• Mycobiology
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• v.34 no.3
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• pp.138-142
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• 2006

Soil cyanobacteria isolated from the rice paddy fields of 10 different locations across Korea were evaluated by agar plate diffusion test for antifungal activity. Aqueous, petroleum ether, and methanol extracts from one hundred and forty two cyanobacterial strains belonging to the 14 genera were examined for antifungal properties against seven phytopathogenic fungi causing diseases in hot pepper (Capsicum annuum L). Of total cyanobacteria, nine cyanobacteria (6.34%) exhibited antifungal effects. The nine cyanobacteria selected with positive antifungal activities were two species of Oscillatoria, two of Anabaena, three of Nostoc, one of Nodularia, and one of Calothrix. Alternaria alternata and Botrytis cinerea were inhibited by nine and eight species of cyanobacteria, respectively. Rhizopus stolonifer was suppressed by only methanol extract of Nostoc commune FK-103. In particular, Nostoc commune FK-103 and Oscillatoria tenuis FK-109 showed strong antifungal activities against Phytophthora capsici. Their antifungal activity at the late exponential growth phase is related to the growth temperature and not associated with the growth parameters such as cell biomass and $chlorophyll-{\alpha}$ concentration. The high inhibition levels of antibiotics were 22.5 and 31.8 mm for N. commune FK-103 and O. tenuis FK-109, respectively. The optimal temperature for antibiotic productivity was $35^{\circ}C$.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.113-128
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• 2011

The study analyzed the physico-chemical quality of water and the resident phytoplankton community, and evaluated the water trophic status in So-ok stream flowing into Daechung lake from October 2007 to July 2008. Algal blooming by cyanophytes and diatoms continued throughout the year, with Microcystis aeruginosa and Aulacoseira granulata being prevalent. Ten taxa that are indicators of polluted water, including Oscillatoria limosa appeared. Results based on (Trophic status index) TSI and (Lake trophic status index) LTSI evaluations of water quality status indicated mesotrophication.

• Journal of Korean Society on Water Environment
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• v.39 no.3
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• pp.223-230
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• 2023

Harmful algae blooms have become a serious environmental problem in major river basins in Korea. They are known to produce various algal organic matters (AOMs) including intracellular organic matters (IOMs) and extracellular organic matters (EOMs). Generally AOMs cannot be easily removed by coagulation/flocculation process in conventional drinking water plants. AOMs produced by blue-green algae also include various toxins such as Microcystins, Anatoxin-a, and Saxitoxin known to have harmful effects on living organisms in aquatic environment. In this study, toxic effects of EOMs produced by three different algae species (Microcystis sp., Anabaena sp., and Oscillatoria sp.) on zebrafish were investigated using electroencephalography (EEG) recording method, a technology for recording brain activity. Electroencephalographic changes in zebrafish revealed that a low EOM had a negative effect on zebrafish compared to both Anabaena sp. and Oscillatoria sp. at 30 ppm EOM exposures. This result might be due to Microcystins present in EOMs produced by Microcystis sp. As a result of power spectrum density anallysis, exposure to EOMs produced by Microcystis sp. caused a state of vigilance in zebrafish. This EEG based toxicity test can be used to examine effects of harmful materials at low levels on living organisms in an aquatic system.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.121-129
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• 2007

This study was conducted to evaluate the causes and effects of cyanobacterial development and succession in a shallow eutrophic reservoir from March 2003 to February 2004. Phytoplankton succession, sedimentation rate, and sediment composition were analyzed. Algal bioassay also was conducted with the consideration of light, water temperature and nutrients. Cyanobacteria dominated throughout the year, except for spring season (March${\sim}$April) in which diatoms and flagellates dominated. Total cell density increased in July and November when P loading through inflows was high. Oscillatoria spp. and Aphanizomenon sp. were dominant in May and June, respectively, but replaced with Microcystis spp. in July. Thereafter, Microcystis spp. sustained until December, and again shifted to Oscillatoria spp. and Aphanizomenon sp. The dominance of Oscillatoria spp. in May was accompanied with high TN/TP ratio and the increase of water temperature and light intensity. While the dominance of Microcystis spp. was related with relatively low TN/TP ratio, ranging from 46 to 13 (average: 27). The sedimentation rate was highest in March (0.6 m $day^{-1}$) when diatoms dominated. During the period of cyanobacterial dominance, relatively high sedimentation rate was observed in May (0.4 m $day^{-1}$) and October (0.36m $day^{-1}$). C/N ratio of the sediment ranged $6{\sim}8$. Inorganic P concentration in the pore water was low when DO concentration was < 2 mg $O_2$ $L^{-1}$ in the hypolimnion, reflecting the P release from the sediment. Cyanobacterial growth rate depended on phosphorus concentration and water temperature, and high P concentration compensated for the low temperature in the growth rate. Our results suggest that the potential of cyanobacterial development and substantiality in eutrophic reservoirs be high throughout the year, as being supplied with enough P, and emphasize the consideration of sediment man. agement for the water quality improvement and algal bloom control.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.166-172
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• 1992

The identification on blue-queen algae which were collected from paddy rice fields of the whole nation was carried out in 1991. The blue-green algae identified were 20 species in 5 families including 7 species in the Chroococcaceae. 1 species in the Chamaesiphonaceae. 1 species in the Pleurocapsaceae, 6 species in the Nostocaeae and 5 species in the Oscillatoriaceae. Among the blue-green algae, 6 species in 4 genera including Cylindrospernum, Anabaenopsis, Anabaena and Nostoc were characterized by heterocysts concerning with nitrogen fixation capacity. A concentrated population of Oscillatoria spp. induced soil flakes with blue tint in paddy rice fields. The genera. Spirulina and Oscillatoria, showed their specific motility.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.1-6
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• 1993

