• Journal of Ecology and Environment
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• 제33권4호
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• pp.289-298
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• 2010

A number of characteristics of the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed, such as the lake's location at the edge of the Central Asian continuous permafrost zone, provide a unique opportunity to evaluate possible anthropogenic impacts in this remote area in northern Mongolia. In this study, we compared stream solute concentrations in six sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed. Water samples were collected during the summer months between 2003 and 2005. Concentrations of $Cl^-$ ranged from 9.8 to $51.3\;{\mu}mol/L$; average nitrate concentrations were very low and ranged from undetectable to $1.1\;{\mu}mol/L$ and average ${SO_4}^{2-}$ concentration at sampling stations with minimal animal grazing ranged from 66 to $294\;{\mu}mol/L$. Average dissolved organic carbon (DOC) concentrations ranged from 642 to $1,180\;{\mu}mol$ C/L. We did not find statistically significant differences in DOC concentrations among the six streams, although DOC concentrations tended to be higher in the two northernmost streams, possibly related to differences in the active layer above the permafrost. Dissolved organic nitrogen (DON) concentrations were correlated with DOC concentration, and followed the same spatial pattern as those for DOC. In streams in this remote watershed, total dissolved nitrogen was made up of mostly organic N, as has been found for other regions distant from anthropogenic N sources. Overall, these results suggest that future research on the dynamics of DOC and DON in this watershed will be especially insightful in helping to understand how changes in climate and land use patterns will affect transformations, retention, and export of dissolved organic matter within these sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l region.

• 한국해양공학회지
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• 제19권4호
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• pp.42-48
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• 2005

The sediment of Shihwa Lake contains an abundant quantity of cohesive sediments. The transport processes of the cohesive sediments are complex and difficult to predict, quantitatively. The cohesive sediments are the primary reason for the pollution of the environment and water quality in the coastal region. In this study, a column test has been performed. In order to quantify the settling velocities of sediment from Shihwa Lake, an experiment was conducted using a specially designed 1.8m tall settling column. A series of settling tests and physico-chemical property tests on Shihwa Lake cohesive sediments has been conducted to investigate the correlation between settling properties and their physico-chemical properties, which are represented as grain size distribution, mineralogical composition, and percentage oj organic contents. Experimental results of physico-chemical property tests show that Shihwa Lake sediments are relatively large in average grain $size(74\mu m)$ contain very small organic $material(6\%)$, and are dominantly composed of Quarts, which has relatively low cohesion. Thus, Shihwa Lake sediments might be specified as those whose settling properties are more influenced by gravity than cohesion. It is concluded that the magnitude of settling velocities of muddy sediments can be quite different, regionally, and it implies that field or laboratory experiments for settling velocity measurement should be preceded over the numerical modeling of muddy sediment transport, in order to obtain the reliable prediction results for a given specific site.

• 한국어류학회지
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• 제17권2호
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• pp.131-141
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• 2005

본 연구는 2004년 5월부터 2005년 2월까지 합천호를 중심으로 댐 내부에서 4곳, 댐 상 하류 하천에서 각각 1곳씩 모두 6개 지점을 중심으로 어류상을 조사 분석하였다. 그 결과 모두 12과 31속 36종으로 확인되었다. 본 조사 기간동안에 출현한 어류 가운데 우점종으로는 H. eigenmanni로 전체 어류의 28.4%의 출현률을 나타내었고, 아우점종으로는 H. labeo가 24.1%였다. 또한 출현한 어류 중 생산량이 가장 높은 어종은 H. labeo로서 전체의 36.5%의 비중을 차지하였고, 다음으로는 H. eigenmanni 22.3%, C. carpio 7.5%, H. nipponensis 6.9%의 순이었다. 합천댐 일대에서 종별 출현빈도가 가장 높은 분류군은 Cyprinidae 어류가 24종으로 전체의 66.7%였고, 그 다음으로는 Cobitidae와 Centropomidae가 각각 2종씩이고, 나머지는 1종씩이었다. 본 조사 구역에서 출현하는 우리나라의 특산어종은 모두 10종, A. koreensis, C. splendidus, S. gracilis majimae, S. chankaensis tsuchigae, M. yaluensis, H. eigenmanni, N. multifasciata, L. mediadiposalis, C. herzi, O. platycephala 등이며, 이 중 H. eigenmanni와 C. herzi는 출현 개체수가 많았으나, 그 외의 종은 비교적 희소하였다. 본 합천댐에서 출현하는 어류 중에서 외래어종은 C. carpio (Israeli), C. cuvieri, L. macrochirus이었고, 우리나라의 다른 하천에서 유입된 P. fulviraco가 확인되었다.

