• Journal of Plant Biology
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• v.29 no.2
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• pp.117-127
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• 1986

Phytoplankton community was investigated at the Paldang Dam Reservoir in the Mid-Han River by it's depth, in spring and summer known as the period of phytoplankton's blooming. It was only in summer that phytoplankton bloomed at the investigated area. 128 kinds of phytoplankton were identified and of them, diatoms were abundunt in spring but cyanophyta and chlorophyta were in summer. Because some species with high pollution index were observed in summer, it could be proved that the investigated area was polluted especially in summer. In spring shown the circulation period by vertical distribution pattern of chlorophyll-a and isothermal distribution pattern of water temperature, maximum value of phytoplankton standing crops appeared at the upper layer, except for surface layer. In summer shown the circulation period after the stagnation period by vertical distribution pattern of chlorophyll-a and immediate destruction after stratification of water temperature, maximum value of phytoplankton standing crops appeared at the lower layer. the layer at which the maximum value of chlorophyll-a appeared also accorded with that of phytoplankton standing crops. So, it could be approved that there existed a close relationship among phytoplankton standing crops, chlorophyll-a, and water temperature.

• ALGAE
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• v.23 no.1
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• pp.31-52
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• 2008

This study analyzes characteristics of phytoplankton communities around Wolseong nuclear power plant by selecting 16 stations from July 2006 to June 2007 and understands the influences on standing crops and chlorophyll a of phytoplankton by passing through the cooling water system. The total species number is 283, among which diatoms is 208 occupying 73.5% of total taxa. The mean of total standing crops is 469,380-3,704,114 cells L-1. It is the highest in April 2007 because blooming of Chaetoceros socialis occurs during this period. The mean standing crops of microplankton and nanoplankton are average 129,666-3,392,640 cells L-1 and 240,943-650,505 cells L-1 respectively, which occupy 54.01% and 46.54% of total standing crops. The mean concentrations of total chlorophyll a is 0.64-5.39 μg L-1. The mean concentrations of chlorophyll a of microplankton, nanoplankton and picoplankton are 1.33 μg L-1, 0.21 μg L-1 and 0.49 μg L-1 respectively. Dominant species around Wolseong neclear power plant during this study are Chaetoceros debilis, Chaetoceros socialis, Leptocylindrus danicus, Pseudo-nitzschia fraudulenta, P. subfraudulenta and Thalassiosira decipiens. Fluctuation rates of standing crops and chlorophyll a concentrations of phytoplankton passing through the cooling water system are 22.80% and 50.48% respectively. Decrease of standing crops and chlorophyll a concentrations of phytoplankton means that community structure of phytoplnakton may change at the discharge areas.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.111-122
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• 2002

Seasonal changes of the phytoplankton community was investigated from July 2000 to April 2001 at five stations in the Imjin River. A total of phytoplankton were composed of 193 taxa, belonging to 5 divisions, 145 species, 28 varieties, 1 form, 19 unidenfitied species. Of those, the diatoms and green algae were present during the investigation periods more frequently than the other taxa. The phytoplankton standing crops varied from $89{\times}10^3\;cells/l$ at station 1 in October 2000 to $8,825{\times}10^3\;cells/l$ at station 3 in April 2001. Throughout the investigation periods, at station 1, there was low in the size of phytoplankton standing crops at large. Otherwise, at station 2, staion 3 and station 4, we could see the maximum of phytoplankton standing crops in July 2000 and then phytoplankton standing crops decreased and it reached to the minimum in January 2001, and after then, it increased again. But exceptionally, we could see the maximum of phytoplankton standing crops in April at station 3. And also, at staion 5, we could see the similar variation pattern of phytoplankton standing crops at station 2, station 3 and station 4 with a little differences in seasonal variation pattern of phytofllankton standing crops. The major dominant species were Achnanthes minutissima, Anabaena sp., Aulacoseira ambigua, A. granulata, A. granulata v. angustissima, Cymbella affinis, Cylindrotheca closterium, Diatoma vulgare, Merismopedia glauca, Stephanodiscus hantzschiif. tenuis.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.355-365
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• 2000

