1 m depth and water's edge using a sledge-net. Of these sites, the abundance of A. omorii was the highest in the bottom. Seasonal abundance data showed that A. omorii was more abundant in winter than other seasons. During the study period, the abundance of A. omorii was always higher during ebb tide than flood, The distribution patterns of A. omorii were more influenced by tide than diel change, Strong current during spring tide possiblely affected the diel migration pattern, In winter A. omorii showed a diel vortical migration in neap tide, whereas it showed a reverse vortical diel migration in spring tide. Distribution centers were located at a layer of $50\~100\;cm$ below mean sea level (MSL) during neap tide, and then it moved slightly upward during spring tide.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.3
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• pp.29-35
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• 1986

The characteristics of tidal exchange in Masan Bay were studied on the basis of salinity observations and current measurements in the summer of 1985. The exchange ratio of the sea water was calculated using three different formulas. The tidal exchange rate was estimated to be smaller than that of another bays in the southern coast of Korea. The tidal exchange ratios in Masan Bay at spring tide were deduced to be 2.4-11.7%. While those at neap tide were 2.0-9.1%. Though tidal range of neap tide is smaller than that of spring tide. the tidal exchange ratio in the bay can be increased in case of highly stratified vertical structure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.353-362
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• 1993

Behaviors of effulent are observed and discussed with reference to the tide and freshwater discharge in the estuary of Suyoung Bay. The esturine front is located at $0.5{\sim}1.3km$ seaward from of the Suyoung Bridge at the spring tide, and $0.8{\sim}1.0km$ at the neap tide. After the heavy precipitations, the front moved seaward and was located at $1.3{\sim}2.5km$ southeast of the Suyoung Bridge. Internal Froude numbers in the estuarine salinity front are estimated approximately to be 1 both at the spring and neap tide. Entrainment coefficient decreases down stream to the estuarine front, and then increases seaward from the estuarine front due to the tidal mixing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.90-100
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• 2021

In the north and northeast of Cheonsu Bay, short-term fluctuations of surface water temperature are large owing to shallow water depth, weak current, and freshwater runoff. However, in the south of the bay, water temperature fluctuations are small owing to the inflow of offshore water by tidal currents. The water temperature in the north of the bay is higher in spring and summer than in the south of the bay, but lower in autumn and winter. During spring season, the fluctuation in the northern surface water temperature is the highest. The temperature fluctuations owing to tides are in phase with the tide in autumn and winter, and in the reverse phase with the tide in spring and summer. The dominant periods of water temperature fluctuations are half a day, daily, 15 days, and 1 month owing to the tide and 7 to 10 days, which are estimated based on atmospheric factors. Half a day and daily water temperature fluctuations are also highly correlated with air temperature and wind fluctuations. The sea area where water temperature fluctuations are highly correlated is divided into the north and south of the bay. The fluctuation phase is faster in the north of the bay than in the south or in the center.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.589-600
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• 2019

In order to investigate the flow structures around Geumo archipelago on Southern Waters of Korea, water movements were measured for 25 hours during spring tide in May and neap tide in September 2002 using ADCP (Acoustic Doppler Current Profiler) attached to a running boat. Dominant directions of ebb and flood current at spring tide are SE-NW, representing the average flow rate of approximately 40cm/s in the surface layer. However because of the topographical reason, the direction and speed of the flow in the narrow waterway sea area around the northwest of Gae Island were different. There was no notable baroclinic component of tidal flow at spring tide. This indicates that the sea area has been actively engaged in vertical mixing due to island wake or eddy due to narrow waterways, shallow water depth and rapid flow rate around archipelago. At neap tide, dominant directions of tidal flows are SSE-NNW and the average flow rate in the surface layer is about 85 percent of the spring tide. The duration and intensity of the flow direction are shorter and less dominant than the spring tide. It is expected that asymmetrical tidal mixing will occur due to vertical velocity shear and horizontal eddies. From daily mean tidal flows obtained from the ADCP observation, it was found that the northwest of Gae Island have flows in NW~NE, the west of Geumo Island have the average currents of up to 21 cm/s WSW~SSW and counterclockwise circulation or eddy currents are formed in the west of Sori Island.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.353-359
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• 1990

Chinhae Bay, included small ports, is the region which the red tide phenomenon is occurred frequently in summer season. Field sampling of 4 cross-sections in the bay resulted in detailed informations on cross-sectional velocity distributions, salt concentrations and discharge during one consecutive tidal cycle in summer season, 1983. High velocity cores reoccur two times a semi-diurnal tidal cycle at the same cross-sectional location, lower layer, in Kadok Channel during the spring tide. The tidal exchange ratio was estimated by Eulerian method. The range of exchange ratios in central Kadok Channel are 9.3-17% at the spring tide and 16.9-21.8% at the neap tide. On the other hand, its range in Masan bay-mouth is 8.7% at the spring tide and 2.0% neap tide, respectively.