• The Korean Journal of Quaternary Research
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• v.3 no.1
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• pp.47-54
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• 1989

Pyrite ($FeS_2$) content in brackish and salt marsh sediments is relatively higher than the amount in freshwater marsh sediments. Different values of pyrite sulfur ($FeS_2$-S) content in sediments from the Hiroshima Delta indicate that poorly drained salt marsh had developed between 27.0m and 28.0m below mean sea-level and palaeo-sea-level was constant for several hundreds of years in the same depth during the early Holocene Epoch.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.53-64
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• 2009

Wetlands can remove organic contaminants, metals and radionuclides from wastewater through various biogeochemical mechanisms. In this study, a mathematical model was developed for simulating the fate and transport of chemical species in marsh wetland sediments. The proposed model is a one-dimensional vertical saturated model which is incorporated advection, hydrodynamic dispersion, biodegradation, oxidative/reductive chemical reactions and the effects from external environments such as the growth of plants and the fluctuation of water level due to periodic tides. The tidal effects causes periodic changes of porewater flow in the sediments and the evapotranspiration and oxygen supply by plant roots affect the porewater flow and redox condition on in the rhizosphere along with seasonal variation. A series of numerical experiments under hypothetical conditions were performed for simulating the temporal and spatial distribution of chemical species of interests using the proposed model. The fate and transport of a trace metal pollutant, chromium, in marsh sediments were also simulated. Results of numerical simulations show that plant roots and tides significantly affect the chemical profiles of different electron acceptors, their reduced species and trace metals in marsh sediments.

• 한국해양학회지
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• v.30 no.4
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• pp.320-331
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• 1995

The closely spaced cores were analyzed to find detailed reconstruction of paleoenvironments and sealable changes along the Delaware Bay coast. Three areas, Kitts Hummock Beach mars, the St. Jones River marsh, and Bowers marsh near the St. Jones River's mouth, were chosen because these areas are compose of their own geomorphic characteristics and sea-level history. since significance of the stratigraphic correlations was to determine sedimentary fancies and paleoenvironments, multidisciplinary methods such as lithological description, grain-size analysis, organic/inorganic content, water content, mineral composition, botanical analysis, micropaleontological analysis, and /SUP 14/C datings were performed. Five major divisions of marsh environments were recognized in the stratigraphic sections: freshwater marsh, initialfreshwater marsh, slightly brackish marsh, brackish marsh, and salt marsh. Most of the lower part in the stratigraphic sections show freshwater marsh. On the top of this, either brackish marsh or tidal flat/tidal stream was recorded. The pro-Holocene sediments consist of sand, mud, and sandy mud, The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene sediments consist of sand, mud, and sandy mud. The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene surface within short distances permitted the concurrent development of variable environments such as freshwater marsh, brackish marsh or salt marsh at similar elevations. The freshwater marsh in this case was formed in the areas of isolation, so saline-water cannot encroach upon these areas. This complex development of paleoenvironments leads to a difficulty in stratigraphic correlation and interpretation of local relative sea-level changes. The deposition of subsurface sediments was affected by sediment supply, compaction, fluvial activity, biological competition, local tectonics and isostacy, climate and local relative sea-level changes. It was interpreted that the positions in the changes from freshwater environments to brackish environments or ice versa are the turning points of transgressions and regressions. Therefore, multiple transgressions and regressions were identified in the stratigraphic sections of the study area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.180-188
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• 2006

We examined the effect of salt marsh vegetation on the benthic environment in macro-tidal flats at Donggeomdo, Ganghwa, on the west coast of Korea. Nine stations were established along a transect across the tidal flats, including salt marsh, and field sampling was conducted monthly from July 1997 to June 1998. During the study period, environmental parameters fluctuated as follows: salinity, 15.0 to 28.2 psu, exposure time, 613 to 702 hr/m, inundation time, 28 to 117 hr/m, sediment organic carbon, 0.71 to 1.34%, nitrogen, 0.07 to 0.16%, sulfur from 0.07 to 0.22%, mean grain size from 6.3 to $6.9{\phi}$, water content from 19.4 to 44.4%, water temperature from 4.4 to $20.4^{\circ}C$ and temperature of the surface sediments, 2.7 to $31.1^{\circ}C$, in total, seven halophyte species were sampled and found to be vertically distributed across the tidal levels. Carer scabrifolia, Suaeda maritima, Limonium tetragonum and Phragmites communis dominated the upper zone of the salt marsh, Juncus haenkei, Triglochin maritimum and P. communis dominated the middle zone, and Suaeda japonica predominated in the lower area. Principal component analysis (PCA) and non-metric multi-dimensional scaling revealed that the zonation of halophytes was related to environmental variables such as salinity and exposure time. The halophyte communities were likely related to the organic content of the surface sediment.

