Single and combined effects of Zn and Al on photosystem II of the green microalgae Raphidocelis subcapitata assessed by pulse-amplitude modulated (PAM) fluorometry.

Autor: Gebara RC; Department of Hydrobiology. Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil; Post-Graduate Program in Ecology and Natural Resources (PPGERN), Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil. Electronic address: nangebara@gmail.com., Alho LOG; Department of Hydrobiology. Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil; Post-Graduate Program in Ecology and Natural Resources (PPGERN), Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil., Mansano ADS; Department of Hydrobiology. Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil; Post-Graduate Program in Ecology and Natural Resources (PPGERN), Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil., Rocha GS; NEEA/CRHEA/SHS, São Carlos School of Engineering, Universidade de São Paulo (USP), Av. Trabalhador São-carlense, 400, 13560-970 São Carlos, Brazil., Melão MDGG; Department of Hydrobiology. Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil; Post-Graduate Program in Ecology and Natural Resources (PPGERN), Universidade Federal de São Carlos (UFSCar). Rodovia Washington Luís, Km 235, 13565-905, São Carlos, SP, Brazil.
Jazyk: angličtina
Zdroj: Aquatic toxicology (Amsterdam, Netherlands) [Aquat Toxicol] 2023 Jan; Vol. 254, pp. 106369. Date of Electronic Publication: 2022 Dec 05.
DOI: 10.1016/j.aquatox.2022.106369
Abstrakt: Increasing metal concentrations in aquatic environments are mainly due to anthropogenic actions, which is a matter of concern for the biodiversity of aquatic biota. It is known that metals coexist in environments, however environmental risk assessments do not usually take into account the effects of these mixtures. We aimed to test Zn and Al mixtures on the photosynthetic apparatus of a green microalga, for the first time, using PAM fluorometry. After 72 h exposure, single concentrations from 0.08 to 0.46 µM Zn and 22.24 to 37.06 µM Al affected the photosynthetic parameters of Raphidocelis subcapitata. Metals affected the efficiency of the oxygen-evolving complex - OEC (F 0 /F v ), increasing it by 25% at 0.46 µM Zn and by 82% at 37.06 µM Al - concentrations where, 57% and 78% of growth inhibition occurred, respectively. We observed that the algal growth was more sensitive to infer Zn toxicity, while F 0 /F v was more affected by Al. Regarding quenching, there was an increase in passive energy dissipation ((Y(NO)) at 0.46 µM Zn, and we observed an increase in both regulated ((NPQ and Y(NPQ)) and non-regulated energy dissipation ((qN and (Y(NO)) at 37.06 µM Al. Our results showed synergism and antagonism at different concentrations in mixtures, the antagonism prevailing at higher metal concentrations and, in some cases, synergism at lower concentrations of Zn and Al. Since we observe more than additive and less than additive effects, it is of the utmost importance to take mixture toxicity tests into account when performing risk assessments on green algae.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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