• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.454-466
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• 2013

To evaluate the organic matter and trace metal pollution in intertidal sediment of the coastal zone, various geochemical parameters (grain size, ignition loss [IL], chemical oxygen demand [COD], acid volatile sulfide [AVS], and metals [Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As]) were measured for the intertidal surface sediment of the mainland and islands between Mokpo and Haenam in the southwestern coast of Korea. The surface sediments consist mainly of finer sediments, such as mud and silt. The concentrations of IL, COD, and trace metals in intertidal sediment were relatively high in the shoreline of the mainland than in that of islands and those in some stations exceeded the sediment quality guidelines (SQGs). Moreover, the concentrations of IL, COD, and trace metals (except As) in sediment showed relatively good positive correlations with mean grain size, indicating that the concentrations of organic matter and trace metals in intertidal sediment of the study region are dependent on grain size of sediment. Pollution evaluation for trace metals using geochemical assessment techniques, such as enrichment factor, geoaccumulation index, and SQGs, suggested that the intertidal sediments in the study region show light pollution with Cr and moderate pollution with As. More extensive interdisciplinary studies are required to determine the potential causes of As pollution in intertidal sediment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.638-648
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• 2013

To understand the geochemical characteristics of intertidal sediment in a semi-enclosed bay, we measured various geochemical parameters, including grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Hg, and As), in intertidal sediment from three bays (Deukryang Bay, Yeoja Bay, and Gamak Bay) in the southern region of Jeollanam Province. The intertidal sediment in Deukryang Bay consisted of various sedimentary types, such as sand, gravelly muddy sand, mud, and silt, whereas the intertidal sediments in Yeoja and Gamak Bays were composed mainly of mud. The concentrations of IL, COD, AVS and trace metals in the intertidal sediments of the three study regions were relatively high near areas affected by input of stream waters and/or shellfish farming waste. The concentrations of organic matter and trace metals in Gamak Bay were much higher than those in Deukryang and Yeoja Bays, which appears to be due to the influence of anthropogenic pollutants, originating from the city and the industrial complex near Gamak Bay. The evaluation results of organic matter and metal pollution using the sediment quality guidelines showed that the intertidal sediments in the three study regions were not polluted in terms of organic matter and trace metals. In future, sustainable management for sources of organic matter and trace metal is necessary to conserve a healthy benthic ecosystem in intertidal sediments.

• ALGAE
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• v.24 no.3
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• pp.149-161
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• 2009

Characteristics of benthic microalgae and sediment properties were investigated for the intertidal flats of Kwangyang Bay, Korea. Sampling stations were selected every 100 m in the intertidal flats from land-side to open ocean at two different sampling sites. Samples were collected in June 2004, July, September, November, February and May 2005. Sediments properties were measured including temperature, water contents, sediment bulk density, nutrient concentrations in porewater. Chlorophyll a concentrations in surface sediment (0.5 cm) were measured and relationships between the chlorophyll a and various sediment properties were analyzed to identify major mechanisms regulating biomass of benthic microalgae in the intertidal flats using simple linear regression analysis. Sediment chlorophyll a concentrations were maximum during winter and minimum during warm seasons ranging from 4.4 mg $m^{-2}\;to\;81.2\;mg\;m^{-2}$. No clear spatial variations were observed for the sediment chlorophyll a in the study sites. Results from regression analysis suggested that benthic microalgae biomass was affected by sediment temperature and nutrients especially ammonium and silicate. Grazing effect was estimated using chlorophyll: pheopigments ratio, indirect indicator of grazing activity, and the positive correlation of the ratio and chlorophyll a implied that microalgae biomass is affected by grazing of zoobenthos although direct measurement of grazing activity is required to determine the importance of top-down controls in the benthic microalgae dynamics.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.225-231
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• 2009

The characteristics of morphological shapes, wave heights, tidal ranges and sediment sizes are observed and compared between intertidal beach and mudflat. The Mohang sand beach, southwest coast of Korea, is located just next to the large mudflat and has tidal range over 5 meters. Wave measurements are conducted at each entrance of the beach and mudflat as well as at the outside waters representing the incident waves to these different coastal environments. The morphological characteristics are also examined including the sediment size and the slope of the bathymetry, For the observation of morphological shapes, camera monitoring technique is used to measure the spatial information of intertidal bathymetry. The water lines moving on the intertidal flat/beach durinq a flood indicate depth contours between low and high water lines. The water lines extracted from the consecutive images are rectified to get the ground coordinates of each depth contours and integrated to provide three dimensional information of intertidal topography. The wave data show that sand beach is in the condition of severer wave forcing but tidal range is almost identical in both environment. The slope of the mudflat is much milder than the sand beach with finer sediment.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.93-96
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• 2017

