• ALGAE
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• v.20 no.2
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• pp.113-120
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• 2005

The freshwater blooms mainly blue-green algal blooms occur frequently in the lower Naktong River in summer, which provoke many socio-economical problems; therefore, the early detection of bloom events are demanding through the quantitative and qualitative analyses of blue green algal species. The in vivo fluorescence properties of cultured strains of Microcystis aeruginosa, M. viridis, M. wesenbergii, M. ichthyoblabe, Anabaena cylindrica, A. flos-aquae, and Synedra sp. were investigated. Wild phytoplankton communities of the lower Naktong River were also monitored at four stations in terms of their standing stocks, biomass and fluorescence properties compared with its absorption spectram. The 77K fluorescence emission spectra of each cultured strains normalized at 620 nm was very specific and enabled to detect of blue green algal biomass qualitatively and quantitatively. The relative chlorophyll a concentration determined by chlorophyll fluorescence analysis method showed significant relationship with chlorophyll a concentration determined by solvent extraction method ($R^2$ = 0.906), and the blue-green algal cell number determined by microscopic observation ($R^2$ = 0.588), which gives insight into applications to early detection of blue green algal bloom.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.287-292
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• 2005

The cyanobacterial diversity was analyzed by restriction fragment length polymorphism (RFLP) of PCR-amplified rpcBA-Intergenic Spacer (IGS) genes and cpcBA-IGS gene sequencing with a sample collected at Chuso-ri in Daechung Reservoir on March 15, 2005, The Shannon-Weiner diversity index was 0.65, indicating that the cyanobacterial community structure was simple. PCR-RFLP profiles obtained were Phormidium spp. (58 clones), Anabaena spp. (14 clones), Microcystis spp. (4 clones), Spirulina sp. (1 clone) and uncultured cyanobacteria (2 clones). The PCR-RFLP of cpcBA-IGS revealed that Phormidium spp. and Anabaena spp. dominated in the invested sample. As a consequence, it seems that the analysis of functional genes such as cpcBA-IGS can be used for the species identification and community analysis of cyanobacteria.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.319-331
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• 2004

This study was conducted to evaluate the ecological impact of freshwater bivalve (Corbiculidae) on plankton communities in experimental enclosure systems (2 m ${\times}$ 2 m ${\times}$ 2 m). During the acclamation period of one month, cyanobacteria, including Microcystis viridis and Microcystis aeruginosa, dominated in both control and treatment enclosures with no noticeable density difference. After the addition of 100 mussels, dominant species of phytoplankton shifted from Microcystis to Scenedesmus in concert with slight decrease in the cell density and the increase of N/P ratio. However, cell density in the control quickly increased, accompanied with changes of dominant species to Oscillatoria spp. With the introduction of additional 500 musseles in the treatment enclosure, dominant phytoplankton species in both enclosures were replaced with Selenastrum spp. and Cryptomonas sp. In the initial stage, the total zooplankton abundance in the control was higher than that of treatment, but it was reversed after the addition 100 mussels. After mussel density increased up to 600 indivisuals, zooplankton density in the treatment decreased with dominance of small taxa, such as rotifers and nauplius. However, abundance and carbon biomass of large zooplankton, such as Bosmina longirostris and Diacyclops thomasi were maintained in a high level compared with those of control. During the study period, Chl. a concentration in mussel treatment and control increased with DIP and $NH_3-N$, respectively. Due to the increase of $NH_3-N$, especially after the introduction of additional 500 mussels, nitrogen limitation did not occur in the treatment enclosure in contrast with strong nutrient limitation occurred in the control. These results indicate that filter-feeding Corbicula could exert important impact on nutrient recycling and plankton community structure in a freshwater ecosystem, through direct feeding and competition for the same food resource as zooplankton on one hand, and through alteration of nutrient availability on the other.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.7-16
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• 2007

