• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.115-124
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• 2010

In order to find out the short-term phytoplankton dynamics during summer season in Jinhae Bay, we investigated the environmental factors and phytoplankton population densities at 16 stations. A total of 66 phytoplankton species were appeared, diatoms occupied more than 80% of total species, and the others were dinoflagellates and raphidophyceaes. The dominant species were diatoms Chaetoceros affinis, C. didymus, C. pseudocurvisetus, Leptocylindrus danicus, Pseudonitzchia pungens, Skeletonema costatum and dinoflagellates Cochlodinium polykrikoides, Gymnodinium impudicum, Karenia mikimotoi, Prorocentrium minimum, Protoperidinium bipes and Scrippsiella trochoidea. According to multidimensional scaling (MSD) and cluster analysis based on phytoplankton community data from each station, the Jinhae bay was divided into two groups. The first group included stations in the inner part of Masan Bay, which is strongly influenced by high nitrogen loading and low salinity by river discharge. The second group included the other remained stations. Based on canonical correspondence analysis (CCA), small-size dinoflagellates K. mikimotoi, P. minimum, P. bipes and S. trochoidea and centric diatom C. pseudocurvisetus and S. costatum, which is dominanted in the inner area of bay, were related with DIN (ammonium, nitrate, nitrite). These results imply that the study area was grouped into the two water masses (inner and outer water of Masan Bay) and inner waters had higher phytoplankton abundances and Chl.a concentration than outer waters. As a result, summer phytoplankton peaks in the inner shallow bay were stimulated by increases in nitrogen and temperature.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.232-241
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• 2009

The dynamics of phytoplankton communities were investigated for Upo wetland from march 2005 to December 2007 on monthly basis. During the investigation, totally 213 phytoplankton taxa which belonged to 86 genera of 35 families in 8 classes were observed. Chlorophyceae was the most diverse in the Upo wetland. Number of phytoplankton taxa was in the range 14${\sim}$50 for monthly investigation and the average number of taxa was 34${\pm}$10. Phytoplankton standing crops were the lowest value of 161 cells $mL^{-1}$ in August 2005 and the highest with 159,283 cells $mL^{-1}$ in August 2006. Especially during summer season in 2006, phytoplankton standing crops showed the highest value due to the waterbloom occurred by cyanobacteria. The number of the dominant taxa of Upo wetland were 13 and among them chlorophyceae and cyanophyceae dominated 8 times. In the view of seasonal changes of phytoplankton community, Upo wetland had high portion of cryptophyceae, dinophyceae and bacillariophyceae in the winter season and chlorophyceae and bacillariophyceae in the other season. However, in the summer season of 2006, cyanobacteria showed the highest portion. The diversity indices had range from 0.50 to 2.86 and showed the tendency of gradual decrease in each year.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.95-115
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• 1999

The dynamics of phytoplankton community in Lake Imha and its tributaries was investigated at nineteen stations in August and September 1996. A total of 171 taxa ［171 species (including 1 forms and 27 varieties),66 genus, 25 families, 6 suborders, 13 orders and 6 class］ were identified. The standing crops of phytoplankton ranged from $47.35{\times}10^3 to 184.65{\times}10^3 individuals/ml in surface layer, 1.08{\times}10^3~54.33{\times}10^3 individuals/ml in middle layer and 0.69{\times}10^3~115.85{\times}10^3individuals/ml$ in low layer. Dominant species determined by standing crops of each species were Oocystis lacustris, Elakatothrix gelatinosa, Aulacoseira ambigua, and Synedra acus, however, the most species dominated from 1992 to 1994 disappeared.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.449-456
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• 2008

