• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.273-288
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• 2021

We analyzed the spatio-temporal distribution characteristics of water quality and phytoplankton communities in the Isa Stream systems (ISS) from Sangsa Lake to Suncheon Bay. Sangsa Lake showed relatively oligotrophic and mesotrophic conditions, but the freshwater and mixed brackish water zones showed more severe eutrophication than Sangsa Lake and Suncheon Bay due to the influence of industrial waste such as livestock waste. In terms of the phytoplankton community, the number of phytoplankton species was higher in freshwater and mixed brackish water zones than in Sangsa Lake and Suncheon Bay, but the cell density and Chlorophyll-a concentrations (Chl-a) were relatively high in Sanga Lake and Suncheon Bay. In particular, the mesotrophic species Fragilaria crotonensis and Asterionella formosa showed different dominance in the surface and bottom layers, and the influence of A. formosa was significant in the freshwater and mixed brackish water zones in spring and summer. However, Skeletonema costatum-ls, a eutrophic indicator species, dominated in mixed brackish water zones to seawater in autumn and winter. Thus, the severe eutrophication and rapid environmental changes in the ISS could seriously damage the coastal ecosystem in Suncheon Bay. These ecosystem changes are threatening in terms of conservation and management of the UNESCO Suncheon Biosphere Reserve and Yeoja Bay including Suncheon Bay, which recorded the first Ramsar wetland in Korea. Therefore, further research is needed to establish an in-depth management plan.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.445-456
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• 2013

In this study, desalination by electrodialysis with ion exchange membranes was applied to synthetic waters with various ion concentrations and also for ground waters from coastal areas in Korea. Electrodialysis performance on the synthetic solutions showed the similar tendency in operation time and current curves, i.e., shorter operation time and higher maximum current with increasing applied voltages. The ED results of synthetic waters with different ion compositions, i.e., $Na_2SO_4$, $MgSO_4$, $CaSO_4$, at the similar conductivity condition, i.e., $1,250{\mu}s/cm$ revealed that effects of mono- and divalent ions on water quality and performance in electrodialysis were different. The divalent ions had less efficiency in the ED compared to monovalent sodium ions and also divalent calcium ions showed better performance than Mg ions. The electrodialysis on the ground waters produced high quality of drinking water. The groundwater from SungRoe however showed a buildup of membrane resistance. Organic matter concentrations and great portions of divalent ions in the groundwater were possible causes of the deteriorated performance.

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

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.448-454
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• 2004

In order to evaluate the water quality (N, P and C) and the biological mass balance of semi-enclosed brackish Lake Obuchi, Japan, an ecosystem model was developed and applied to the lake, using the flow field calculated by a hydrodynamic model. The time series data of the observed tide level, river discharge and meteorological parameters from January 2001 to December 2002 were incorporated as the parameters of the hydrodynamic model. Water quality and biomass balance were estimated by the ecosystem model, and simulated fluctuations In water quality agreed with our observations. The carbon contents of POC, phytoplankton and zooplankton in the lake were calculated by the model at an average 7200, 1500 and 22 kg, respectively, which somewhat agreed with our observations of POC (5900 kg), phytoplankton (3800kg), and zooplankton (150kg).

• Korean Journal of Environmental Biology
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• v.35 no.3
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• pp.296-304
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• 2017

Samples were collected between August 2016 and May 2017 at Sangju-si, Gyeongsangbuk-do, Jeju-do, and Uljin-gun, Gangwon-do. As a result, one genus and six species were newly recorded in Korea. The unrecorded indigenous genus was Borzia, and the six species were Anagnostidinema acutissimum, Komvophoron bourrellyi, Hydrocoleum stankovicii, Borzia trilocularis, Phormidium tinctorium and Pseudanabaena lohchoides. Phormidium tinctorium and Pseudanabaena lohchoides had been reported to inhabit freshwater, but in this study, these were found in brackish water. It had also been reported that B. trilocularis trichomes are composed of up to 8 cells, but in this study, a maximum of 10 cells was observed.

• Journal of Environmental Science International
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• v.3 no.4
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• pp.333-348
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• 1994

The groundwater levels at 11 sites and the vertical variations o( the water Quality at 1 site were measured to study the characteristic of the groundwater level fluctuation of Cheju Island. The results of the measurements for the groundwater levels were as follows; In the eastern part, inculding Kimnyong, Jongdal and Sungsan, a sinusoidal fluctuation of groundwater levels occurred in response to oceanic tides. The tidal effect on the groundwater level was reduced depending upon the distance from seashore. But time lag showed that the trend is reversed. However, in the Samyang, Kosan and Shinhyo areas show that the groundwater level was directly influenced by the amount of precipitation. Especially, Shinhyo area which southern part in Cheju was affected the most and show upper parabasal groundwater level. In Susan- I which eastern part in Cheju, well rovealed that water Quality changed with the period of a tide. Salinity at the lim, bellow the natural groundwater level, was approched to the brackish groundwater(1000ppm).

• Parasites, Hosts and Diseases
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• v.47 no.4
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• pp.401-404
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• 2009

A 33-year-old Korean man visited a medical clinic with complaints of throat discomfort and pain for one week. The symptoms occurred one day after eating raw brackish water fish, perch. Endoscopy revealed a fluke, about 5 mm in length, attaching to and peristaltically moving on the surface of the mucosa at the arytenoid region of the larynx. Microscopically, the testes were triangular, tandem, and separated by the uterus. The ovary and cirrus pouch were placed apart from median line between testes. Numerous blood cells were observed in the ceca. The worm was identified to be Clinostomum complanatum. This is the second human case of clinostomiasis in Korea.

• Animal Systematics, Evolution and Diversity
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• v.24 no.2
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• pp.229-240
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• 2008

Four harpacticoid species belonging to the family Tachidiidae are reported from the coastal waters and salt marshes in South Korea: Tachidius discipes Giesbrecht, 1881, Neotachidius parvus Huys, Ohtsuka, Conroy-Dalton and Kikuchi, 2005, Microarthridion litospinatus Shen and Tai, 1973 and Geeopsis incisipes (Klie, 1913). The latter two species and genera are new to Korean fauna. The previous record of T. discipes reported by Song and Chang (1995) from Korea is affirmed by the finding of male specimens. Microarthridion litospinatus is first known outside the type locality, and redescribed herein in detail. A key to the five species and four genera of the family Tachidiidae hitherto known from South Korea is presented.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.63-66
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• 2006

Huge numbers of non-biting midges emerged from brackish water which were made at the harbor construction field in Jinhae City, Kyongsangnam-do, Korea in late summer in 2005, and caused a serious nuisance to villagers. The midges were collected and identified as Chironomus salinarius (Kieffer, 1921). Although this species was recorded in Korea for the first time in 1998, the morphological descriptions were so brief and simple. A full redescription is made with detailed illustrations for ecological and control workers of this nuisance midge.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.271-276
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• 2018

Phytoplanktons were collected from various environments including small marshes, small ponds, reservoirs and brackish water from March 2017 to November 2017. In this study, five species of family Scenedesmaceae were newly recorded in Korea. The genus Desmodesmus was newly reported in Korea. The newly recorded species are Scenedesmus nanus, S. praetervisus, Desmodesmus costato-granulatus, D. lunatus and D. spinulatus. S. nanus and S. praetervisus are known to occur in freshwater, but they were found in the brackish water in this study.