• 한국농공학회논문집
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• 제58권2호
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• pp.53-63
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• 2016

Monitoring of cyanobacteria bloom in reservoir systems is important for water managers responsible of water supply system. Cyanobacteria affect the taste and smell of water and pose considerable filtration problems at water use places. Harmful cyanobacteria bloom in reservoir have significant economic impacts. We develop a new method for estimating the cyanobacteria bloom using Landsat TM and ETM+ data. Developed model was calibrated and cross-validated with existing in situ measurements from Daecheong Reservoir's Water Quality Monitoring Program and Algae Alarm System. Measurements data of three stations taken from 2004 to 2012 were matched with radiometrically converted reflectance data from the Landsat TM and ETM+ sensor. Stepwise multiple linear regression was used to select wavelengths in the Landsat TM and ETM+ bands 1, 2 and 4 that were most significant for predicting cyanobacteria cell number and bio-volume. Based on statistical analysis, the linear models were that included visible band ratios slightly outperformed single band models. The final monitoring models captured the extents of cyanobacteria blooms throughout the 2004-2012 study period. The results serve as an added broad area monitoring tool for water resource managers and present new insight into the initiation and propagation of cyanobacteria blooms in Daecheong reservoir.

• ALGAE
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• 제21권1호
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• pp.125-131
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• 2006

Long-term preservation of bloom-forming cyanobacteria was evaluated using cryopreservation and freeze-drying of nine strains belonging to four genera and seven species. All test strains, except Aphanizomenon flos-aquae NIER- 10028, showed partial or complete survival following cryopreservation and freeze-drying. Frozen and freeze-dried strains were preserved for more than two years and were revived monthly. Most strains showed higher post-thaw viability after cryopreservation, especially without cryoprotectant compared to freeze-drying. Microcystis aeruginosa NIER-10010, M. viridis NIER-10020, M. ichthyoblabe NIER-10023, M. novacekii NIER-10029 and Oscillatoria sancta NIER-10027 were revived after 2.5 years of cryopreservation. These results suggest that cryopreservation may be an easy and timesaving long-term preservation method for bloom-forming cyanobacteria.

• Journal of Microbiology
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• 제45권2호
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• pp.98-104
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• 2007

Chlorophyll ${\alpha}$ concentration and cyanobacterial cell density are regularly employed as dual criteria for determinations of the alert level for cyanobacterial bloom. However, chlorophyll ${\alpha}$ is not confined only to the cyanobacteria, but is found universally in eukaryotic algae. Furthermore, the determination of cyanobacterial cell counts is notoriously difficult, and is unduly dependent on individual variation and trained skill. A cyanobacteria-specific parameter other than the cell count or chlorophyll ${\alpha}$ concentration is, accordingly, required in order to improve the present cyanobacterial bloom alert system. Phycocyanin has been shown to exhibit a strong correlation with a variety of bloom-related factors. This may allow for the current alert system criteria to be replaced by a three-stage alert system based on phycocyanin concentrations of 0.1, 30, and $700\;{\mu}g/L$. This would also be advantageous in that it would become far more simple to conduct measurements without the need for expensive equipment, thereby enabling the monitoring of entire lakes more precisely and frequently. Thus, an alert system with superior predictive ability based on highthroughput phycocyanin measurements appears feasible.

• 환경생물
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• 제23권3호
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• pp.304-314
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• 2005

