Ignored effects of phosphite (P+III) on the growth responses of three typical algae species

Nowadays, the ubiquitous distribution and increasing abundance of P+III in waterbodies have caused serious concerns regarding its bioavailability and potential toxicity. However, our knowledge on these issues is relatively limited. We addressed previously unknown effects of P+III on three dominate algae species i.e. Microcystic aeruginosa (M. aeruginosa), Chlorella pyrenoidesa (C. pyrenoidesa) and Cyclotella. sp in eutrophic waterbodies in China. Remarkable declines in biomass, specific growth rate and Chl-a of algae cells treated with 0.01–0.7 mg/L P+III as sole or an alternative P source were observed, indicating P+III had an inhibitory effect on the algal growth. Besides, the intracellular enzyme activities e.g superoxide dismutase (SOD) and malondialdehyde (MDA) were significantly increased with P+III stress. M. aeruginosa and Cyclotella. sp cells seemed to be more sensitive to P+III toxicity than C. pyrenoidesa since cell membrane suffered more serious stress and destruction. These findings combined, it confirmed P+III could not be utilized as bioavailable P, but had certain toxicity to the tested algae. It indicated that the increased P+III abundance in eutrophic waterbodies would accelerate the algal cell death, which could have a positive effect against algal blooms. Our results provide new insights into assessing the ecological risks of P+III in aquatic environments. 

Chao Han, Jinghua Ren, Baoying Wang et al., Ignored effects of phosphite (P+III) on the growth responses of three typical algae species, Environmental Pollution, Volume 294, 2022, 118672,

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