Spatial variations of physicochemical and microbiological variables were examined to understand spatial heterogeneity of those variables in intertidal flat. Variograms were constructed for understanding spatial autocorrelations of variables by a geostatistical analysis and spatial correlations between two variables were evaluated by applications of a Cross-Mantel test with a Monte Carlo procedure (with 999 permutations). Water content, organic matter content, pH, nitrate, sulfate, chloride, dissolved organic carbon (DOC), four extracellular enzyme activities (${\beta}-glucosidase$, N-acetyl-glucosaminidase, phosphatase, arylsulfatase), and bacterial diversity in soil were measured along a transect perpendicular to shore line. Most variables showed strong spatial autocorrelation or no spatial structure except for DOC. It was suggested that complex interactions between physicochemical and microbiological properties in sediment might controls DOC. Intertidal flat sediment appeared to be spatially heterogeneous. Bacterial diversity was found to be spatially correlated with enzyme activities. Chloride and sulfate were spatially correlated with microbial properties indicating that salinity in coastal environment would influence spatial distributions of decomposition capacities mediated by microorganisms. Overall, it was suggested that considerations on the spatial distributions of physicochemical and microbiological properties in intertidal flat sediment should be included when sampling scheme is designed for decomposition processes in intertidal flat sediment.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1882-1889
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• 2006

A 16S rDNA clone library was generated to investigate the bacterial diversity in intertidal sediment from the coast of the Yellow Sea, P. R. China. A total of 102 clones were sequenced and grouped into 73 OTUs using a phylogenetic approach. The sequenced clones fell into 11 bacterial lineages: Proteobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Acidobacteria, Actinobacteria, Firmicutes, Spirochaetes, and candidate divisions of BRCl, OP3, and OP1l. Based on a phylogenetic analysis of these bacteria, together with the ten most closely related sequences deposited in the GenBank, it was concluded that intertidal bacteria are most likely derived from marine bacteria with a remarkable diversity, and some are particularly abundant in intertidal sediment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.626-637
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• 2013

We measured the grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS) and trace metals (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) of intertidal surface sediment collected from 11 islands (62 stations) in the southern region of Jeollanam Province. The objective of this research was to evaluate the organic matter and trace metals contaminations of sediments from coastal island tidal flats. Surface sediment texture was characterized as follows: mud, sandy silt, muddy sand, and slightly gravelly sand facies. The finer sediments are mainly dominated in the northern part of each island. The concentrations of IL, COD, AVS and some trace metals (Al, Fe, Zn, Cr, Cu, and Hg) were higher in the northwestern part of Wan Island and the area between Gogeum and Sinji Islands, and were associated with relatively finer sediment, as compared to other locations. The concentrations of Mn, Pb, Cd, and As were higher in the northwestern and southeastern parts of Geoguem and Pyungil Islands, but were not correlated with mean grain size. Based on sediment quality guidelines (SQGs), the concentrations of trace metals were lower than the values of effect range low (ERL), used in United States, and threshold effects level (TEL), used in Korea, with exception of As. Similarly, the intertidal sediments were moderately contaminated with As, based on the the enrichment factor (EF) and the geoaccumulation index ($I_{geo}$). The high concentration of As in intertidal sediments from this study region may be due to the input of naturally or artificially contaminated submarine groundwater, contaminated waste from seaweed aquaculture operations and/or land-based seaweed processing facilities. Further studies are needed to identify the sources of As in this study region, and to determine the effects of As contamination on coastal ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1014-1025
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• 2014

We measured the concentrations of various geochemical parameters [grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and trace metals (Fe, Cu, Cd, Pb, Cr, Mn, As, Zn, and Hg)] in the surface sediments of two intertidal oyster Crassostrea gigas farming areas (Iwon and Mongsan tidal flats) on the Taean Peninsula, Korea, to evaluate the pollution level of organic matter and trace metals in sediment. The intertidal sediments in the study region comprise mostly sand with a mean grain size of 2.5-3.5 Ø. The concentrations of IL, COD, AVS, and trace metals in the sediment of two study regions were either similar or lower in oyster farming areas relative to non-farming areas, apparently due to biological uptake or physical and biological sediment reworking. Based on the results for the pollution evaluation of organic matter and trace metals derived from sediment quality guidelines, enrichment factor, and geoaccumulation index, our results suggest that the sediment in these two intertidal oyster farming regions is not polluted by organic matter and trace metals.

• 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 the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.47-58
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• 1999

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in coastal marine environment. PAHs enter estuarine and nearshore marine environment via several routes such as combustion of fossil fuels, domestic and industrial effluents and oil spills. In August of 1997, sediment and mussels (Mytilus edulis) were collected at 6 sites near Kori nuclear power plant in order to analyze the PAH content by HPLC with uv/vis detection. The concentrations of 15 PAH in sediment ranged from < 1 to 5,900 ppb ( mean 173.5$\pm$99.7 ppb), and in mussels, from < 0.5 to 4,125 ppb (mean 105$\pm$60.5 ppb). Compared with other studies world over, the concentrations of carcinogenic PAHs were relatively low in both sediment and mussels from the intertidal zone of Kori. This study presents preliminary data for the PAH levels in sediment and mussels from the intertidal zone of Kori, and the data will hopefully be utilized for the assessment of oil pollution in the Southeast East Sea, Korea (especially for the PAHs).