• 한국해양바이오학회지
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• 제3권1호
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• pp.13-17
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• 2008

The Congo has a maritime coastline of 40 km, covering an area of $2,345,409km^2$. The fluvial system covers around $34,000km^2$ in a network of more than 33,000 km of rivers, principal tributaries, and streams. There are around 1,000 known species of fish, essentially freshwater and some brackish. The lakes of the Rift Valley contain the richest lacustrine fauna in the world. The family of Cichlidae alone has more than 900 species. At the same time, the lakes are profoundly different. Lake Tanganyika has 250 species of fish, of which 216 are endemic, whereas Lake Kivu contains only 32 and 16, respectively. A dense hydrographic network of water surfaces, inundated plains and lakes cover around $86,080km^2$ (3.5% of the national area) and have a considerable aquatic potential. The large peripheral lakes of the East cover around $48,000km^2$ of which 47% are under Congolese jurisdiction. The respective areas belonging to the Congo are: Lake Tanganyika, $14,800km^2$; Lake Albert, $2,420km^2$; Lake Kivu, $1,700km^2$; Lake Edward, $1,630km^2$; Lake Mo$\ddot{e}$ro, $1,950km^2$. Another two important lakes in the interior, Lake Tumba and Lake Mai-Ndombe, cover (between them) 2,300 and $7,000km^2$, depending on season (less in the dry season and more in the rainy season). There are also the lakes of the Kamalondo depression ($6,256km^2$), Lake Tshangalele ($446km^2$) and Lake N'Zilo ($280km^2$).

• 수산해양기술연구
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• 제59권3호
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• pp.196-205
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• 2023

This study investigated the species composition and bycatch status of fishes by fyke net between June and November 2020 in Asanho lake and Chungjuho lake. During the survey period, the catches in Asanho lake were identified as 2,931 individuals of 16 species from a total of six families and in Chungjuho lake were identified as 1,645 individuals of 14 species from a total of eight families. The dominant species in Asanho lake was Erythroculter erythropterus which accounted for 59.6% of the the total number of individuals and 40.5% of the total biomass caught. The dominant species in Chungjuho lake was Lepomis macrochirus which accounted for 48.2% of the the total number of individuals and Erythroculter erythropterus which accounted for 60.2% of the total biomass caught. The bycatch rates of non-commercial species in Asanho lake and Chungjuho lake were 77.0% and 82.6%, respectively. As a result of analyzing the frequency distribution of the total length of Carassius auratus and Siniperca scherzeri, which were the dominant species among commercial species, the bycatch rate of small individuals was 87.1%, and 42.7%, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.173-176
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• 2008

Lake studies play an important role in water management, ecology, and other environmental issues. Typically, monitoring lake levels is the first step on the lake studies. However, for the Prairie Pothole Region (PPR) of North America having millions of small lakes and potholes, on-site measurement for lake levels is almost impossible with the conventional gage stations. Therefore, we employed Geographic Information System (GIS) and remote sensing approach with the Shuttle Radar Topography Mission data to extract lake levels. Several image processing techniques were used to extract lake levels for January, 2000 as a one-time snapshot which will be useful in historic lake level reconstruction. This study is associated with other remote sensing datasets such as Landsat imagery and Digital Orthophoto Quadrangle (DOQ). In this research, firstly, image processing techniques like FFT filtering, Lee-sigma, masking with Canny Edge Detector, and contouring were tested for lake level estimation. The semi-automated contouring technique was developed to accomplish the bulk processing for large amount of lakes in this region. Also, effectiveness of each method for bulk processing was evaluated.

• 생태와환경
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• 제38권spc호
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• pp.8-11
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• 2005

Carbon stable isotope ratios of producers varied in lake ecosystems. In tile present study, we tried to estimate the seasonal variations of carbon isotope ratios of phytoplankton and benthic diatoms in a strongly acidic lake ecosystem. Lake Katanuma is a volcanic, strongly acidic lake (average pH of 2.2), located in Miyagi, Japan. Only two algal species dominate in Lake Katanuma; Pinnularia acidojaponica as a benthic diatom, and Chlamydomonas acidophila as a green alga. Carbon isotope values of P. acidojaponica varied seasonally, while those of particulate organic matter, which were mainly composed of C. acidophila remained fairly stable. The differences suggested that $CO_2$ gas was more frequently limited for P. acidojaponica than C. acidophila, since high density patches of benthic diatoms were sometimes observed on the lake sediment. Generally, carbon concentration mechanisms (CCMs)of microalgae can fix bicarbonate in lakes, and affect the carbon isotope values of microalgae. While, in Lake Katanuma, CCMs of the microalgae may scarcely function because of high $CO_2$ gas concentration and low pH. This is the reason for low seasonal amplitude of carbon isotope values of phytoplankton relative to those in other lakes.