Recent studies reveal that the endocrine disrupter nonylphenol can also influence the growth of planktonic organisms. To clarify the effect of nonylphenol on the whole planktonic community, we monitored planktonic abundances after addition of nonylphenol using small-scale microcosms in a laboratory. Nonylphenol was added at final concentrations of 1.25 and $2.5{\mu}g\;L^{-1}$, close to the EC50 for the growth of the rotifer, Brachionus calyciflorus. Chlorophyll $\alpha$ concentration increased significantly between 2 to 5 days after nonylphenol treatment compared to the control. The abundance of the predominant phytoplankton, Stephanodiscus hantzschii, followed the same pattern as chlorophyll a concentration. While there was no negative effect on the abundance of ciliates and rotifers, crustacean zooplankton abundance was higher in nonylphenol treatments. Although the relationship did not reach significance, the growth rate of rotifers tended to decline with increasing nonylphenol dosing. It is likely that the decreased rotifer grazing on S. hantzschii caused significant increase in their abundance. This study emphasizes the importance of considering indirect effects of environmental pollutants when predicting the response of biological community to toxicant exposure.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.832-839
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• 2009

Since construction of the estuarine barrage at the mouth of the Nakdong River, eutrophication and increased abundance of phytoplankton have occurred mainly due to the increased retention time in the reach. However, during the spring, there is a decrease in chlorophyll-a, as a result of an increase in zooplankton number, which preys upon phytoplankton and affects the value of chlorophyll-a. In order to emphasize the importance of zooplankton data in water quality simulation, zooplankton community data were used to simulate water quality and eutrophication at Mulgeum located in 27 km upstream from the barrage. WASP 7.2 was used as the water quality model for the river, using a monthly data set from 2003 to 2005 for model calibration and verification. The results showed that chlorophyll-a, DO, and total nitrogen in the river were simulated well during the verification period. The results of water quality simulation using zooplankton community data in the model were better than those with phytoplankton death rate, in terms of the absolute value of percent bias, root mean square error, and Nash-Sutcliffe efficiency. Those results indicate the use of zooplankton data provides more accurate simulation results for chlorophyll-a and eutrophication.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.362-369
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• 2013

Phytoplankton and zooplankton communities were investigated from 8 weir sites of the Nakdong River system to provide basic information on plankton community after weir construction and to estimate its effects on major water quality parameters. The relationship between plankton community structure and environmental factors was analysed with CCA (Canonical Correspondence Analysis). The results suggested that discharge and total phosphorus and nitrogen concentrations are important factors determining the phytoplankton species composition. For zooplankton community, the difference in discharge between September and October induced different distribution pattern of zooplankton community with more homogeneous distribution with extreme dominance of rotifers during the high discharge season. Chlorophyll a concentration representing phytoplankton biomass has been suggested as the main environmental factor affecting zooplankton community followed by COD and total nitrogen concentration.

• ALGAE
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• v.20 no.4
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• pp.333-343
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• 2005

Spatial and temporal variations of environmental factors and phytoplankton community were investigated in the three stations of Andong Reservoir in 1997 and 2003. The changes of physico-chemical water quality and phytoplanktonic biomass were higher in 2003 than that of 1997, due to rainfall difference. The concentration of total nitrogen (TN) and total phosphorus (TP) in the reservoir decreased, but total nitrogen fell relatively more between them. TN/TP ratio decreased from 109 to 90 showing no change at the downstream but a big decrease at the midand upstream. Predominant phylum of phytoplankton in Andong Reservoir were six genus that composed to Anabaena, Aphanizomenon and Microcystis of Cyanophyceae, Cosmarium and Scenedesmus of Chlorophyceae and Synedra of Bacillariophyceae, respectively. Among the observed phytoplankton, diatom Synedra occured as the maximum amount of 3,400 cells mL$^{-1}$ even at the above 30°C. Green algae Scenedesmus observed along with Microcystis. It seemed to be compete with Microcystis during the high water temperature period. Although trophic state of Andong Reservoir was decreased, the standing crops of phytoplankton were increased. Moreover bluegreen algae, Aphanizomenon and Microcystis in the region of upstream to midstream and diatom, Synedra in the region of midstream to downstream were increased until to reach the algal bloom, respectively. It seemed necessary to attention the changes of blue-green algae Aphanizomenon, that has an ability of nitrogen fixation.

