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

Hydrogen peroxide (H 2 O 2) is an environmentally friendly algaecide with good prospects for cyanobacterial bloom control. In this study, 0.2–1.5 mg L⁻¹ of H 2 O 2 was applied to an aquatic microcosm containing cyanobacteria, bacteria, and eukaryotic phytoplankton at the early cyanobacterial growth stage·H 2 O 2 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 H 2 O 2 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 H 2 O 2 for 15 days, H 2 O 2 -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 H 2 O 2 -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 H 2 O 2 during the early cyanobacterial growth stage could effectively prevent the formation of cyanobacterial blooms without disrupting non-target organisms. [Display omitted] • Low-dose H 2 O 2 prevents cyanobacterial bloom without affecting eukaryotic algae. • H 2 O 2 reduces the dominance of Microcystis and Anabeana in cyanobacterial community. • H 2 O 2 regulates prokaryotic and eukaryotic community towards a healthy direction. • H 2 O 2 treatment reduces intracellular and extracellular microcystin concentrations. • H 2 O 2 stress induces interactions among bacteria, cyanobacteria and eukaryotic algae. [ABSTRACT FROM AUTHOR]