• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.8 no.4
• /
• pp.349-356
• /
• 2003

A continuous monitoring of sedimentation rate and textural characteristics of surface sediments was carried out on the tidal flats in Kwangyang Bay, middle South Sea for two years on an every-two-monthly basis. This study shows that during the winter the tidal flats receive a thin surface layer of which texture becomes finer. In summer, the surface sediments were subject to rather abrupt erosion by occational typhoons and heavy rainfall resulting in a coarse-silt dominated texture. Due to nearly closed geomorphology of Kwangyang Bay, local waves created in the bay during winter are much subdued, in contrast to the rough wave climate and associated sedimentary cycle for open-type tidal flats in the Yellow Sea. In addition, unexpected artificial effects on the tidal-flat sedimentation by construction of a huge industrial complex along the shoreline of the bay are observed from a nearby tidal flat. Here, the sediments were consistently eroded without any sign of natural seasonal variations.

• Journal of the Korean earth science society
• /
• v.23 no.7
• /
• pp.565-574
• /
• 2002

Based on previous investigations of aerial photographs and topographical surveys, this study focuses on the sedimentologic features of the Daebudo area including sedimentation processes, sedimentary facies and hydrologic conditions of the erosional coast. A total of 137 surface sediments and one core (by hand auger) sediment were obtained to interpret the depositional environment of the erosional coast in the macro-tidal coast. Surface sediments are distributed from sandy gravel (sG) to silt (Z). Textural parameters are characterized not only by coarse, poorly sorted, positive skewed and multi-modal distribution in the supra-tidal flat, but also finer, relatively well-sorted, symmetric distribution in the intertidal flat. According to the C/M diagram, sediment transport modes of study area are characterized by the mixed mode of suspension and bedload in the upper-, middle-tidal flat and by uniform suspension in the lower-tidal flat due to tidal effect. Vertical sediment distribution of the core, collected near shoreline, shows coarsening-upward, poorly sorted pattern by the input of detritus resulting from coastal erosion. Considering the sedimentological features of the study area, it appears to be composed of a coastal zone changed by not only artificial reclamation, but also by natural processes such as strong wave action due to typhoons and storms during high water level and long/short-term sea level rising. As a result, tide-dominated erosional coasts show that the shore is affected by local, temporal and hydrological conditions near high tide level and that the intertidal flat is represented by a general tide-dominated sedimentary environment.

• Journal of Aquaculture
• /
• v.21 no.2
• /
• pp.111-122
• /
• 2008

This study was conducted to assess the usefulness of the temperature characteristics of the tidal flat sediments during low tide as a environmental factor, and burrowing behaviour, fatness, total hemocyte counts(THCs) and differential hemocyte counts(DHCs) of hard clam Meretrix lusoria as biological activity indices for the management of hard clam farms located in Taean(Chungnam province) and Gimje(Jeonbuk province) tidal flat in Korea. Temperature ranges of the sediment at 1cm depth during spring(March to May) and summer(June to August) in Taean(where the exposure time was about $5.5{\sim}6$ hours during low tide) were $8.7{\sim}26.8^{\circ}C\;and\;27.6{\sim}32.8^{\circ}C$, respectively. Even though there was no significant difference(P>0.05), temperatures of the surface sediment where submerged with remained seawater were generally higher than that of uncovered with seawater. Burrowing depths of normally digged hard clams were 0.9{\sim}3.6cm from March to October, 2002. In the field experiment performed at Taean farming ground covered with seawater, burrowing times of the clams under natural water temperatures were $41.6{\pm}10minutes$ in February and $5.4{\pm}1.3minutes$ in August, respectively, and these were influenced by water temperatures. Fatness of hard clams began to decrease from May(at Taean tidal flat) and June(at Gimje tidal flat), showed the lowest level in August and increased again from September. Total hemocytes counts in the hemolymph of the hard clams were decreased to the lowest level in July($24.7{\times}10^4cells/mL$, at Taean tidal flat) and August($28.2{\times}10^4cells/mL$, at Gimje tidal flat), and significantly increased again from September(at Taean tidal flat, P<0.01) and October(at Gimje tidal flat, P<0.001), respectively. We observed three types of hemocytes from the hemolymph of hard clams according to whether hemocytes retain the granules or not and the size of the granules. As a results, we could found that periodical monitoring of the sediment temperatures, clam burrowing behaviour and hemocyte parameters were very helpful for the management of hard clam farming.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.6
• /
• pp.1197-1206
• /
• 2019

