• Animal Systematics, Evolution and Diversity
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• v.3 no.2
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• pp.175-207
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• 1987

A taxonomic Study was carried out on the freshwater cladocerans from Korea during the period from August 1985 to May 1987. Materials consist of both the specimens deposited at Department of Zoology, College of Natural Sciences, Seoul National University and those collected at the freshwater regions such as rivers, lakes, ponds, bogs, rice fields, etc. During the period. As a result of examining the speciemens collected at the 123 locations in South Korea, 31 species of 7 families were identified and classified. In this paper, the authors submit the figures of the 31 species, of which the following 13 species were descirbed as hitherto unrecorded species in Korea : Diaphanosoma Leuchtenbergianum Fisher, 1858 : Simocephalus vetulus 9O.F.Mller, 1776) ; S. esxpinosus (koch, 1841); Ceriodaphnia reticulata (Jurine, 1820) ; Scapholeberis mucronata (O.F. Mller, 1785) ; Moina weismanni Ishikawa, 1896 : Ilyocryptus agilis Kurz, 1878 ; Biapertura affinis (Leydig, 1860) : Camptocercus rectirostris Schodler, 1862 ; alona costata Sars, 1862 ; Disparalona rostrata (Koch, 1841); Pseudochydorus globosus (Barird, 1843) ; Leptodora kindtii(Focke, 1844)

• The Korean Journal of Zoology
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• v.36 no.3
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• pp.380-390
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• 1993

The freshwater cladocerans collected from the riverside of Han-gang and from the ricefields at Kojedo were identified as Leydigia leydigi (Schoedler, 1863) and L. ciliata Gauthier, 1939. These two species are redescrihed with illustrations. This is the first report of the chydorid species belonging to the genus Leydigia from Korea.

• The Korean Journal of Ecology
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• v.21 no.5_2
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• pp.565-573
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• 1998

In order to clarify the species composition of freshwater zooplankton community inhabiting Lake Sochonji and chonji on the top of Mt. Paektu, the present study have been carried out based on the materials collected during the periods from 24 to 25 July, 1997. As a result of examing the specimens, from the Lake Chonji, a total of 10 species (Keratella cochlearis cochlearis, K. quadrata quadrata, K. valga valga, Notholca squmula squmula, Colurella adriatica adriatica, Lepadella patella patella, Lecane hua luna, L. (Monostyla) bulla bulla, Cephalodella gibba gibba, philodina roseola) appeared rotifers only. >From the lake Sochonji, a total of 7 species were identified. It consists of 3 species (Keratella valga valga, Cephalodella gibba gibba, Asplanchna (Asplanchnella) brightwelli) of rotifers, 2 species (Daphnia hyalina, Alona quadrangularis) of cladocerans, and 2 species (Acanthodiaptomus pacificus, Bryocamptus zschokkei caucassicus) of copepods, respectively. Also, appeared nauplius of copepoda.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.52-61
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• 2006

The aim of this study was to analyze the seasonal patterns of zooplankton community dynamics in the lower Nakdong River (Mulgum, RK; river kilometer; 27 km from the estuarine barrage), with a Self-Organizing Map (SOM) based on weekly sampled data collected over ten years(1994 ${\sim}$ 2003). It is well known that zooplankton groups had important role in the food web of freshwater ecosystems, however, less attention has been paid to this group compared with other community constituents. A non-linear patterning algorithm of the SOM was applied to discover the relationship among river environments and zooplankton community dynamics. Limnological variables (water temperature, dissolved oxygen, pH , Secchi transparency, turbidity, chlorophyll a, discharge, etc.) were taken into account to implement patterning seasonal changes of zooplankton community structures (consisting of rotifers, cladocerans and copepods). The trained SOM model allocated zooplankton on the map plane with limnological parameters. Three zooplankton groups had high similarities to one another in their changing seasonal patterns, Among the limnological variables, water temporature was highly related to the zooplankton community dynamics (especially for cladocerans). The SOM model illustrated the suppression of zooplankton due to the increased river discharge, particularly in summer. Chlorophyll a concentrations were separated from zooplankton data set on the map plane, which would intimate the herbivorous activity of dominant grazers. This study introduces the zooplankton dynamics associated with limnological parameters using a nonlinear method, and the information will be useful for managing the river ecosystem, with respect to the food web interactions.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.189-195
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• 2006

The purpose of the current study was to develop a standard method to assess the ecological effect of pesticides using the representative Korean freshwater cladocerans. The indigenous cladocerans, Daphnia obtusa, Daphnia sp., Moina macrocopa, Simocephalus vetulus and Daphnia magna formally endorsed by the major international organizations were tested to select optimal culture media in laboratory condition. All of the Korean water flea tested showed good growth and fecundity in the moderately hard water ($CaCO_3$ ranged 80 to 100 mg $L^{-1}$) and soft water ($CaCO_3$ ranged 40 to 48 mg $L^{-1}$). However, considering that the total hardness of fresh water collected from 5 rivers ranged from 60.2 to 127.2 mg $L^{-1}$ ($CaCO_3$) and Ca deficiency could be a major determinant of species success and community structure among crustacean zooplankton, the present study suggests that the optimal water hardness for growing Daphnia sp., Daphnia obtusa, Moina macrocopa and Simocephalus vetulus is $80{\sim}100$ mg $L^{-1}$ of $CaCO_3$.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.146-159
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• 2005

