The harmful cyanobacterium Microcystis aeruginosa PCC7806 is more resistant to hydrogen peroxide at elevated CO2

Hongjie Qin; Giovanni Sandrini; Tim Piel; Pieter C Slot; Jef Huisman; Petra M Visser

doi:10.1016/j.hal.2023.102482

The harmful cyanobacterium Microcystis aeruginosa PCC7806 is more resistant to hydrogen peroxide at elevated CO₂

Harmful Algae. 2023 Oct:128:102482. doi: 10.1016/j.hal.2023.102482. Epub 2023 Aug 2.

Authors

Hongjie Qin¹, Giovanni Sandrini², Tim Piel³, Pieter C Slot³, Jef Huisman³, Petra M Visser⁴

Affiliations

¹ Guangdong Provincial Key Lab of Ornamental Plant Germplasm Innovation and Utilization, Environmental Horticulture Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China; Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
² Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands; Department of Technology & Sources, Evides Water Company, Rotterdam, The Netherlands.
³ Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands.
⁴ Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, The Netherlands. Electronic address: P.M.Visser@uva.nl.

PMID: 37714576
DOI: 10.1016/j.hal.2023.102482

Abstract

Rising atmospheric CO₂ can intensify harmful cyanobacterial blooms in eutrophic lakes. Worldwide, these blooms are an increasing environmental concern. Low concentrations of hydrogen peroxide (H₂O₂) have been proposed as a short-term but eco-friendly approach to selectively mitigate cyanobacterial blooms. However, sensitivity of cyanobacteria to H₂O₂ can vary depending on the available resources. To find out how cyanobacteria respond to H₂O₂ under elevated CO₂, Microcystis aeruginosa PCC 7806 was cultured in chemostats with nutrient-replete medium under C-limiting and C-replete conditions (150 ppm and 1500 ppm CO₂, respectively). Microcystis chemostats exposed to high CO₂ showed higher cell densities, biovolumes, and microcystin contents, but a lower photosynthetic efficiency and pH compared to the cultures grown under low CO₂. Subsamples of the chemostats were treated with different concentrations of H₂O₂ (0-10 mg·L^-1 H₂O₂) in batch cultures under two different light intensities (15 and 100 μmol photons m^-2·s^-1) and the response in photosynthetic vitality was monitored during 24 h. Results showed that Microcystis was more resistant to H₂O₂ at elevated CO₂ than under carbon-limited conditions. Both low and high CO₂-adapted cells were more sensitive to H₂O₂ at high light than at low light. Microcystins (MCs) leaked out of the cells of cultures exposed to 2-10 mg·L^-1 H₂O₂, while the sum of intra- and extracellular MCs decreased. Although both H₂O₂ and CO₂ concentrations in lakes vary in response to many factors, these results imply that it may become more difficult to suppress cyanobacterial blooms in eutrophic lakes when atmospheric CO₂ concentrations continue to rise.

Keywords: Climate change; Harmful algal blooms; Microcystin; Oxidative stress; Photosynthetic yield; Rising CO(2).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Batch Cell Culture Techniques
Carbon Dioxide / pharmacology
Cyanobacteria*
Hydrogen Peroxide
Microcystis*

Substances

Hydrogen Peroxide
Carbon Dioxide