• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.619-626
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• 2014

In this paper, it was constructed the halophyte Mesocosm experimental which was used tidal flat and dredged sediment as a substrate material. Depending on the vegetation and substrate material of Mesocosm, Mesocosm A(tidal flat sediment + Salicornia herbacea), Mesocosm B (only dredged sediment), Mesocosm C(dredged sediment + Salicornia herbacea). Monitoring was carried out of Warter quality factots(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P), water temperature, salinity), Sediment factors(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P)) and growth of Salricornia herbacea. Habitat Stability Index of vegetation was calculating by using the monitoring results. HSI of Mesocosm C was calculated from 0.87 to 0.95 as compared to the relatively high HSI in Mesocosm A, it was evaluated to be able to be used in the restoration and construction of the coastal salt marsh with dredged sediment.

• 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 Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.215-225
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• 2004

Biomass and community composition of microphytobenthos in the Saemankeum tidal flat were studied by HPLC analysis of the photosynthetic pigments from November 2001 to November 2002. The environmental factors of sediment were also investigated to examine the relationship between microphytobenthos biomass and sedimentary environments. The detected photosynthetic pigments of microphytobenthos were chlorophyll a, b, c, fucoxanthin, 19'-hexanoyloxyfucoxanthin, violaxanthin, diadinoxanthin, alloxanthin, diatoxanthin, zeaxanthin+lutein, peridinin and beta-carotene. Pheophytin a, the degradation product of chlorophyll a, was also detected. The results of pigmen analysis suggest the presence of diatom (fucoxanthin), euglenophytes (chlorophyll b), chlorophytes (chlorophyll b + lutein), cyanobacteria (zeaxanthin), cryptophytes (alloxanthin), chrysophytes (fucoxanthin + violaxanthin), prymnesiophytes (19'-hexanoyloxyfucoxanthin) and dinoflagellates (peridinin). Chlorophyll a concentration in the top 0.5 cm of sediment was in the range of $0.24\;mg{\cdot}m\^{-2}\;-32.11\;mg{\cdot}m\^{-2}$ in the study area. The increase of chlorophyll a concentration in the spring indicates the occurrence of a microphytobenthic bloom. In the summer, there was a sharp decrease of the chlorophyll a concentration which was probably due to high grazing activity by macrobenthos. The annual mean chlorophyll a concentration in the study area was low compared to that in most of other tidal flat areas probably due to active resuspension of microphytobenthos and high grazing activity by macrobenthos. There was no clear relationship between microphytobenthos biomass and sedimentary environments because of a large variety of physical, chemical and biological factors, Pigment analysis indicated that while diatoms were dominated in the microphytobenthic community of the Geojon tidal flat, euglenophytes and/or chlorophytes coexisted with diatoms in the Mangyung River tidal flat.

• Korean Journal of Remote Sensing
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• v.21 no.5
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• pp.405-415
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• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• Journal of Environmental Science International
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• v.32 no.3
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• pp.181-189
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• 2023

In this study, sediment cores from unvegetated tidal flats in the Hampyeong Bay (west coastal wetland) and Dongdae Bay (south coastal wetland) were sampled, the blue carbon stock in the sediments was calculated, and the characteristics of the blue carbon stock were analyzed based on particle size of the sediments. The sediments in the Hampyeong Bay tidal flat had large particle size and low mud content, and the Dongdae bay tidal flat had small particle size and high mud content. The organic carbon content and blue carbon stock in the sediments were higher in the Dongdae tidal flat than in the Hampyeong Bay tidal flat. As a result of the regression function, in both the Hampyeong Bay and Dongdae Bay tidal flats, the sediments had the smaller particle size and higher mud contents the higher the organic carbon content and blue carbon stock. The sediments with smaller particle size had the larger specific surface area, so were feasible to adsorb and store more organic matters.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.22-24
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• 2007

Waterline extraction is the one of widely used methods for studying changes in tidal flat environment and coastlines using multi-temporal optical images such as Landsat TM and Landsat ETM+. High dynamics of tidal currents and land reclamation which accelerate sedimentation and/or erosion cause waterline change in tidal flats. The amount of sediment deposited or eroded can be evaluated by precisely estimating waterline changes in tidal flats. The objective of this study is to detect the change of waterlines during 17 years and analyze the trends of erosion and sedimentation in the study areas. The Ganghwado tidal flat on the west coast of the Korean Peninsula was selected. The study area is famous for high dynamics of tidal currents and vast tidal flats. Land reclamation which has been carried out on a large scale is also considered as one of elements that have accelerated the environmental changes in this tidal flat. In this study, we acquired 26 waterlines from Landsat TM and Landsat ETM+ images. We extracted the waterline from each satellite image to generate a digital elevation map (DEM) which was used for reference and to compare with the other waterline which was extracted from DEM having a same tide. The result of comparison well depicted the areas of dominant sedimentation and erosion, and general trends of sedimentation and erosion according to sub-regions are also revealed during the investigation time. Results showed that erosion during a decade was dominant at the west of the Southern Ganghwado tidal flat, while sedimentation was dominant at the wide channel between the Southern Ganghwado tidal flat and the Yeongjongdo tidal flat. This area has been commonly affected by high currents and sedimentation energy. Although we were not able to verify the accuracy of the waterline changes, this result clearly showed the waterline change and therefore, the waterline extraction method used in this study has proven as an effective tool for long term tidal change estimation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.687-697
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• 2019

