• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.245-254
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• 2000

This study was conducted to investigate the community structure and distributional pattern of meiobenthos in the deep sea bottoms of northeastern Pacific during July 1998. The faunal samples were collected using the multiple corer at ten stations; eight stations along the transects from 5$^{\circ}$N to 12$^{\circ}$N, and two stations in the Preservation Zone and Impact Zone of the KODOS (Korea Deep Ocean Study) area. The organic carbon content in sediments ranged from 0.79 to 1.76 mg cm$^{-3}$, and higher concentration appeared at stations in lower latitudes than 8$^{\circ}$N. The most abundant meiobenthos was nematodes and followed by foraminiferans; these two taxa comprised more than 70% of the total abundance at all stations. The most abundant meiobenthos occurred with mesh size of 0.063 nm. The maximum density of meiobenthos was 442 ind./10 cm$^2$ at station N5, and the density gradually decreased toward station N8 where the minimum density of 92 md./10 cm$^2$ was found. More than 60% of meiobenthos were distributed at surface sediment layer within 1.0 cm, and the peak abundance was found at 0-0.25 cm layer. The latitudinal distribution pattern of meiobenthos in the study area seemed to be related with the primary productivity of the surface water that is also connected to the water circulation pattern of the Pacific Ocean near the Equator, diverging at latitude of 8$^{\circ}$N and conversing at 5$^{\circ}$N.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.32-41
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• 2001

We measured the fluxes of COD, TN and 55 in addition to composition and quality of sediment in Komso Bay, West Coast of Korea. The fluxes of TN, SS and COD were measured during flood tide and ebb tide in April and August, 2000. Denitrification rates in the sediments was also measured by direct produced $N_2$ gas technique on April and August from 1999 to 2000 in the same sea area. The composition of the sediments were 0.33~5.67 % of sand, 20.2~25.6 of gravel and 68.7~77.0 % of silt. Ignition loss of the sediments were 6.58~7.50 %. The concentration of hydrogen sulfide in the sediments were 0.028~0.326 mg/gㆍdry and oxidation reduction potential of the sediments were -28~-15 mV Diurnal fluxes of COD, total nitrogen, and suspended solids with tidal current and denitrification rate in the tidal flat have been determined in Komso Bay The diurnal net flux of COD was same in April. While 14.4 ton COD/hr of net influx into the tidal flat was recorded in August. The diurnal net influx of total nitrogen was 0.16 ton N/hr in April and 1.13 ton N/hr in August. The diurnal net influx of suspended solids was 0.05 ton SS/hr in April, and also net influx of suspended solids was 0.29 ton SS/hr in August. The overall purification ability of the tidal flat were estimated 0.00~5.69 g COD/$m^2/day$, 0.06~0.45 g N/m²/day and 0.02~0.12 g SS/$m^2/day$ for COD, TN and SS, respectively. Denitrification rate was 0.009~1.720 m mole ${N_2}/m^2/day$ (average 0.702 m mole ${N_2}/m^2/day$) in April and 0.033~0.133 m mole ${N_2}/m^2/day$ (average 0.077 m mole ${N_2}/m^2/day$) in August, 1999. 0.000~l.909 m mole ${N_2}/m^2/day$ (average 0.756 m mole ${N_2}/m^2/day$) in April, 0.000~1.691 m mole ${N_2}/m^2/day$ (average 0.392 m mole ${N_2}/m^2/day$) in August, 2000. Even with a wide range of denitrification rate depending on the sampling location and studied periods, the average denitrification rate was estimated 0.482 m mole ${N_2}/m^2/day$ in the tidal flat of Komso Bay.

• Korean Journal of Environment and Ecology
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• v.24 no.3
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• pp.249-257
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• 2010

