• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.3
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• pp.117-124
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• 2011

Many studies of the phytoplankton community structure have been conducted using the CHEMTAX program on the basis of the photosynthetic pigment concentrations measured by a HPLC (High-Performance Liquid Chromatography) technique. The CHEMTAX program determines the contribution of each phytoplankton class to total phytoplankton biomass (chlorophyll a) based on the ratios of marker pigment to chlorophyll a of phytoplankton group. In this study, the marker pigment/chlorophyll a ratios were investigated in phytoplankton species isolated from marine waters around the Korean peninsula. These results were used as the input pigment ratios of the CHEMTAX program to investigate phytoplankton community structure in Korean coastal waters (Yeoja and Gamak Bay). There were significant differences in the ratios of marker pigment to chlorophyll a among the different species within the same algal class. There was a significant difference between the values of our ratios and the previously used ratios in other regions of the world. When phytoplankton community composition was calculated using our initial ratios in Yeoja and Gamak Bay, our results were significantly different from the results calculated on the basis of initial ratios of marker pigment in phytoplankton suggested in other marine waters. The estimates of the contributions of the major algal groups (bacillariophyceae and dinophytes) to total chlorophyll a varied within 5% depending on the initial ratios chosen. The variations of estimates for the pico- and nanoplankton (cyanophytes and prasinophytes), which have relatively low contributions to total chlorophyll a, were higher than those for major algal group. Although the HPLC-pigment measurements combined with CHEMTAX analysis are useful for identifying and qualifying phytoplankton community structure, further researches for the pigment ratios of the dominant phytoplankton species presenting in a given area are also needed.

• ALGAE
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• v.20 no.3
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• pp.197-205
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• 2005

Temporal variability in lake phytoplankton is controlled by a complex between hydrological and chemical factors, and biological interactions. We explored annual change of phytoplankton in Lake Daecheong, using phytoplankton analysis data from 1997 to 2002 (except 2000). The standing crop of phytoplankton was ranged from 3.5 x 10 to 1.5 x 106 cells mL$^{-1}$ and the highest mean value was at site 1. The class composition ratios of phytoplankton standing crop were divided into three classes. From January to March, diatoms showed a dominance (68.1-77.7%). From April to June, diatoms were mixed with cryptomonad etc. or blue-green algae. From July to October, blue-green algae showed a dominance (54.7-84.0%). In the case of green algae, the class composition ratios were below 10%. But green algae appeared all the year round.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.43-50
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• 2000

The obseuations on the seasonal fluctuations of phytoplankton community in Haechang Bay of the Korean southern sea were carried out during four seasons from 1997 to 1998. A total of 77 species of phytoplankton including 10 freshwater species, belonging to 51 Benera was identified. Seasonal succession of dominant species was evident in Haechang Bay; Chaetoceros cunisetus, Skeletonema costatum, Eurampia zodiacus, Dictyocha fibula and Ceratium furca in summer, C. curisetus in autunm, C. cunisetus Rhizosoienia setigera and E. zodiacus in winter and S. costatum in spring. The phytoplankton community in Haechang Bay showed various species composition and was occupied with centric diatoms all the year round, Densities of the phytoplankton cell number by the samples of Haechang Bay ranged from $8.4{\times}10^3\;cells/l\;to\;2.0{\times}10^5\;cells/l$ with the mean value of $9.2{\times}10^4\;cells/l$ in summer, from $3.2{\times}10^3\;cells/l\;to\;4.6{\times}10^6\;cells/l$ with mean of $6,2{\times}10^4\;cells/l$ in autumn, from $8.4{\times}10^3\;cells/l\;to\;4.3{\times}10^4\;cells/l$ with mean $2.2{\times}10^4\;cells/l$ in winter and from $1.0{\times}\;10^3\;cells/l to\;4.6{\times}10^4\;cells/l$, with mean of $1.1{\times}10^4\;cells/l$ in spring. Phytoplankton standing crops fluctuated with an annual mean of $4.7{\times}10^4 cells/l$ between the lowest value of $1.0{\times}10^3\;cells/l$ in spring and the highest value of $4.6{\times}10^5 cells/l$ in autumn, That is, phytoplankton standing crops was high in summer and autumn, while it was very low in winter and spring.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.38-50
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• 2000