• 한국환경과학회지
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• 제7권4호
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• pp.441-450
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• 1998

The purpose of this study is to evaluate and to predict of eutrophication in lakes by using VollenweiderGECD model and total phosphorus concentration and inflow rate which were measurded in 1993-1996. The results of study was as follows. The annual total phosphorus loading from the watershed was calculated to be 181-195tP /yr at lake Soyang, 591-680tP/yr at lake Chungju, 420-466tP/yr at lake Taechong, 229-278tP/yr at lake Andong, 103-106tP/yr at lake Hapchon, 57-59tP/yr at lake Imha, 194-244tP/yr at lake Namgang, 8386tP /yr at lake Chuam, 99-109tP /yr at lake Somjin. These are discharged, for the most parts, from population and ftshfarm facility. TP loading on the surface area at lake Soyang was 3.0lgP/$m^2$/yr, 2.82gP/$m^2$/yr, 2.84gP/$m^2$/yr, 3. 03gP/$m^2$/yr, at lake Chungju 7.91gP/$m^2$/yr, 6.87gP/$m^2$/yr, 7.38gP/$m^2$/yr, 7.l8gP/$m^2$/yr, at lake Taechong 6.7lgP/$m^2$/yr, 7.25gP/$m^2$/yr, 7.24gP/$m^2$/yr, 6.53gP/$m^2$/yr and TP loading on the surface area of Nakdong river basin, that is, lake Andong, Imha, Hapchon and Namgang were 5.39gP/$m^2$/yr, 4.47gP/$m^2$/yr, 4. 56gP/$m^2$/yr, 4.45gP/$m^2$/yr and 2.20gP/$m^2$/yr, 2.23gP/$m^2$/yr, 2.24gP/$m^2$/yr, 2.l7gP/$m^2$/yr and 4.50gP/$m^2$/ yr, 4.50gP/$m^2$/yr, 4.54gP/$m^2$/yr, 4.43gP/$m^2$/yr and 8.25gP/$m^2$/yr, 8.48gP/$m^2$/yr, 8.48gP/$m^2$/yr, 10. 39gP/$m^2$/yr respectively. Also those of lake Chuam was 2.51gP/$m^2$/yr, 2.61gP/$m^2$/yr, 2.52gP/$m^2$/yr, 2. 54gP/$m^2$/yr and TP loading on the surface area at lake Somjin was analysed 4.09gP/$m^2$/yr, 4.l0gP/$m^2$/yr, 3.98gP/$m^2$/yr,3.73gP/$m^2$/yr. The tropic states of nine lakes can be assessed as eutrophy because phosphorus loading exceeds the critical phosphorus loading by Vollenwelder-GECD model.

• Journal of Plant Biology
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• 제16권3_4호
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• pp.17-34
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• 1973

The physico-chemical factors, the distribution of chlorophyll and the primary production of the lakes Hwajinpo, Yongrangho, Chunchonho, Uiamho, Soyangho and Changjamot have been studied in order to make ecological comparison among these lakes during summer stagnation period of August to September of 1973. On the basis of the characteristics of these lakes, the lake types have been discussed. Thermocline is observed at 3-4m zone in the lake Changjamot and 4-5m zone in the lake Yongrangho. In the case of lake Hwajinpo and impoundments, the distinct thermal stratification is not observed at the summer stagnation period. As to vertical distribution of dissolved oxygen, a positive heterograde curve is obtained in the lakes Hwajinpo and Yongrangho. In the lake Changjamot the typical clinograde curve and the oxygen depletion in hypolimnion are observed. In the case of impoundments, however, the orthograde curve is observed in the lakes Chunchonho and Uiamho. While in the lake Soyangho, any stratification of the disssolved oxygen is not found. In the brackish lakes, such as lakes Hwajinpo and Yongragho, the salinity of hypolimnion is found to be much higher than that of epilimnion. In the lake Hwajinpo, the salinity of hypolimnion is exhibited 32.7$\textperthousand$, which is nearly the same as sea water. The distribution of nitrogenous compounds and phosphates is found to be high in the lake Changjmot. The silicate is also found in high concentration in the lake Chunchonho, and the distribution of nutrients in the brackish lakes is generally low. As to the vertical distribution of chlorophyll level, the lake Changjamot shows a stratum type and the brackish lakes L-type stratification. In the impoundments, lakes Chunchonho and Uiamho appear to be homogeneous type. Seasonal variation of chlorophyll level in the lake Changjamot is examined from January to September 1973. The vertical distribution of chlorophyll during the period of circulation from January to April is homogeneous type and is stratum type thereafter. The maximum chlorophyll level is 277.4mg/$m^2$ on June 23 and the pattern of seasonal variation of chlorophyll level is comparable to the type of eutrophy. The horizontal distribution of chlorophyll level is studied in the brackish lakes, Hwajinpo and Yongrangho. The pattern of distribution is found to be an irregular type. On the basis of measurements of primary production by means of the carbon-14 method and the distribution of chlorophyll level, it is concluded that the interior part of the lake Hwajinpo and Changjamot are eutrophic and the exterior part of the lake Hwajinpo, lake Yongrangho and the impoundments, lake Uiambo and Soyangho are mesotrophic.