The objective of this research was to review the correlation between microalgae and agricultural water quality. Although microalgae has been considered as an essential factor for control1ing of water ecosystem, little attention has been paid for evaluating of microalgae as an important factor for water quality management. But it can be use to make us know the water pollution state at saprobic system, LTSI (Lake Tropic State Index), DAIpo (Diatom Assemblage Index to Organic Pollution), and AGP (Algal growth potential). In saprobic system, it is used microalgae such as Actinastrum hantzschii var. fluviatile, Asterionella gracillima, Coelastrum microporum, Synedra acus, Dictyosphaerium pulchellum, Micractinium pusillum, Cyclotella meneghiniana, Microcystis aeruginosa, Scenedesmus quadricauda, and Nitzschia palea for assessment water quality. In addition, they have ecologically significant characteristics such as dominant species, cosmopolitan species, redtide causative species etc. Also, microalgae such as Botryococcus braunii, B. sp., Chlorella vulgaris, C. sp., Phormidium sp., Scenedesmus quadricauda, Selenastrum capricornutum, Spirulina maxima, and S. platensis have an effect on improvement of water quality.

• Journal of Life Science
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• v.18 no.9
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• pp.1249-1256
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• 2008

We investigated the effect of the water quality on the phytoplankton community in the 2 sites of Andong reservoir. The water temperature in 1 m and 4 m depth (LH) was changed, but the temperature in 7 m depth (HD) was constant irrespective of the season. The dissolved oxygen in LH was lower than that of the HD. The turbidity of water and pH were similar in both depths. The concentration of chlorophyll-a decreased with increased depth of water. Fifty nine phytoplankton taxa were identified and the most abundant phytoplankton group was Chlorophyceae with 25 taxa (43%). Cyanophyceae and Bacillariophyceae consisted of 17 taxa (29%) and 10 taxa (17%), respectively. Cryptophyceae had 3 taxa (5%) and Synurophyceae and Dinophyceae had 2 taxa (3%) in Andong reservoir. Dominant species were Elakatothrix gelatinosa (Aug, 23) and Eutetramorus fottii (Aug. 23 and Sep. 28) from Chlorophyceae, Aphanizomenon cf. flos-aquae (Aug. 16), Microcystis aeruginosa (all sampling periods), and Aphanocapsa delicatissima (Oct. 27) from Cyanophyceae, and Cyclotella stelligera (Oct. 13), Cyclotella sp. (Oct. 13 and Oct. 27) and Synedra acus (Aug. 16) from Bacillariophyceae.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.311-318
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• 2000

The purpose of this study was to determine the optimum water intaking depth for water treatment plant based on the changes of phytoplankton distributions in Unmun reservoir. Sampling was carried around of intaking tower near the Dam site at monthly intervals from February to Ocotber in 1998. Total 79 phytoplankton taxa were observed and they were classified into 4 varieties, 75 species within 51 genera. Diatoms were mainly dominated from February to July. However Rhodomonas sp. was a dominant species in August, and Microcystis ichthyblabe in September and October. Cell density of 122,800 cells/mL in October was the highest, and 415 cells/mL in May was the lowest. The pattern of vertical distribution was similar until May; however, the cell density in the epilimnion was much higher than it in the hypolimnion during the periods with the high water temperature over $20^{\circ}C$ since June. The water depths showing over 5,000 cells/mL ranged from the surface to 9m in June, surface to 6m in September, and on the only surface in October. Based on water temperature and phytoplankton vertical distribution, the depth of 6m appeared to be the optimum intaking depth far water treatment plant: 75.4 to 98.0% of phytoplankton cell densities could be avoided and the temperature over $18.3^{\circ}C$ was preserved to prevent cold water damage for rice growth at the water depth during cyanobacterial blooming period in Unmun reservoir.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.541-547
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• 2015

Formation of disinfection by-products (DBPs) including trihalomethans (THMs) and haloacetic acids (HAAs) from chlorination of six different species (Chlorella vulgaris, Scenedesmus sp., Anabaena cylindrical, Microcystis aeruginosa, Asterionella formosa and Aulacoseira sp.) of algal extracellular organic matter (EOM). The EOM characteristics evaluation of six algal species reaching at the stationary phase in the growth curve showed most of its SUVA254 showed below 1 and this means hydrophilic organic matter is much higher than hydrophobic organic matter. Chloroform formation potential (CFFP), dichloroacetic acid formation potential (DCAAFP) and trichloroacetic acid formation potential (TCAAFP) were mainly composed of THMFP and HAAFP in the EOM of various algal species. In the case of THMFP/DOC and HAAFP/DOC values, EOM of blue-green algae has appeared highest and EOM of green algae and diatom in order. THMFP/DOC was higher than HAAFP/DOC in EOM of blue-green algae. In comparison of formation potential by unit DOC composed of HAAFP in algal species EOM, DCAAFP/DOC was 1.5 times to 7.5 time higher than TCAAFP/DOC in the EOM of blue-green algae, while DCAAFP/DOC was found to be relatively high compared to TCAAFP/DOC in the EOM of green algae and diatom.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.185-199
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• 2023