Seasonal changes of the phytoplankton and the periphyton community were investigated from August 1998 to April 1999 at five stations at the Suer stream in Kwangyang. A total of 112 species of phytoplankton were identified. Of those, the diatoms were present at all stations but the green algae, the bluegreen algae, and the dioflagellates were present at Station 4 and Station 5 more frequently than the other stations. The phytoplankton standing crops varied from 10,100 cells/1 at Station 4 in April 1999 to 1,489,100 cells/1 at Station 4 in October 1998. The seasonal variation patterns of phytoplankton standing crops were different among stations as well as the pattern of presence. The dominant species were as follows: Achnanthes minutissima, Aulacoseira distans v. alpigena, Cocconeis placentula v. lineata, Cymbella minuta, C. silesiaca, Fragilaria arcus v. recta, Peridinium cinctum, Rhizosofenia longiseta, Synedra rumpens and filamentous algae. Of those, Achnanthes minutissima, Rhizosolenia longiseta, Synedra rumpens and filamentous algae showed the highest rate of occupation in the phytoplankton standing crops during the investigated periods. A total of 99 species of periphyton were identified. Among those, the diatoms of the periphyton community were observed frequently rather than those of the phytoplankton community. The ecological indicator values showed ${\bate}$-mesosaprobous in saprobity and was close to eutraphentic in trophic state. There were no considerable differences between the ecological indicator values by planktonic diatoms and periphytic diatoms.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.375-384
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• 2016

Phytoplankton community is one of the important factors for the management of aquatic environment due to generation of varying toxins by harmful algal species. This study was performed to examine the phytoplankton community structure (PCS) in the midstream of Geum River (GR) from January 2014 to December 2015. The water sampling was performed in five stations on 2014, and three stations on 2015. Subsequently, the morphological identification was performed by microscopic observation in laboratory condition. As results, total 265 species were identified and it was comprised of 40.8% of Bacillariophyceae, 9.1% of Cyanophyceae, 44.5% of Chlorophyceae, and the others (4.9%). During the investigation period, total average standing crop of phytoplankton was $12,948cells\;mL^{-1}$, and it was comprised of $7,702cells\;mL^{-1}$ of Bacillariophyceae, $2,821cells\;mL^{-1}$ of Cyanophyceae, $2,121cells\;mL^{-1}$ of Chlorophyceae, and $305cells\;mL^{-1}$ of others. To verify which tributaries of upstream area influence on PCS of midstream of GR, the phytoplankton standing crops of two stations including Mihocheon (MH) and Gapcheon (GC) were examined on 2014, and compared to result of on 2015. The results were shown that the MH station had more similar phytoplankton standing crops with midstream of GR than GC station. The relationship between environmental parameters and phytoplankton dynamics was studied at the investigated station. As results, whereas water temperature and total phosphorus were represented the positive correlation, N/P ratio was remarkably exhibited negative correlation. From the results, it is suggested that the PCS of midstream of GR was more affected by MH station than GC station, and the changes of temperature, phosphorus concentration, and N/P ratio may be important factors on the PCS formation of midstream of GR.

• Ocean and Polar Research
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• v.32 no.2
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• pp.97-111
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• 2010

