Effects of phosphorus availability and phosphorus utilization behavior of Microcystis aeruginosa on its adaptation capability to ultraviolet radiation

Lingxiao Ren; Peifang Wang; Chao Wang; Hans W Paerl; Huiya Wang

doi:10.1016/j.envpol.2019.113441

Effects of phosphorus availability and phosphorus utilization behavior of Microcystis aeruginosa on its adaptation capability to ultraviolet radiation

Environ Pollut. 2020 Jan:256:113441. doi: 10.1016/j.envpol.2019.113441. Epub 2019 Oct 21.

Authors

Lingxiao Ren¹, Peifang Wang², Chao Wang³, Hans W Paerl⁴, Huiya Wang⁵

Affiliations

¹ Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China; College of Environmental Engineering, Nanjing Institute of Technology, 211167, Nanjing, PR China.
² Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China. Electronic address: pfwang2005@hhu.edu.cn.
³ Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
⁴ University of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC, USA.
⁵ College of Environmental Engineering, Nanjing Institute of Technology, 211167, Nanjing, PR China.

PMID: 31672370
DOI: 10.1016/j.envpol.2019.113441

Abstract

Phosphorus (P) plays a critical role in eutrophication and algal growth; therefore, improving our understanding of the impact of P is essential to control harmful algal blooms. In this study, Microcystis aeruginosa was treated with 5-h ambient irradiation in the medium with different dissolved inorganic P (DIP) concentrations, DIP-free, moderate-DIP, and high-DIP, to explore its growth and other physiological responses. Compared to photosynthetically active radiation (PAR), UV-A (320-400 nm) and UV-B (280-320 nm) radiation had inhibitive effects on the photosynthesis and growth of M. aeruginosa, while high P availability could alleviate or eliminate the negative effects of UV radiation. The photosynthetic parameters had a minimum reduction and quickly recovered after re-inoculation under high-DIP conditions. Confirmed by SEM, photosynthetic pigments, the generation of reactive oxygen species (ROS), superoxide dismutase (SOD) activity and other methods, ambient UV radiation exerted oxidative stresses rather than direct lethal effects on M. aeruginosa. Photosynthetic parameters indicated that algal UV-adaptation processes could include decreasing photo-induced damages and increasing self-repair efficiency. The P acquired by M. aeruginosa cells can have two function, which included alleviating UV-induced negative effects and sustaining algal growth. Consequently, UV-adaptation processes of M. aeruginosa resulted in an elevated demand for DIP, which resulted to increased P uptake rates and cellular P quota under moderate and high-DIP conditions. Therefore, the production of carotenoid and phycocyanin, and SOD activity increased under UV stress, leading to a better adaptation capability of M. aeruginosa and decreased negative effects of UV radiation on its growth. Overall, our findings demonstrated the significant interactive effects of P enrichment and irradiation on typical cyanobacteria, and the strong adaptation capability of M. aeruginosa in the eutrophic UV-radiated waters.

Keywords: Adaptation capability; Microcystis aeruginosa; Phosphorus utilization behavior; Photosynthesis; Ultraviolet (UV) radiation.

MeSH terms

Acclimatization*
Carotenoids
Cyanobacteria
Harmful Algal Bloom
Microcystis / growth & development
Microcystis / physiology*
Oxidative Stress
Phosphorus / metabolism*
Photosynthesis / drug effects
Phycocyanin
Reactive Oxygen Species
Ultraviolet Rays*

Substances

Reactive Oxygen Species
Phycocyanin
Phosphorus
Carotenoids