• Journal of the Korean association of regional geographers
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• v.12 no.3
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• pp.339-351
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• 2006

The purpose of this study is to investigate and analyze the relationships between tidal cycles, surface landforms, and sediments of tidal flats and their resident life. The study areas are Uengdo Ri in the Garolim Bay with wide the mud flat, Doou Ri in the Youngwang tidal flat which is developed sand flat and salt field, and Gomso Bay which is developed aquaculture industry. For resident around tidal flats, sea working takes precedence over farming, and main earnings gets from tidal flats. Resident life around the tidal flats is deeply related to tidal cycles, and low water level of spring tide becomes, they are most active and get more earnings than usual day, so it seems to be periodic markets. It is usually developed shellfish aquafarms in the mud flat, the stow net fishery in the sand flat, and salt fields in the mixed flat near the coast. Also a tidal flat has specialization of economic activity, and is divided into salt field and fish-farming in the supratidal zone, shellfish aquafarm in the intertidal zone, and oyster and porphyra culture in the subtidal zone.

• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.19-22
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• 2004

Seasonal changes of topograpy, sediment grain size and accumulation rate on the Gomso-Bay tidal flat(Fig. 1), west coast of Korea, have studied in order to understand the seasonal accumulation pattern and preservation potential of tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheiers accelerates during the winter and typhoon period, but it almost stops in summer when mud deposition is instead predominant on the middle to upper tidal flat. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods(Fig. 2). Measurements of accululation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface(Table 1) : the upper flat, where the accumulation rate of summer was generally higher than that of winter, was characterized by a continuous deposition throughout the entire year, whereas on the middle flat, sediment accumulations were concentrated in winter realtive to summer, and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Cancores taken across the tidal flat reveal that sand-mud interlaers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore(Fig. 3). Based on above results, it is suggested that the storm deposits formed by winter stors and typhoons would consist of the major part of the Gomso-Bay deposits(Fig. 4).

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.357-366
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• 2007

In Gomso Bay, on the west coast of Korea, the surface sediments sampled in 1991 and 2006 were analysed to identify the long-term variations of tidal flat sediments. Silt and clay contents have decreased in the bay-mouth tidal flats whereas sand and clay contents have decreased on the inner-bay and bay-head tidal flats over the last 15 year period. In particular, the clay contents of the tidal flats in 2006 were relatively low when compared to those of both tidal flats adjacent to other semi-enclosed bays and those of the tidal flats in 1991. The variations of textural compositions in the tidal flat sediments have led to changes of the sedimentary facies. It indicates that the changes must have been made by the changes of hydrodynamic conditions impacted by human activities, such as the construction of sea-walls, land reclamation, structures of farms constructed compactly near the low water line, and the Saemangeum dyke constructed in the northern part of the area where this research was conducted.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.552-561
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• 2023

The seafloor topography of Gomso Bay on the west coast of Korea was investigated using subtidal bathymetry and tidal-flat altimetry. Gomso Bay consists of 80% tidal flats and 20% subtidal zone, and is divided into an outer bay and an inner bay by the Jujincheon esturary channel. The outer bay tidal flat, has few tidal channels, has a concave topographic profile, and is characterized by the development of chenier and intertidal sand bars, giving it the appearance of gently sloping, dissipative beaches. The inner bay tidal flat has wide upper and middle tidal flats with a well-developed tidal channel system without cheniers. Moreover, the topographical cross-section between these tidal channels is convex upward, and shows the characteristics of a depositional environment greatly influenced by tidal channels and tidal action. An analysis of the horizontal movement of the tidal flat environment over the past 37 years investigating changes in the iso-depth lines in the Gomso-Bay tidal flat between 1981 and 2018 revealed that the Gomso-Bay tidal flat retreated gradually landward. As a result of analyzing the erosion and sedimentation characteristics of Gomso Bay, assuming that most of the water depth changes were due to changes in the elevation of the sea floor and sea level, an average of 1 cm (0 mm/y) of sediment was eroded in the outer bay over the past 37 years (1981-2018), In the inner bay, an average of 50 cm (14 mm/y) was deposited. Notably, the high tidal flats of the outer bay were largely eroded. Monitoring photographs of the coast showed that most of the erosion of the high tidal flats in the outer bay occurred in a short period around 1999 (probably 1997-2002), and that the erosion resulted from the erosion of sand dunes and high-tide beaches caused by temporarily greatly raised high tide levels and storms.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.869-877
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• 2017

Recently, Gomso Bay saw a decrease in the production of manila clam, which accounted for 17.8 % of production across the whole country in 2015, while Geunso Bay saw an increase that raised its contribution to 49.1 %. The tidal flats in these bays are inhabited by various benthos, and material flows in and out according to the tide. It is essential to understand the mass balance of these regions while giving consideration to the characteristics of these tidal flats. In this study, we compared areas where aquaculture farms were located in Gomso Bay with those without from May to August 2015. We divided the region into three sea areas (Sector I, Sector II, and Control), and the mass balance was estimated using the LOICZ model. As a result, the DIP of Sector II in Gomso Bay and another region in Geunso Bay, where a manila clam farm was located, were found to be -207.2 kg/day and 77.2 kg/day. The DIN was -4,996.7 kg/day and 926.6 kg/day. These results suggest that Gomso Bay han a higher density than Geunso Bay, which is thought to be mainly due to the feeding action of organisms. Therefore, in order to maintain a healthy tidal flat ecosystem and to sustain the production of manila clams, sustainable management to reduce the high density of tidal flat farms is necessary.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.149-157
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• 1998

