• Ocean and Polar Research
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• v.28 no.2
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• pp.119-127
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• 2006

We measured oxygen microprofiles using an oxygen microelectrode in Ganghwa intertidal flat in April and September. Oxygen consumption rate was calculated by using three different methods based on the oxygen microprofiles. The method using the PROFILE software was thought to be the most reliable among the three methods. The oxygen consumption rates calculated at station D1 by using the PROFILE software were 10.5 and 6.27mmol $m^{-2}d^{-1}$ in April and September, respectively. At station D2, they were 10.9mmol $m^{-2}d^{-1}$ in April and 5.39 mmol $m^{-2}d^{-1}$ in September. There was little spatial variation, but large seasonal variation, with almost two times larger values in April than in September. The higher rate in April is ascribed to higher oxygen concentration in the seawater and higher organic carbon content in the surface sediments, which probably accelerate oxygen consumption for organic matter decomposition in the sediments. Aerobic remineralization rates estimated from the oxygen consumption rates ranged from 4.14 to 8.07 mmol C $m^{-2}d^{-1}$ in Ganghwa intertidal flat, which were much lower than the anaerobic remineralization rate.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.149-162
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• 2019

In the macro-tide open coast of the Korean western coast, typhoon effects were investigated in terms of variations on topography, surface sediment, and sedimentary environment, which appeared before and after the typhoon Kompasu of 2010. The Kompasu of small size and strong intensity landed on the southwestern coast of the Korean Peninsula and passed across the inland between September 1st and 2nd in 2010. Topography and surface sediments before and after the typhoon were measured and sampled along the survey line of 22 sites in the Gochang Donghori intertidal flat. The intertidal area was divided into high tidal zone, middle tidal zone, and lower tidal zone on the basis of mean high water level, mean sea level, and mean low water level. Topographic variation before and after the typhoon represented deposition of average 0.03 m in high tidal zone, erosion of average -0.15 m in middle tidal zone, and erosion of average -0.39 m in lower tidal zone, respectively. Surface sediments of the intertidal flat consisted mainly of fine to medium sands, and the ratio of fine sand was the largest both before and after the typhoon. Surface sediments after the typhoon became finer in mean grain size showing well sorting rather than those before the typhoon.

• Ocean and Polar Research
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• v.35 no.1
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• pp.39-50
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• 2013

Biomass and community composition of microphytobentos in tidal flats were studied by HPLC analysis and also investigated to examine the relationship between microphytobenthic pigments and Adenosine-5' triphosphate (ATP) as an index of total microbial biomass in intertidal environments (muddy and sandy sediment) of Gyeonggi Bay, west coast of Korea. Microphytobenthic pigments and ATP concentration in muddy sediment were the highest at the surface while the biomass of microphytobenthos in sandy sediment was the highest at the sub-surface (0.75 cm sediment depth). The detected pigments of microphytobenthos were chlorophyll a, b (euglenophytes), $c_3$, peridinin (dinoflagellates), fucoxanthin (diatom or chrysophytes), diadinoxanthin, alloxanthin (cryptophytes), diatoxanthin, zeaxanthin (cyanobacteria), ${\beta}$-carotein, and pheophytin a (the degraded product of chlorophyll a). Among the pigments which were detected, the concentration of fucoxanthin was the highest, indicating that diatoms dominated in the microphytobenthic community of the tidal flats. There was little significant correlation between OC (Organic Carbon) and ATP in both sediments. However, a positive correlation between chlorophyll a concentration and ATP concentration was found in sandy sediment, suggesting that microbial biomass could be affected by labile OC derived from microphytobenthos. These results provide information that may help us understand the relationship between microphytobenthos and microbial biomass in different intertidal sediment environments.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.243-263
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• 2011

In order to understand the sedimentary environment of the southern intertidal zone of Shihwa Lake, west coast of Gyeonggi-do, 10 surface and 2 core sediment samples were analysed for grain size, water content, AVS (Acid Volatile Sulfide), TOC (Total Organic Carbon), concentrations of metals (Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd, and Cr). The surface sediments are generally poorly sorted (0.60~2.31 ${\phi}$) sandy Silt, slightly gravelly muddy Sand, silty Sand, Sand with mean grain size of 2.95 to 6.00 ${\phi}$. The sediments contain Al (1.54%), Fe (1.75%), Cu (9.1ppm), As (1.1ppm), Pb (18.8 ppm), Ni (11.0 ppm), Cd (0.02 ppm), and Cr (30.1 ppm) on the average. Heavy metals are concentrated less than ERL (Effect Range-Low), verified by NOAA (National Oceanic and Atmospheric Administration). In the core sediments, they are also less than the ERL. Based on the uniform vertical distribution of excess radioactivity of $^{210}Pb$, the core sediments seen to have been actively mixed biologically or rapidly deposited after the construction of Shi-Hwa Seawall. The 'enrichment factor' of metals, normalized to Al, shows that the upper sediments of 35 cm in depth are more polluted. infect was significant in 2 core sediment samples in 35 cm below layer.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.561-570
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• 2004

