• Korean Journal of Environmental Biology
• /
• v.26 no.2
• /
• pp.94-101
• /
• 2008

The aim of this study was to assess the responses of mixed function oxygenase (MFO) and antioxidative systems of feral Javelin goby, Acanthogobius hasta, caught in two sites of different pollution level in Shihwa lake, which has been a highly polluted lake by organic pollutants from nearby industrial complexes and sites. Enzymes analyzed in phase I of MFO system are cytochrome P450 (CYP), NADPH-cytochrome P450 reductase (P450R), NADH-cytochrome b5 reductase (b5R), and ethoxyresorufin deethylase (EROD). Phase II enzyme of glutathione S-transferase (GST) in MFO system was also investigated. Moreover, oxidative-enzyme system including catalase (CAT), glutathione reductase (GR) and total-glutathione peroxidase (GPX) activities and glutathione concentration in both of oxidized (GSSG) and reduced form (GSH) were determined. P450R, b5R, and GST activities of fish are relatively high in the polluted area, whereas hepatic EROD activity levels of fish in polluted area were lower than those of unpolluted area. CYP concentrations are not different between areas. These results indicated that feral Acanthogobius hasta were adaptive to highly polluted environment and exposed to oxidative stress in Shihwa lake.

• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.206-215
• /
• 2008

Temporal and spatial distributions of salinity, temperature, dissolved oxygen (DO), and turbidity were investigated at seven sites in the upper regions of brackish Lake Sihwa with a limited water exchange, from March to October 2005. During the study period, salinity and temperature varied $0.1{\sim}29.9\;psu$ and $4.7{\sim}28.1^{\circ}C$, respectively, depending on seasons and sites sampled. A distinct halocline profile showing the maximum density gradient (difference over $20\;psu\;m^{-1}$ between surface and bottom layers) was observed during the rainy season, due to the decrease of salinity in surface layers by freshwater inflow. This result implies that rainfall event is the important factor forming the halocline. On the other hand, the depth and location of haloeline varied with the amount of seawater through the sluice gates and the operation systems (inflow or outflow). High DO (over 300% saturation) was observed at surface layer above the halocline in April when red tide occurred, whereas low DO (below 20% saturation) was at the bottom layer below the halocline in the rainy season. Turbidity ranged $1.5{\sim}80.3\;NTU$ showing the maximum turbidity at the layers above or upper the halocline. As a result, the distributions of DO and turbidity in the upper regions of brackish Lake Sihwa were largely affected by the variation of salinity. Also, when the halocline was formed, the water quality between upper and lower water layers may be expected completely different. This study suggests that the physicochemical characteristics of water in the brackish regions are closely associated with the causes of eutrophication such as red tide and DO deficit.

• The Korean Journal of Ecology
• /
• v.27 no.6 s.122
• /
• pp.383-390
• /
• 2004

This study was conducted in three sites, Si-Hwa Lake, Dongman and Seoman island and Janguyeop island, from march, 1999 to september, 2002. The behaviors of pre-breeding season, territorial behaviors, reproductive ecology, foraging sites and behaviors, and the competition of reproduction and foods between intraspecific or interspecific of Eurasian Oystercatcher (Haematopus ostralegus) were observed in each studying sites. The breeding of Eurasian Oystercatcher started on the middle of April in Si-Hwa Lake and on the middle of May in Dongman and Seoman island and Janguyeop island. For intension of pair bond on pre-breeding season, Eurasian Oystercatcher foraged with pair and behaved male-female chasing flight behavior. The pair foraged with male and female before copulation. If other pairs and individuals approached in feeding site of pair, this pair attacked them with piping calling and intruder chasing flight. If continuos serial behaviors were not observed, the discrimination of male-female chasing flight and intruder chasing flight was difficult. Territorial behaviors classified four types; butterfly flight, calling behavior, chasing behavior, fight behavior. The important foraging sites in Si-Hwa Lake are the land place in Daeboo island, tidal flat of Bangameori, tidal flat a front of a stationary net for catching fishes and tidal flat a front of a view station for bird watching. Eurasian Oystercatcher foraged at tidal flat on low water of the tide and foraged at feeding sites near island on flood tide in Dongman and Seoman island. Eurasian Oystercater in Janguyeop island usually foraged feeding sites near island, because water level was not different between low water of the tide and flood tide. Eurasian Oystercatcher competed on foods of intraspecific and interspecific. They chased for taking foods by force in feeding sites and drove out intruders in feeding sites. The foods interspecific competition happened with Black-tailed Gull (Larus crassirostris). Eurasian Oystercatcher was robbed of foods and attacked by Black-tailed Gull. The individual of food competition with Black-tailed Gull was low foods intake rate comparison with other feeding sites and this individual flied out other feeding sites.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.26 no.2
• /
• pp.110-123
• /
• 2021

