title: Dynamic variation of toxic and non-toxic Microcystis proportion in the eutrophic Daechung Reservoir in Korea.
abstract: This study was conducted to determine the environmental factors affecting the level of potentially toxic Microcystis. The long-term tendencies of temperature, precipitation, and water quality factors were analyzed to determine the environmental characteristics of the Daechung Reservoir in Korea, and water samples were directly collected to analyze the dynamics of toxic and non-toxic Microcystis at weekly intervals from May to October 2012. Microcystis was the dominant genus during the study period, and it was composed of potentially toxic and non-toxic Microcystis. The fraction of potentially toxic Microcystis ranged from 6.0% to 61.1%. The amount of toxic Microcystis was highly related to the intracellular microcystin concentration (r = 0.760, P < 0.01). Therefore, the fraction of potentially toxic Microcystis is an important concern in Microcystis blooming because the intracellular microcystin concentration may reflect microcystin levels in the water. The prevalence of potentially toxic Microcystis was highly related to water temperature in Daechung Reservoir (r = 0.585, P < 0.01). Thus, temperature increase during Microcystis blooming may lead to more frequent toxic Microcystis blooms in eutrophic water bodies.
authors.affiliation: Dongjin Engineering Co., LTD., Daegu, 740978, Republic of Korea. ezpops@naver.com.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Joung
authors.affiliation: Biochemical and Bioenergy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea.
authors.forename: Hee-Mock
authors.initials: HM
authors.lastname: Oh
authors.affiliation: Water Environment Research Department, National Institute of Environment Research, Incheon, 22689, Republic of Korea.
authors.forename: Kyung-A
authors.initials: KA
authors.lastname: You
mesh_terms: D044822:Biodiversity; D060106:Lakes / Q000032:analysis / Q000382:microbiology*; D052998:Microcystins / Q000378:metabolism / Q000633:toxicity; D046931:Microcystis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D010802:Phylogeny; D056910:Republic of Korea; D012621:Seasons; D013696:Temperature; D060753:Water Quality
chemical_list: D052998:Microcystins; C078588:microcystin
keywords: Daechung Reservoir; blooming; intracellular microcystin; potentially toxic Microcystis; temperature