• Journal of Environmental Science International
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• v.15 no.8
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• pp.727-735
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• 2006

In this study, the PHYTO-PAM-fluorometric method was used to evaluate the ETR$_{max}$ in terms of sensitivity to DIN/DIP against 14 microalgae: Prorocentrum micans, Heterocapsa triquetra, Gymnodinium impudicum, Cymnodinium catenatum, Amphidinium caterae, Chlorella vulgaris, Chroococcus minutus, Microcystis aeruginosa, Chlorella ellipsoidea, Nannochloris oculata, Oocystis lacustris, Chroomonas salina, Gloeocystis gigas, and Prymnessium parvum. We found that P. micans, H. triquetra, and A. caterae exposed to the maximum level of DIN/DIP were significantly smaller in the ETR$_{max}$ than that of the minimum and moderate mixture. Unlikely the ETR$_{max}$, the initial slope alpha was not significantly different at the level of 60 DIN/DIP. In G. catenatum, the moderate levels of 15 and 20 in DIN/DIP were found to be significantly different from the ETR$_{max}$ at Chl-Ch4. Gymnodinium impudicum had a higher value than that of the ETR$_{max}$ than that of dinoflagellates used in this study, ranging from 306.1 (Ch4, DIN/DIP: 10) to 520.1 (Ch4, DIN/DIP: 30). The ETR$_{max}$ value obtained from other microalgae was similar to C. impudicum at any of the ratios of DIN/DIP and channels. Consequently, the influence of offshore water current assures us of the suppression of photosynthesis and electron transport rate in dinoflagellates. Gymnodinium impudicum has not been researched in the area of red tides in Korea, but it will be enough to creat the massive algal blooms in the future because of higher potential photochemical availability.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.69-79
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• 2004

This study focuses on the relationship between pollution factors around Masan, Changwon and Chinhae city considerd as main pollution sources and marine environment in Masan bay of Korea. Water quality data measured In Jinhae bay and environmental investigation data in Masan, Changwon and Jinhae cities from 1981 to 1998 were used for this study. Annual means and standard deviations of COD, DIN and DIP concentrations from 1981 to 1998 showed that both their concentration and fluctuations were higher in the inner part of Masan bay (region A) than near Somodo (region B). Sediment dredging in Masan bay had been done from 1990 to 1994. After dredging, COD concentration has been decreasing In surface layer. Also water pollution was gradually spreaded from the inner part to the outer part of the bay due to the continuous inflow of domestic sewage and industrial wastewater. In the late of 1990s, the pollution was heavier. DIN and DIP concentrations were found to be increased by establishment of industry complex and decreased by sewage treatment plant near the city adjacent to Jinhae bay, 1993. The correlation between COD, DIN and DIP changes and neighbor cities' pollution sources were calculated From 1981 to 1998, correlation coefficient (r) was over 0.8 except for the bottom of region A From 1981 to 1998, r between the DIP concentration and population was over 0.65 except for the surface of region A, and the r between the DIP and the number of factories was over 0.6 too, in region B.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.248-254
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• 2009

Budgets of fresh water, salt, DIP and DIN in the Youngsan river estuary were estimated seasonally in order to clarify the characteristics of material cycling and flux of nutrients with a simple box model. Inflow volumes of freshwater into system was approximately $36.481{\times}10^6{\sim}663.634{\times}10^6m^3/month$ and existing water mass of freshwater in system calculated by salt budget was approximately $2.515{\times}10^6{\sim}5.812{\times}10^6m^3$. Mean residence time of freshwater was calculated to be about 0.26~2.03 day. water exchange $1,248{\times}10^6{\sim}9,489{\times}10^6m^3/month$ assumed with salinity between estuary and adjacent ocean. Inflow mass of DIN and DIN were approximately 76.63~1,149.91 ton/month and 2.91~61.22 ton/month, respectively. Residence times of DIP and DIN were calculated to be 0.45~1.10 day and 0.28~1.92 day, respectively. The ratio of water residence time versus DIP, DIN residence time was calculated that freshwater residence time was longer than DIP, DIN residence time except for summer season. Thus, We assume that circulation of Nutrients in the system will happen rapidly except for summer season. Specially DIP in Winter could assume to outer input source existence because of seawater inflow in system and high DIP concentration in open sea.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.307-317
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• 2003

In this study, the material cycle model was applied to suggest alternative management of water quality for Jeju Harbor. The distribution of COD, DIN (dissolved inorganic nitrogen) and DIP (dissolved inorganic phosphorus) concentrations was reasonably reproduced by simulations on the model area of the Jeju Harbor using a material cycle model. The simulations of COD, DIN and DIP concentrations were performed under the conditions of 20∼100% pollution loadings reductions from pollution sources. In case of the 100% reduction of the input loads from Sanzi river, concentrations of COD, DM and DIP were reduced to 39%, 78% and 52%, respectively at Jeju harbor. In contrast, in case of the pollutant loadings reductions from sediment, the effect of DIN and DIP reduction relatively seemed to increase around the center of study area. The 95% reduction of the pollutant loadings from river and sediment is required to meet the COD and nutrients concentration of second grade of ocean water quality criteria.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.76-90
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• 2000

