• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.553-559
• /
• 2007

The vertical distributions of sulfate reducing bacteria (SRB) in sediments of lakes in Korea (Lake Sihwa and Lake Soyang) and China (Lake Aha and Lake Erhai) were investigated by fluorescence in situ hybridization (FISH). SRB from sediment of Lakes of China were located to deeper layer than those in Lakes of Korea. SRB were not detected below 19 cm and 10 cm depth in sediments of Lake Sihwa and Lake Soyang, respectively. SRB numbers were, however, detected at all observed sediments in Lake Aha and Lake Erhai. In case of lakes in Korea, the proportion of SRB ranged from 2.9 to 25.6% (Lake Sihwa) and ranged from 0.6 to 7.1% (Lake Soyang). For lakes in China, the proportions of SRB were from 0.6 to 19.4% and from 2.9 to 11.2% within sediments from Lake Aha and from Lake Erhai, respectively. The high peaks of SRB numbers in sediments of all lakes were appearing at depths between 0 cm and 2 cm.

• Korean Journal of Microbiology
• /
• v.44 no.2
• /
• pp.147-155
• /
• 2008

The diversity of sulfate reducing bacteria was investigated in different depths of sediments in Lake Sihwa, Korea and Lake Aha, China by PCR amplification, denaturing gradient gel electrophoresis (DGGE) and clone libraries targeting dissimilatory sulfite redectase (dsr) gene. In the analysis of DGGE band patterns, the community compositions of dsr gene in the sediments of both lakes were significantly different whereas bands in all depths of each environment revealed similar patterns. Bands from Lake Sihwa were produced much more than those from Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Total 68 clones containing dsr gene were obtained to analyze their sequences. Sequences from the sediment of Lake Sihwa were affiliated to Deltaproteobacteria, the Gram-positive thermophilic sulfate reducers belonging to the genus Desulforomaculum and archaeal thermophilic SRB belonging to the genus Archaeoglobus, whereas sequences from the sediments of Lake Aha were related to genus Desulfotomaculum. Clones retrieved from sediment of Lake Sihwa revealed a higher numbers than those of Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Most of clones (59%) were distantly related to the known cultivated SRB with $60\sim65%$ of similarity, which were clustered only the sequences from the environments showed less than 90% similarity. These habitat specific sequences suggested that the clustered dsr sequences represent species or groups of species that were indigenous to these environments. This study showed that these lakes have a specific bacterial communities having dsr gene distinct from those in other environments such as soil and marine ecosystems around the world.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.4
• /
• pp.310-316
• /
• 2015

The intertidal area in Lake Sihwa formed after operation of Sihwa-Lake tidal power plant and the change of the area in Lake Sihwa by period were analyzed. For computation of the intertidal area, remote sensing techniques were applied and high resolution Digital Elevation Model (DEM) was generated with root mean square (rms) error 14.4 cm. The intertidal area was $165.1km^2$ in 1910s, $115.2km^2$ in 1991 before completion of Sihwa dyke, $5.6km^2$ in 2010 during the period on operation of sluice gate, and $20.3km^2$ in 2013 after operation of Sihwa tidal power plant. Intertidal in Lake Sihwa was nearly dissipated after completion of Sihwa dyke, but significantly increased with operation of Sihwa tidal power plant from April 2012 as developing a regular tide environment and increasing of sea water flux. The re-formation of tidal flat of Sihwa Lake is an uncommon case. This study that precisely analyzed on the area of artificially formed Sihwa tidal flat would be applicable for management and making conservation plan.

• KCID journal
• /
• v.8 no.2
• /
• pp.64-72
• /
• 2001

Sihwa dyke was constructed during the period from June, 1987 to January, 1994 and the sluice gates were opened to allow sea water intrusion and outflow to improve water quality of the lake since June, 1997. Bottom sediment samples from 29 stations were co

• Journal of Environmental Impact Assessment
• /
• v.20 no.3
• /
• pp.349-356
• /
• 2011

This research is aim to analyze of changing landscape and according to phenological cycle from image information of coastal environment obtained by multi-media were analyzed by camera and satellite image. The digital camera and satellite image were used for tidal flat vegetation monitoring during the construction of Sihwa lake. The vegetation type and phenological cycle of Sihwa tidal flat have been changed with the Sihwa lake ecosystem. The environment changes of Sihwa tidal flat area and ecological change were analyzed by field work digital camera images and satellite images. The airborne, UAV and satellite images were classified with the changed elements of coastal ecological environment and tidal flat vegetation monitoring carried out the changed area and shape of vegetation distribution with time series images.

