Resilience of Microbial Communities after Hydrogen Peroxide Treatment of a Eutrophic Lake to Suppress Harmful Cyanobacterial Blooms

Abstract

Applying low concentrations of hydrogen peroxide (H2O2) to lakes is an emerging method to mitigate harmful cyanobacterial blooms. While cyanobacteria are very sensitive to H2O2, little is known about the impacts of these H2O2 treatments on other members of the microbial community. In this study, we investigated changes in microbial community composition during two lake treatments with low H2O2 concentrations (target: 2.5 mg L−1) and in two series of controlled lake incubations. The results show that the H2O2 treatments effectively suppressed the dominant cyanobacteria Aphanizomenon klebahnii, Dolichospermum sp. and, to a lesser extent, Planktothrix agardhii. Microbial community analysis revealed that several Proteobacteria (e.g., Alteromonadales, Pseudomonadales, Rhodobacterales) profited from the treatments, whereas some bacterial taxa declined (e.g., Verrucomicrobia). In particular, the taxa known to be resistant to oxidative stress (e.g., Rheinheimera) strongly increased in relative abundance during the first 24 h after H2O2 addition, but subsequently declined again. Alpha and beta diversity showed a temporary decline but recovered within a few days, demonstrating resilience of the microbial community. The predicted functionality of the microbial community revealed a temporary increase of anti-ROS defenses and glycoside hydrolases but otherwise remained stable throughout the treatments. We conclude that the use of low concentrations of H2O2 to suppress cyanobacterial blooms provides a short-term pulse disturbance but is not detrimental to lake microbial communities and their ecosystem functioning.

Phytoplankton responses to repeated pulse perturbations imposed on a trend of increasing eutrophication

“…Concentrations between 0.5 and 5 mg/L are reported to be somewhat selective, affecting cyanobacteria preferentially (Drábková et al, 2007 ). However, concentrations over this threshold are expected to induce mortality to most biological groups evenly (see Matthijs et al, 2012 ; Piel et al, 2021 ). Here, we spiked the content of the water vessels with 10 mg/L H 2 O 2 (Hydrogen peroxide 30%, EMSURE ® , Supelco ® , Merck, Darmstadt, Germany, Figure 2 c iii ) overnight under similar conditions as in the carboys (light and temperature), except for the constant aeration used to keep particles in suspension (Figure 1 b).…”

Can Alkyl Quaternary Ammonium Cations Substitute H2O2 in Controlling Cyanobacterial Blooms—Laboratory and Mesocosm Studies

“…The dynamics of the phytoplankton population in the mesocosm experiment was reflected in the rise in the eukaryotic algae proportion, especially green algae and diatoms, in response to the application of the cyanocides, likely because they are less susceptible to ODTMA-Br (C18) or H 2 O 2 than cyanobacteria [37]. In the whole lake experiment, the selective damage of H 2 O 2 to cyanobacteria was further aggravated [11,38]. The specific advantage of H 2 O 2 is more significant when two applications of a low concentration of H 2 O 2 are applied [5,34].…”

Effect of Hydrogen Peroxide on Cyanobacterial Biofilms

“…Oxidative stress-based treatments are also a major approach to prevent or mitigate cyanobacterial blooms [ 13 , 14 , 15 , 16 ]. Oxidizing agents, including hydrogen peroxide (H 2 O 2 ), are broad-spectrum disinfectant agents and their costs are relatively low [ 9 ].…”

“…One notable benefit associated with the use of H 2 O 2 is related to its degradation to water and oxygen within a few days, thus, it does not persist in marine environments [ 18 ]. Notably, some studies reported that the use of H 2 O 2 to suppress cyanobacterial blooms can promote a short-term pulse disturbance in the ecosystem but is not detrimental to microbial communities [ 15 ]. Additional studies reported that H 2 O 2 may affect other aquatic organisms [ 19 , 20 ].…”