• 한국해양학회지
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• v.13 no.1
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• pp.9-18
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• 1978

The intertidal flat depositional environment of Southern Nam Yang Bay, west coast of Korea has been studied to understand textural, geochemical and mineralogical characteristics. The intertidal flat environment can be divided into two subenvironments, that is, the mud flat and the sand flat due to the sediment textures. From thd outer sand flat to the inner mud flat the grain size of the sediments decreases and the mud content increases. It is suggested that the intertidal flat environment is in the progradation of marsh deposits in the mud flat. The chemical composition of the sediments is related to the sediment textures. The chemical index of maturity of the mud flat sediments is higher than that of the sand flat sediments. The clay minerals of the sediments are chlorite, illite, montmorillonite and kaolinite.

• Ocean and Polar Research
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• v.24 no.1
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• pp.63-71
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• 2002

This preliminary study on the changes of macrobenthic assemblages in experimental sediment fences was conducted as a part of tidal marsh restoration project. Intertidal sediment fences were designed to increase the efficiency of trapping sediments on unvegetated tidal flats in order to raise sediment elevation and to allow colonization of intertidal vegetation. Although increment of soil surface level was not observed over the first three months of the study, it was possible to obtain some effects of the sediment fence. Three months later, the particle sizes of the surface sediment at experimental plots became much finer compared to unfenced areas on the natural mudflats located in the same tide level as that of the plots. The difference was much greater on the plot with drainage canals than on the plot without ones. Species diversity of the experimental plots became much higher than that of natural sites. Perinereis aibuhitensis and Glauconome chinensis which were absent from initial community appeared with high density in the plot with drainage canals. Those species were significantly different in abundance between the experimental plot and the natural mudflat. Changes in species composition were not detected in another experimental plot without drainage canals.

• The Korean Journal of Quaternary Research
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• v.24 no.1
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• pp.35-45
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• 2010

The aims of this study are to clarify the geomorphological development of a alluvial plain and discuss the vegetation environments and agriculture activities in the Wangpo-River alluvial plain at Neungsan-ri, Buyeo by analyzing geomorphological classification, sedimentary facies and age datings. The alluvial plain at Wangpo-River was formed by the influences of Geum-River with the sea-level rising during the Holocene. The basin of Wangpo-River consists of natural levees, back marsh-type alluvial plains, valley plains and hills. The natural levees by Geum-River largely distributes at the area where Wangpo-River flows to Geum-River and the alluvial plains at the middle and lower reach are the back marsh areas of Geum-River. Moreover, the area along Wangpo-River show higher contents of coarse materials and thinner peat sediments than the back marsh. The lower sandy deposits in the alluvium of Wangpo-River was formed with the influences of human in the Bronze Age during the sea level falling and the peaty deposits was formed due to the water level rising of Wangpo-River during the sea level rising in the early Iron Age.

• Journal of The Geomorphological Association of Korea
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• v.28 no.1
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• pp.35-50
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• 2021

In this study, we analyzed the changes in the topographical landscape and the sedimentary environment to evaluate the ecological value of the Dongcheon Estuary and protect the wetland, and presented the conservation management method of the Dongcheon Estuary. Based on the result of topographical landscape analysis, agricultural land tended to decrease continuously, and artificial structures gradually increased. Moreover, in sediment analysis, the Dongcheon Estuary showed both the characteristics of river sediments and coastal sediments, and in some areas problems such as acidification and nutritional imbalance appeared. Therefore, in order to protect and manage the Dongcheon Estuary with high ecological value, it is necessary to limit the development around micro topography and minimize the artificial damage in the Dongcheon Estuary. In addition, efforts such as securing facilities for reducing pollutants and freshwater wetlands for pollutants, that flow in from nonpoint pollutants are required.

• Animal Systematics, Evolution and Diversity
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• v.24 no.1
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• pp.89-98
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• 2008

Two copepod species of Leptocaris belonging to the family Darcythompsoniidae are recorded from sandy mud sediments of salt marshes in South Korea: L. brevicornis (van Douwe, 1905) and L. trisetosus pacificus n. ssp. The genus Leptocaris is newly known from Korea. Leptocaris trisetosus pacificus differs from the nominate subspecies in exhibiting a sexual dimorphism in setal armature of leg 3, that is, bearing an additional seta on the second endopodal segment of leg 3 in male and an allopatric geographical distribution. This paper deals with the description and systematic accounts of them with detailed illustrations.

• Journal of the Korean earth science society
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• v.44 no.4
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• pp.264-274
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• 2023

The Korea Strait comprises a continental shelf in a shallow sea that experienced glacio-eustastic sea-level changes during the Quaternary period. A long core of 76.6 m in length was acquired at the South Sea Drilling Project site (SSDP-101; 34°19.666'E and 128°16.335'N) with a 60 m water deep. The uppermost massive sand beds were interpreted as sandy sediments of the nearshore marine sand ridge in the shallow sea during the transgression of sea level, whereas the lower parts of alternating sandy and muddy beds were interpreted as deposits in marsh, estuary, and tidal flat environments. A three-layered geoacoustic model was reconstructed for the sedimentary succession in the high-resolution seismic profile based on a 140-grain size and sediment type of core SSDP-101. For the actual underwater simulation and experiments, the in-situ P-wave speeds were calculated using the sound speed ratio of the Hamilton method.