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(es)

Gebara, Renan Castelhano ; Alho, Lays de Oliveira Gondalves ; Mansano, Adrislaine da Silva ; Rocha, Giseli Swerts ; Melao, Maria da Grada Gama

• Tipo de documento: Artigo Científico
• Fonte: AQUATIC TOXICOLOGY; v. 254, p. 10-pg., 2022-12-08.

Resumo

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 mu M Zn and 22.24 to 37.06 mu M Al affected the photosynthetic parameters of Raphidocelis subcapitata. Metals affected the efficiency of the oxygen-evolving complex - OEC (F0/Fv), increasing it by 25% at 0.46 mu M Zn and by 82% at 37.06 mu M 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 F0/Fv was more affected by Al. Regarding quenching, there was an increase in passive energy dissipation ((Y(NO)) at 0.46 mu M 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 mu M 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. (AU)

• Processo FAPESP: 21/13583-0 - Efeitos Ecotoxicológicos de Nanopartículas de ZnWO4 e CuWO4 Sobre Uma Cadeia Alimentar Dulcícola: Aferindo Possíveis Impactos Ambientais de Contaminantes Emergentes
• Beneficiário: Renan Castelhano Gebara
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 16/00753-7 - Efeitos tóxicos de microcontaminantes emergentes sobre cadeias alimentares planctônicas
• Beneficiário: Maria da Graça Gama Melão
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 14/14139-3 - Biodiversidade e processos microbianos em ecossistemas aquáticos
• Beneficiário: Hugo Miguel Preto de Morais Sarmento
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores