• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.850-859
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• 2010

Structure and succession of zooplankton community studied by hydraulic and ecological characteristics targeting the five lakes in the Han river system from March to December 2008. Results separated by river-type lake and lake-type lake depending on the type of hydraulic, Paldang lake and Cheongpyeong lake were river-type lake, while Chungju lake, Hoengseong lake and Doam lake was lake-type lake. The Paldang lake was a eutrophic lake, zooplankton community density and species number were the most among the five lakes. Relative dominance of the rotifera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Cheongpyeong lake was a mesotrophic-eutrophic lake, hydraulic characteristics and zooplankton community changes were similar the Paldang lake. Relative dominance of the cladocera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Chungju lake was a oligotrophic-mesotrophic lake, zooplankton community density was the least among the five lakes. Relative dominance of the copepoda was the largest and the yearly first dominant species was a large cladocera Daphnia galeata. The Hoengseong lake was a oligotrophic-mesotrophic lake, relative dominance of the rotifera was the largest and the yearly first dominant species was a small cladocera Bosmina longirostris. The Doam lake was a mesotrophic-eutrophic lake, zooplankton community density showed dramatic difference at the investigation time. Relative dominance of the rotifera was the largest and the yearly first dominant species was the copepoda Nauplius.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.126-137
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• 2006

Effect of night-lights on zooplankton attraction has been studied in Tongyeong marine ranch area during the period from 12 July to 30 August, 2004. Each sampling has been carried out to collect zooplankton from both control area in natural waters experiment area of night-lights waters at night. A total of 43 taxa of zooplankton occurred during the study. Copepods showed the prosperity in species number with 15 species. Acartia erythraed and Copepodite occurred abundantly in night-lights waters. Zooplankton abundance appeared to increase in night-lights mainly due to the gathering of copepods and larvae through the study period. Average $3\sim166$ times of zooplankton abundance was recorded in night-lights when compared with that in control area of natural waters due to the gathering of copepods and larvae. Cluster analysis, based on monthly abundance data of the 13 most frequent species, showed that the species were seperated into two different groups: the photo-positive group and the photo-negative group.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.329-336
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• 2006

Distribution of zooplankton communities was sampled vertically with a NORPAC net investigated in costal area of Wando from 30, August at 7 stations. A total of 37 taxa were sampled with a total abundance of zooplankton ranged from $147{\sim}1,696indiv.\;m^{-3}$. Evadne tergestina, Acartia pacifica, Paracalanus parvus s. 1, Decapod larvae, Sagitta crassa were dominant species in coastal area of Wando and they contributed 90% of mean abundance of total zooplankton. Multivariate analysis revealed significant differences in community structure among the three regions: the site 1 (A), the middle part of the sampling area (B) and other sites (C). The number and abundance of zooplankton varied significantly among the three regions (p < 0.05). Of these, the distribution of zooplankton communities in the coastal area of Wando was controlled by Tsushima Warn Current and bottom cold water of Yellow Sea.

• Ocean and Polar Research
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• v.23 no.3
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• pp.245-253
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• 2001

To investigate the community structures and the their seasonal variation of phytoplankton and zooplankton, a study was conducted at 6 selected stations during the period from April 1999 to October 2000 in the marine ranching ground off Tongyeong. One hundred ninety species of phytoplankton were identified, including 146 diatoms, 38 dinoflagellates, 4 silicoflagellates and 2 euglenophytes. Phytoplankton standing crops varied extensively by months and stations, ranging from $3.0{\times}10^4\;cells/l\;to\;1.0{\times}10^6\;cells/l.$. The dominant species varied from the vertical distribution as well as seasonal changes. In April and July 1999, Skeletonema costatum and Ceratium fusus were predominant in both the surface and the bottom water columns. Leptocylindrus danicus was the dominant species in April and June 2000, and Thalassiosira spp. were also predominant in bottom waters in June 2000. Pseudonitzschia pungens and Chaetoceros spp. were the dominant species at both surface and near bottom waters in August and October 2000, respectively. Zooplankton abundance was comparatively high in April and July in 1999, and April, June, and October in 2000, but extremely low in November 1999. The density of dominant zooplankton was higher in 2000 than in 1999. Copepods were the most predominant group except for July 1999 when the bivalve larvae showed extremely high abundance. Acartia omorii and Oithona similis were the dominant or subdominant copepod species mainly in April 2000, and June/July, while O. davisae and O. plumifera had peaks in August and October 2000. Corycaeus affinis and Paracalanus sp. also showed higher peaks in April and June (or July), even though they occurred in all sampling time. Centropages abdominalis occurred abundantly only in April 1999. Oikopleura dioica, a gelatinous zooplankton, was another important zooplankton, showing high density in all samples except in July 1999.