• KCID journal
• /
• v.9 no.1
• /
• pp.38-47
• /
• 2002

The Lake Sihwa gradually changes from freshwater lake to saline lake due to inflow of seawater by sluice gates . The changes of lake water are closely related to characteristic and distribution of turbidity and suspended matter. During the period April-Ma

• KCID journal
• /
• v.7 no.1
• /
• pp.8-18
• /
• 2000

The variations of water quality due to inflow of sea water by gate operation were observed in Sihwa Lake. The distributions and concentration of salinity, temperature, dissolved oxygen, nutrient were investigated from Feb. 1997 to Jul. 1998. The salinity

• International Journal of Fluid Machinery and Systems
• /
• v.5 no.4
• /
• pp.174-179
• /
• 2012

A numerical study to investigate the effect of intake vortex occurrence on the performance of an axial hydraulic turbine for generating tidal power energy in Sihwa-lake tidal power plant, Korea, is performed. Numerical analysis of the flow through an sxial hydraulic turbine is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes dquations with the shear stress transport turbulence model. In the real turbine operation, the vortex flows are occurred in both the side corners around the intake of an axial hydraulic turbine due to the interaction between the inflow angle of water and intake structure. To analyze these vortex phenomena and to evaluate their impacts on the turbine performance, the internal flow fields of the axial hydraulic turbines with the different inflow angles are compared with their performances. As the results of numerical analysis, the vortex flows do not directly affect the turbine performance.

• Journal of Wetlands Research
• /
• v.7 no.2
• /
• pp.105-120
• /
• 2005

This study was carried out at Reed Marsh of Sihwa Lake from July 2003 to June 2004. We observed total(sum of maximum population) 5,752 individuals of 70 species including 12 species of ducks, 10 species of egrets, 6 species of wagtails and buntings, 4 species of eagles. The most dominant species was Spotbill Duck(Anas poecilorhyncha - 3,518 individuals, 61.16%), and other species were Mallard(Anas platyrhynchos - 540 individuals, 9.39%), Great Reed-Warbler(Acrocephalus arundinaceus - 217 individuals, 3.77%). Reed Marsh of Sihwa Lake were observed many kinds of protected species such as Great Bittern(Botaurus stellaris), Mandarin Duck(Aix galericulata), Chinese Sparrow Hawk (Accipiter soloensis), Eurasian Sparrow Hawk(Accipiter nisus), Japanese Buzzard(Buteo buteo), Hen Harrier(Circus cyaneus), Eurasian Hobby(Falco subbuteo), and Common Kestrel(Falco tinnunculus). Since the Reed Marsh of Sihwa Lake arrived many individuals of waterbird, crop damage by the waterbird occurred in the surrounding rice fields. It was an area adjacent to the reed marsh of sihwa lake such as Yoopori and Samhwari Bibongmyoun, Yamokri Maesongmyoun Hwaseong City. Bird of crop damage was ducks openly. The most species was Spot-billed Duck. Crop damage types by the Spot-billed Duck were grazing, used the grain up or lower in quality with step on the rice. Crop damage size was about 560bags of rice during the one month on August 2002. In 2003, After carrying out the various crop damage reduction countermeasures, which measured crop damage size in 2002's crop damage area. It happened about 152bags of rice during the two months from on August to September 2003. Migration routes of Spot-billed Duck were that it was migrated from up the sihwa lake to reed marsh. It took a rest at reed marsh and migrated the surrounding rice fields for the feeding action. In 2002, it was migrated direct from up the sihwa lake to in surrounding rice fields. But as environment of reed marsh was improved better than 2002, it was migrated to reed marsh because of reducing the energy attrition rate. Crop damage reduction countermeasures are get on ears to use explosion machine, searchlight, start-gun and patrol at regular intervals. Which was an effect short term. Indirect method is to make a feeding area of substitution at up the sihwa lake and reed marsh of sihwa lake.

• Journal of Korean Society on Water Environment
• /
• v.18 no.2
• /
• pp.213-220
• /
• 2002

In this study the effects of initial pH, temperature, dissolved oxygen concentration, and sediment depth on the release of phosphorus from sediment in Lake Sihwa were investigated. No phosphorus release occurred at $10^{\circ}C$ for all pH values. DO concentrations were decreased and equilibrium was obtained 4-8 days after phosphorus release started. The DO concentrations were less than 1 mg/L. Sediment depth had little effect on phosphorus release rate. In order to control the released phosphorus, raw sludge and chalk were used. Results showed that a portion of phosphorus was removed by adsorption to chalk and raw sludge. About 90 % phosphorus removal was observed using sludge and calcinated chalk from the water sample in Lake Sihwa.