• 한국해양학회지:바다
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• 제2권2호
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• pp.110-116
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• 1997

시화호가 건설 된 후인 1995년 10월에서 1996년 8월 사이 시화호 내부와 외부에서 계절 별로 어류를 채집하여, 출현종의 조성 변화를 분석하고 내부의 수질이 어류에 미치는 영향을 고찰하였다. 호수 외부에서는 청어목 어류 및 참서대와 민태가 우점하여 인접 해역과 유사한 경향을 보였다. 호수 내에서는 가을에 연안성 부어류, 망둑어류 및 민불어류인 붕어가 채집되었으나, 겨울이 지난 후 외해에서 월동하여야 하는 부어류들은 채집되지 않았고, 망둑어류와 붕어도 숫적으로 감소하였다. 봄이 되어 소수 풀망둑을 제외한 어류는 채집되지 않았고, 여름에는 해수와 호수물 교환 과정에서 들어 온 두둘망둑과 구굴무치가 대량 출현하였으나 8월 중순 폐사하였다. 1996년 3월 이후 암모늄 농도는 다른 어류에서 관찰된 반치사농도보다 높았으며, 수온과 pH의 상승으로 암모니아의 어류에 대한 독성이 강하여지고 다른 요인들과 복합적으로 작용하여 어류들이 폐사한 것으로 보인다.

• 생태와환경
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• 제37권4호통권109호
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• pp.448-454
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• 2004

반폐쇄성 기수호인 Obuchi호에서 수질과 생물학적 mass balance를 평가하기 위해 생태계 모델을 개발하고 적용하였다. 2001년 1월부터 2002년 12월까지 관찰된 조석의 차이, 강으로부터의 유입수 및 기상 변수들에 대한 시계열 자료들을 hydrodynamic 모델의 변수들로 접목시켰다. 수질과 생물생체량 balance는 생태계 모델에 의해 평가되었으며, 모의된 수질 값은 관찰 값과 일치하였다. 호수에서 모델에 의해 계산된 POC와 식물플랑크톤, 동물플랑크톤의 carbon 함량은 각각 7,200 kg, 1,500 kg, 22 kg으로 나타났으며, 이는 관찰 값 POC (5,900 kg), 식물플랑크톤 (3,800 kg)밍, 동물플랑크톤 (150 kg)과 어느 정도 비교할 수 있었다.

• 한국해양학회지
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• 제5권2호
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• pp.59-64
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• 1970

지표를 스치며 많은 분,지류가 모여 이루어지는 각 하천수에는 적지않은 수량의 세균류가 혼입된다. 이것들은 결국 바다로 유입되어 연안 동,식물에 섭취되거나 또는 부착되어 또다시 우리의 식생활에 이입되는 순환을 거듭하고 있고, 이러한 과정에서 각종 질병의 원인이 유발되는 수가 적지 않다. 이러한 관점에서 환경수의 세균오염은 우리의 보건위생면에서, 가정용수 또는 산업용수의 이용면에서 매우 중요한 의의를 갖는 것이라고 하겠다.

• 한국물환경학회지
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• 제21권6호
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• pp.584-594
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• 2005

The spatio-temporal abundance pattern of algae in Lake Paldang from 2002 to 2004 was investigated. The concentration of chlorophyll a representing algal biomass had fluctuated intensively throughout the year. Among three years, the highest algal biomass was shown in 2002, and typical growth peak of concentration of chlorophyll a was occurred in spring and autumn. There had been frequent rainfall in spring drought period in 2003 and it resulted in the decrease of the algal biomass. The distribution pattern of four algal groups on the surface water of Lake Paldang showed different abundance by season and by water area. In particular, different algal growth characteristics by water areas were observed. Influences of various environmental parameters on algal abundance in four water areas of Lake Paldang were analyzed statistically. From the results of Peason correlation analysis, it was understood that the kinds and affects of environmental parameters were different according to water areas and seasons. Based on the factors analysis of environmental parameters on the concentration of chlorophyll a, stepwise regression models whose independent variables were the factors produced by factor analysis and dependent variable was the concentration of chlorophyll a were derived by water areas and seasons. As a whole, factors related with organics and photosynthesis were revealed to have high affects to algal abundance, whereas limiting nutrients such as phosphorus and nitrogen showed little affect in Lake Paldang.