• 한국습지학회지
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• 제20권1호
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• pp.43-53
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• 2018

라구나 호(Laguna Lake)는 필리핀(Philippines)에서 가장 큰 담수호이며 주로 양식, 수력발전, 운송 및 상수도 산업을 위한 목적으로 활용된다. 라구나 호의 다양한 이용목적은 물 이용자 간의 경쟁과 반목을 초래하고 있으며, 이 과정에 다양한 오염원으로 인하여 수질은 악화되고 있으며, 수생태계의 건전성도 영향을 받고 있다. 따라서 본 연구는 라구나 호(Laguna Lake)의 수질평가를 통해 현 수질관리 정책을 생태학적 환경관점에서 평가하고자 수행되었다. 라구나 호(Laguna Lake)의 $NH_3$, BOD, $Cl^-$, pH 및 TSS 등의 수질오염물질 농도는 필리핀 Department of Environment and Natural Resources (DENR)에서 제시하는 수질기준을 모두 초과하는 것으로 나타났다. 또한 호의 수질은 유역에서 발생하는 농업 및 도시 강우유출수로 인한 오염물질 부하량의 영향을 받고 있는 것으로 조사되었으며, 파시그 강(Pasig River)의 염분과 오염된 수질도 라구나 호(Laguna Lake)의 수질에 영향을 주는 것으로 분석되었다. 장기적인 수질 분석 결과는 라구나 호수(Laguna Lake)의 수질이 강우량과 관련되는 계절의 영향을 받고 있는 것으로 나타났다. 이러한 라구나 호(Laguna Lake)의 수질영향인자 연구결과는 필리핀의 환경관리 기법을 향후 호내관리에서 유역관리로의 전환이 필요하다는 것을 의미하며, 선진국형 유역관리대책의 연구 및 도입이 필요한 것으로 평가되었다.

• 대한원격탐사학회지
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• 제28권3호
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• pp.267-276
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• 2012

Terminal lakes are widely distributed in the arid and semi-arid Gobi of Mongolia, and serves as important water resource for local people and livestock. However, such lakes are subject to great fluctuations in its size depending on climatic conditions and human water utilization. The Orog Lake is one such example that has shown remarkable fluctuation in recent years. In this study, we investigated the temporal changes of Orog Lake surface area by using 16-day MODIS 250 m NDVI products from 2000 to 2010. The results were compared with climate variability represented by monthly precipitation and temperature. Our results show that the Orog Lake gradually shrank for the period from 2000 to 2010, but with a significant range of seasonal and inter-annual variability. The lake area showed considerable seasonal variations, as it expanded in spring and fall, primarily due to snow melt and summer precipitation, respectively. Extreme drought period from 2000 to 2002 triggered the substantial reduction in lake area, leading to dry-up in year 2005, 2006, 2007, and 2009. After dry-up once occurred in 2005, the lake repeated reappearance and disappearance depending on seasonal and annual precipitation. Our findings implicate that the ground water fluctuated around the lake bottom level since 2005. This suggests the highly vulnerable nature of Orog lake, which greatly depends on future precipitation change.

• Environmental Engineering Research
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• 제20권1호
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• pp.19-24
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• 2015

This paper mainly focuses on the research of the monitoring data about the total nitrogen (TN), total phosphorus (TP) of ten monitoring points of Hongze Lake in 28 years. Our study adopts the technical methods such as difference comparison, correlation analysis, Mann-Kendall, etc. to analyze the statistical characteristics, regional differences, and temporal and spatial variation condition of ten monitoring points of Hongze Lake in 1986-2013 as well as the reason for the time and space variation of TN and TP. The results show that the TN and TP of Hongze Lake change dramatically during the period of 1994-2004. In all the monitoring periods, TN and TP of the HZ5, HZ6, HZ7, HZ8 monitoring points in the estuary surrounding the Huaihe River are the highest, which suggests that TN and TP of Hongze Lake should not be ignored for the pollution along the Huaihe River. The TN concentration in the core area is the highest, but that in the development control area is the lowest. In most of the years, TN concentration is higher than 2 mg/L, and the water quality is V class and poor V class water quality in China's Environmental Quality Standards for Surface Water (GB3838-2002). TP concentration of the three areas is basically close, that is lower than 2 mg/L in most of the years, and the water quality is within the V class. The TN and TP concentration of Hongze Lake decreased and intensifying trend of eutrophication is controlled after 2004.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.299-307
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• 2009

New lake dike in Saemanguem area is 125km length and require a great amount of fill materials, but it's difficult to get the amount of materials and develop a quarry because of environment conservation. Therefore, the solution is to use the dredged soil in project area as the fill materials not to develop quarry. However, characteristic of dredged soil as a silty fined sand is very weak at seepage, sliding, erosion of dike due to infiltration of rainfall, wind etc. So, lake dike using dredged soil must be constructed safely against the unstable problem of dredged sand. The objective of research is to make safe lake dike using dereged soil on construction of Saemangeum new lake dike. So, we analyzed the characteristic of dredged soil and suggested a standard section of lake dike.