The purpose of this paper is to weigh the possibility of endangered Jang-hang wetland at the estuary of Han River to be included on the Ramsar List of Wetlands of International Importance and come up with ways to manage the wetland depending on its biotope patterns. The target area is located between Gimpo bridge and Isanpo I.C. with about $2.7km^2$ area. Through the analysis of RIS(Information Sheet for Ramsar Wetlands), it was known that the wetland is located on the sedimentary topography and formed as a result of sediment at the estuary of the river owing to the concentration of rainfall during summer. The vegetation environment in the area is divided into brackish water and fresh water areas depending on salinity. Rhizosphere soil(RS) of the area was analyzed to be Silt loam while bottom RS to be Sand loam. The plant ecology was composed of 52 families 135 species and 11 varieties and 146 types. Among indigenous species found are Salix koreensis, Phragmites communis and Miscanthus sacchariflorus. The analyzed results of the actual vegetation showed that willow community accounts for 37% of the area and rice field is 13.5%. As for animal ecology, total of 62 species and 25,977 individual wild birds were observed. After comparing and analyzing the RIS we compiled with the Ramsar Site designation standards, it turns out that the Jang-hang wetland meets criteria 1(biographic region), criteria 2,3 and 4(species and ecological communities) and criteria 5 and 6(water birds). Thus, Jang-hang wetland is eligible for the Ramsar site. As a result of establishing and evaluating the biotope types for setting management areas, Jang-hang wetland has a total of 13 different types, and the grade I represents 75.4% of the area while the grade III 0.8% of the land status. We categorized four management zones for the wetland depending on the biotope patterns - preservation, restoration, use and buffer zones and suggested management methods for each zone.

• Journal of the Korean Society of Groundwater Environment
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• v.1 no.1
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• pp.23-32
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• 1994

To determine the apparent equilibrium constants, K$_{ad,app}$, for the adsorption reactions of trace metals on amorphous iron oxyhydroxide (AIO) in the Taebag coal mine area, time-adsorption and pH-adsorption experiments were performed for a selected bottom sediment mainly comprised of AIO from the study area. The results from the adsorption experiments indicate that most of the trace metals, except Pb, achieve equilibrium states with AIO and thus, the calculated K$_{ad,app}$ may represent the true apparent equilibrium constants. K$_{ad,app}$ and the stoichiometric coefficients of proton, x, of the adsorption reactions between the trace metals and AIO were respectively calculated from the intercepts and slopes of the regression lines of log($\Gamma$/ ［M］$_{aq}$)against pH provided by pH-adsorption experiments. The calculated K$_{ad,app}$ this study has the values of the range from 10$^{－4.5}$ to 10$^{2.75}$ , which is much different from the reported values by other investigators for simple experimental systems. K$_{ad,app}$ of this study is more or less close but not exactly pertinent to the estimated values for the other natural systems. It indicates that K$_{ad,app}$ for the adsorption reactions in the aquatic system in the study area is unique and thus should be determined befor the adsorption modelling. The calculated x of this study has the values of the range from -0.3 to 0.7, which is also much different from what most geochemists generally accept. The discrepancy in x may be due to the competition among different kinds of ionic species on the adsorption site or simulataneous occurrence of different kinds of adsorption reactions. The results from this study should help construct an appropriate adsorption model for the aquatic systems polluted by the coal mine drainage in the Taebag area. With the constructed model, one can describe the concentration variations of trace metals due to the adsorption in the system, which is an essential part of the investigation on the water quality affected by coal mine drainage in the Taebag coal field.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• 한국해양학회지
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• v.22 no.3
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• pp.130-142
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• 1987

Sedimentological characteristics of the surface sediments in the southern sea off Cheju Island are described from analyses of bottom sediments. The sediments are subdivided into seven textural classes, muddy sand, slightly gravelly muddy sand, sand, clayey sand, sandy clay, sandymud, silty sand. Sand-size sediments are distributed in the southeastern part and/or around the Island, whereas sandy and muddy sediments are mainly distributed in the central and southern parts of the study area. A small portion of mud patch is located in the southwestern part of the area. According to the textural parameters analysis, sediments in the study area are poorly sorted(av.2.52 ), positive skewed(av.1.61 ), leptokurtic(av.1.74 ), transported by saltation and/or suspension, and roundness of quartz is varied from angular to surrounded, which suggesting that the depositional environment is not simple. The calcium carbonate content is on the average 26.99%, and commonly abundant in sand-size sediments, whereas organic matter content in the bulk sediment is on the average 6.70% and usually dominant in fine-grained sediments.Light minerals consist of quartz(av56.01%),Na-Ca feldspar(av.6.15%),K-feldspar(av.9.22%) and rock fragments(av28.11%).The contect onquartz and K-feldspar increases continuously away from the Cheju Island. As a result of geochemical analysis,concentrations of the elements are as follow:Zn:19.42-43.52 ppm (av.30.67ppm),Mn:50-304 ppm(av139.39ppm),Cr:3.54-10.68ppm(av6.50ppm),Pb:5.52-41.68ppm(av.15.60ppm), Co:7.08-14.68ppm (av.10.78ppm),Ni:19.70-42.42ppm(av.29.57ppm),Cu:3.14-9.12ppm(av.5.14ppm),Fe:0.48-2.08% (av1.22%),Ca:0.32-13.16%(av6.60%),Al:0.06-0.08%(av.0.27%),Mg:0.12-0.76%(av.0.53%)na:0.11-0.51%(av.0.36%) Ag:0.48-4.08ppm(av.1.22ppm).Among these elements,the content of Zn,Cu,Cr,Mn,Fe,Al,Mg,Pb and Na increase toward the southwestern area,while the content of Ca and Ag SHOWS the reversed distribution trend.Such a distribution pattern seems to imply that spatial distrivution of heavy metals is closely related to the variation in grain size. X-ray diffractogram show that the minerals in clay from the southwestern mud patch are illite ,chlorite, kaolinte,feldspar and calcite.The bulk of illite in th mud zone is believed to be originated from Huanghe and Yangytze River.The mud patch in this region contains the diagnostic calcite peak,and the concentration of Ca,ni,Pb,Ag are similar to Huanghe type,which indicates that the greater part of these clay fractions may have been derived from the Huanghe River.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.71-79
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• 1999

