• Applied Biological Chemistry
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• v.41 no.8
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• pp.587-594
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• 1998

The objective of this research was to characterize effects of Cu or Cd additions on chemistry of soil quality indices, such as pH, EC, cation distribution and buffering capacity. Metals were added at rates ranging from 0 to 400 mg $kg^{-1}$ of soil. Soil solution was sequentially extracted from saturated pastes using vacuum. Concentrations of Cu or Cd remaining in soil solutions were very low as compared to those added to the soils, warranting that most of the added metals were recovered as nonavailable fractions. Adsorption of the added metals released cations into soil solution causing increases of ionic strength of soil solution. At metal additions of $200{\sim}400\;mg\;kg^{-1}$, EC of soil solution increased to as much as $2{\sim}4\;m^{-1}$; salinity levels considered high enough to cause detrimental effects on plant production. More divalent cations than monovalent cations were exchanged by Cu or Cd adsorption. The nutrient buffering capacity of soils was decreased due to the metal adsorption and release of cations. pH of soil solution decreased linearly with increasing metal loading rates, with a decrement of up to 1.3 units at 400 mg Cu $kg^{-1}$ addition. Influences of Cu on each of these soil quality parameters were consistently greater than those of Cd. These effects were of a detrimental nature and large enough in most cases to significantly impact soil productivity. It is clear that new protocols are needed for evaluating potential effects of heavy metal loading of soils.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.189-195
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• 1999

Determining factors and temporal & spatial characteristics of COD(Chemical Oxygen Demand) at the sea surface in Jinhae bay have been examined by using seasonal data, taken at twenty six stations over the whole bay during 1989~1994 by NERDA. The data have been analyzed in terms of long term means, anomalously large values. Jinhae bay is divided into three regions based on the time mean : mouth of Jinhae bay, inner sea of Masan bay, western sea of Jinhae bay called region 1,2 and 3, respectively. The horizontal distribution of the long term mean of COD at each station is similar to those of nitrogen and phosphorus. Characteristics of whole mean variation in the year shows high range of variation in region 2. It was appear to decreases every year in whole trend. Factors determining seasonal variation in whole COD mean are relative to salinity and nutrient, affected by precipitation in summer. Spatial variation shows high range of fluctuation in region 2 compare to other region. Factors determining of spatial variation of COD was appear to nutrient, affected by pollutant load of land area and bottom sediment. The long term mean of COD at each station is closely related with thats of nutrients. The correlation coefficient between COD and nitrogen, phosphate phosphorus was found to be high as 0.75, 0.78, respectively. Anomalously large COD was observed 14 times at 6 stations. These stations are located in inner sea of Masan bay(Region 2) and Songjeong bay(Region 1). The seasonal frequency of the observed anomalous COD is large in April, and other seasons are much the same.

• Journal of Environmental Science International
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• v.17 no.4
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1243-1263
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• 2011

This study was carried out to determine marine environments and phytoplankton community in Deukryang Bay during the period of summer in 1987-2010. Water temperature, salinity, pH and dissolved oxygen were shown in much yearly fluctuations. In August, water temperatures in surface and on bottom were the highest, compared with average surface (24.54$^{\circ}C$) and bottom (22.90$^{\circ}C$) water temperature for 18 years in Deukryang Bay. The main reason is assumed to longer duration of sunshine during the period of August. Although the amount of the rainfall in August was the highest, significant impact of marine environment did not show. Most of dissolved inorganic nitrogen and phosphate in Deukryang were lower concentration during summer and N:P ratio also showed below 18 in Redfield. In particular, extreme increasing of N:P ratio in August was occurred by intensive precipitation. Distribution of phytoplankton community was a consistent occurrence for 18 years. The genus of Chaetoceros, Cosinodisucs and Skeletonema were regarded as the represent diatom, whereas the highest occurrence of genus among dinofagellates was Ceratium. It is thought that the relationship between phytoplankton and nutrient has a strong positive signal, although nutrients persist a little concentration and much fluctuations in marine environments were observed. High availability in phytoplankton is contributed to consistently provide the food organism of shellfish. Consequently, recent decreasing production of shellfish and seed are probably associated with higher temperature during the period of summer. However, higher temperature is also occurred ago and after 2000. On the basis of geography, Deukryang Bay had a small mouth and long channel, which is attributed to decreasing genetic diversity. It is assumed that higher temperature and lower genetic diversity have a extreme impact of larvae and shellfish for reproduction in Deukryang. It is necessary to persistently monitor based on water quality and phytoplankton community.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1683-1690
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• 2013

