A combination cyanobacterial treatment approach using hydrogen peroxide and L-lysine successfully improved the removal efficiency of toxic cyanobacteria.

Autor: Dahedl EK; Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, FL, 33965, USA., Hancock TL; Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, FL, 33965, USA; School of Geosciences, University of South Florida, Tampa, FL, 33620, USA., Kratz MA; Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, FL, 33965, USA., Urakawa H; Department of Ecology and Environmental Studies, Florida Gulf Coast University, Fort Myers, FL, 33965, USA; School of Geosciences, University of South Florida, Tampa, FL, 33620, USA. Electronic address: hurakawa@fgcu.edu.
Jazyk: angličtina
Zdroj: Journal of environmental management [J Environ Manage] 2024 Dec 12; Vol. 373, pp. 123503. Date of Electronic Publication: 2024 Dec 12.
DOI: 10.1016/j.jenvman.2024.123503
Abstrakt: Harmful cyanobacterial blooms have been increasing globally, introducing new challenges for protecting aquatic ecosystems and human health. A combined algaecide treatment, similar to combination antibiotic therapy, may more rapidly and effectively remove cyanobacteria by broad targeting of different growth mechanisms, reducing the recovery of bloom-forming cyanobacteria. To confirm this hypothesis, hydrogen peroxide (10.5 mg/L), L-lysine (8.2 mg/L), and mixed treatment (hydrogen peroxide: 8.4 mg/L; L-lysine: 6.7 mg/L) of both chemicals were examined for cyanobacterial removal in a 7-day mesocosm study. We found that both hydrogen peroxide and L-lysine effectively reduced cyanobacterial abundance to less than 1% at the end of the experiment. Mixed mesocosm phytoplankton communities responded similarly to hydrogen peroxide treatment throughout the sampling period. Microcystis abundance sharply dropped within 24 h (94% reduction) and Microcystis was no longer detected by day 7. Of the three treatments, the mixed treatment had the greatest impact on Microcystis abundance and gene expression. In lysine mesocosms, cyanobacteria were replaced by Chlorophyta, whereas the hydrogen peroxide and mixed treatments led to a shift toward the eustigmatophyte Nannochloropsis. Transcriptomics revealed that heterotrophic bacteria such as Exiguobacterium, which was resilient to hydrogen peroxide and mixed treatments, benefited from increased catalase expression, which helped mitigate oxidative stress and allowed them to dominate in bacterial succession. Lysine toxicity on microbial communities and taxa sensitivity likely stemmed from amino acid homeostasis disruptions as well as abnormal lysine riboswitch and degradation activity. Overall, a combination cyanobacterial treatment approach using hydrogen peroxide and L-lysine successfully improved the removal efficiency of toxic cyanobacteria.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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