As cyanobacteria are established into the water, different strategies are used for mitigating that, such as oxidation processes mediated by H2O2. Several authors have described them as more sensitive than Green Algae (GA) to this treatment but few studies have assessed the recovery of planktonic communities and the potential mechanisms of resistance after H2O2 exposure. Here, we tested the effect of different concentrations of H2O2 (1, 10 and 100mg.L-1) on the survival of a phytoplankton community from a freshwater reservoir co-dominated by M. aeruginosa and R. raciborskii, as well as both in isolated cultures. Before H2O2, cyanobacteria chlorophyll(Chl) was 29μg.L-1 and it contributed to most of the Chl compared to GA (14μg.L-1). After 48h, total Chl decreased in all conditions, although cyanobacteria dominated the 10mg.L-1 treatment (59%). In the 100mg.L-1 treatment, Chl decreased to 1.9μg.L-1 with dominance of GA (86%). After 7 days, only GA were detected in the conditions, except 100mg.L-1. Evaluating the community recovery, after the 7th-day, ASM-1 was added and only GA were able to grow in all the conditions, except 100 mg.L-1. We are evaluating the expression of antioxidant enzymes as well as the influence of environmental contaminants on the efficiency of H2O2 for suppressing cyanobacteria.
Acknowledgement:
All the supporting funding for contribution and confidence to this study: CNPq and FAPERJ (Brazil)
Key words:
Cyanobacteria, Green algae, Oxidation, Mitigation, Environmental Contaminatio