• Ocean and Polar Research
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• v.28 no.3
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• pp.305-315
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• 2006

In order to examine the transition of zooplankton community by the Saemangeum sea dyke, the temporal and spatial distribution of zooplankton community with relation to environmental variables was investigated using data collected in 2004 and 2005. Sixty-one zooplankton taxa were identified. Average abundance (except Noctiluca scintiliam) ranged from 236 to 1810 indiv. $m^{-3}$, and was the highest in May 2005 and the lowest in february 2005. Dominant species were Acartia hongi and Paracalanus indicus, and cirripedia nauplii and zoea were dominant groups. After the closure of the 4th sea dyke, brackish species such as Tortanus derjugini and Pseudodiaptomus inopinus are widely distributed while the abundance of N. scintillans decreased in the northern area inside the dyke. In canonical correspondence analysis (CCA) for examining the relationships among zooplankton, stations and environmental variables, the northern area inside the dyke was distinguished from the other areas and was represented by Acartia spp, and brackish copepods.; Also, this area was characterized by high chlorophyll a concentration and COD, and low diversity.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.215-220
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• 2003

Three lakes (lake Homanpo, Hyunkum and Daein) were revealed to be brackish by the results of zooplankton fauna and salinities (2.8 ppt and 0.8 at lake Hyunkum in May and October 2002, and 1.5 and 0.5 at the Daein) in Shinpo district, North Korea. Among 34 taxa of zooplankton occurred, copepods and rotifers showed the prosperity in species number with 15 species and 7 species, respectively. Twenty four taxa of freshwater animals, six brackish ones and four marine ones were found, Brackish copepods, Pseudodiaptomus inopinus and Sinocalanus tenellus, were found in all lakes. More than 90% of zooplankton abundances consisted of brackish and marine species in three lakes. The outburst of S. tenellus was observed (59,000 indiv./$m^3$) at lake Hyunkum in May, when the proportion of brackish and marine zooplankton exceeded 99% of total zooplankton abundance. Long-term monitoring appears to be needed to provide basic data to protect brackish lakes in the study area.

• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.240-247
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• 2006

The dynamic of zooplankton community and its relationship with dissolved oxygen were studied at the Soho area of Gamak Bay from 22 August to 15 September in summer. We found that zooplankton were in low abundance or absent from bottom waters when oxygen concentrations were <3 mg $L^{-1}$. The relationship between summer low-oxygen in bottom-layer and zooplankton community structure was discussed at vertical abundance in Soho area of Gamak Bay. To examine effects of bottom-layer low-oxygen on abundance and vertical distributions in the stratified Soho area, zooplankton was surveyed near-surface, within the near-bottom in the study area under a range of near-bottom dissolved oxygen conditions. There were vertical variation in total zooplankton abundance in the study area (ANOVA, P<0.05). Overall abundance of zooplankton: copepod nauplii, Oithona sp. and tintinnids were lower throughout the water column when bottom-layer DO was low (${\leq}3mg\;L^{-1}$). In this context it was postulated that zooplankton distribution in the Soho area of Gamak Bay might be controlled by dissolved oxygen condition.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.2
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• pp.51-63
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• 2004