In order to study the relationship between water quality and phytoplankton standing crops, the authors investigated the physicochemical factors, phytoplankton standing crops and chlorophyll-a at two stations in the Daechung Reservoir during the period from May to November 1998. Nutrients (nitrite, nitrate, ammonia and phosphate) have gradually increased more than those of the previous reports. Concentrations of the total nitrogen, phosphorus, chlorophyll -a and transparency exceeded the standard value of eutrophication. It could be assumed that the eutrophication of the Daechung reservoir was caused by various pollutants. Chlorophyll-a concentration was under the influence of phytoplankton standing crops, but very tiny cell-sized blue-green algae were less important in regards to the chlorophyll-a. Except at station 1 from July to August, phytoplankton standing crops bloomed during the time of the survey. Spring phytoplankton blooms caused by nitrate and phosphate in the surface layer. High concentrations of the suspended solids in July and August were caused by an inflow of them due to heavy rains. Density of heterotrophic bacteria was high in August owing to the high water temperatures and the organic nutrients which were from the nearby reservoir.

• ALGAE
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• v.18 no.3
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• pp.207-215
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• 2003

Dynamics of phytoplankton communities were investigated at five stations in Youngsan River from December 1995 to November 1996. Phytoplankton were identified to the total of 466 taxa, which were composed of 136 genera, 438 species, 27 varieties and 1 forma. The standing crops ranged 1,163-50,765 cells ${\cdot}ml^{-1}$ during the investigation periods. The variation of classes was in order to Chrysophyceae - Bascillariophyceae - Chlorophyceae at St. 1 and was only Bacillariophyceae at the other stations. The dominant species were 12 taxa including Aulacoseira ambigua, A. garnulata, Cyclotella meneghiniana, C. pseudostelligera, Chlorella vulgaris, Dinobryon sertularia, Flagilaria elliptica, Monoraphidium contortum, Micractinium pusillum, Nitzschia palea, Scenedesmus grahneisii and Stephanodiscus hantzschii f. tenuis. The standing crops of dominant species ranged from 10.6% to 94.7%. The genus Dinobryon in Chrysophyceae was dominant species at St. 1 in December 1995, but not recorded in the other months. The dominant species were composed with the planktonic diatoms from winter to spring and were the tychoplanktonic and the benthic species at St. 2-5 from summer to fall. The relationships between total standing crops and water temperature, pH, $NH_4$, $NO_2$, $NO_3$ and $PO_4$ showed low positive or negative coefficients. Stephanodiscus hantzschii f. tenuis had low positive or negative coefficients with water temperature, $NH_4$, $NO_2$, $NO_3$ and $PO_4$. The fluctuations of standing crops in the Youngsan river phytoplankton community were not caused by a single factor but controlled by the complex factors with interaction between phytoplankton community and envirowmental factors.

• ALGAE
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• v.23 no.1
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• pp.53-61
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• 2008

In order to understand variation and relationship between standing crops and biomass of phytoplankton dominant species for the long term periods, this study was seasonally investigated in the marine ranching ground of Tongyeong coastal waters from 2000 to 2007. Total 268 taxa representing 217 Bacillariophyceae, 46 Dinophyceae, 4 Dictychophyceae, 1 Euglenophyceae were observed in phytoplankton communities. Dominant species consisted of 5 species as standard in standing crops: Chaetoceros curvisetus (18.01%), Chaetoceros socialis (12.95%), Skeletonema costatum (8.39%), Chaetoceros compressus (6.87%), Asterionellopsis glacialis (5.02%). However, to determine dominant species as biomass concept, Ditylum brightwellii, Guinardia striata, Rhizosolenia spp. and Skeletonema costatum were occupied with dominant species (19.67%). As determining for cell sizes, dominant species were divided with two groups such as micro- and nanophytoplankton (standing crops) and mesophytoplankton (biomass). However, Skeletonema costatum in anophytoplankton was associated to affect fluctuation between standing crops and biomass.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.347-353
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• 2000

Standing crops of freshwater phytoplankton was studied from October 1998 to September 1999 in Hyendo, Maam, Jangam, and Napo of Kumgang River. Standing crops peaked in July in Hyendo $(39.5{\times}10^3Cells ml^{-1}), Maam (112.1{\times}10^3Cells ml^{-1}), and Jangam (125.5{\times}10^3Cells ml^{-1}), while in August in Napo (288.6{\times}10^3Cells ml^{-1}), respectively. The standing crops ranged less than 5,000 cells ml^{-1} in most of months in Hyendo and Maam, while more than 5,000 cells ml^{-1}$ throughout the year in Napo, Jangam's standing crops being intermediate. Total standing crops throughout the year increased with downstream; the standing crops of Napo was 9.6 times higher than that of Hyendo. The standing crops peaked from spring to early summer in Jangam and peaked in other seasons in Napo. The small centric diatoms Cyczotella spp., Stephanodiscus spp. and filamentous diatoms Aulacoseira spp. played an important role to form the peak of standing crops.