Suncheon Bay is a very important natural resource and various efforts have been made to protect it from the environmental pollution. Although the project to monitor the environmental changes in periodically by observing the creatures in tidal flats is processing, it is being done inefficiently by people directly observing it. In this paper, we propose an object segmentation method that can be applied to the method to automatically monitor the living creatures in the tidal flats. In the proposed method, a foreground map representing the location of objects is obtained by using a temporal difference method, and a superpixel method is applied to detect the detailed boundary of an image. Finally the region of crab is extracted by combining the foreground map and the superpixel information. Experimental results show that the proposed method separates crab regions from a tidal flat image easily and accurately.

• Journal of Korean Society of Rural Planning
• /
• v.13 no.3
• /
• pp.61-72
• /
• 2007

Natural resource of the island and coastal regions is one of the most important element of ecological network system in Korea. Currently, there is trend that natural and biological resources such as fishing and tidal wetland have been used to local economic activation in island and coastal regions. According to the 5-days work in a week, island and coastal regions become important amenity resource of citizen's recreation area. Korea is peninsula surrounded by maritime. Especially, South and West Sea surrounded by many islands and tidal flat wetlands are emerging marine ecosystem and seascape in the world. Natural resource is limited, so we have to sustain those resource to current tourism. In this study, I would like to suggest that importance of cultural resource as well as natural resource for 'eco-cultural tourism' in order to keep both biological diversity and cultural diversity as amenity resource for future island economic activation in Korea.

• Journal of the Korean association of regional geographers
• /
• v.19 no.2
• /
• pp.223-233
• /
• 2013

Yeonpyeong Island, an island of Ong-jin County, is a very important and meaningful area in terms of its geo-politics and natural environment. But in spite of well preserved natural environment, because of limited access and security risk, there were little researches. In this sense this study would be meaningful for inquiring into the regional geomorphology of Yeon-pyeong Island. The major findings of this study are as follows. 1) 12 sites among 20 sites was evaluated 1st grade, and this means that geomorphic value of Yeon-pyeong Island is very excellent. 2) Coastal landforms of Yeon-pyeong Island are classified three major types which are rocky coast which consist of wave-cut platform and sea cliffs, sand or shingle beaches and coastal plain in the embayment area, and tidal flat areas and small uninhabited islands. 3) Cross sectional shape of Yeon-pyeong Island is asymmetric, since coastal erosion of island concentrate on the northern and western shore. 4) Quality and value of tidal flats will be deteriorate unless the dyke construction is stopped.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.25 no.2
• /
• pp.41-51
• /
• 2013

The tidal creek dependent mass transport characteristic in Gyeong-Gi Bay (west coast of Korea) was studied using field measured data and numerical model. Gyeong-Gi Bay consists of 3 main tidal channels and contains a well-developed vast tidal flat. This region is famous for its large tidal difference and strong current. We aim to study the effect of tidal creek in the tidal flat on the mass exchange between the estuary and the ocean. For numerical application, the application of unstructured grid feature is essential, since the tidal creek has complicated shape and form. For this purpose, the FVCOM is applied to the study area and simulation is performed for 2 different cases. In case A, geographic characteristics of the tidal creek is ignored in the numerical grid and in case B, the tidal creek are constructed using unstructured grid. And these 2 cases are compared with the field measured cross-channel mass transport data. The cross-channel mass transport at the Yeomha waterway mouth and Incheon harbor was measured in June, 9~10 (Spring tide) and 17~18 (Neap tide), 2009. CTD casting and ADCP cross-channel transect was conducted 13 times in one tidal cycle. The observation data analysis results showed that mass transport has characteristic of the ebb dominance Line 1 (Yeomha waterway mouth), on the other hand, a flood dominant characteristic is shown in Line 2 (Incheon harbor front). By comparing the numerical model (case A & B) with observation data, we found that the case B results show much better agreement with measurement data than case A. It is showed that the geographic feature of tidal creek should be considered in grid design of numerical model in order to understand the mass transport characteristics over large tidal flat area.