• ALGAE
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• v.18 no.4
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• pp.273-280
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• 2003

The physico-chemical characteristics and seasonal variations of phytoplankton community were investigated in the Paksil and Jungyang marshes. Water and phytoplankton samples for analyses were collected monthly from April 2002 to March 2003. A total of 421 taxa of phytoplankton belonging to eight classes identified. The number of taxa was highest in Bacillariophyceae, followed by Chlorophyceae, Euglenophyceae, Cyanophyceae, Chrysophyceae, Dinophyceae, Xanthophyceae and Cryptophyceae. The standing crops ranged from 1.25 ${\times}$ $10^6$ to 5.85 ${\times}$ $10^6$ cells ${\cdot}l^{-1}$ in Paksil marsh and 0.25 to 9.63 ${\times}$ $10^6$ cells ${\cdot}l^{-1}$ in Jungyang marsh. The highest algal density at Paksil marsh was recorded in October during the high development of Chlorococcales while the lowest value occured in July. In the Jungyang marsh, the maximum algal density was recorded in October when Cryptomonas sp. and Mallomonas sp. accounted for 64% to total cell numbers and the lowest cell density was observed in January due to the decrease of Chlorophyceae. The dominant species were represented by Euglena proxima, Trachelomonas oblonga, Trachelomonas volvocina of Euglenophyceae, Dictyosphaerium pulchellum, Monoraphidium griffithii, Oocystis parva of Chlorophyceae, Dinobryon sertularia, Kephyrion rubri-claustri of Chrysophyceae, Achnanthes minutissima of Bacillariophyceae and Cryptomonas sp. of Cryptophyceae in the Paksil and Jungyang marshes. Phytoplankton diversity(H’) and dominance index varied rather irregularly throughout the sampling period but they were significantly correlated. The highest diversity(H’Paksil = 3.68, H’Jungyang = 3.63) coincided with the lowest values of dominance(DPaksil = 0.05, DJungyang = 0.05)

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.249-258
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• 2014

Phytoplankton species composition and ecological index (diversity, evenness, richness and dominance) were analysed from April 2013 to March 2014 at 10 stations of cupped oyster, Crassostrea gigas culture area in Iwon coast, Korea. Seasonal and positional variation of phytoplankton standing crops, biomass, dominant species and water quality were distinctively different according to occasionally inflow of Iwon dam reservoired water. The composition of phytoplankton species were Bacillariophyceae 98, Dinophycease 22, Chlorophycease 13, Cyanophyceae 8, Silicofalgellate 4, Euglenophyceae 2, Cryptophyceae 1 species. The most dominant species was Bacillariophyceae as 64.0%. The highest biomass of phytoplankton recorded in September as $40,910{\times}10^3$ cell/L at the station 1, near from inland water inflow area. Ecological indices (diversity, richness, evenness, and dominance index), used for structural change of phytoplankton community and water quality (temperature, dissolved oxygen, salinity) showed difference of spatiotemporal property also.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.37-46
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• 2016

This study describes the spatio-temporal distributions in phytoplankton community such as species composition, standing crops and dominant species from April to November 2008 in the Uljin Marine Ranching Area (UMRA). A total of 123 species of phytoplankton belonging to 67 genera was identified. In particular, diatoms and dinoflagellates were occupied more than 60.5% and 34.6% of total species, respectively. The annual dominant species were Thalassiosira sp., Pseudo-nitzschia pungens in spring, Leptocylindrus danicus, Guinardia striata in early summer, Cheatoceros cirvisetus, Ch. decipiens in early autumn and Skeletonema costatum -ls (like species), Pn. pungens in autumn. Phytoplankton cell density fluctuated with an annual mean of $48cells{\cdot}mL^{-1}$ between the lowest value of $1.8cells{\cdot}mL^{-1}$ in early autumn and the highest value of $240cells{\cdot}mL^{-1}$ in spring. According to the cluster analysis, the phytoplankton community of the UMRA was characterized by the nutrient supply from land side and water movement as current.