Water Environ Res. 2026 Apr;98(4):e70386. doi: 10.1002/wer.70386.
ABSTRACT
BACKGROUND: Harmful algal blooms (HABs) pose a significant threat to aquatic ecosystems worldwide, with freshwater environments being particularly vulnerable. Among the primary contributors to these blooms is Microcystis aeruginosa, a cyanobacterium known for producing toxins that are harmful to both human health and aquatic life. Given its toxic nature and ecological impact, understanding the factors that influence its growth is crucial. Since M. aeruginosa naturally inhabits sunlit surface waters, it is especially vulnerable to ultraviolet (UV) radiation stress, making this an ecologically and practically relevant area of study. Investigating the effects of UV radiation on M. aeruginosa growth can provide valuable insights into bloom dynamics, ecological consequences, and potential strategies for bloom management and control.
OBJECTIVES: This study aims to examine the effects of UV radiation on the growth dynamics of both toxic and nontoxic strains of M. aeruginosa, specifically PCC 7806 and PCC 7005.
METHODS: M. aeruginosa cultures PCC 7806 and PCC 7005 were exposed to varying levels of UV radiation (80, 60, and 20 mW/cm2). Key parameters such as growth rates, cell concentrations, and the relative UV effects were monitored. Cell counts were determined microscopically and subsequently used to calculate the growth rate.
RESULTS: UV radiation was found to exert a significant influence on the proliferation of both strains of M. aeruginosa, inducing discernible alterations in growth patterns and physiological mechanisms as compared to the control group. A one-way analysis of variance (ANOVA) indicated a significant effect of treatment intensity, with an F statistic of 13.71, p < 0.0001, and an R2 value of 0.5950. Pairwise comparisons revealed that the mean difference for the 80 mW/cm2 treatment was -4.458 (95% CI: -8.937 to -0.02000, p = 0.0514). Overall, the findings indicate that UV treatment intensity significantly influences growth, with the most pronounced effects observed at 80 mW/cm2.
CONCLUSIONS: Our data suggest that the growth of both M. aeruginosa strains, PCC 7806 and PCC 7005, is reduced under high UV radiation during algal blooms. A reduction in dense Microcystis blooms as a result of increased UV exposure could enhance light penetration in water bodies. These findings provide valuable insights for water resource management teams, enabling them to develop strategies to mitigate the public health risks associated with HABs.
PMID:41988826 | DOI:10.1002/wer.70386