Fifty-four zooplankton species from Daecheong Lake were identified during the research period from June to October 2001. The representative zooplanktons mostly comprised the index species indicating the intermediate stage from oligosaprobity to ${\beta}$-mesosaprobity. During the blooming season of blue-green algae, the population of large cladocerans like Daphnia galeata precipitously decreased in size, while rotifers and small cladocerans like Bosmina longirostris increased in population size. Therefore, soon after the peak of the blooming of blue-green algae, whole zooplankton standing crop and number of species showed the tendency of recovery, or even the sharp increase. The population size of Daphnia galeata was affected very sensitively by the change of cyanobacterial density.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.371-376
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• 2014

A Study on zooplankton fauna and phytoplankton flora was carried out three times in June, August and September 2012 at the Hyuncheon wetland in Gangwon-do, Korea. A total of 14 taxa of zooplankton were distributed, which consisted of six rotifers, four cladocerans, two copepods, one nematode and one aquatic insect larvae. Occurrence of Simulium japonicum supports that studied water is the first grade clear water. It was observed that the abundance of zooplankton was never exceeded over $55ind.L^{-1}$. Rotifers dominated in the months of June and August, whereas cladocerans in September, respectively. The phytoplankton flora was consisted of 26 species. The standing crops varied between $4,080{\sim}10,120cell.L^{-1}$. Docidium undulatum is the typical species distributed in muddy wetland and Closterium acerosum is distributed widely from wetlands through lakes. Navicula spp. and Nitzchia spp. were recorded to be distributed in lentic waters of big lakes such as Paldang Lake. Species diversity indices decreased gradually from June to September between 1.3~1.9 in zooplankton but lowest in August between 0.9~1.6 in phytoplankton, respectively. Based on my study observation, I anticipate that the poor distribution of zooplankton, phytoplankton, and low values of species diversity index are likely to be a cause of narrow area with shallowness of waters during the short period.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.86-93
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• 2013

We monitored 32 wetlands in order to investigate the influence of aquatic plants on zooplankton density and diversity in the littoral zone in Gyeongsangnam-do from May to June in 2011. A total of 65 zooplankton species were identified in the study sites. Among them, the diversity of epiphytic zooplankton were higher (40 species) than planktonic zooplankton. Littoral zones of all wetlands were covered by various aquatic plants, and influenced the epiphytic zooplankton assemblages. Based on the data from $1{\times}1$ (m) quadrat sampling, epiphytic and planktonic rotifer density showed no significant relationships with macrophyte cover. However, the epiphytic cladocerans density significantly increased under high aquatic plant cover ($r^2=0.39$, p<0.05, n=32). Types of aquatic plants strongly influenced epiphytic zooplankton density. Upo and Jangcheok are locations which have well developed Phragmites communis and Ceratophyllum demersum communities in the littoral zone, and a higher density of epiphytic zooplankton was recorded on the surface of C. demersum. Especially, rotifers such as Lepadella, Monostyla and Testudinella showed obvious differences (One-way ANOVA, p<0.05 for all three species). This result suggests that epiphytic zooplankton have a substrate preference for larger surface areas, likely for adherence, on C. dimersum. In conclusion, the complex structure of the littoral plant community is expected to provide diverse refuge and microhabitats to epiphytic zooplankton.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.476-486
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• 2009

Major objective of our study was to introduce initial researches of national long-term ecological monitoring studies on Daechung Reservoir, as one of the representative lentic reservoir ecosystems in Korea. For the long-term ecological research (LTER), we conducted preliminary field monitoring during 2008~2009 and analyzed biological parameters such as phytoplankton, zooplankton, and freshwater fish along with chemical water quality and empirical model analysis. According to phytoplankton surveys, major taxa have varied largely depending on seasons and sites sampled. Overall phytoplankton data showed that cyanophyta dominated in the summer period and diatoms dominated in the winter. In zooplankton analysis, 25 species including 20 rotifers, 3 cladocerans and 2 copepods were collected during the survey. The relative abundance of rotifers (86.5%) was always greater than that of cladocerans (6.3%) or copepods (5.1%). There were distinct spatial and inter-annual changes in the abundance of zooplankton in the reservoir, displaying similar patterns in three sites with the exception of S3 during the study. According to fish surveys, 8 families and 39 species were observed during 2008~2009. The most dominant fish was an exotic species of Lepomis macrochirus (23%), indicating an severe influence of exotic species to the ecosystem. TP averaged $17.9\;{\mu}g\;L^{-1}$ ($6{\sim}80\;{\mu}g\;L^{-1}$), which was judged as a mesotrophy, and showed a distinct longitudinal gradients. TN averaged $1.585\;{\mu}g\;L^{-1}$ during the study and judged as hypereutrophic condition. Unlike TP, TN didn't show any large seasonal and spatial variations. Under the circumstances, nitrogen limitation may not happen in this system, indicating that nitrogen control is not effective in the watershed managements. These data generated in the LTER station will provide key information on long-term biological and water quality changes in relation to global warming and some clues for efficient reservoir ecosystem managements.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.1-10
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• 2010

We used stable isotope analysis to investigate the hypothesis that zooplankton were not able to utilize Microcystis as a food source. We also studied seasonal variation of the zooplankton community in a eutrophic Wangsong reservoir. The dominant copepod species changed from Cyclops vicinus to Thermocyclops taihokuensis. Density of zooplankton was suppressed by high density of Microcystis in June and the density of phytoplankton and chlorophyll a concentration was lowest in July. The difference in $\delta^{13}C$ and $\delta^{15}N$ between cladocerans (Daphnia galeata and Bosmina longirostris) and copepods showed the maximum difference of $12^{\circ}/_{\circ\circ}$ and $4^{\circ}/_{\circ\circ}$, respectively, indicating different energy sources and trophic positions between two taxonomic groups. The difference in $\delta^{13}C$ between Microcystis and zooplankton ranged from $3{\sim}7^{\circ}/_{\circ\circ}$, supporting the hypothesis that Microcystis could not be used as food source of zooplankton.