This study aimed to predict the effects of water ecology on the supply of hydrothermal energy to model a housing complex in Eco Delta Smart Village in Busan. Based on the results, engineering measures were recommended to minimize problems due to possible temperature variations on the supply of hydrothermal energy from the river. The current distribution of fish, benthic macroinvertebrates, and phytoplankton in the Pyeonggang Stream was monitored to determine their effects on water ecology. In the research area, five species and three families of fish were observed. The dominant species was Lepomis macrochirus, and the subdominant species was Carassius auratus. Twenty-five species and 21 families of benthic macroinvertebrates were found. The distribution of aquatic insects was poor in this area. The dominant species were Chironomidae sp., Lymnaea auricularia, Appasus japonicus, and Caridina denticulata denticulata in February, May, July, and October. Dominant phytoplankton were Aulacoseira ambigua and Nitzschia palea in February and May. Microcystis sp. was dominant in July and October. The health of the ecology the Pyeonggang Stream was assessed as D (bad) according to the benthic macroinvertebrate index (BMI). Shifts in the location of the discharge point 150 m downstream from intake points and discharge through embedded rock layer after adding equal amounts of stream water as was taken at the beginning were suggested to minimize water temperature variations due to the application of hydrothermal energy. When the scenario (i.e., quantity of water intake and dilution water, 1,600 m³/d and water temp. difference ±5 ℃) was realized, variations in water temperature were assessed at -0.19 ℃ and 0.59 ℃ during cooling and heating, respectively, at a point 10 m downstream. Water temperatures recorded at -0.20 ℃ and 0.68 ℃ during cooling and heating, respectively, at a point 10 m upstream. All stream water temperatures after the application of hydrothermal energy recovered within 24 hours. Future work on the long-term monitoring of ecosystems is suggested, particularly to analyze the influence of the water environment on hydrothermal energy supply operations.

• Journal of Environmental Science International
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• v.32 no.5
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• pp.315-328
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• 2023

Cyanobacteria have been used as pollution indicator species in freshwater ecosystems, and identifying their fluctuations can be an important part about management of surface waters globally. Cyanotoxins produced by cyanobacteria are directly or indirectly a threat to human and environmental health. In order to confirm the potential risk of these cyanotoxins, the fluctuations of phytoplankton and phylogenetic analysis of cyanotoxin synthetase genes were conducted at each point in the Yeongsan River water system in Gwangju from November 2021 to October 2022. Diatoms which grow well in winter were dominant at 99.4 ~ 99.5%, and diatoms and green algae were dominant from the spring to autumn when the water temperature rises. Stephanodiscus spp. were dominant at 92.7 to 97.5 % at all sites in the winter, and Aulacoseira spp., which grow in warm water temperatures, were dominant in summer and autumn. Microcystis aeruginosa was dominant at 25.2% in summer only at site 5. mcyB and anaC have been detected as cyanotoxin synthetase genes. The phylogenetic tree of anaC could be divided into two groups (Group 1 & Group 2). Group 1 contained Aphanizomenon sp. and Cuspidothrix issatschenkoi. It is combined with Aphanizomenon sp. and Cuspidothrix issatschenkoi, which are known to produce cyanotoxins.

• Journal of Environmental Science International
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• v.14 no.9
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• pp.873-879
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• 2005

This study was investigate to evaluate the phosphate uptake rate of green algae in relation to diurnal rhythm and algae control method. The phosphate uptake rates of Chlorella vulgaris and Ankistrodesmus convolutus increased in light period and decreased in dark period. On the contrary, those of Chlamydomonas sp. showed a peak in the late dark period. The differences among species in phosphate uptake in relation to diurnal rhythm were due to the severe competition among species and seemed to alleviate the competition for nutrient supplies. The compound of CellCaSi, Ca and Fe showed the effective removal of the phosphorus. The extracts from rice and barley straw exhibited a significant effect on the growth inhibition of Microcystis aeruginosa.