• Membrane and Water Treatment
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• v.14 no.2
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• pp.77-83
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• 2023

As a result of algal bloom, algal organic matters (AOMs) are rapidly increased in surface water. AOMs can act as precursors for the formation of harmful disinfection by-products (DBPs), which are serious problems in water treatment and human health. The main aim of this study is to characterize the formation of DBPs from AOMs produced by three different algae such as Oscillatoria sp., Anabaena sp., and Microcystis aeruginosa under different algal growth phases. In an effort to examine formation of DBPs during chlorination, chloroform (TCM), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were determined under various CT (product of disinfectant concentration and contact time, mg·min/L) values. Generally, the amounts of DBPs tended to increase with increasing CT values at the most growth phases. However, there was a significant difference between the amounts of DBPs produced by the three algal species at different growth phases. This result is likely due to the chemical composition variability of AOM from different algae at different growth phases. In addition, the effect of pre-ozonation on coagulation for the removal of AOMs from three algal species was investigated. The pre-ozonation had a positive effect on the coagulation/flocculation of AOMs.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.28-34
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• 2019

This study analyzed the occurrence pattern of Dolichospermum (= Anabaena) in the Bukhan river from March 2012 to December 2014 in order to identify the genotypes of Dolichospermum. Furthermore, 16S rRNA were analyzed to identify the genotypes of Dolichospermum that occurred in 2015 which were then compared to the reference sequence deposited at NCBI. During this period, the occurrence of Dolichospermum was highly correlated to water temperature. In the year 2012 and 2013, Dolichospermum appeared in Lake Cheongpyeong (CP), Sambong (SB), and Lake Paldang (P2) between July and August. However, in 2014, it appeared in SB and P2, but not in CP. This reduction in appearance was attributed to the decreased inflow to Lake Uiam as a result of low rainfall in 2014 as compared to 2012. In July 2015, the Dolichospermum 16S rRNA genotype was confirmed in five locations; Lake Cheongpyeong (CP), Seojong (SJ), Songchon Sewage Treatment Plant (SC), Joan (P4), and Lake Paldang (PD). Anabaena crassa of spiral clone, A. planctonica of linear clone, and A. circinalis of spiral clone exhibited high genetic similarity with the reference sequence. The 16r RNA genotype showed approximately 3 % sequence variation between the locations and were more similar to each other in locations that were closer.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.121-127
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• 2001

Seven cyanobacteria strains (Anabaena macrospora NIERl0016, Oscillatoria sp. NIER10042, Microcystis aeruginosa NIER10015, M. ichtyoblabe BIER10025, BIER10040, M. novacekii NIER10029, M. wesenbergii NIER10068) were tested with four rRNA - targeted oligonucleotide probes labelled with horseradish peroxidase (HRP) and specific for cyanobacteria. Non- fluorescent detection of hybridization signal was used. The hybridization with artificial mixture of cyanobacteria have shown the possibility to use 2 species-specific probes in duplicate hybridization and detection with different colored substrates.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.54-65
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• 2008

The seasonal dynamics of phytoplankton and water quality were evaluated bimonthly at 7 park ponds in the capital region from October 2004 to August 2005. With out the change of water temperature $(0.4\sim26.0^{\circ}C)$, cyanobacteria dominated in park ponds such as Gyungbokgung Gyunghyaeru and Seokchon reservoir. The standing crops of phytoplankton was significant related with cell densities of cyanobacteria (r=0.993), while they did not significant correlation with environmental factors. Almost of all park ponds in the capital region were classified as eutrophic state with high TP concentrations and TN/TP ratios less than 10. Major dominant cyanobacteria were as followed; Anabaena sp., Aphanocapsa elachista, Lyngbya contorta, Merismopedia elegans, Microcystis aeruginosa, M. wesenbergii, Microcystis sp., Oscillatoria sp., Phormidium tenue, and Plectonema sp. To date, although the concentration of chlorophyll-${\alpha}$ and cyanobacterial densities in the capital region was below the 'danger' level of WHO guidelines value, the monitoring of cyanobacterial densities and its toxin (microcystin) in recreational/bath water should be continued.