• The Korean Journal of Quaternary Research
• /
• v.1 no.1
• /
• pp.21-34
• /
• 1987

In the present study area, a part of intertidal flat in the Seosan Bay, west coast of Korea, characteristic three dominant tidal sedimentary facies and their related several typical sedimentary structures are described, Furthermore, a possible interpretation about the time stratigraphic developments of these intertidal deposits is suggested by introducing very late Quaternary (Holocene) sea-level rise in Korean Seas.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.4
• /
• pp.402-408
• /
• 2003

A quantitative method was suggested for estimating damages in fishery production due to the diffusion and deposition of suspended silt and clay by various construction processes in tidal flat fishing grounds. Marine populations are maintained through the process of spawning, growth, recruitment, natural death and death by fishing each year. All of the year classes of the population in a fishery ground could be affected when damages occur by human activities such as land filling or reclamation. The propose of this study is to calculate damages in terms of fishery production using a quantitative population dynamic method. If the maximum age in the population is $X_\lambda,$ the starting year of damage is $t_s,$ and the ending year of damage is $t_e,$ the number of year classes damaged is $t_{s-n\lambda}-t_e,$ Many year classes present in the year $t_s,$ and so if damages occur, they Influence all the year classes which are present in the population. Damaged year classes in year $t_e$ would still be in the population until the year $t_{e+n\lambda}$, where $n_{\lambda}$ is the oldest age class. If the expected yield of a year class is constant, the total yield from year classes in the fishing ground during the construction periods can be calculated as follows: $Y_\Phi=[(t_e-t_s+1)+n_c]{\cdot}Y_E+\sum\limits^{n_\lambda-n_c}_{l=1}\;\sum\limits^{n_\lambda-n_c}_{l=i}\;Y_{n_c+i}$ This method was applied for damage estimation in the production of Ruditapes philippinarum in a tidal flat fishing ground.

• Journal of Ecology and Environment
• /
• v.38 no.1
• /
• pp.57-65
• /
• 2015

A natural mixed stand of Phragmites australis and Phacelurus latifolius was studied to clarify the distribution properties in a microsite in a tidal flat of Suncheon Bay. The height, density, and biomass of the shoots, as well as the biomass of the root system, were monitored for both species along with the altitude on a mound from June 2010 to October 2013. Firstly, the mean height and dry weight of both species were similar during the growth season. However, individual variations of the sizes of plants in the same species were noticeable. Secondly, the density and dry weight per unit area of P. latifolius increased, but that of P. australis decreased with the altitude on the mound. Thirdly, the root system (rhizomes and roots) of P. latifolius was mostly located in the upper layer (up to 20 cm depth), while that of P. australis was in the lower layer (over 70 cm depth) of the sediment. The roots of P. australis penetrated to the lower parts of the water table, while the roots of P. latifolius did not make contact with free water of the sediment. Fourthly, the removal of the shoot in the early growth season led to a visible reduction of biomass in the late growth season. The reduction rate was larger in P. latifolius than in P. australis. Lastly, in the area where the mound was removed, the density of P. australis increased in the first two years (2010-2011) and was highly sustained inthe last two years (2012-2013). However, the density of P. latifolius was low, and this plant was distributed at the edge of the mound only.