As part of an on-going project investigating flux of materials in the Keum River Estuary, we have monitored seasonal variations of nutrients, suspended particulate matter (SPM), chlorophyll, and salinity since 1997. Meteorological data and freshwater discharge from the Keum River Dike were also used, Our goal was to answers for (1) what is the main factor for the seasonal fluctuation of nutrients in the Keum River Estuary? and (2) are there any differences in nutrient distributions before and after the Keum River Dike construction? Nitrate concentrations in the Keum River water were kept constant through the year. Whereas other nutrients varied with evident seasonality: high phosphate and ammonium concentrations during the dry season and enhanced silicate contents during the rainy season. SPM was found similar trend with silicate. During the rainy season, the freshwater discharged from the Keum River Dike seemed to dilute the phosphate and ammonium, but to elevate SPM concentration in the Keum Estuary. In addition, the corresponding variations of SPM contents in the estuarine water affected the seasonal fluctuations of nutrients in the Estuary. The most important source of the nutrients in the estuarine water is the fluvial water. Therefore, the distribution patterns of nutrients in the Estuary are conservative against salinity. Nitrate, nitrite and silicate are conservative through the year. The distribution of phosphate and ammonium on the other hand, display two distinct seasonal patterns: conservative behavior during the dry season and some additive processes during the rainy days. Mass destruction of freshwater phytoplankton in the riverine water is believed to be a major additive source of phosphate in the upper Estuary. Desorption processes of phosphate and ammonium from SPM and organic matter probably contribute extra source of addition. Benthic flux of phosphate and ammonium from the sediment into overlying estuarine water can not be excluded as another source. After the Keum River Dike construction, the concentrations of SPM decreased markedly and their role in controlling of nutrient concentrations in the Estuary has probably diminished. We found low salinity (5~15 psu) within 1 km away from the Dike during the dry season. Therefore we conclude that the only limited area of inner estuary function as a real estuary and the rest part rather be like a bay during the dry season. However, during the rainy season, the entire estuary as the mixing place of freshwater and seawater. Compared to the environmental conditions of the Estuary before the Dike construction, tidal current velocity and turbidity are decreased, but nutrient concentrations and chance of massive algal bloom such as red tide outbreak markedly increased.

• Journal of the Mineralogical Society of Korea
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• v.26 no.4
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• pp.245-262
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• 2013

We analyzed 29 surface sediment samples in five submarine volcanoes (TA12, TA19, TA22, TA25, and TA26) located in the southern part of the Tonga arc for trace elements and rare earth elements to investigate characteristics of the hydrothermal alteration of surface sediments. Based on analytical results of trace element and rare earth element (REE), surface sediments of TA12, TA19, and TA22 submarine volcanoes, which are located in the northern part of the study area, were very little or not influenced by hydrothermal fluids. In contrast, some stations of TA25 and TA26 submarine volcanoes were strongly affected by hydrothermal fluids. However, these two submarine volcanoes showed different features in element concentration in the sediments. Some stations of TA25 submarine volcano showed enrichment of Ni, Cu, Sn, Zn, Pb, Cr, Cd, Sb, W, Ba, Ta, Rb, Sr, and As, however, those of TA26 submarine volcano showed enrichment of Sn, Zn, Pb, Cd, Sb, Ba, Rb, and Sr. Stations which enriched trace elements were observed, enriched REEs were also observed. Average upper continental crust (UCC)-normalized REE patterns of the surface sediments generally showed low light REE (LREE) abundances and increased heavy REE (HREE) abundances. Eu enrichment was identified at several stations of TA25 and TA26 submarine volcanoes. In addition, enrichment of Ce was found at some stations of TA26 submarine volcano and these enrichment patterns were similar with hydrothermal fluid of near stations. Furthermore, TA25 and TA26 submarine volcanoes showed different enrichment characteristics of trace elements and REE. Trace elements were concentrated at TA25 submarine volcano. TA26 submarine volcano, on the other hand, observed highly enrichment of REE especially, Eu and Ce. As a result of the investigation, the characteristics and concentrations of REEs and trace elements in the surface sediments of each submarine volcano can be applied to identify hydrothermal alteration of sediments during exploration for hydrothermal deposits.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.75-84
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• 2011