• ALGAE
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• v.19 no.4
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• pp.329-337
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• 2004

Monthly variations of phytoplankton communities were conducted to the investigation at five stations in mid and lower parts of the Nakdong River from December 1995 to November 1996. The phytoplankton communities were identified a total 456taxa which were composed of 136 genera, 427 species, 27 varieties and 2 forma. The standing crops of phytoplankton communities ranged from 2.7 to 52.8 (${\times}$10³)cells·ml$^{-1}$ during the investigation periods. Bacillariophyceae was the dominant classes at all stations. The dominant species were 7taxa and the standing crops of these ranged from 18.3 to 95.1% of the standing crops of phytoplankton communities. The dominant species in the mid parts (st. 1, 2) of this river system were benthic species such as Navicula gregaria, N. viridula var. rostellata and Nitzschia palea, however it was planktonic species (Stephan discus hantzschii, Golenkinia radiata) and meroplanktonic species (Aulacoseira ambigua, A. granulata) in the lower parts (st. 3, 4, 5). The seasonal variations of the dominant species in the lower parts were appeared to the planktonic species (S. hantzschii) from winter to spring, and were the meroplanktonic species (A. ambigua and A. granulata) in from summer to fall. The lower parts of the Nakdong river were entropic states because the dominant species were composed A. ambigua, A. granulate and S. hantzschii which were indicators of entropic water quality. The interrelationships between total standing crops and environmental factors(water temperature, pH, NH$_4$, NO$_2$, NO$_3$ and PO$_4$) were low positive or negative coefficients. S. hantzschii had low positive or negative relations with water temperature, NH$_4$, NO$_2$, NO$_3$ and PO$_4$. As the result, the variations of standing crops of phytoplankton were not caused by a single factor but controlled by the complex factors.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.167-176
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• 1995

A study on phytoplankton community was carried out from June, 1992 to May, 1993 at selected stations in Hoedong Reservoir. The phytoplankton are identified as 176 taxa including 5 phylum, 67 genera. The important species in this reservoir were Asterionella formosa, C meneghiniana, Dictyosphaerium plilchellum, Fragilaria crotonensis, Melosira distans, M grantulata, M. granulata var. angustissima, M. granulate var. angntissima f. spirdis, Micractinium pussillum, Microcystis aeruginosa, Pundorina morn, Pediastrum boryanum, P. duplex, Peridinium sp., Scenedesmus quadriauda, Synedra acus, S. rumpens and S. ulna. The causative species of water bloom were identified as Microcystis aeruginsa, Trahellomonas hispida, Ceratium hirwdinella, Peridinium sp., Melosira italica, Staurastrum dorsidentiferum var. onatum in the area. During the study periods standing crcps of phytoplankton were maximum in August, 1992 and minimum in December 1992. The species dominance index and diversity index were ranged 24.7-99.9, 0.001-3.06, respectively. Key Words : phytoplankton community, causative species of water bloom, standing crops. dominance index, species diversity index.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.90-97
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• 2001

The seasonal changes in phytoplankton standing crops, species composition, dominant species, species diversity and physico-chemical characteristics in Woopo and Mokpo swamps were studied from January to December, 1998. Phytoplankton of a total 353 taxa were identified, the composition of phytoplankton community was characetrized by green algae and diatoms and quantity composition of standing crops was dominated by green alga Oscillatoria sp. was especially prominent. The standing crops varied from 108 cells/ml and 118 cells/ml to 19,178 cells and 38,393 cells/ml in Woopo and Mokpo swamps, respectively. The maximum algal density was observed in November, Micractinium pusillum and Oscillatoria sp. usually contributed 83.2% to total cell numbers in Woopo swamp. However, the maximum density occurred in May when Oscillatoria sp. formed bloom in Mokpo swamp. The low species diversity of the phytoplankton coincided with maximum standing crops of the filamentous blue-green alga Oscillatoria sp. and green alga Micractinium pusillum in May and November.