Academic Positions Europe

LabEx OT-Med, France

Postdoc – Remineralization of organic particles in presence of ballast minerals (ROBIN)

AMidex

About the role

We seek a biogeochemist to join a project that draws together field and laboratory controlled experiements aiming to better understand the complex interaction between mineral and sinking organic carbon in the context of the biological carbon pump (BCP).
The BCP is a major term in the global carbon cycle which annually transfers 5-15 GT C yr-1 from the atmosphere to the ocean’s interior in the form of sinking particles with an organic component. As these particles sink they are remineralised with the constituent elements returning to solution. The controls on remineralisation rate of sinking organic matter (OM) is an important issue with far wider implications than achieving greater understanding of a major flux in the global carbon cycle. If a link between OM remineralisation depth and presence of mineral concentration (calcite, opal or dust) exists, we can expect changes in air-sea CO2 partitioning resulting from ocean acidification and/or change in aerosol deposition. It is therefore critical to understand the factors regulating remineralisation depth if one wants to assess how ocean biological processes contribute to regulate the global climate. To date no direct in situ observations of OM remineralisation depth combined with assessment of the of mineral content of sinking particles have been performed.
Two field experiments (Mediterranean Sea and Porucupine Abyssal Plain, North Atlantic) will be undertaken to evaluate the role of ballast minerals in regulating particle decomposition in the mesopelagic zone using pressurized incubation chambers (PArticles Sinking Simulator or PASS system,http://www.com.univ-mrs.fr/LMGEM/sinpas/) and modified sediment traps (Marine snow catcher, lent by the National Oceanography Centre).
The ROBIN project is structured around two objectives: (i) Determine whether organic carbon mineralization rate is a function of mineral to organic carbon ratios in sinking particles and (ii) Assessing whether or not bacteria and/or ectoenzymes are excluded from within mineral associated particles.

Relevant references

- Engel, A., L. Abramson, J. Szlosek, L. Zanfei, G. Stewart, D. Hirschberg, and C. Lee (2009), Investigating the effect of ballasting by CaCO3 in Emiliania huxleyi: II. Decomposition of particulate organic matter, Deep-Sea Research Part II-Topical Studies in Oceanography, 56(18), 1408-1419.
Hedges, J. I., J. A. Baldock, Y. Gelinas, C. Lee, M. Peterson, and S. G. Wakeham (2000), Evidence for non-selective preservation of organic matter in sinking marine particles., Nature, 409, 801-804.
- Kwon, J. G., S. J. Hwang, G. W. Hennig, Y. Bayguinov, C. McCann, H. Chen, F. Rossi, P. Besmer, K. M. Sanders, and S. M. Ward (2009), Changes in the Structure and Function of ICC Networks in ICC Hyperplasia and Gastrointestinal Stromal Tumors, Gastroenterology, 136(2), 630-639.
- Le Moigne, F. A. C., M. Gallinari, E. Laurenceau, and C. L. De La Rocha (2013), Enhanced rates of particulate organic matter degradation by microzooplankton are diminished by added ballast minerals, Biogeosciences 10, 5755-5765.
- Tamburini, C., J. Garcin, G. Gregori, K. Leblanc, P. Rimmelin, and D. L. Kirchman (2006), Pressure effects on surface mediterranean prokaryotes and biogenic silica dissolution during a diatom sinking experiment, Aquatic Microbial Ecology, 43, 267-276.
- Tamburini C., Goutx M., Guigue C., Garel M., Lefèvre D., Charrière B., Sempéré R., Pepa S., Peterson M. L., Wakeham S., Lee C. (2009). Effects of hydrostatic pressure on microbial alteration of sinking fecal pellets. Deep-Sea Research II 56 (18): 1533-1546.

About you

Candidates are expected to have experience in carbon biogeochemistry and/or microbial ecology, a PhD in oceanography, a MASTER (or equivalent) in marine or environmental sciences. Previous experience in field experiments and measurments is desirable. You will be expected to publish in the relevant peer reviewed literature and to present your work at international conferences. This is a 1 year Fixed Term Appointment position with the possible extension for the second year, offered on Aix Marseille University terms and conditions in the framework of the OT-Med labex (http://www.otmed.fr).

About us

The Robin project will be lead by C. Tamburini (MIO, Marseille, France) in collaboration with Kazuyo Tachikawa (CEREGE, Aix-en-Provence, France) and Frédéric Le Moigne (GEOMAR, Kiel, Germany).
The Mediterranean Institute of Oceanography (MIO, http://mio.pytheas.univ-amu.fr/). It is composed of members of several organizations: the CNRS, IRD, Aix Marseille University, and Toulon Var University. It MIO employs about 200 permanent staffs and 60 contrated staffs (including students). The research themes are marine ecosystems functioning, including biodiversity, elemental fluxes, hydrodynamics, all in the context of global change. Our research is performed in close interaction with teaching through internships of students, from undergraduate to post graduate levels. MIO includes scientists specialized in many different disciplines, including Oceanography: Biology, Microbiology, Marine Ecology, Biogeochemistry, Geochemistry, Physics, Teledetection, and Mathematics. OT-Med (Objectif Terre: Bassin Méditerranéen) is a “Laboratoire d’excellence” (LABEX) selected by the French program Investissements d’Avenir. Its was founded in 2012 for the duration of 8 years. It brings together 9 research laboratories and 1 research federation specialised in different fields : environmental sciences, law, economy and social sciences.
Elemental analyis will be performed at CEREGE (https://www.cerege.fr/spip.php?arti…) using an ICP-QMS for measurment of element like Ca and Al.
PArticles Sinking Simulation using the PASS system will be performed at the MIO (http://www.com.univ-mrs.fr/LMGEM/po…).

How to apply

Informal enquiries, curriculum vitae, motivation letter, names and contact information of two academic referees have to be sent to christian.tamburini@mio.osupytheas.fr.
Application deadline : 30 September 2014

Job details

Employer : Aix Marseille University
Location : Marseille, France
Job type : Postdoctoral
Net salary : 1960€ or 2300€ (less or more than 3-years of post experience after PhD, respectively)
Qualification : PhD in oceanography
Employement type : full time from December 2014

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The research of OT-Med is focused on global change and natural hazards in the Mediterranean basin and semi-arid regions of Sahel.

Application details

Published:
July 9, 2014
Application deadline:
September 30, 2014

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