Proposal for a USTH Thesis
Supervisor's name : Thierry Bouvier & Yvan Bettarel USTH Thematic Group : Aquatic Microbial Ecology
Status (prof., assistant prof., …) : Chercheur
Laboratory : Université Montpellier 2, CNRS UMR 5119 ECOSYM Website address : http://www.ecosym.univ-montp2.fr/
CC093, Place Eugène Bataillon, 34095 Montpellier cedex 05
Institution : CNRS (to TB) & IRD (to YB) Website address :
http://www.cnrs.fr/ et http://www.ird.fr/
Scientific domain : Microbial ecology aims to understand the relationship of the microorganisms with one another and with their environment.
It concerns the three major domains of life Eukaryota, Archaea, Bacteria, and viruses which are present in virtually all of our planet's
environments. They mediate some of the most important aspects of ecosystem function, including nutrient cycling, the degradation of detritic
organic matter and its conversion into living biomass, and the regulation of the major biogeochemical cycles. They are also engage in symbiotic
relationships (either positive or negative) with other organisms, and these relationships affect the life of the host and the ecosystem. Their study
improve our knowlimpact the entire biosphere. Their study allows us to better understand the functioning of ecosystems and their inhabitants.
Two major publications in the field proposed for the PhD :
BETTAREL Y, BOUVIER T, AGIS M, BOUVIER C, CHU VT, COMBE M, MARI X, Ngoc MT, NGUYEN TT, PHAM TT, PRINGAULT O,
ROCHELLE-NEWALL E, TORRETON JP, TRAN QH (2011) Viral distribution and life strategies in the tropical Bach Dang estuary (Vietnam)
Condon RH, Steinberg D.K., del Giorgio P.A., Bouvier T., Bronk D.A., Grahamb W.M., Ducklow H.W. (2011) Jellyfish blooms result in a major
microbial respiratory sink of carbon in marine systems. PNAS (in press).
Website address of the personal page : http://www.ecolag.univ-
Supervisor's email : firstname.lastname@example.org et email@example.com
Description of the research work proposed for a PhD
Title Animal-associated microbial communities structures and functioning in aquatic ecosystems.
Microorganisms, i.e. Bacteria, Archaea, viruses, protists and fungi, are vital to the function of all ecosystems. This is largely because they exist
in enormous numbers (there are roughly 5 × 1030 bacteria alone worldwide) and so have immense cumulative mass and activity. They are also
probably more diverse than any other organisms, so it is easy to see why the structure of microbial communities is so important to the way in
which ecosystems function.
Microorganisms inhabit all ecosystems including aquatic and terrestrial ecosystems, but are also associated with most of living macroorganisms
such as plants and animals. From a microbial perspective, animals present a diversity of environments due to individual differences in
physiology, immune response, ecology and food preferences. This will influence and drive functional and phylogenetic composition of the
associated microbial communities (microbiome). Microbiome composition can have a profound inﬂuence on the health and nutrition of the
macroorganism host. Yet the ecological processes governing microbial community assembly on and in animals remain poorly understood.
Recent meta-analyses of microbiome diversity on a broad phylogenetic scale have suggested that animals represent highly selective
environments since only a small subset of microbial phyla can associate with them. Other studies suggest that the microbiome contribute to
many aspects of animal biology, including carbon and nitrogen nutrition, chemical defence or biological shield against pathogens.
The main objectives of that PhD will be to (i) describe the microbial community diversity associated to various animal including corals, jellyfishes
and fishes, (ii) disentangle the influence of environment, host species and diet on this diversity, (iii) assess whether certain microbial species
can be used indicator of health status of the animals, and (iii) explore the interactions between the microbiome diversity and its ecological roles.
The PhD will be carried out at the Ecologie des Systèmes Marins Côtiers laboratory (ECOSYM) in Montpellier (France) under the supervision of
Aquatic microbial ecology, animal-associated microbial communities, ecology, coastal zones.
Expected collaborations in Vietnam
The student will carried out her/his PhD and part of her/his field sampling and experiments in Vietnam as a collaborator of an ongoing
EC2CO program. As such, she/he will strongly interact with local faculties and students. This EC2CO research project brings together nine
french scientists and seven vietnamese scientists from four institutes, the NIO in Nha Trang, the IMER in Haiphong, the IBT in Hanoi and the
NIHE in Hanoi.
If a cosupervision is possible, please give the name and institution of the Vietnamese cosupervisor :
Cosupervision is possible and desired. We asked several Vietnamese researchers and are awaiting their responses.