We investigated the spatial and temporal variations of phytoplankton in Youngil Bay as well as the effect of water physico-chemical parameters. Water samples at three stations were collected and measured monthly from May to November in 2010. The taxa of phytoplankton observed in this study were classified as 33 Bacillariophyceae, 23 Dinophyceae, 1 Euglenophyceae, 2 Crysophyceae and 1 Cryptophyceae. The highest biomass of phytoplankton was observed at inner station in September, which was characterized high concentration of dissolved inorganic phosphate(DIP) in surface water after rainfall. Nutrient concentrations, chlorophyll-a and phytoplankton biomass values showed the marked trend to decrease from the inner bay to the outer bay. Pearson's correlation co-efficient between salinity and other water parameters including chlorophyll-a, pH and DIP showed the strong negative relationship r=-0.82, r=-0.78 and r=-0.75 (p<0.01), respectively. These results indicate that the water quality of Youngil Bay could be stimulated by nutrient enriched input from Hyeogsan River discharge, and the spatial and temporal distribution of phytoplankton biomass principally limited to DIP concentration from Hyeogsan river.

• Ocean and Polar Research
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• v.33 no.4
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• pp.447-455
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• 2011

Using results from an earth system model, the distribution of partial pressure of $CO_2$ ($pCO_2$) in surface seawater over the East China Sea is investigated. In this area $pCO_2$ shows minimum along the edge of the continental break along the path of the Taiwan-Tsushima Current System. Apparently modelled chlorophyll is also great along the current but the maximum of the chlorophyll and the minimum of $pCO_2$ do not coincide suggesting that the primary production is not the main cause of the $pCO_2$ minimum. As we move toward the Yellow Sea from the Kuroshio area the temperature decreases so that the $pCO_2$ becomes smaller. If we move further toward the Yellow Sea beyond the Taiwan-Tsushima Current System, alkalinity starts to drop substantially to intensify $pCO_2$ while overcoming the effect of decreasing temperature and salinity. Thus $pCO_2$ minimum occurs along the Taiwan-Tsushima Current System. Of course, the primary production lower $pCO_2$ during spring when it is high but the effect is local. Near the Yangtze river mouth and northeastern corner of the Yellow Sea the fresh water input is large enough and dissolved inorganic carbon (DIC) becomes low enough so that $pCO_2$ becomes lower again.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.30-34
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• 2004

To verify the characteristics of deep ocean water, oceanographic observation and qualitative analysis were carried out from March of 2001 to February of 2002. Spatiotemporal variation of water quality of deep ocean water were discussed from survey results around development site and along northeastern coastal sea of Korean peninsular. Vertical distribution of water temperature and salinity were measured, and sampled seawater were analyzed in order to determine the definition of deep ocean water resource and the position of intake device for supplying qualified deep ocean water resource.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.918-929
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• 2015