Seasonal changes of topography, sediment grain size and accumulation rate in the Gomso-Bay tidal flat, west coast of Korea, have been studied in order to understand the seasonal accumulation pattern and preservation potential of the tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheniers accelerates during the winter and typhoon periods, but it almost stops in summer when mud deposition is instead predominant at the middle and upper tidal flats. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods. Measurements of accumulation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface. The upper tidal flat where the accumulation rate of summer was generally higher than that of winter was characterized by a continuous deposition throughout the entire year, whereas in the middle tidal flat, sediment accumulations were concentrated in winter relative to summer and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Can cores taken across the tidal flat reveal that sand-mud interlayers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore. Based on above results, it is suggested that the storm deposits by winter storms and typhoons would consist of the major part of the Gomso-Bay sediments.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.610-619
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• 2018

This study was carried out in August and September 2016 to investigate the species composition and biomass of benthic diatoms in Yubu Island, Gomso Bay, Imja Island, and Yeoja Bay tidal flat of Southwestern coast. There were 181 species of 48 genera in Yubu Island tidal flats, 194 species of 51 genera in Gomso Bay tidal flats, 224 species of 64 genera in Imja Island tidal flats and 188 species of 56 genera in Yeoja Bay tidal flats. A total of 274 species of 70 genera appeared. Pennales appeared more widely than Centrales and were dominated by Paralia sulcata and Navicula spp. Biomass of Yubu Island tidal flat ranged from $18.8-136.1mg\;m^{-2}$, $31.9-215.7mg\;m^{-2}$ in Gomso Bay, $2.9-120.2mg\;m^{-2}$ in Imja Island and $10.1-147.7mg\;m^{-2}$ in Yeoja Bay. The range of total biomass from 4 areas was $2.9-215.7mg\;m^{-2}$. The concentration of phaeopigment and degradation product of chlorophyll-a was $1.7-470.8mg\;m^{-2}$ in Yubu Island tidal flat, $52.3-277.2mg\;m^{-2}$ in Gomso Bay, $0.6-78.9mg\;m^{-2}$ in Imja Island and $39.1-346.3mg\;m^{-2}$ in Yeoja Bay. Compared with the results reported in this study area and the domestic tidal flats, it cannot be directly compared and evaluated due to various factors such as the timing of the survey, the frequency of the survey, the analysis method and geography. The southwestern coast of Korea has a variety of benthic diatoms and the high concentration of chlorophyll-a is the main determinant of primary productivity.

• Korean Journal of Remote Sensing
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• v.19 no.2
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• pp.117-133
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• 2003

A field survey and Landsat ETM+ image acquisition carried out simultaneously. Using these data, we attempted to establish relationships between tidal flat environmental factors and reflectance observed by ETM+, and to set up a new critical grain size useful for optical remote sensing. Although the grain size of 4 $\Phi$ has been conventionally used as a critical size by sedimentologists, the correlation with optical reflectance was very low. Instead, the grain size of 2 $\Phi$ showed a relatively high correlation coefficient, 0.699, with ETM+ band 4, except near tidal channels in upper tidal flat. We concluded that the grain size of 2 $\Phi$ would be better to use for a critical grain size in Gomso Bay. The grain size also correlated well with moisture content having a correlation coefficient of -0.811 when the 2 $\Phi$ criterion was used. The results of factor analysis showed moisture content was more important parameter than topographic relief, and they were different from German tidal flats in which topographic relief was the prior factor This can be explained by finer grain composition of the Gomso bay tidal flat. In short, moisture content and topography as well as grain size should be considered in tidal flat remote sensing.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.1
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• pp.44-56
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• 2000

Through the ISODATA method of unsupervised classification, the micro-landform of Gomso-Bay tidal flat was classified into mud, mixed, and sand flats by using Landsat TM image. Each tidal flat shows on apparent differences in its topographical characteristics and grain size compositions. Mud flat is occupied the innermost part of the tidal flat. Sand flat is distributed adjacent to the entrance of the bay, while the mixed one is located in the central part of the bay. Mud flat deposits have fine grain size, more than 4 in average mean phi, bad sorting, more than 1 phi in standard devation, and positive skewness. Mixed and sand flat deposits have coarse grain size, less than 4 average mean phi, good sorting, less than 1 phi in standard daviation, and negative skewness. Topographically, the mud flat consists of flat surfaces and dissected channels. The average depth of dissected channels is about 2 meters. Meanwhile, sand flat has a very flat landform with well-developed ripple marks of less than 10 centimeters in average relief. And the mixed one shows the intermediate topographical characteristics of those of mud and sand flats.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.878-884
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• 2017

It is important to understand interactions in the sediment-water environment because nitrate (N) and phosphorus (P) nutrient fluxes released into overlying water can represent a significant fraction of the total nutrient requirement for primary productivity. In this study, we analyzed and estimated benthic nutrient fluxes at the sediment-water interface, investigating environmental conditions in Gomso and Geunso Bays. Also, we compared previously reported nutrient flux data to identify regional differences. As a result, benthic nutrient fluxes in Beopsan were DIN: $6.14mmol\;m^{-2}d^{-1}$ and DIP: $0.32mmol\;m^{-2}d^{-1}$ higher than other survey sites. Sediment COD were $4.0-10.8mg/g{\cdot}dry$, and environmental deterioration was observed due to organic pollution. If no solution is found for tidal flat farm management, problems such as a decrease in aquaculture production will follow. Therefore, long-term monitoring of tidal flat environments should be pursued to enable the sustainable use of biological resources.