대청호 남조세균 수화 기작에 대한 이해를 돕고자, 1997년부터 2002년까지 (2000년 제외)의 조사 자료를 바탕으로 남조세균 군집 특성을 해석하고 수화 발달 단계를 3단계로 구분하여 환경요인과의 관련성을 파악하였다. 남조세균 수화의 시작은 6월 하순부터 시작하며, 강과 호소의 중간 성향을 가진 정점 1부터 발생하였다. 대청호의 수화 발생 기간은 댐축 앞 지점인 정점 4를 기준으로 하는 경우, 약 $60\~70$일이었으나, 1999년의 경우는 7월 19일부터 11일로 이례적인 현상이었다. Microcystis aeruginosa은 6월에 출현하기 시작하여 1998년과 2002년은 8월 말에서 9월 초, 1999년과 2001년은 7월 말에 절정을 이루었다. M. aeruginosa의 현존량이 처음 증가하는 시기는 1998년은 6월 22일, 1999년은 6월 28일,2001년은 7월 4일 그리고 2002년은 6월 25일로 모두 표층 수온이 $25^{\circ}C$를 넘는 시기였다. M. aeruginosa의 구성비는 식물플랑크톤 현존량에 대해서는 $68.1\%,$ 남조세균에 대해서는 $74.2\%$, Microcystis속에 대해서는 $88.8\%$이었다. M. aeruginosa의 연도별 남조세균 대비 구성비는 1998년 $30.3\%,$ 1999년 $34.\6%,$ 2001년 $94.4\%,$ 2002년 $42.9\%$이었다. 1998년 Anabaenu spp.는 4월부터 출현하기 시작하여 8월 하순부터 9월 중순까지 정점에 따라 $1.0{\times}10^4\;cells\;mL^{-1}$ 이상으로 분석되었다. Anabaena속은 준비기에 남조세균 수화 추이에 한 축을 담당하고 있었다. 소멸기에서는 Anabaena spp., Oscillatorin spp., Aphanizomenon flos-aquae가 M. aeruginosa의 소멸을 대신하여 현존량이 증가하는 것으로 나타났다. 남조세균 수화에 미치는 강우의 영향은 시기별로 달라, 준비기의 강우는 남조세균 성장을 돕고, 소멸기의 강우는 남조세균의 소멸을 가속화하는 것으로 해석되었다. 수화기에는 강우의 양이 많을 경우에는 수화 발달을 저해하였으나, 적을 경우에는 그 영향력이 낮았다.

• 한국환경복원기술학회지
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• 제7권5호
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• pp.75-84
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• 2004

Loess, PAC, MACF and plants were applied to the control of the phytoplankton bloom in laboratory and in field, In field experiment using oil fence, 5ppm concentration of coagulant(PAC) was observed to be effective in controlling the cyanobacterial bloom, resulting in 90% removal of cyanobacteria and phytoplankton from the water column, hi case of Synedra sp., however, only 50% of biomass decreased with the same PAC concentration. MACF(micro-air bubble coagulation and floating), a kind of physicochemical method, was applied to the column of the Kyongan stream and resulted in over 80% chlorophyll a and 73.5% TP removal, Chlorophyll a and total phosphorus were effectively removed from water body when 2.0 g/L of loess with the particle radius of 125 ${\mu}m$ was inputted. In case of experiments involving plants, big cone pine, gingko, and pine needle were observed to be effective in restraining phytoplankton bloom at 0.5g/200ml level. During a field test done at Kyungan stream, where Microcystis heavily occurred, Pine needle and big cone pine were observed to be effective on suppressing algal growth.

• 대한환경공학회지
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• 제36권5호
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• pp.378-385
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• 2014

한강유역 조류경보제의 클로로필-a 농도는 남조류의 우점을 예측할 수 없어 본 연구에서는 남조류 개체수에 영향을 미치는 환경인자를 분석하여 남조류 우점 예측인자를 제시하였다. 2012년 1월~2013년 9월까지 하천의 계절변화에 따른 조류의 우점종을 분석한 결과, 저수온기인 1~4월에는 규조류, 5~6월에는 녹조류, 7~8월에는 남조류가 우점하는 것으로 나타났다. 또한, 남조류 개체수 증감에 영향을 미치는 영양염류(TN, TP), 기온, 강수량, 댐 방류량과의 상관성을 분석한 결과, 기온보다는 낮은 댐 방류량으로 댐 내의 체류시간이 길어져 남조류 개체수가 급속히 증가한 것으로 나타났다. 마지막으로 남조류 개체수와 TN:TP 농도 비를 분석한 결과 TN:TP 농도 비가 29 이하로 낮아질 때 남조류가 우점하는 것으로 분석되어 한강유역 조류경보제에 남조류 우점 예측인자인 TN:TP 농도 비를 도입할 필요가 있다.

• 생태와환경
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• 제36권4호통권105호
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• pp.413-419
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• 2003

1999년과 2001턴, 여름부터 가을까지 대청호의 남조류 수화현상에 대한 강우영향을 조사하였다. 두 해의 6,7월 강수량은 매우 유사하였으나, 수화발생 시기인 8,9월의 강수량은 현저한 차이를 보였다. 1999년에는 8월 하순 이후 그전 2개월에 비해 약 70%의 강수량 증가가 있었으나, 2001년에는 같은 기간 동안 5분의 1수준으로 감소하였다. 더 높은 엽록소-a, 파이코시아닌, 남조류 농도가 2001년 측정되었으며, 이것은 극심한 수화의 발생으로 이어졌다. 또한 2001년에는 조사기간동안 남조류의 비율이 항상 80%를 상회하였으며, 남조류는 Microcystis spp.가 대부분을 차지하였다. 이와는 반대로 1999년에는 수화의 발생이 보고되지 않았다. 이러한 차이에도 불구하고 수화가 절정을 이루는 시기는 두 해 모두 8월 하순에서 9월 초순으로, 강수량에 관계없이 일정하였다. 수화 이전 시기의 적당한 강수와 이후의 충분한 일조 시기가 남조류의 수화 형성에 영향을 끼치는 중요인자들 중의 하나로 판단되었다.