• 한국물환경학회지
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• 제21권4호
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• pp.360-367
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• 2005

We have performed to analyze the trophic state resulting of Lake Yongdam as a result of water quality and nutrient concentration. Lake Yongdam is artifitial multi-purpose Dam resulting from the floods of 2001. The water quality of Lake Yongdam may affect the status of the Geum river basin including the Daecheong reservoir. It is necessary to understand the trophic state to assess water quality until stability after flooding. Water quality was surveyed using depth and hydraulic condition analysis. Further density flow was estimated for stratification and trophic state of Lake Yongdam by chlorophyll ${\alpha}$ concentration (2001~2004). And Environmental factors on chlorophyll ${\alpha}$ concentration were analyzed statistically. Trophic state was evaluated as the oligotrophic state at the main stream of the reservoir and eutrophic state at the upper stream in 2001, but evaluated as eutrophic state in 2002 and 2003 by TSI of Aizaki. From the results of multiple regression analysis using stepwise method, chlorophyll ${\alpha}$ concentration was shown to be very significant when nutrient concentration is high upon initial filling of the Dam. Chlorophyll ${\alpha}$ concentration varied according to sample site, season and year. Concentration were high in the upper stream of Lake Yongdam 4, algae bloom in these watershed were affected by location and high nutrient levels in the summer season which have in turn increased phytoplankton bloom into the reservoir.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제26권1호
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• pp.59-73
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• 1998

Sediment samples from five stations at the Shihwa Lake sewage outfall, west cost of Korea, were collected to evaluate the effect of the outfall on benthic foraminifers. Heavy metal (Cu and Zn) polluted the eastern part of the Shihwa Lake, adjacent to the Shihwa-Banwol Industrial Complexes, shows barren or nearly barren of benthic foraminifers, and the lowest number of species both at the core top and downcore. Excepting for the barren zone, pyritized benthic foraminifers abundantly occur both at the surface and downcore sediments in the western part of the Shihwa Lake, suggesting that foraminiferal disease by anoxic bacteria. Recent intrusion of pollutants form the Shihwa-Banwol Industrial Complexes and adjacent six major streams severely polluted the Shihwa Lake as shown by the low abundance (number/10 g) of benthic foraminifers, low number of Ammonia beccarii, low species diversity, and absence of both Elphidium spp. and ostracodes at the surface sediments compared of both downcore. Except the barren zone, both pyritized and non-pyritized Ammonia beccarii occur dominantly in the surface sediments and downcore. Elphidium spp. (either pyritized or non-phyritized) do not occur in the surface sediments of whole stations. However, they occur from the entire downcore sediments except in the eastern part of Shihwa Lake. Arenaceous foraminifers do not inhabit in the heavily polluted areas as evidenced by the occurrence of relatively deep core depth (11-15 cm). Ostracodes occur at the downcore sediments, but they do not occur at the surface sediments. Ostracodes also do not occur at the heavily polluted areas in the eastern part of the Shihwa Lake both at the surface and downcore sediments, indicating that the abundance of ostracodes also can be used for a pollution indicator.

• 한국환경과학회지
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• 제11권12호
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• pp.1205-1215
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• 2002

To evaluate the change for water quality after the water gate operation in Shiwha lake, in situ survey were conducted on september in 2000 and January, march, jane in 2001. Chemical characteristics and eutrophication level was estimated from the survey data. The water quality of the Shihwa lake was greatly affected by pollutant load from rainfall, and formation of stratification in summer and winter was increased to effect on nutrient release from sediment. Especially, high concentration of chlorophyll-a was occurred in autumn, due to increased nutrient, high water temperature and low salinity after rainfall runoff. The mean concentration of DIN, DIP were 0.346mg/L, 0.0217mg/L in surface water and 0.826mg/L, 0.0415mg/L in bottom water, respectively, which were over III grade of seawater standard. Also high percentage of ammonia nitrogen to DIN in bottom water for autumn and winter was affected by released nutrient from sediment. Correlation analysis of chlorophyll-a versus TSS was shown that organic matter was affected by autochthonous organic matter stem from the algae, these factor showed reverse correlation about salinity. Closely correlations among to the water quality constituent in continuity survey was appeared. The results of eutrophication index estimation showed the high potentiality of red tide occurrence in Shiwha lake, particularity in summer or fall. Overall water quality was greatly improve to compared with measuring data during 1997~1998 at the beginning water gate operation, which reported by KORDI. Therefore, to improve of water quality in Shiwha lake, we need to establish of management plan about nutrient release from sediment, rainfall runoff, maximum of seawater exchange.