We examined the effect of the turbid water on the periphytic diatom community in an artificial stream system. The artificial stream was constructed with transparent acryl and composed of four channels. Each channel ($20\;cm{\times}200\;cm{\times}40\;cm$) was supplied continuously with eutrophic lake water. In order to the freely colonize and grow diatoms, artificial substrate was installed with commercial slide glass soaked in 1% agar. Prior to introducing turbid water, the artificial stream was operated with lake water for 6 days to permit the propagation of diatom community on the substrates. The turbid water prepared with sediment sieved with ${\varphi}$ $64\;{\mu}m$ at $2\;g\;L^{-1}$ (final concentration, 300 NTU) was provided daily for 50 minute duration. The experiment was conducted for 7 days with manipulated experimental condition of light ($50{\sim}80\;{\mu}mol\;m^{-2}s^{-1}$, light:dark=24:0), temperature ($10{\pm}1^{\circ}C$), and flow rate ($0.31\;cm\;s^{-1}$). Sampling and analysis were conducted daily for water quality and diatom. Turbidity of the water varied 162.2~173.2 NTU during the experiment. After introduction of turbid water, DO, pH and TN were decreased, while SS and TP increased significantly. A total of 14 genera and 47 species of diatoms was observed on the artificial substrates during the experimental period. Of these, Navicula appeared to be a most dominant genus with 10 species, followed by Cymbella (6 species), Fragilaria (6 species) and Gomphonema (5 species). Achnanthes minutissima was the most dominant species (>70% of total frequency) in both control and treatment experiments. Increase in diatom abundance lasted for three days since turbid water introduction, after that they gradually decreased by the termination of the experiment. These results suggest that frequent supply of highly-concentrated turbid water significantly decreases the periphytic diatom community, and retard the recovery of the stable food-web within the stream.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.481-490
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• 2003

The objectives of this study are (1) to determine the extent and degree of As contamination of the water and sediments influenced by mining activity of the abandoned Au-Ag mines, (2) to examine As speciation In contaminated water, (3) to monitor variation of As contamination in water system throughout the dry and wet seasons, and (4) to investigate the As chemical form in the sediments through the sequential extraction analyses. Natural water(mine water, surface water and groundwater) and sediments were collected in six abandoned Au-Ag mine(Au-bearing quartz veins) areas. The contamination level of As in mine water of the Dongil(524${\mu}m$/L) is more higher than the tolerance level(500 ${\mu}m$/L) for waste water of mine area in Korea. Elevated levels of As in stream water were also found in the Dongil(range of 63.7∼117.6 ${\mu}m$/L.) and Gubong(range of 56.1∼62.9 ${\mu}m$/L) mine areas. Arsenic contamination levels in groundwater used by drinking water were more significant in the Dongil(11.3∼63.5 ${\mu}m$/L), Okdong(0.2∼68.9 ${\mu}m$/L) and Gubong(2.0∼101.0${\mu}m$/L) mine areas. Arsenate[As(V), $H_2AsO_4^-$] is more dominant than arsenite[As(III), $H_3AsO_3$] in water system of the most mine areas. The concentration ratios of As(III) to As(total), however, extend to the 95% in stream water of the Okdong mine area and 70∼82% in groundwater of the Okdong and Dongjung mine areas. As a study of seasonal variation in the water system, relatively high levels of As from the dongil mine area were found in April rather than in September. Sequential extraction analysis showed that As was predominantly present as coprecipitated with Fe hydroxides from sediment samples of the Dongjung and Gubong mine(35.9∼40.5%), which indicates its possibility of re-extraction and inducing elevated contamination of As in the reductive condition. In sediments from the Dongil, Okdong and Hwachon mine area, high percentage(55.2∼83.4%) of As sulfide form was found.