This study was carried out to survey the pollution of nonylphenol (NP) in surface sediments around Gwangyang bay and Yeosu sound. NP was suspected chemicals as endocrine disruption. Gwangyang bay is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO (Pohang Steel Company) and Gwangyang container harbor are there. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of NP in surface sediments were in the range of 6.89 to 202.70 ng/g dry wt.. Seasonal range (mean value) of NP is 13.98 to 30.48 (23.46) ng/g dry wt. at October, 10.35 to 54.91 (28.10) ng/g dry wt. at February, 29.05 to 202.70 (82.32) ng/g dry wt. at May and 6.98 to 83.40 (25.37) ng/g dry wt. at August. NP was seasonally fluctuated, and the highest mean value and range was detected at May, 2000. NP was highly distributed in the inner part of Gwangyang bay than Yeosu sound. Concentrations of NP in stream and intertidal sediments showed the highest value in downstream near Yeosu petrochemical industrial complex and Yondung stream. It suggests that the source of NP is industrial wastewater and municipal sewage.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.331-336
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• 1990

Annual distribution of hiterotrophic marine bacteria and seasonal characteristics were investigated in the intertidal waters and sediments in the vicinity of Kunsan of Yellow Sea, Korea. Annual distribution of heterotrophic marine bacteria ranged from $ 7.5*10^{2}$ to $1.1*10^{5}$ c.f.u./ml in water and from $1.6*10 ^{4}$ to $4.8*10^{6}$ c.f.u.per g dry sediments. As for the morphological distribution measured by epifluorescence microscopy, rod-form bacteria were distributed more than 74% of total observed bacteria during surveying periods. Average biovolume of sampled bacteria ranged from $3.19\;+-\;0.59*10^{-2}$ to $6.19\;+-\;0.76*10^{-2}$ $\mu$$m^{3}$ for coccus-form bacteria. Isolated bacteria showed various utilization of carbon sources such as glucose, maltose, lactose, xylose and arabinose, and showed tolerance at various range of salinity. It was isolated 82 genus in seawater and 114 genus in sediments. Dominant genera were Pseudomonas, Vibrio, Flavobacterium and Acinetobacter in seawater, and Pseudomonas, Acinetobacter, Vibrio, and Mycobacterium in sediments.

• 한국해양학회지
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• v.20 no.3
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• pp.20-29
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• 1985

Sediment transport by tidal currents as well as the distribution and properties of intertial surface sediments are investigated using the data obtained from an anchor station on the main tidal channel and 56 tidal flat surface samples. Sedimentation in the intertidal zone appears to occur mainly during the spring tide period in this environment. The tidal flat can be classified into three depositional facies. The tidal flat deposits are ubiquitously bioturbated by various bottom dwelling organisms among which the crabs and polychaetes predominate. Average trace metal contents of the intertidal surface sediments are: 74.8 ppm co, 67.8 ppm Ni, 32.6 ppm Cu and 30.7 ppm Pb. Compared with the northen Kyeonggi Bay bottom sediments, these contents are significantly high, except for Pb.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.467-473
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• 2015

In the present study, we investigated the physical characteristics of ground water behaviors and sediment properties in intertidal flat of Nakdong River Estuary. Variations in level and temperature of the groundwater depended on tides. And increase of river discharge led to increase in groundwater level and decrease in ground salinity at a depth of several ten cm. Difference in permeability of the intertidal flat sediments due to content of fine fraction affect velocity of groundwtaer level decrease at low tide. Furthermore, enhancement of groundwater flow due to the increase in permeability leaded to decrease of fine fraction in the intertidal flat sediments.

• Journal of the Korean earth science society
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• v.23 no.8
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• pp.722-735
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• 2002

In order to reveal sedimentary facies and geochemical characteristics on sediments distributed in upper intertidal zone, the southwestern coast of Korea, grain size and metal content analyses to the sediments were carried out. The grain size distribution of sediments shows very wide range from gravel to mud. The sediments are very well sorted to very poorly sorted and mostly positively skewed. Geochemical behavior of metals in the sediments is dependant on grain size, in part, but might be much controlled by complex submarine topography, highly varied tidal currents and surrounding land geology in the study area. Igeo (index of geoaccumulation) representing metal condensation in the sediments moderately/strongly polluted in Co and Cr and moderately polluted in Cu and Ni. But notable metal condensations are not found in the study area. So, it might be interpreted that grain size and metal content distribution tendencies in the sediments are considerably influenced by complex submarine topography, highly varied tidal currents and surrounding land geology.

• Ocean and Polar Research
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• v.24 no.1
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• pp.79-86
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• 2002

It was found that 14 coastal habitats in South Korea have comparetively natural vegetation. The habitats were classified into three types - intertidal flats, sand dunes, and estuaries. There were four intertidal flats, five sand dunes and five estuaries. Except for Cynodon dactylon and Tetragonia tetragonoides, all of the main halophytes and sand dune plants were found in the habitats. These two species were mainly distributed on the southern coast. This study identified coastal vegetation, such as pure stands of Suaeda japonica on intertidal flats, mixed halophyte communities around the high-water mark, pure stands of Vitex rotundifolia on stable sand dunes, mixed communities dominated by Carex kobomugi on unstable sand dunes, and pure stands of Phragmites communis in estuaries. The types of coastal vegetation may depend on sediment types, the inundation time of seawater and the stability of sediments.