Impacts of chemical contamination on bacterio-phytoplankton coupling. (October 2020)

• Record Type: Journal Article
• Authors: Pringault, Olivier; Bouvy, Marc; Carre, Claire; Fouilland, Eric; Meddeb, Marouan; Mejri, Kaouther; Leboulanger, Christophe; Sakka Hlaili, Asma
• Is Part Of: Chemosphere. Volume 257(2020)
• Publication Date: 2020-10
• Subjects: Pesticides -- Trace metallic elements -- Carbon cycle -- Primary production -- Bacterial carbon demand; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127165
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Phytoplankton and bacterioplankton are the key components of the organic matter cycle in aquatic ecosystems, and their interactions can impact the transfer of carbon and ecosystem functioning. The aim of this work was to assess the consequences of chemical contamination on the coupling between phytoplankton and bacterioplankton in two contrasting marine coastal ecosystems: lagoon waters and offshore waters. Bacterial carbon demand was sustained by primary carbon production in the offshore situation, suggesting a tight coupling between both compartments. In contrast, in lagoon waters, due to a higher nutrient and organic matter availability, bacteria could rely on allochthonous carbon sources to sustain their carbon requirements, decreasing so the coupling between both compartments. Exposure to chemical contaminants, pesticides and metal trace elements, resulted in a significant inhibition of the metabolic activities (primary production and bacterial carbon demand) involved in the carbon cycle, especially in offshore waters during spring and fall, inducing a significant decrease of the coupling between primary producers and heterotrophs. This coupling loss was even more evident upon sediment resuspension for both ecosystems due to the important release of nutrients and organic matter. Resulting enrichment alleviated the toxic effects of contaminants as indicated by the stimulation of phytoplankton biomass and carbon production, and modified the composition of the phytoplankton community, impacting so the interactions between phytoplankton and bacterioplankton. Highlights: Phytoplankton and bacterioplankton were strongly coupled in offshore waters. Coupling between both compartments was less evident in lagoon waters. Sediment resuspension and chemical contamination differently impacted lagoon and offshore waters. Chemical contamination loosened the coupling between both compartments. Nutrients and organic matter released during sediment resuspension strongly decreased the bacterio–phytoplankton coupling.