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

Hydrogen peroxide (H(2)O(2)) 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 H(2)O(2) on cyanobacteria and non-target members of the microbial community. H(2)O(2) 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 H(2)O(2) 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 H(2)O(2), with Actinobacteria being the most sensitive. The ability of H(2)O(2) 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.