TY - JOUR
T1 - Immediate and long-term impacts of UV-C irradiation on photosynthetic capacity, survival and microcystin-LR release risk of Microcystis aeruginosa
AU - Ou, Huase
AU - Gao, Naiyun
AU - Deng, Yang
AU - Qiao, Junlian
AU - Wang, Hao
PY - 2012/3/15
Y1 - 2012/3/15
N2 - In this study, the immediate and long-term impacts of shortwave ultraviolet (UV-C) irradiation on photosynthetic capacity, survival, and recovery of Microcystis aeruginosa were investigated. The risk of microcystin-LR (MC-LR) release during irradiation was also estimated. The cell density was determined by a flow cytometry, and typical chlorophyll fluorescence parameters, including the effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse amplitude modulated (PAM) fluorometer. Under various UV-C dosages (140-4200mJ cm-2), photosynthetic capacities were reduced, to different degrees, accompanied by slight cytoclasis and complete degradation of extracellular MC-LR immediately after irradiation. In a 6-d cultivation following UV-C irradiation, cell density and extracellular MC-LR in the samples treated by 140mJcm-2 UV-C irradiation increased from 4.0×106cellsmL-1 and 8μgL-1 to 5.1×106cellsmL-1 and 20μgL-1, respectively. Significant M. aeruginosa cytoclasis (cell density from 4.0×106 to 1.0×106cellsmL-1) and MC-LR release (2-25μgL-1) occurred when the UV-C dosage reached 350mJcm-2. Cell cytoclasis and MC-LR release were enhanced in the cultivated samples under higher UV-C dosages. Results revealed that photosynthetic parameters were useful tools to predict the recovery profiles of M. aeruginosa cells, and the MC-LR release risk should be considered after UV-C inactivation.
AB - In this study, the immediate and long-term impacts of shortwave ultraviolet (UV-C) irradiation on photosynthetic capacity, survival, and recovery of Microcystis aeruginosa were investigated. The risk of microcystin-LR (MC-LR) release during irradiation was also estimated. The cell density was determined by a flow cytometry, and typical chlorophyll fluorescence parameters, including the effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse amplitude modulated (PAM) fluorometer. Under various UV-C dosages (140-4200mJ cm-2), photosynthetic capacities were reduced, to different degrees, accompanied by slight cytoclasis and complete degradation of extracellular MC-LR immediately after irradiation. In a 6-d cultivation following UV-C irradiation, cell density and extracellular MC-LR in the samples treated by 140mJcm-2 UV-C irradiation increased from 4.0×106cellsmL-1 and 8μgL-1 to 5.1×106cellsmL-1 and 20μgL-1, respectively. Significant M. aeruginosa cytoclasis (cell density from 4.0×106 to 1.0×106cellsmL-1) and MC-LR release (2-25μgL-1) occurred when the UV-C dosage reached 350mJcm-2. Cell cytoclasis and MC-LR release were enhanced in the cultivated samples under higher UV-C dosages. Results revealed that photosynthetic parameters were useful tools to predict the recovery profiles of M. aeruginosa cells, and the MC-LR release risk should be considered after UV-C inactivation.
KW - Cyanobacteria
KW - Microcystin-LR
KW - Microcystis aeruginosa
KW - Photosynthesis
KW - UV-C
KW - Ultraviolet irradiation
UR - http://www.scopus.com/inward/record.url?scp=84856083052&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2011.12.025
DO - 10.1016/j.watres.2011.12.025
M3 - Article
C2 - 22209277
AN - SCOPUS:84856083052
SN - 0043-1354
VL - 46
SP - 1241
EP - 1250
JO - Water Research
JF - Water Research
IS - 4
ER -