Microbial enhanced oil recovery (MEOR) is being used more widely, and the biological contributions involved in MEOR need to be identified and quantified for the improvement of field applications. Owing to the excellent interfacial activity and the wide distribution of producing strains in oil reservoirs, lipopeptides have proved to be an essential part of the complex mechanisms in MEOR. In this study, crude lipopeptides were produced by a strain isolated from an indigenous community in an oil reservoir. It was found that crude lipopeptides can effectively reduce the IFT (interfacial tension) to 10^-1~10^-2 mN/m under high salinity without forming stable emulsions, and the wettability of natural sandstone can be enhanced (Amott index, from 0.36 to 0.48). The results of core flooding experiments indicate that an additional 5.2% of original oil in place can be recovered with a 9.5% reduction of injection pressure. After the shut-in period, the wettability of the core, the reduction of injection pressure, and the oil recovery can be improved to 0.63, 16.2% and 9.6%, respectively. In the microscopic flooding experiments, the crude oil in membrane, cluster, and throat states contribute nearly 90% in total of the additional oil recovery, and the recovery of membranestate oil was significantly enhanced by 93.3% after shut in. Based on the results in macro and pore scale, the IFT reduction and the wettability alteration are considered primary contributors to oil recovery, while the latter was more dominant after one shut-in period.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.132-143
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• 2005

In order to investigate the seasonal variation of watermass and fishery creatures in the adjacent sea of Naro Island, an oceanographic observation was carried out seasonally on the fishing grounds, and the sales performance data of the fisheries cooperative's joint market of Naro Island was examined by using a principal component analysis. The temperature and salinity ranged from 8.1 $^{\circ}C$ to 13.7 $^{\circ}C$ and from 33.1 psu to 34.3 psu in spring, from 14.5 $^{\circ}C$ to 24.2 $^{\circ}C$ and from 30.5 psu to 34.1 psu in summer, from 14.8 $^{\circ}C$ to 18.6 $^{\circ}C$ and from 30.1 psu to 34.0 psu in autumn, and from 4.3 $^{\circ}C$ to 10.1 $^{\circ}C$ and from 33.1 psu to 34.9 psu in winter, respectively. In winter and spring, the offshore water spread out to all sea areas of all water layers. In summer, the mixed waters covered the entire sea surface whereas the mixed water and offshore water covered the bottom. In autumn, the coastal water and mixed water appeared on the surface, but the mixed water was distributed widely on the bottom and the offshore water began to appear in the open sea. For two years from 2002 to 2003, 58 fishery creature species in total were sold in the fisheries cooperative's joint market of Naro Island. In general, the total of 50% fish were sold, and crustacea and mollusc by each 25%. Medium shrimp, whiparm octopus, blue crab, and octopus predominated. A number of species and biomass of fishery creatures were sold mostly in April and May, while they were sold the least in January and February. The seasonal sales results showed that mullet, angler, short necked clam, large shrimp, and webfoot octopus were sold mainly in spring, tonguefish, flathead, pomfret, glass eel, blue crab, whiparm octopus, and squid were sold mainly in summer, and octopus, medium shrimp, and spanish mackerel were sold mainly in autumn.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.381-387
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• 2016

The scientific information on the microbial differentiation according to the changes in chemical properties of paddy soil in reclaimed tidal lands is not enough to understand the reclamation processes. The changes in microflora based on the chemical properties of paddy soils at the same sites of reclaimed tidal lands (21 samples from Nampo, Ewon, Sukmoon and Shihwa sites) were investigated in 2013 and 2015. In general, organic matter in paddy soils increased whereas pH decreased with the reclamation time. The electrical conductivities (EC) of soil samples were closely related to the exchangeable $Na^+$. With an increases in EC of paddy soils from 0.39 to $48.9dS\;m^{-1}$, the ratios (%) of halotolerant and halophilic bacteria to mesophilic bacteria proportionally increased from 0.2% to 102,000%. The population of halotolerant and halophilic bacteria in total microflora was also differentiated with the changes in EC of the same sites from reclaimed tidal soils within 2 years. The population of mesophilic bacteria decreased with an increase in EC above $5dS\;m^{-1}$. The microflora including halotolerant and halophilic bacteria could be a candidate as a biological parameter in evaluating the reclamation processes in addition to the chemical index of EC.