Community succession during the preventive control of cyanobacterial bloom by hydrogen peroxide in an aquatic microcosm

Abstract

Hydrogen peroxide (H2O2) is an environmentally friendly algaecide with good prospects for cyanobacterial bloom control. In this study, 0.2–1.5 mg L−1 of H2O2 was applied to an aquatic microcosm containing cyanobacteria, bacteria, and eukaryotic phytoplankton at the early cyanobacterial growth stage·H2O2 generated hormesis in cyanobacteria at 0.2 mg L−1; significantly (p < 0.05) inhibited cyanobacterial growth, cyanobacterial photosynthesis, and microcystin production at 0.5–1.5 mg L−1; and effectively prevented the formation of cyanobacterial bloom without generating adverse effects on eukaryotic phytoplankton at 1.0 and 1.5 mg L−1. Application of 0.5–1.5 mg L−1 H2O2 directly inhibited the abundance of five typical bloom-forming cyanobacterial genera (Microcystis, Anabeana, Synechococcus, Nostoc, and Oscillatoria), which were negatively correlated with four bacterial genera (Actinotalea, Flavobacterium, Fluviicola, and Exiguobacterium) and five eukaryotic phytoplankton genera (Cyclotella, Desmodesmus, Dinobryon, Fragilaria, and Mychonastes) and positively correlated with six proteobacterial genera (Brevundimonas, Devosia, Limnohabitans, Porphyrobacter, Pseudomonas, and Rhodobacter). After application of 1.0 and 1.5 mg L−1 H2O2 for 15 days, H2O2-treated groups showed significantly (p < 0.05) different prokaryotic community structures from that of the control group at the bloom stage (15th day), while eukaryotic community structures in H2O2-treated groups remained stable and showed high similarity with that of the control group at a non-bloom stage (5th day). Application of low-dose H2O2 during the early cyanobacterial growth stage could effectively prevent the formation of cyanobacterial blooms without disrupting non-target organisms.