• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.23-36
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• 2000

Bottom sea waters in eight stations including from inner bay to outer bay to understand the importance of the submarine groundwater discharge for the environmental assessment of Chinhae Bay was collected in August 1999 and January 2000. Generally, /sup 222/Rn is very useful tracer to assess the submarine groundwater discharge because it is 2-4 orders of magnitude more concentrated in groundwater compared to surface water. The /sup 222/Rn activities ranged between about 33 to 182 dpm/100kg within the bay. Higher activities more than 100 dpm/100kg were found at the inner bay. The /sup 226/Ra activities, its parent, however, were little different between stations. /sup 222/Rn activities at the same station varied with season. It suggests that the major source of /sup 222/Rn is not from the bottom sediment, but from the change of submarine groundwater discharge by precipitation. The contents of Cl/sup -/ and SO/sub 4//sup 2-/ in the groundwater of Wonjeon-ri were very high as 1,312 and 369 ppm, respectively, indicating that this groundwater along the Chinhae coast was affected by seawater. Therefore, the submarine groundwater in the inner Bay may discharge to the overlying water. It indicates that these submarine groundwater discharges may play an important role as another important source of nutrients in the Chinhae Bay, because groundwater around the Chinhae Bay showed high concentration of dissolved inorganic nutrients (average , nitrate>174 μM, silicate>262 μM). Therefore, further studies are required to assess the contribution by the submarine groundwater discharge in the biogeochemical processes of the Chinhae Bay.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.279-287
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• 2010

To identify characteristics of the water quality at Goseong bay, we analyzed long term monitoring data collected at surface and bottom water which was accumulated during the period of 1987~2009. The result showed that the waters of Goseong bay represented mesotrophic level that is based on chlorophyll-a, DIP and DIN and seasonal average of COD that indicates level by the COD criteria. This analysis can be translated that the waters is comparatively clean even though the waters is in the closed bay that slowly diffuses influx mass. We also did the time series analysis, correlation analysis and regression analysis on the moving average of the water parameter at Goseong bay. According to the results, DIP showed a increasing trend as time passed while DIN was on a decreasing trend under the same condition. In the waters of Goseong bay, the phyto-plankton growth was shown to be limited by DIN concentration. The chlrophyll-a was at the peak in August, at $4.60{\mu}g/L$. As the seasonal average and index were the highest in November, it was understood that the balance of nutrient at Goseong bay was dependent more on inner factors, ie, mass farming of aquatic species and release of bottom sediment rather than on inflow of fresh water. Accordingly, it is needed to consider the balance of nutrient like DIP and DIN to manage the water quality or estuaries at Goseong bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.115-132
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• 1992

This study was conducted to clarify the distribution pattern of macrobenthic soft-bottom dwelling animals near the shellfish farming ground in Chinhae Bay, Korea Sampling was seasonally performed with van Veen grab$(0.1m^2)$ from October 1990 to July 1991. Benthic animals collected during the study comprised 107 species which amounted to 6,978 individuals: 52 species from polychaetes$(48.6\%)$, 34 species from crustaceans$(31.8\%),$ 14 species from molluscs$(13.1\%)$ and 7 species from other faunal groups$(6.5\%)$. The dominant species were four polychaetes and one amphipod: Lumbrineis longifolia, Capitella capitate, Mediomastus sp., Sigambra tentaculata and Erictonius pugnax. The study area could be divided into 3 regions based on the faunal similarity which was closely related to the content of organic matter in the surface sediment. The benthic community located near the shellfish farming ground showed large spatial and seasonal variations in species diversity and evenness in contrast to the stable values off the farming area. The oxygen deficient water mass below 2 ml/l In thi bottom layer during the summer stressed and depauperated the benthic community in the autumn of 1990. However, the benthic community did recover during the winter. It is postulated that the cyclic phenomenon of summer mortality followed by winter recovery may be a common characteristic in benthic communities subjected to a high level of organic pollution.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.3
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• pp.148-157
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• 2005