Appearance of cold water in the coastal area off Ulsan-Campo, Southeastern coast of Korea, during summer has been well observed. To see the effect of this cold water on zooplankton distribution, we have collected zooplankton at 4 to 8 sites in the near coast as well as off coast for three times about two weeks of interval from July to August, 2001. Appearance of cold water was confirmed and total of about 195 zooplankton taxa were identified. Both the numbers of taxa appeared and zooplankton abundances did not show significant difference among the three sampling periods. On the other hand, the numbers of taxa appeared were generally greater in off coastal area while zooplankton abundances were greater in the near coastal area. These two variables showed different relationship with seawater temperatures. That is, the numbers of taxa appeared showed positive correlation with seawater temperatures (p<0.05) but abundances showed no significant relationship (p>0.05) with seawater temperatures of which variations were comparable with seasonal variations. It was postulated that the upwelling induced appearance of cold water enriched the nutrients, enhanced phytoplankton production and then provided better food conditions for smaller zooplankton in the near coastal part of this study area. In this context it was postulated that zooplankton distribution in the upwelling area might be controlled by food condition rather than seawater temperatures in spite of the large temperature variations caused by the appearance of cold water.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.295-302
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• 2009

This study was conducted to identify the influences of light-to-nutrients ratio on the zooplankton and phytoplankton community. Various experiment conditions such as HL (high-light and without zooplankton), HLZ (high-light and with zooplankton), LL (low-light and without zooplankton), and LLZ (low-light and with zooplankton) were adjusted. Changes in biomass of phytoplankton species with the incubation time showed a similar tendency in the continuous cultures, but the change of species composition in the continuous cultures was detected. Cyanophyeeae (Phormidium sp.) seems to be affected by the existence of zooplankton. Also, the predominant species were Chlorophyceae (Staurastrum spp., S. dorsidentiferum, Coelastrum cambricam, Chlorella sp., Krichnerialla sp.) in a high-light environment and Bacillariophyceae (Melosyra granulata, Synedra acus, Fragilaria crotonensis) in a high-light environment. The estimated mean POC concentration (after twenty days) in a high-light environment was two times higher than that for a low-light environment. P : C ratio of seston component in a low-light environment was higher than that for a high-light environment. Changes in biomass of zooplankton species during the incubation time were higher than that for a high-light environment.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.424-434
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• 2006

This study investigates bacteria-zooplankton grazing link and factors affecting their grazing relationship at trophically different two sites (Paldang Dam and Kyungan Stream) of Lake Paldang Ecosystem from April to December, 2005. Zooplankton were divided into two size groups; microzooplankton (MICZ) : 60-200 ${\mu}m$ and macrozooplankton (MACZ): >200 ${\mu}m$), and their grazing rates on bacteria were conducted for each size group separately. Bacterial abundance and seasonal change pattern were similar between two sites. MICZ, mostly rotifers (e.g., Brachionus, Keratella, Polyathra) were numerically dominant at both sites, while carbon biomass was highest in cladocerans. Zooplankton biomass was higher at the Kyungan Steam site compared to Paldang Dam site, and their high biomass during spring decreased as they were passing through the storm events in summer season at both sites. Zooplankton clearance rate (CR) was high in spring and autumn while low in summer at Paldang Dam site. However, zooplankton CR was high during the summer at Kyungan Stream site. Bacterial C-flux was high in spring and autumn when MACZ (esp. cladecerans) developed at a high biomass level at both sites. Overall, MACZ community CR and carbon flux (C-flux) were higher than those of MICZ, and the degree of difference between them was higher at Kyungan Stream site. Short hydraulic residence time and physical disturbance caused by summer storm event appeared to affect the zooplankton grazing on bacteria at both sites. The results of this study indicate that bacteria are potentially important carbon source of zooplankton, and that both biotic (e.g,, prey and predator taxa composition and abundance) and physical parameters appear to alter energy transfer in the planktonic food web of this river-reservoir hybrid system.