By monitoring sediment grain size and level variation of tidal flat surface for 6 years (2005-2011), and also by mooring TISDOS (tidal-flat sediment dynamics observation system) on the low intertidal flat in 2008, we investigated the sedimentary environment of tidal flat in the dammed Yeongsan River Estuary. The tidal flat of the Yeongsan River Estuary lost 82 % of its area because of coastal development projects, and a narrow tidal flat below mean sea level now remains. Most of the tidal flat sediments are composed of silt up to 70-94 %, and show the characteristics of clay deficiency and silt dominance. This is closely related with the coastal development, which led to the destruction of high tidal flats where most mud settled, and the modification of tidal current patterns. Moreover, the estuarine tidal-flat sediments reveal seasonal variation. They are coarse with abundant silt during windy autumn to spring, fine with abundant clay during the less-windy and high-discharge summer. This phenomenon indicates that the behavior of sediment particles on the low intertidal flats of the Yeongsan River Estuary is influenced by wind waves for silt and fresh water discharge and the tidal process for clay. Monitoring results of the altitude of tidal flat surface showed that the study area had eroded at an average rate of -2.6 cm/y during the period of 2005-2011, and also that an unusual deposition with a rate of 4 cm/y occurred in 2010. The erosion can be explained by an increased tidal amplitude and a strengthened ebb-dominant tidal asymmetry after the construction of an estuary dike and the Yeongam Kumho Seawall. The deposition in 2010 seems to have been closely related to the mass production of suspended materials from dredging of the estuary.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1018-1020
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• 2003

The costal area where takes up over 32% in domestic teritory is considered as very importantly because it has not only economic facilities such as harbor and an industrial complex but also recreation facilities. Moreover, the tidal flat area has been used as culture ponds and salt farms because this area is occupied by various oceanic species. Also, the tidal flat area has played an important role to purify ocean pollution and maintain an ecosystem. However, the costal ecosystem has seriously threatened by domestic reclamation projects and a large-scale tide embankment during recent 10 years in Korea. This serious problem results in loosing 34%(810$km^2$) of the entire domestic costal area. In this paper, the micro-landform in the tidal flat area, which is called as Garolim bay in Korea, is classified by using Landsat TM images also verified through a filed report. Through the result of this, the tidal flat area is expected to manage efficiently especially through analyzing sediment environment and characteristic of grain size by using satellite images.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.500-509
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• 2021

This study investigated the characteristics of a macrobenthos community and sediment environment and assessed the health of tidal flats along the west coast of Korea. A survey was conducted from Ganghwa-do to Mokpo, Jeollanam-do in April (spring) and August (summer) 2017, and April (spring) 2018. The sediment grain sizes in the Chungcheongnam-do region were coarser, and the sediment in the Gyeonggi-do·Incheon, Jeollanam-do, and Jeollabuk-do regions were finer. A total of 140 macrobenthic species were collected from this study and using a cluster similarity analysis of the macrobenthos community, they were divided into four groups. Group2 was associated with Manila clam farm stations, and Ruditapes phillipinarum, Nephtys polybranchia and Lumbrineris nipponica were dominant. Group4 included some sites with finer sediment composed relatively, and Eteone longa and Nemertea unid. appeared at a high frequency. From the health assessment of the western tidal flat, the ISEP and BHI indices had a "High status," and the AMBI index had a "Good status." In conclusion, the tidal flats along the west coast of Korea have good ecological health. However, pollution indicator species such as Theora lata and Capitella capitata have appeared in some areas. Therefore, periodic administration and interventions are necessary to prevent deterioration of the tidal flat environment.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.15-20
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• 2010

The contamination loadings generated in Changwon City are coming into Masan Bay through the Bongam tidal flat except the loadings collected and transferred by sewer lines to the wastewater treatment plant. The recovery of waterbirds, shellfishes, and fishes has been quite well recognized in recent years after the first implementation of Masan Bay TPLM (Total Pollution Loads Management) in Korea. This tidal flat has been conserved by the cooperation of several stakeholders and utilized as an ecosystem field site for in situ education. A large industrial complex has been operated since 1970's, therefore increasing the level of pollutants in estuary and costal sediments, especially by heavy metals. Zinc, copper, and lesd contamination of sediment was revealed at higher level by Clean-up guideline (MOMAF) or heavily polluted level by SQC (USEPA). There was a significant difference between two sites at the 95% confidence level, which implies no homogeneity in the processes of transport and deposition even at 500 m of distance. The heavy metal concentrations in the Bongam sediments have been gradually decreased with comparing the data of 2006, and 2009.