We investigated geochemical constituents of pore-water and sediment, rates of organic carbon (C_org) oxidation and sulfate reduction (SR), and benthic nutrient flux (BNF) to elucidate characteristic of C_org oxidation and its control in the coastal area near Lake Shihwa. The study sites were selected in the vicinity of Soraepogu (E0), Songdo tidalflat (E1) and Oido dock (E3) and in front of floodgate Shihwa tidal plant (E5). The C_org contents in the sediments and concentrations of ammonium and phosphate in pore water exhibited the highest value at EO, and gradually decreased toward the outer sea (E1, E3, E5). Rates of anaerobic C_org oxidation (260.6 mmol C m^-2 d^-1) and SR (91.4 mmol S m^-2 d^-1) at E0 were 4-9 and 6-54 times higher than at the site of outer sea (E1, E3, E5). Rates of SR at E3 and E5 accounted for 11-23% of anaerobic C_org oxidation, whereas it comprised 47-70% of anaerobic C_org oxidation at E0 and E1. Rates of C_org oxidation and SR showed a highly positive correlation with the concentration of dissolved organic carbon (r² = 0.795 and 0.777, respectively). The BNF at E0, E1, and E3 accounted for 120-510% and 26-178%, respectively, of the N and P required for primary production in the water column. Overall results suggest that the C_org oxidation in the sediment controlled by concentration of dissolved organic carbon in the pore water and the excessive C_org oxidation stimulates the benthic nutrient flux, which may cause a phytoplankton bloom in the water column.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2007.10a
• /
• pp.215-216
• /
• 2007

• 월간 기계설비
• /
• s.227
• /
• pp.40-49
• /
• 2009

해양에너지는 해양의 조수 파도 해류 온도차 등을 변환시켜 전기 또는 열을 생산하는 기술로서 전기를 생산하는 방식은 조력 파력 조류 온도차 발전 등이 있다. 해양에너지는 타 신재생에너지에 비해 부존량이 풍부하고 에너지 밀도가 높으며 대규모 개발이 가능하다는 장점을 가지고 있다. 특히 조력과 조류발전은 발전량의 정확한 장기예측이 가능해 전력계통망 운영에 유리하다는 큰 장점이 있다. 그러나 전 세계적으로 해양에너지의 보급은 미미한 실정이다. 화석에너지에 비해 경제성이 낮기 때문이다. 특히 조력발전은 막대한 초기건설비가 소요되고 입지가 제한적이다. 하지만 전문가들은 에너지자원 빈국인 우리나라의 경우 해양에너지 산업화가 시기적인 문제만 있을 뿐 향후 이에 따른 건설 및 서비스 시장도 확대될 것으로 전망하고 있다. 조력 조류발전의 경우 대규모 건설공사가 수반되며 이로 인한 산업적 파급효과는 막대할 것으로 예상되고 있다. 국내의 경우 시화호 조력발전소, 가로림 조력발전소, 울돌목 조류발전소의 경우 각각 약 3,600억원, 약 1조원, 약 2,500억원 총 건설비가 소요될 것으로 전망되고 있다. 이중 토목건설 부분이 약 50%, 기계 전기 부분이 약 50%를 차지한다. 이는 향후 5년간 약 1조 6,000억원 정도의 토목건설과 기계 전기 설비시장이 새롭게 형성될 수 있다는 것을 의미한다. 이번 호에는 해양에너지 중 가장 집중적으로 추진되고 있는 조력 조류발전에 대해 알아본다.

