Does cobalt antagonize P limitation effects on photosynthetic parameters on the freshwater microalgae Raphidocelis subcapitata (Chlorophyceae), or does P limitation acclimation antagonize cobalt effects? More questions than answers.

Autor: Rocha GS; Universitat Rovira i Virgili, Escola Tècnica Superior d'Enginyeria Química, Departament d'Enginyeria Química, Av. Països Catalans, 26, 43007, Tarragona, Spain. Electronic address: swertsbio@gmail.com., Melão MGG; Departamento de Hidrobiologia, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luís, Km 235, CEP, 13565-905, São Carlos, SP, Brazil. Electronic address: dmgm@ufscar.br.
Jazyk: angličtina
Zdroj: Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2024 Jan 15; Vol. 341, pp. 122998. Date of Electronic Publication: 2023 Nov 21.
DOI: 10.1016/j.envpol.2023.122998
Abstrakt: Phosphorus (P; macronutrient) and cobalt (Co; micronutrient) are essential for algal healthy metabolism. While P provides energy, Co is a co-factor of several enzymes and component of B12 vitamin. However, in concentrations higher or lower than required, P and Co alter algal metabolism, impacting physiological processes (e.g., growth and photosynthesis), usually in a harmful way. In the environment, algae are exposed to multiple stressors simultaneously and studies evaluating the algal response to the combination of macronutrient limitation and micronutrient excess are still scarce. We assessed the effects of P limitation and Co excess, isolated and combined, in Raphidocelis subcapitata (Chlorophyceae), in terms of growth, pigments production, and photosynthetic parameters. Except for the photochemical quenching (qP) and the efficiency in light capture (α) under P limitation, all parameters were affected by both stressors, isolated and combined. Under P limitation, chlorophyll a was the most sensitive parameter; while excess of Co affected most the photoprotective mechanisms of algae, altering the non-photochemical quenchings qN and NPQ, influencing the light use and dissipation of heat by algae. The combination of two stressors resulted in a significant decrease in algal growth, with synergistic responses in growth and pigments production, and antagonism in the photosynthetic parameters. We suggest that algal metabolism was altered during P limitation acclimation and the excess of Co was used in a beneficial way by P-limited algae in photosynthesis, resulting in the well-functioning of the photosynthetic apparatus in the combination of both stressors. However, more studies are needed to understand which mechanisms are involved in this adaptation which resulted in antagonism in photosynthetic processes and synergism in growth and pigments production.
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 © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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