• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.31-39
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• 2002

Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water column can accumulate in sediments at much higher levels. The purpose of this study was to make optimal treatment and disposal plan o( sediment for water quality improvement in small-scale resevoir based on an evaluation of degree of contamination. The degree of contamination were investigated for 23 samples of 9 site at different depth of sediment in small-scale J river. Results for analysis of contaminated sediments were observed that copper concentration of 4 samples were higher than the regulation of hazardous waste (3 mg/L) and that of all samples were exceeded soil pollution warning levels for agricultural areas. Lead and mercury concentration of all samples were detected below both regulations. Necessary of sediment dredge was evaluated for organic matter and nutrient through standard levels of Paldang lake and the lower Han river in Korea and Tokyo bay and Yokohama bay in Japan. The degree of contamination for organic matter and nutrient was not serious. Compared standard levels of Japan, America, and Canada for heavy metal, contaminated sediment was concluded as lowest effect level or limit of tolerance level because standard levels of America and Canada was established worst effect of benthic organisms. The optimal treatment method of sediment contained heavy metal was cement-based solidification/stabilization to prevent heavy metal leaching.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.149-155
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• 2016

To assess the effects of environmental factors on the sustainability of cultured ark shell Scapharca broughtonii production, we investigated the habitat characteristics of shellfish-farming bays (Gangjin Bay, Yeoja Bay, Keoje Bay and Deukryang Bay). We measured the physiochemical parameters (temperature, salinity, dissolved oxygen, nutrients, chemical oxygen demand and Chlorophyll a) and the geochemical characteristics (chemical oxygen demand, ignition loss, C/N ratio and C/S ratio). Surface sediments were collected from several shellfish-farming bays to examine the geochemical characteristics of both the benthic environment and heavy metal pollution. The grain sizes for Gangjin Bay, Yeoja Bay and Keoje Bay were similar, at the ratio of silt and clay in comparison with Deukryang bay of it. The C/N ratio was more than 5.9, reflecting the range arising from the mix of marine organisms and organic matter. The C/S ratio (more than 4.2) showed that the survey area had anoxic or sub-anoxic bottom conditions. The index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. We suggested that the growth of ark shell Scapharca broughtonii in the shellfish-farming bay was effected by the various environmental conditions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.38-46
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• 2005

This study was carried out to quantify the rates of anaerobic mineralization and sulfate reduction, and to discuss the potential effects of benthic fauna on sulfate reduction in total anaerobic carbon respiration in Ganghwa intertidal flat in Korea. Anaerobic carbon mineralization rates ranged from 26 to 85 mmol $C\;m^{-2}\;d^{-1}$, which accounted for approximately 46 tons of daily organic matter mineralization in the intertidal flat of southern part of the Ganghwa Island (approximately $90\;km^2$). Sulfate reduction ranged from 22.6 to 533.4 nmol $cm^{-3}\;d^{-1}$, and were responsible for $31{\sim}129%$ of total anaerobic carbon oxidation, which indicated that sulfate reduction was a dominant pathway for anaerobic carbon oxidation in the study area. On the other hand, the partitioning of sulfate reduction in anaerobic carbon mineralization in October decreased, whereas concentrations of Fe(II) in the pore water increased. The results implied that the re-oxidation of Fe(II) in the sediments is stimulated by macrobenthic activity, leading to an increased supply of reactive Fe(II), and thereby increasing Fe(III) reduction to depress sulfate reduction during carbon oxidation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.142-148
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• 1998