In order to understand distribution characteristics and pollution of heavy metals in the artificial Lake Shihwa in the vicinity of Kyunggi Bay in relation with huge environmental changes, various environmental samples including seawaters, surface sediments and settling particulate matters were collected from Lake Shihwa in 2004. Due to extreme pollutant discharge from various anthropogenic sources such as the Banweol and Shihwa Industrial Complexes and cities, the highest metal concentrations in the samples such as waters, sediments and settling particulate matter were found in inner part of the lake. High metal contents (Cu, Zn and Hg) in sediments were observed at Sts. 2-4 and 9. The contents of Cr, Co, Ni, Cu, Zn and Pb in SPMs were high at St. 5 and low in the outer part of the lake. Spatial distribution of heavy metals were mainly controlled various biogeochemical factors and physical mixing as well as input of industrial and municipal wastewaters. Although tile environmental qualities of heavy metals in the lake have been improved partially due to inflow of outer seawater, it is not clear to reach a good environmental quality. Therefore, further environmental programs should be conducted continuously for environmental improvement.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.182-197
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• 1993

Algal community on the subtidal rocky zone of the South Sea of Korea was divided into two or three sequencing zones. The upper subtidal zone was characterized by the wave exposure-tolerant surf wrack(Pachymeniopsis, Gigartina), which formed dense swirling carpet. Its vertical range was from the surface to $3{\sim}5$ meters in depth, and more deeply extended in turbid waters including Sorido, Yokchido, Pijindo, Manjedo. The mid subtidal zone ranging from 5 to 25 meters in depth was characterized by a large brown algal forest (Ecklenia, Sargassum). But it was generally unrecognizable in that turbid waters, in which the vertical limit of vegetation was at most $10{\sim}15$ meters in depth. The low subtidal zone was characterized by a general lack of algal species and was not easily distinguished from the mid or sometimes from the upper zone. There was a distinct difference in abundance of vegetation between turbid waters and clear waters including Munsom, Kwantaldo, Yosodo, Hongdo, Ch'ujado. In turbid waters the vegetation was much poorer because the tubidity caused from the muddy sediment inhibited an algae to settle down and to grow up. On the basis of the phytogeographical methods using UPGMA, the 10 studied islands were classified into two groups, Munsom and the others. This floristic discontinuity between the two groups might be caused from the difference of water temperature.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.657-662
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• 2005

Iron sulfide(FeS) is significantly produced through both abiotic and biotic processes in natural sediments and pore waters. In this study, chromium(VI) reaction with iron sulfide at various initial concentrations and at pH values of 4 and 8 was conducted to better understand the interactions between Cr(VI) and Fe(II) species dissolved from iron sulfide in both the aqueous and solid phases. Also, the removal efficiency of iron sulfide was compared with zero valent iron and other iron bearing oxides such as ${\alpha}-Fe_2O_3$, ${\alpha}-FeOOH$ and $Fe_3O_4$. The Cr(VI) removal rate by iron sulfide was higher at pH 4 than at pH 8 because more dissolved Fe(II) existed at pH 4 than at pH 8. Chromium and iron(oxyhydroxide) could be identified on the iron sulfide surface with transmission microscopy imaging and energy dispersive spectroscopy. The removal capacity of iron sulfide was much higher than zero valent iron and other iron oxide minerals due to the synergic effect of hydrogen sulfide and ferrous iron.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.1-8
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• 2010

To investigate the effects of sediments on the water quality of an estuary reservoir, Asan reservoir, we analyzed physical and chemical characteristics of the sediments and estimated nutrients release rate from the sediments. The sediments characterized as sandy loam are mainly composed of Nonapatite-P(64.7%) which has strong influence on the eutrophication of the reservoir by releasing from the sediments under the condition of increasing pH and anaerobic environment. High nutrient release rates was observed in April. Negative release rates in June show that there is no significant nutrient release from the sediments. The nutrient release was active at the Site B around the confluence of tributary compared to the Site A near the embankment. Based on the information of nutrient release rates and sediments surface area, daily average nutrient release rates of Asan reservoir are estimated; TN 6,609 kg/d, TP 3,877 kg/d. Since the amount of N and P released from the sediments corresponds to the 7.06% of N and 22.04% of P incoming from the watershed, it can be concluded that there is little influence of sediments on the water quality of Asan reservoir.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.2
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• pp.95-105
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• 2020

