Nos tutelles

Centre National de la Recherche Scientifique


Accueil > Emplois/Thèse > Sujets de thèse 2020

Sujet de thèse au LOG ouvert à candidature pour 2020

par Valérie PLOUVIN - publié le , mis à jour le

Université de rattachement :Université du Littoral
Graduate School ED585

Role of Rhizaria in biogeochemical Cycles in the epi- and mesopelagic ocean (RhiCycle)

Call description : The French National Research Agency has selected the project RhiCycle to co-finance a PhD position. RhiCycle is a 4-years project, led by Tristan Biard, aiming to characterize the contribution of siliceous rhizarians, a group of marine protists secreting mineral tests made out of biogenic silica, to global marine biogeochemical cycles, in particular the carbon biological pump and silica cycle.

The team involved in RhiCycle already published a number of pioneering studies about the importance of the elusive Rhizaria in modern oceans (i.e., a substantial fraction of living biomass in the ocean, high contribution to fluxes of particulate organic carbon and biogenic silica exported to the deep ocean). Nevertheless, rhizarians encompass a large diversity of species, spanning a wide size range (0.04 - >4 mm) and inhabiting diverse ecological niches (epi- and meso-pelagic). Therefore, the role and significance of Rhizaria to biogeochemical cycles cannot be resumed to the study of a few taxa (which was the case for the previous studies mentioned above). Altogether, this raises the question : Considering their broad size spectra and extended range of vertical habitats, what is the significance of silicified rhizarians in biogeochemical cycles, in particular carbon and silica cycling ?

To investigate such diverse questions, an original combination of tools and expertise encompassing marine biogeochemistry, quantitative high-throughput in situ imaging (Underwater Vision Profiler systems), sediment trap fluxes and molecular characterizations of diversity will be used. Designed to complement regional field studies (in particular in Villefranche-sur-Mer, French Riviera) and oceanographic cruises in a variety of ecosystems, laboratory experiments will generate information needed to interpret large- scale studies in different major oceanic basins (Northeastern Pacific, North Atlantic), in particular via collaborations with the CCELTER program (led by the Scripps Institution of Oceanography - USA) that include an oceanographic cruise off the californian coast in 2021.

Duration : The PhD position is for 3 years. Start date : October 1, 2020.

Supervision : The PhD candidate will be supervised by Dr. Tristan Biard and Pr. Urania Christaki. Dr. Tristan Biard is a recent laureate of the ANR 2019 Young Researcher Call with the project RhiCycle. He has an extensive experience in working with rhizarians using multidisciplinary approaches. U. Christaki is a renowed expert in the carbon cycle and microbial ecology, and has supervised numerous PhD so far.

Location : The position will be based at the Laboratoire d’Océanologie et Géosciences (LOG), Wimereux, France. It is a joint research unit of the University of the Litoral Opal Coast, the University of Lille and the Centre National de la Recherche Scientifique. It is renowned in the fields of zoo- and phytoplankton ecology/physiology, microbial ecology, biogeochemistry, marine optics, physical oceanography and geosciences.

Hours and Compensation : The PhD candidate will be given a fully equipped work station at the LOG, and will be expected to work full time for a duration of 36 months, starting in October 2020. The minimum gross monthly remuneration under the contract shall be €1,800.

Application Requirements : Interested candidates should send an email to Tristan Biard Tristan Biard until 25 June 2020 (this deadline will be extended if the suitable candidate could not be found), with the subject line : PhD-RhiCycle, and include the following :
• Cover letter of 1 or 2 pages (with a brief summary of the candidate’s academic and research experiences and goals)
• CV