Environmental baseline information is necessary in order to assess the potential environmental impact of future manganese-nodule mining on the deep-seabed ecosystem. Total ATP (T-ATP), dissolved ATP (D-ATP) and particulate ATP (P-ATP) were measured to estimate total microbial biomass and to elucidate their vertical distribution patterns in the seabed of KODOS (Korea Deep Ocean Study) area, northeast equatorial Pacific Ocean. Within the upper 6 cm depth of sediment, the concentrations of T-ATP, D-ATP and P-ATP ranged from 4.4 to 40.6, from 0.6 to 16.1, and from 3.0 to 29.2 ng/g dry sediment, respectively. Approximately 84% of T-ATP, 81% of D-ATP, and 74% of P-ATP were present within the topmost 2 cm depth of sediment, and the distributions of ATP were well correlated with water content in the sediment. These results indicate that the distribution of total microbial biomass was largely determined by the supply of organic matter from surface water column. Fine-scale vertical variations of ATP were detected within 1-cm thick veneer of the sediment samples collected by multiple corer, while no apparent vertical changes were observed in the box-cored samples. It is evident that the box-core samples were disturbed extensively during sampling, which suggests that the multiple corer is a more appropriate sampling gear for measuring fine-scale vertical distribution pattern of ATP within thin sediment veneer. Overall results suggest that the concentrations of ATP, given their clear changes in vertical distribution pattern within 6 cm depth of sediment, are a suitable environmental baseline parameter in evaluating the variations of benthic microbial biomass that are likely to be caused by deep-seabed mining operation.

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.112-117
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• 2011

This study was conducted for searching the functional feeding groups, and community stability of the macroinvertebrate on forest fire area of Uljin-gun. The samples were collected from 2 sites of control area and 2 sites of experimental area during 2007 to 2009. The identified species were 89 belonged to 47 families, 16 order, 6 class, and 4 phylum in control area. And 84 belonged to 43 families, 16 order, 6 class, and 4 phylum were identified in experimental area. As a result of changes in species and individuals of E.P.T. taxa investigated in experimental area by year, Ephemeroptera was 21 species, $2,434.6inds./m^2$, Plecoptera was 3 species, $199.8inds./m^2$, and Trichoptera 14 species, $540.2inds./m^2$ in 2007. And in 2009, Ephemeroptera was 9 species, $296inds./m^2$, Trichoptera was 4 species, $44.4inds./m^2$, and Plecoptera was none, showing that species and individuals belonging to E.P.T. taxa decrease rapidly every year. Community analysis by year, in 2008 when the water system started to be influenced by the fire directly, it showed a trend that H' and RI decreased in the experimental area. Functional feeding group by year, it showed a trend that species and individuals of GC type which is a functional group picking up and eating FPOM (fine particulate organic matter) from deposits in the bottom of water or benthic areas and performs an important function of material circulation in ecosystem decrease every year. Community stability by year, an environment of water system in forest fire area started to be somewhat destroyed, from 2008, it is shown that both species in I area which have great ability of resistance and recovery and species in III area which live in relatively stable water system decreased a little.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• The Korean Journal of Malacology
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• v.29 no.1
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• pp.51-63
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• 2013

To assess the effect of environmental factors on the sustainability of cultured production shellfish, we investigated the habitat characteristics of tidal flat (Namhae-po in Taean). We measured the physiochemical parameters (temperature, salanity, pH, dissolved oxygen and nutrients) and the geochemical characteristics (chemical oxygen demand, ignition loss, C/N ratio and C/S ratio). Surface sediments were collected from several site of tidal flat to examine the geochemical characteristics of both the benthic environment and heavy metal pollution. The grain size for research area of tidal flat were similar at the ratio of silt and clay in comparison with the other site of it. The C/N ratio was more than 5.0, reflecting the range arising from the mix of marine organism and organic matter. The C/S ratio (about 2.8) showed that survey area had anoxic or sub-anoxic bottom conditions. The enrichment factor (Ef) and index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. Adult surf clam (Mactra veneriformis) density was highest at St. 2 (middle part of the Namhae-po), on the other hand, surf clam spat density was highest at St. 3 (lower part of the Namhae-po). Heavy rain, terrigenous suspended clay with fresh water from neighboring agricultural land, and severe high air temperature during summer could be thought as detrimental causes of spat and adult mortality in Namhae-po tidal flat. We suggested that the growth of shellfish in the tidal flat was effected by the various environmental conditions, so an improvement in the cultured method was needed.