Combination of P-limitation and cadmium in photosynthetic responses of the freshwater microalga Ankistrodesmus densus (Chlorophyceae)

Author(s)

Rocha, Giseli Swerts ^[1] ; Lombardi, Ana Teresa ^[2] ; Espindola, Evaldo L. G. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, NEEA CRHEA, Ave Trabalhador Saocarlense 400, BR-13566590 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Bot, Rodovia Washington Luis, Km 235, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Environmental Pollution; v. 275, APR 15 2021.
• Web of Science Citations: 0

Abstract

In the environment, microalgae are exposed to a multitude of stressors simultaneously, inducing physiological adjustments. It is well documented that both phosphorus (P) limitation and trace metals exposure affect microalgal physiology. However, investigations regarding the combination of both P limitation and excess trace metals still deserve attention. In the present study, we evaluated the changes in photosynthetic parameters in the green microalga Ankistrodesmus densus acclimated to different P concentrations prior to exposure to Cd. Our results indicate that different concentrations of P in the medium were responsible for significant changes in some parameters, especially those related to photoprotection mechanisms. Cadmium also altered some of these variables in all P scenarios, and greater damage (i.e., synergism) was observed in the combination P-limited and high Cd, with all the evaluated parameters affected under the adverse scenario. Among the parameters analyzed, rapid light curves were the most sensitive to exposure of one or the combination of both stressors (Cd and P limitation). Based on our data, we suggest that P-limited algae activated photoprotective mechanisms as a response to nutrient limitation, especially at the most limited condition. The addition of Cd did not change linearly the parameters related to photoprotection mechanisms under P-limitation, i.e., synergism was observed in the intermediate P-limitation combined with Cd, while in the most P-limited, P seems to be the driving force affecting these mechanisms. Based on our results, we suggest the use of rapid light curves as a tool to complement the assessment of the impacts of stressors, such as metals, in ecotoxicological studies. (C) 2021 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 18/07988-5 - Bioprospecting, characterization and optimization of Brazilian microalgal strains for CO2 biofixation and bioproducts of commercial importance
• Grantee: Ana Teresa Lombardi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/25436-1 - Influence of copper and cadmium in algae and their ecotoxicological effects in freshwater zooplankton
• Grantee: Giseli Swerts Rocha
• Support Opportunities: Scholarships in Brazil - Post-Doctoral