• Journal of Conservation Science
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• v.27 no.2
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• pp.145-154
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• 2011

This research was to examine the biological pollution class by color of the polluted section and calculate the biological pollution coverages of 9 stone heritages in Korea, from June to November 2008. Three storied stone pagoda in Mulgeol-ri, Hongcheon, Three storied stone pagoda in Suta Temple and Stupa to Hongudang in Sutasa Temple showed 90% biological pollution coverage and each stone cultural heritages showed 15~23% range of Bryophyte coverage, proving severe biological pollution. The Four-lion three storied stone pagoda of Gwaeseok-ri, Three storied stone pagoda in Suta Temple and Stupa to Hongudang in Sutasa Temple showed the worst biological pollution class by color of class 5. Three storied stone pagoda in Chang-ri showed satisfactory level of class 2. The result of the correlation analysis between biological pollution class and the biological pollution coverage of lichen showed high correlation coefficient of 0.91, however, the correlation analysis between biological pollution class and bryophyte or aerial algae coverage showed the low correlation coefficient. Eight taxa among all the aerial algae, Cosmarium decedens, Chlorella ellipsoidea, Anabaena fertilissima, Botryococcus braunii, Chroococcus turgidus, Navicula cryptocephala and Xenococcus acervatus showed high correlation coefficient of 0.56~0.85 with biological pollution coverage of bryophyte, in the correlation analysis. The correlation coefficient between biological pollution coverage of lichen, Trebouxia sp. and Chroococcus varius, had a range between 0.43 to 0.50. The correlation coefficient between biological pollution coverage of aerial algae, Achnanthes laterostrata and Ulothrix zonata showed a range of 0.57 to 0.76. Since the aerial algae with high correlation between biological pollution coverage showed clear appearance tendency, they can be used as indicator.

• 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.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.286-294
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• 2015

Temporal and spatial characteristics of cyanobacterial communities at the monitoring stations for Harmful Algal Bloom Alert System (HABAS) in Nakdong River and Lake Dukdong were investigated for two years (2013 to 2014). A total of 30 cyanobacterial species from 14 genera were found at the survey stations. Microcystis sp. showed maximum cell density in the total cyanobacterial community in August, 2014 at ND-2 and in September, 2013 at ND-3 station. Lynbya limnetica and Geitlerinema sp., non-target species for alert criteria showed maximum cell density at ND-1 (August, 2013) and Dam station of Lake Dukdong (September, 2014), respectively. Total cyanobacterial cell density and the relative abundance of four target genera (Microcystis, Anabaena, Aphanizomenon and Oscillatoria spp.) for alert criteria was relatively lower in the mesotrophic Lake Dukdong than at the eutrophic riverine stations of Nakdong River, indicating cyanobacterial density and the RA of target genera is affected by the trophic state of the monitoring stations. Simulating the alert system using phycocyanin concentration as an alert criterion resulted in the longer period of alert issued compared to the period of alert issued using the current criterion of harmful cyanobacterial cell density due to the influence of phycocyanin concentration from non-target cyanobacterial species.

• 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.

• Membrane and Water Treatment
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• v.9 no.6
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• pp.447-454
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• 2018

Although flotation techniques are often used for the removal of algal particles, the practicality of algae-harvesting technologies is limited owing to the complex and expensive facilities and equipment required for chemical coagulation. Here, we examined the feasibility of an approach to separating algal particles from water bodies without the need for chemical coagulants, depending on the condition of the algae, and to determine the optimal conditions. Using Anabaena sp., a cyanobacterium causes algal blooms in lakes, we stimulated auto-flocculation in algal particles without coagulants and conducted solid-liquid separation experiments of algal particles under various conditions. The six cultivation columns included in our analysis comprised four factors: Water temperature, light intensity, nutrients, and carbon source; auto-flocculation was induced under all treatments, with the exception of the treatment involving no limits to all factors, and algal particles were well-settled under all conditions for which auto-flocculation occurred. Meanwhile, flotation removal of auto-flocculated algal particles was attained only when nutrients were blocked after algae were grown in an optimal medium. However, no significant differences were detected between the functional groups of the extracellular polymeric substances (EPSs) of floated and settled algal particles in the FT-IR peak, which can cause attachment by collision with micro-bubbles.

• ALGAE
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• v.24 no.2
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• pp.85-91
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• 2009

The filamentous cyanobacterium Anabaena sp. Strain PCC 7120 produces a developmental patten of single hete- rocysts separated by approximately 10 vegetative cells. Heterocysts differentiate from vegetative cells and are spe- cialized for nitrogen fixation. The patS gene, which encodes a small peptide that inhibits heterocyst differentiation, is expressed in proheterocysts and plays a critical role in establishing the heterocyst pattem. Another key regulator of heterocyst development is the hetR gene. hetR mutants fail to produce heterocysts and extra copies of hetR on a plas- mid cause a multiple contiguous heterocyst phenotype. To elucidate the relationship between these two counter act- ing factors in the genetic regulatory pathway during heterocyst differentiation, the expression patterns of a patS-gfp and a hetR-gfp fusion were examined in a patS deletion and a hetR deletion strain. The results, in combination with the result from a hetR and patS double deletion strain, suggest patS and hetR are mutually antagonistic and the bal- ance between these two factors in tow different cell types (heterocysts and vegetative cells) may be critical during the decision making process on their cell fates.