• 한국물환경학회지
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• 제32권1호
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• pp.52-59
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• 2016

This study investigated the occurrences and succession patterns of harmful cyanobacteria, as well as environmental factors, during a 3-year period (September 2012 to August 2015) in the upper region of the Nakdong River around Sangju weir. A total of 27 cyanobacterial taxa were observed in this study, and classified into 26 species and 1 variety belonging to 11 genera, 5 families, and 3 orders. Cell density ranged from 24 to 42,001 cells/ml, with a geometric mean of 33 cells/ml, during the survey period. The dominant orders differed depending on the survey year; order Oscillatoriales in 2013, Chroococcales in 2014 and Nostocales in 2015. An Aphanizomenon bloom occurred in June 2015 at which time the highest cell density of 36,873 cells/ml was detected in the upper region of the Nakdong River, where as the Aphanizomenon spp. cell density (190-1,704 cells/ml) had been low prior to that time. An Aphanizomenon bloom also occurred at around the same time downstream in the Young River, a major inflow branch of the Nakdong River. The Aphanizomenon cell density along the Nakdong River increased markedly after joining of the YoungRiver, indicating that the Aphanizomenon bloom in the YoungRiver caused a bloom in the Nakdong River. Meteorological and environmental parameters, such as very low precipitation, higher water temperature, pH, and TP concentration, and lower TN/TP ratio, in May and June of 2015 than in 2013 and 2014 exerted marked effects on the Aphanizomenon bloom in June 2015 in the Young River.

• 한국물환경학회지
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• 제35권3호
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• pp.257-270
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• 2019

Followingthe Four Rivers Project, cyanobacterial blooms have been frequently observed in the upstream of the installed weirs. The aim of this study was to characterize the major environmental factors that are associated with the cyanobacteria dominance in Baekje Weir (Geum River) and Juksan Weir (Youngsan River) based on intensive experiments and systematic data mining methods. The factors related to the cyanobacteria dominance include7-days cumulative rainfall (APRCP7), 7-days averaged flow (Q7day), water temperature (Temp), stratification strength (${\Delta}T$), electronic conductivity (EC), DO, pH, $NO_3-N$, $NH_3-N$, TN, TP, $PO_4-P$, Chl-a, Fe, BOD, COD, TOC, and $SiO_2$. The most highly correlatedfactors to the dominant cyanobacteria were found to be EC, Temp, Q7day, $PO_4-P$ in theBaekje Weir. On the other hand, those dominant in the Juksan Weir were ${\Delta}T$, TOC, Temp, EC and TN. The EC showed a strong correlation with cyanobacteria dominance in both weirs because a high EC represents a persisted low flow condition. The cyanobacteria dominance was as high as 56 % when the EC was equal or greater than $418{\mu}S/cm$ in Baekje Weir. It was as high as 63% when the ${\Delta}T{\geq}2.1^{\circ}C$ in the Juksan Weir. However, nutrients showed a minor correlation with cyanobacteria dominance in both weirs. The results suggest that the cyanobacteria dominate in astate where the water flow rate is low, water temperature is high and thermal stratification is strengthened. Therefore, the improvement of flow regimes is the most important to prevent persistent thermal stratification and formation of cyanobacteria bloom in theBaekje and JuksanWeirs.

• 환경영향평가
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• 제20권6호
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• pp.915-925
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• 2011

Following the industrialization and urbanization in Korea, algal bloom causes aesthetic displeasure and many other problems such as taste and odor, coloration, scum, increase in pH, filter-bed blockage. There were some cases involving human death by microcystins during summertime in foreign countries. In Korea, Harmful cyanobacteria such as Microcystis and Anabaena develop in summer in the Daecheong reservoir, one of the main water resources, with the retention time of above 200 days. To better control algal bloom, the Ministry of Environment has been running algal bloom alert system from 1998 for the Daecheong reservoir, which needs to be improved to reflect the characteristics of river-type lakes. For this reason, we try to find new measures to improve an algal bloom alert system for each water zone considering the characteristics of harmful cyanobacteria in this study.