PhD Defence – Biofouling and ORE

On 12 April 2023, Aurélie Portas defended her thesis at the University of Toulon. It dealed with the study of prokaryotic and eukaryotic communities in biofouling and the physical structuring parameters in the context of offshore renewable energy. This work was carried out as part of the ABIOP+ project.


Biofouling is a process at the origin of many adverse effects in the field of offshore renewable energy (ORE) where the effects and extent of biocolonisation are still unknown. Within the framework of the ABIOP+ project, the objective of this thesis was to better understand the colonization mechanisms specific to ORE sites. The diversity and composition of eukaryotic communities were first evaluated through different molecular approaches to detect the widest range of taxa from samples collected in several contrasting marine environments. Secondly, this thesis focused on the factors influencing the colonization dynamics of biofouling communities, in particular the effect of hydrodynamics. An in situ and semi-controlled approach was carried out by evaluating the responses of the communities to different hydrodynamic conditions. For this, a multi-scale characterization of the biofilms thus formed was undertaken via complementary approaches linking metabarcoding (prokaryotes and eukaryotes), non-targeted metabolomics, biochemical assays, and microscopy. Finally, we studied the eukaryotic communities in different OMR sites in the Atlantic and Mediterranean submerged between 3 and 24 months. Measurements of general biofouling characteristics (biomass, biovolume, density, etc.) and molecular taxonomy approaches revealed differences in eukaryotic communities.

Composition of the jury

  • Frédérique Viard, Research Director, ISEM / CNRS, Rapporteur
  • Cédric Hubas, University Professor, MNHN, Rapporteur
  • Agnès Bouchez, Research Director, INRAE, Examiner   
  • Antoine Carlier, Research Executive, Ifremer, Examiner
  • Jean-François Briand, Lecturer, Université de Toulon, Thesis Director
  • Gérald Culioli, University Professor, Université d’Avignon, Thesis Co-Director
  • Nolwenn Quillien, Research executive, France Energies Marines, Thesis Co-Supervisor

Photo credit: Thomas Pavy

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