The Efficacy of Hydrogen Peroxide in Mitigating Cyanobacterial Blooms and Altering Microbial Communities across Four Lakes in NY, USA

Abstract

<jats:p>Hydrogen peroxide (H2O2) has been proposed as an agent to mitigate toxic cyanobacterial blooms due to the heightened sensitivity of cyanobacteria to reactive oxygen species relative to eukaryotic organisms. Here, experiments were conducted using water from four diverse, eutrophic lake ecosystems to study the effects of H2O2 on cyanobacteria and non-target members of the microbial community. H2O2 was administered at 4 µg L−1 and a combination of fluorometry, microscopy, flow cytometry, and high throughput DNA sequencing were used to quantify the effects on eukaryotic and prokaryotic plankton communities. The addition of H2O2 resulted in a significant reduction in cyanobacteria levels in nearly all experiments (10 of 11), reducing their relative abundance from, on average, 85% to 29% of the total phytoplankton community with Planktothrix being highly sensitive, Microcystis being moderately sensitive, and Cylindrospermopsis being most resistant. Concurrently, eukaryotic algal levels increased in 75% of experiments. The bacterial phyla Actinobacteria, cyanobacteria, Planctomycetes, and Verrucomicrobia were most negatively impacted by H2O2, with Actinobacteria being the most sensitive. The ability of H2O2 to reduce, but not fully eliminate, cyanobacteria from the eutrophic water bodies studied here suggests it may not be an ideal mitigation approach in high biomass ecosystems.</jats:p>

Diversity Assessment of Toxic Cyanobacterial Blooms during Oxidation

“…Removal of Microcystis using H 2 O 2 was shown by Lusty and Gobler. (2020) and is in accordance with our observations of diverging correlation between Chao1 and Microcystis [ 37 ].…”

“…Cell count based studies show progressive shifts following oxidation [ 12 , 14 ]. Moreover, selective cyanobacteria oxidation has been demonstrated in the lab [ 11 , 60 ], in the field [ 37 , 61 ], and in drinking water treatment plants [ 8 , 62 ].…”

“…The relative abundance of Microcystis aeruginosa is not impacted by chlorine but increases with KMnO 4 and H 2 O 2 exposure, confirming selective removal of Microcystis showed by Lusty and Gobler. (2020) [ 37 ].…”

“…Our results are in accordance with Lusty and Gobler. (2020) [ 37 ]. Figure S12 unveils higher susceptibility of Dolichospermum species to high H 2 O 2 exposure as compared to Microcystis aeruginosa .…”

“…Lusty and Gobler (2020) used 16S rRNA to evaluate the mitigation of cyanobacterial blooms using H 2 O 2 . Results showed relative persistence of Cyanobium and Cylindrospermopsis to a moderate H 2 O 2 dose (4 mg/L); Plankthotrix and Microcystis (abundant genus) were the most sensitive genera, respectively [ 37 ].…”