The experiments were conducted in order to find out the response of algae as affected by fertilizer and salinity, and to determine the chemical control method of algae in 1991. The higher the nitrogen fertilizer level, the more the occurrence of a blue-green alga Oscillatoria concerning with soil flakes. An increase in phosphorus fertilizer level stimulated the growth of green alga Hydrodictyon, whereas an increase in nitrogen level caused its abrupt reduction due to the harmful effect at high concentration of nitrogen, The high level of nitrogen fertilizer also reduced the growth of Euglena, although the detrimental effect was less compared with that of Hydrodictyon. A blue-green alga Oscillatoria, a green alga Cladophora and a diatom Navicula were tolerant to salinity. Piperophos/dimethametryn was highly effective in controlling various algae such as a green alga Hydrodictyon, suspended unicellular green algae and Euglena species. A fungicide propineb and copper sulfate also effectively controlled Hydrodictyon.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.399-403
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• 2002

This study was designed to analyse the odor from Nam river. The characteristic odor in the water occurred from geosmin and phenol, p-cresol and indol were detected from sediment/water samples. The others were detected as alcohols and fat acid compounds. Algae causing odor and taste were identified as Oscillatoria sp. and Synedra acus. 15 species of phytoplankton, a zooplankton, an eelworm and chironomus were identified in water/sediment sample.

• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.225-235
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• 2011

The change of microbial communities during cyanobacterial bloom was comparatively analyzed by 16S rDNA PCR-DGGE in Daechung Reservoir during 2003~2005. Morphological analysis showed that Cyanophyceae dominated algal community in the bloom. Dominant cyanobacteria were Microcystis, Planktothrix (Oscillatoria), Phormidium and Anabaena. We used 16S rDNA-denaturing gradient gel electrophoresis (DGGE) profiles and phylogenetic affiliations of the DGGE bands to analyze the community structure and diversity of the predominant microbial community. The DGGE band patterns demonstrated that the most frequent bands were identified as Microcystis during the monitoring periods, Planktothrix also dominated on September 2003 and 2004, whereas Anabaena was showed a peak on September 2005 and Aphanizomenon on August 2003. DGGE and phylogenetic analysis provided us new information that could not be obtained by traditional, morphological analysis. The relationship between cyanobacteria and other aquatic bacteria can be traced and their genetic diversity also identified in detail.

• Korean Journal of Environmental Biology
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• v.31 no.2
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• pp.105-112
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• 2013

Environmental parameters and phytoplankton community structure were investigated at four sites of Yeongsan River between April 2010 and December 2011. The standing crops of the phytoplankton ranged from $275cells{\cdot}mL^{-1}$ to $58,600cells{\cdot}mL^{-1}$ with an average of $5,850cells{\cdot}mL^{-1}$. The dominant species were Cyclotella sp., Stephanodiscus sp., Aulacoseira granulata, Scenedesmus quadricauda, Pediastrum biwae, Coelastrum sp., Aphnizomenon sp., and Oscillatoria sp.. The most dominant species was Stephanodiscus sp.. The concentration of chlorophyll-a ranged from $2.3mg{\cdot}m^{-3}$ to $164.2mg{\cdot}m^{-3}$. The phytoplankton community structure of the survey area was influenced by temperature and rainfall.

• Journal of Environmental Health Sciences
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• v.8 no.1
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• pp.1-11
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• 1982

A study on the water pollution of Gumho river by the relationship between physio-chemical conditions and water quality level by phytoplankton was examined at 7 sampling positions during the period from Aug. 1 to Nov. 30, 1981. Examination of physio-chemicat water analysis such as temperature, pH, DO, BOD, and biological analysis are as follows: 1. pH was in the range of 6.6-7.3. 2. At all positions DO was0.5-11.9 mg/l. But at Shinchun bridge and Gangchang was 0.5-3.9 mg/l. 3. BOD was in the range of 3.4-29.2 mg/l. Banyawol, Dongchon and Gumdan was shown good condition. But at Shinchun bridge was 21.1-29.2 mg/l. 4. The plankton identification in this study period showed, Cyanophyceae is 7 genera 13 species, Bacillariophyceae is 11 genera 32 species, and Chlorophceae is 17 genera 27 species: total 35 genera 72 species. 5. In the point of phytoplankton classification, upper stream of Banyawol, Dongchon and Gumdan which BOD was 3.4-8.7 mg/l, dominant phytoplanktons were Synedra ulna, Ulothrix sp., Oscillatoria sp. and Frusturia rhomboides. At Shinchun bridge which BOD was 21.1-29.2 mg/l, Microcystis aeruginosa, Closterium acerosum and Oscillatoria sp were found a small. At 3rd gongdan which BOD was 9.2-12.5 mg/l, dominant species were Synedra ulna, Hormidium sp and Actinastrum hantzschii. At Paldal which BOD was 7.8-9.2 mg/l, dominant species were Nitzschia palea, Synedra ulna and Scenedesmus bijuga. At Gangchang of down stream which BOD was 6.9-9.2 mg/l, dominant phytoplanktons were Closterium acerosum, Microcystis aeruginosa and Actnastrum hantzschii. 6. The results of biological water analysis by saprobic system were as follows: Banyawol was from oligosaprobic to $\beta$-mesosaprobic, Dongchon and Gumdan was from $\beta$-mesosaprobic to $\beta$-mesosaprobic, Shinchun bridge was polysaprobic, 3rd gongdan was from $\alpha$-mesosaprobic to $\beta$-polysaprobic, Paldal was $\beta$-polysaprobic and Gangchang was $\alpha$-polysaprobic.