• Journal of Environmental Impact Assessment
• /
• v.17 no.2
• /
• pp.105-112
• /
• 2008

Human activity has been the major threat to wetlands. Agriculture, industrial development, and urban and suburban sprawl have caused the greatest losses of coastal wetlands. In fact, riceland agriculture, because of the flooding that goes with it, provides some additional wetland habitat not otherwise available. The biggest current source of loss for freshwater coastal wetlands is from urban sprawl. In this study, spatial analysis method such as landscape index were applied to Sihwa area in Ansan city. The SMA (Spectral Mixture Analysis) method using Landsat image showed the change distribution of wetland vegetation from 1996 to 2004. The southern part of Sihwa wetland have been changed with Suda japonica of 24% and reed vegetation of 34% on coastal wetland which were covered with tidal flat.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.615-618
• /
• 2003

A prototype of 76 ha Shi-hwa constructed wetland was constructed for the first time in Korea to purify severely polluted stream water. Hydrology, vegetation(macrophyte) and water quality for Banwol and Donghwa wetland built in Shi-hwa tidal reclaimed area were monitored to evaluate the performance of the wetlands. The overall efficiency for the treatment of polluted stream water using the wetlands showed no significant improvement. The monthly average removal rates on SS, BOD, TN and TP for Banwol and Donghwa wetlands showed 66.5% and 62.8%, 14.8 and 34.3%, 33.9 and 47.1% and 20.8 and 51.6%, respectively. It is considered that three major factors, ie. wide fluctuations in inflow rate, short hydraulic retention time and small open area compared with vegetated area could have a great influence on low system efficiency.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2001.11a
• /
• pp.115-122
• /
• 2001

본 개발대상 장치인 풍력을 통한 하강류 형성장치는 심층에 산소를 공급하여 패류가 증식하게 하므로 정화를 할 수 있도록 하는 장치이다. 본 연구의 결과, 풍력 저수지 수질개선장치를 통해 모든 호소의 수질등급을 상향시킬 수 있을 것이다. 특히, 새만금, 시화호 등 문제 있는 호소까지 인간에 유익한 수질로 개선 함으로써 국가적인 이익은 물론 전세계의 수원을 정화하여 인류의 수자원 문제를 해결할 수가 있을 것이다. 동력에 의한 방법은 언제든지 적용할 수 있지만, 풍력에 의한 장치로 에너지 비용과 설치비용을 절감하는 것이 본 개발대상 장치를 통해 얻을 수 있는 효과이다. 현재 국내의 저수지는 약 12,000개소에 달한다 이 저수지들에 오염도에 따라 5대～200대 정도를 설치할 경우(소양이나 새만금 등), 장치의 대당 가격이 1,000 만원～1,500 만원이므로 국내 수요로 약 2조 4천억원의 내수시장이 형성될 수 있을 것이다.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.2222-2223
• /
• 2008

JCS(Joint Control System)는 대규모 조력발전소에서의 조력발전소에 설치된 10대(25.4MWx10기)이상의 발전기에 대한 전자동 운전, 운영의 최적화, 운전 모드, 발전소 특성변수, 각종 운전상의 또는 법적 규제치 등을 고려하여 전력생산량을 극대화한다. 또한 발전소 운영의 단순화(종합설정: Global Setting, 부하특성곡선 등) 안전한 운전을 위한 발전소의 각종 변수 및 제한값을 감시하며 발전소의 발전기를 한 대의 발전기처럼 제어할 수 있도록 한다.