On the theme of "Interactions between scleractinian corals, planktonic diazotrophs and picoplankton in the context of climate change".
Reef-building corals are both autotrophic (they live in symbiosis with microalgae from the Symbiodiniaceae family) and heterotrophic, i.e. they are able to feed on a range of prey from dissolved organic matter to plankton.
Coral reefs are under threat from global warming, which is disrupting the symbiosis between corals and their symbionts, leading to massive coral bleaching. Planktonic diazotrophs, capable of fixing atmospheric nitrogen (N2) into bioavailable nitrogen (N) (ammonium, NH4+), and transferring this N Derived from Diazotrophy (called DDN) along the food web, could provide an alternative source of nutrients for corals.
Only a preliminary study has shown that a coral species can feed on these planktonic diazotrophs. Symbiotic diazotrophs also live in association with corals and also transfer DDN to them.
In the context of climate change, where corals are threatened by both acidification (AO) and ocean warming, the aim of this work is to study the role of planktonic and symbiotic diazotrophy in the acquisition of N by corals and in their resistance/resilience to these changes.
Composition of the thesis jury
Prof. Ilana Berman-Frank (rapporteur, University of Haifa) ;
Dr Francesca Benzoni (rapporteur, King Abdullah University) ;
Dr Sylvain Agostini (examiner, University of Tsukuba) ;
Dr Christine Ferrier-Pagès (examiner, Centre Scientifique de Monaco) ;
Dr Mathieu Pernice (examiner, University of Technology Sydney) ;
Prof. Claude Payri (examiner, IRD) ;
Dr Stéphanie Barnay-Verdier (guest, IRCAN Nice) ;
Dr Fanny Houlbrèque (PhD supervisor, IRD) ;
Dr Sophie Bonnet (thesis co-supervisor, IRD)