Marie Derrien "Chemical mediation in underwater caves: towards a better understanding of how ecosystems function in the ocean".

Marie Derrien, a doctoral student in the UMR IMBE, NEMO team, will publicly present her thesis on Friday 20 December 2024 at 2pm at the Endoume Marine Station.

In front of a jury made up of :

• Mrs Anne-Geneviève BAGNERES, CNRS Research Director, CEFE, Montpellier. Rapporteur
• Ms Maggy NUGUES, Senior Lecturer EPHE, CRIOBE, Perpignan. Rapporteur
• Mr Olivier THOMAS, Professor at the National University of Ireland, Galway. Examiner
• Mr Thierry PÉREZ, CNRS Research Director, IMBE, Marseille. Thesis supervisor
• Mr Pierre CHEVALDONNÉ, CNRS Research Director, IMBE, Marseille. Thesis co-supervisor
• Ms Charlotte SIMMLER, CNRS Research Fellow, IMBE, Marseille. Thesis co-supervisor

Summary of work:

Chemical mediation is one of Nature's languages, enabling organisms to communicate with their environment. The aim of this thesis was to improve our knowledge of the role of chemical mediation in marine ecosystems. The research was carried out in several underwater caves where benthic biodiversity was characterised using non-destructive methods. In addition, an original device was developed to capture chemical landscapes as close as possible to the benthic communities, thus demonstrating the contribution of dominant sponges and the specificity of the landscape in each cave studied. Finally, the influence of cave chemical landscapes on the migration behaviour of cave-dwelling crustaceans was demonstrated. A given population of these crustaceans recognises the specific chemical landscape of its cave, a behaviour called homing. Here we make the link between variations in the composition of biodiversity and the chemical landscape and the consequences for part of the ecosystem's functioning.