In order to promote efficient coastal management, it is important to continuously monitor the characteristics of the terrain, which are changed by various factors. In this study, time series UAV images were taken of Gyeokpo beach. And the standard deviation of ±11cm(X), ±10cm(Y), and ±15cm(Z) was obtained as a result of comparing with the VRS measurement performance for UAV position accuracy evaluation. Therefore, it was confirmed that the tolerance of the digital map work rule was satisfied. In addition, as a result of monitoring the erosion and sedimentation changes using the DSM(digital surface model) constructed through UAV images, an average of 0.01 m deposition occurred between June 2018 and December 2018, and in December 2018 and June 2019. It was analyzed that 0.03m of erosion occurred. Therefore, 0.02m of erosion occurred between June 2018 and June 2019. From the topographical change analysis results, the area of erosion and sediment height was analyzed, and the area of erosion and sedimentation was widely distributed in the ±0.5m section. If we continuously monitor the topographical changes in the coastal regions by using the 3D terrain modeling results using the time series UAV images presented in this study, we can support the coastal management tasks such as supplement or dredging of sand.

• The Korean Journal of Malacology
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• v.30 no.1
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• pp.95-99
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• 2014

In the present study, we surveyed the molluscan fauna in a lagoon located near Seong-san harbor on the east coast of Jeju Island in July 2012. For the survey, a $25{\times}25cm$ quadrat was deployed over 3 randomly selected sites in the intertidal area of the lagoon. Sediment from the surface to a depth of 25 cm in the quadrat was removed and sieved using a 1 mm mesh sieve. All molluscan fauna retained on the sieve was identified to the species level. From the survey, 25 species of mollusca belonging to 2 orders and 16 families were identified. Species richness, in terms of total number of species, was found to be the highest at sampling site 1, where the substrate was composed of coarse sand and some rocks, while it was lowest at sampling site 3, composed of compact fine sand. Regardless of the type of substrate at the sampling sites, the mud-creeping snail Batillaria cumingii (Crosse, 1862) occurred at a high density, ranging from $324-468ind./m^2$. The luciniid bivalve Pillucina pisidium also occurred at a high density at sampling site 1, at $336ind./m^2$, while the density of this species was only $4ind./m^2$ at sampling site 3. The Manila clam Ruditapes philippinarum could be found at all 3 sampling sites with very low density ranging from $16-48ind./m^2$. The density and species richness of molluscs observed in this study was lower compared to the previously reported molluscan fauna in Jeju Island, suggesting that further investigation needs to be carried out to conserve the unique marine lagoon ecosystem in Jeju Island.

• Journal of Life Science
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• v.28 no.4
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• pp.483-487
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• 2018

Cypermethrin, a commonly used domestic and agricultural pyrethroid pesticide, is widely considered detrimental to the environment and to many organisms because of its residual property and toxicity. Cellulophaga lytica DAU203, isolated from coastal sediment, was chosen because it degrade cypermethrin. Cellulophaga lytica DAU203 effectively degraded cypermethrin, as the utilized carbon source and substrate, in a mineral salt medium. Effective factors, such as carbon source, nitrogen source, initial pH, and temperature, for cypermethtin biological degradation by Cellulophaga lytica DAU203 were analyzed by one factor at a time method. Temperature ($22{\sim}42^{\circ}C$), initial pH (5~9), and yeast extract concentration (0.1~2.5%[w/v]) were selected as the three most important factors. There were optimized at $33.4^{\circ}C$, pH 7.7, and 2.4%(w/v) by response surface methodology, respectively. The Box- Behnken design consisting of 46 experimental runs with three replicates was used to optimize the independent variables which significantly influenced the cypermethrin biological degradation. This model for cypermethrin degradation by Cellulophaga lytica DAU203 is highly significant (p<0.05). Under the optimized condition, Cellulophaga lytica DAU203 degraded approximately 83.7 % of the cypermethrin within 5 days. These results suggest that Cellulophaga lytica DAU203 may be useful for the biological degradation of cypermethrin in cypermethrin-contaminated environments.