Phytoplankton production is affected by various physico-chemical factors of environment. However, one of the most critical factors generally accepted as controlling primary production of phytoplankton is nutrients. It has recently been found that the succession of phytoplankton groups and species are closely related to the chemical properties of ambient water including nutrient limitation and their ratios. In Jangmok Bay, silicate and nitrate are primarily supplied by rainfall, while phosphate and ammonia are supplied by wind stress. Typhoons are associated with rainfall and strong wind stress, and when typhoons pass through the South Sea, such events may induce phytoplankton blooms. When nutrients were supplied by heavy rainfalls during the rainy season and by summer typhoons in Jangmok Bay, the dominant taxa among the phytoplankton groups were found to change successively with time. The dominant taxon was changed from diatoms to flagellates immediately after the episodic seasonal events, but returned to diatoms within 3~10 days. Pseudo-nitzschia spp. were dominant mainly in the presence of low phosphate levels during the first of the survey which included the rainy season, while Skeletonema costatum was dominant when phosphate concentrations were high due to the strong wind stress during the latter half of the survey as a result of the typhoon. The competition between S. costatum and Chaetoceros spp. appeared to be regulated by the silicate concentration. S. costatum preferred high silicate and phosphate concentrations; however, Chaetoceros spp. were able to endure low silicate concentrations. These results implied that, in coastal ecosystems, the input patterns of each nutrient supplied by rainfall and/or wind stress appeared to contribute to the summer succession of phytoplankton groups and species.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.665-672
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• 2014

Elemental cellular stoichiometry of natural phytoplankton communities was examined in six large dam reservoirs in the Han River system. Carbon (C) and nitrogen (N) contents of the phytoplankton-dominated seston from Lake Soyang was higher than that from other lakes. Phosphorus (P) content showed slight variations among six lakes in the range of $0.04{\sim}0.18{\mu}mol$ P mg $DW^{-1}$. The phosphorus concentrations of lake water showed obvious positive relationship with P and C contents of the phytoplankton-dominated seston. In all six lakes, N:P ratios and C:P ratios in the phytoplankton-dominated seston were more than 23 and 133 respectively, indicating the phytoplankton communities in six lakes have been exposed in phosphorus limited condition. The relative abundance of diatoms showed significant negative correlation with C, N, P contents of the phytoplankton-dominated seston and that of cyanobacteria showed significant positive correlation. Elemental stoichiometry of diatoms-dominated seston showed distinctive less content than that of cyanobacteria-dominated seston. The cellular N:P ratios of diatoms- and cyanobacteria-dominated seston indicate that both main classes of phytoplankton in six lakes are in phosphorus deficiency. Elemental stoichiometry of the phytoplankton-dominated seston in this study could be used for the further ecological stoichiometric studies in six lakes.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.191-191
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• 2017

• Journal of Environmental Science International
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• v.4 no.3
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• pp.177-186
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• 1995

The seasonal changes and composition of phytoplankton of the Choonsan reservior were studied from November 1990 to October 1991. 195 taxa which belong to 65 genera, 150 species, 40 varieties and 1 forms were identified. Species number during summer monthes was higher than that of other seasons. Standing crops of phytoplankton were varied from $7.8\times10^5$ cells/l to $2.2\timesl0^6$ cells/$\ell$. The dominant species were Cryptomonas erose and Trachelomonas volvoina. Chlorophyll a contents of phytoplankton was varied from $1.36\mu\textrm{g}/\ell$ to $127.46\mu\textrm{g}/\ell$. The biotic indices of phytoplankton were very similar among three sites. Saprobien-system by index of species diversity suggests that the Choonsan reservior belongs to the oligosaprophic.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.101-106
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• 1999

The relationship between primary productivity and changes in water quality was investigated at Mulgum station, a site downstream of the Nakdong River, Korea. Phytoplankton production was characterized by blooms of Microcystis aeruginosa during the summer and Stephanodiscus hantzschii during the winter. Primary production and secondary production by bacterioplankton ranged from 1.5~53.5 mg-C/ι day and 0.1~0.3 mg-C/ι day, respectively. Distribution of total organic carbon appeared to be highly correlated with phytoplankton biomass, especially during blooms of M. aeruginosa, when particulate organic carbon was 81% of total organic carbon and the main source of organic materials supplied into the water. The correlation coefficient between chlorophyll-a and BOD was 0.86. Thus it was concluded that autochthonous phytoplankton mostly affected the BOD level. Total bacterial numbers were also highly correlated with chlorophyll-a ($r^2$= 0.84) and the bacterial community appears to be regulated by phytoplankton biomass in this area.