The estimation of material cycle of pollutants is necessary for the environment management in coastal zone. Model for material budgets are useful tools to understand the phenomena of natural system and to provide an insight into the complex processes including physical, chemical and biological processes occuring in natural system. Budgets of fresh water, salt and nutrients were estimated in order to clarify the characteristics of seasonal material cycle in Keum river estuary. Inflow volumes of freshwater into system was approximately 1.014×10/sup 8/～12.565×10/sup 8/m³/month and discharge in Keum river has occupied 99.7% of total freshwater. Seasonal variations of freshwater volume in the system were found to be very high in the range of about 4 ～ 14 times due to rainfall in summer season. Existing water mass of freshwater in system calculated by salt budget was approximately 0.339×10/sup 8/～0.652×10/sup 8/m³. Mean residence time of freshwater was calculated to be about 1.6～10.0day, and exchange time was calculated to be about 2.2～11.9day. Mean residence time was short as 1.6day in summer due to precipitation, and long as 10.1day in winter due to a drought. Inflow masses of DIP and DIN were approximately 5.57～32.68ton/month and 234.93～2,373.39ton/month, respectively. Seasonal inflow mass of DIP was larger than the outflow mass except for summer season. Thus, we postulate that accumulation of DIP in the system will happen. Residence times of DIP and DIN were calculated to be 1.1～6.4day and 1.8～10.9day, respectively. The ratio of water residence time versus DIP, DIN residence time was calculated to be 0.39～2.31 times and 0.83～1.13 times, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.44-59
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• 2003

The three-dimensional eco-hydrodynamic model was applied to estimate the effect of water quality improvement by the effluent treatment of landbase-seawater culture system in the Kamak bay The computed residual currents were dominated southward flow at the northern narrow strait and eastward flow and clockwise water circulation at the mouth of the bay, strongly. The mean relative errors of DIP, DIN and COD between the simulated and observed results at 9 stations in the Kamak bay were shown 14.3％, 25.8％ and 14.4％, respectively. There were high concentrations of DIP, DIN and COD at the northwestern bay which is influenced by pollution loads. The simulations were performed using an ecosystem model under the conditions of DIP 90％, DIN 80％ and COD 60％ treatment efficiency by the ozone treatment system of landbase-seawater culture system. As a results of simulation, the improvement effects of DIP, DIN and COD are 34.4~54.0％ (average 46.4％), 0.4~25.4％(average 8.4％) and 15.6~29.4％(average 22.7％), respectively. Therefore the area of seawater quality grade I based on COD was extended in the bay.

• Journal of Environmental Science International
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• v.17 no.3
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• pp.269-273
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• 2008

The objective of this study was to evaluate the relationship between nutrients and phytoplankton. This study was done by the comparison to two costal areas Mokpo, which inflow fresh water, and Wando. In August, salinity of the sea water decreased by 3.5-4.5%o in Mokpo coastal area, but was not nearly decreased in Wando coastal area. This suggests a lot of fresh water inflow in Mokpo coastal area. DIN and DIP were decreased by water temperature increasing in Wando. However, in Mokpo, DIN and DIP were increased greatly during the summer season. Nitrogen was limited to a 10 NIP ratio especially during the summer season in Wando coastal area while phosphorus in Mokpo coastal area was limited with over 28 N/P ratio in all the seasons. Coefficient of determination$(r^2)$ between DIP and Chl.-a was 0.91 in Mokpo coastal area. On the other hand, Coefficient of determination$(r^2)$ between Chl.-a and DIN, DIP were 0.93 and 0.89, respectively, in Wando coastal area. These results suggest DIP in Mokpo and DIN and DIP in Wando might be limited at the increase of phytoplankton.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.535-544
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• 2019

To elucidate the cause of Pyropia yezoensis discoloration, the characteristics of an aquaculture environment, as well as the morphology and cell structure of P. yezoensis thallus were examined from 2011 to 2014 in aquaculture farms of the Jeonbuk province. P. yezoensis discoloration did not occur in aquaculture farms at Gaeyado located in the Geum River Estuary but occurred in aquaculture farms of Seonyudo, Munyeodo, Biando, and Docheongri near the Saemangeum embankment in November 2011 and April and November 2014. The injured leaves showed discoloration and intracellular vacuole hypertrophy. During the study period, discoloration occurred at concentrations of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) below 5μM and 0.4μM, respectively. As a result, Pyropia discoloration was determined by low concentrations of DIN and DIP. DIN deficiency affects the early stage and low DIP concentration affects the end stage of aquaculture.

• 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.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.957-966
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• 2003

Gunsan coastal area is one of region increasing pollution problems. To improve water quality, the reduction of these nutrients loads should be indispensible. In this study, the three-dimensional numerical hydrodynamic and ecosystem model were applied to analyze the processes affecting the eutrophication. In field survey, the average concentrations of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus(DIP) at surface waters were found to be 0.43mg/$\ell$ and 0.03mg/$\ell$ respectively, which were exceeding second grade of water quality criteria. In hydrodynamic modelling, the comparison between the simulated and observed tidal ellipses showed fairly good agreement. The ecosystem model was calibrated with the observed data in study area. The simulated results of DIN were fairly good coincided with the observed values within relative error of 32.39%, correlation coefficient(r) of 0.99. In the case of DIP, the simulated results were fairly good coincided with the observed values within relative error of 24.26%, correlation coefficient(r) of 0.82. The simulations of DIN and DIP concentrations using ecosystem model were performed under the conditions of 20∼80% reductions for pollutant loading. At simulation results, concentration of DIN and DIP were reduced to 20∼80% and under 10% in case of the 80% reduction of pollutant loading, respectively.