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Charlotte Nef

CNRS postdoctoral researcher on the ERC H2020 Diatomic (grant agreement no. 835067)

Contact details
Institut de Biologie de l’École Normale Supérieure (IBENS)
46 Rue d’Ulm, 75005 Paris, France
Google scholar

Bachelor of Science (Environmental Biology), University of Nantes, 2014 (Class Salutatorian)
Master of Science (Environmental Biology and Ecosystem Bioproduction), University of Nantes, 2016 (Class Salutatorian)
PhD Biology of Organisms, University of Nantes, 2019, conducted at the Laboratory of Physiology and Biotechnology of Algae at the IFREMER institute (Commended by the jury)

In marine environments, microalgal photosynthetic activity allows the fixation of an estimated 40-50% carbon at planetary scale, that is more than the Amazonian forest, while these microalgae only represent 1% of the global photosynthetic biomass. Principal microalgal groups contributing to this photosynthetic activity are diatoms, dinoflagellates and haptophytes. I have a deep interest in studying how marine phytoplankton communities interact and how these interactions are shaped by environmental factors. I currently focus on diatom genomic diversity, particularly of Chaetoceros, the most abundant and cosmopolitan diatom genus in modern ocean. I investigate population connectivity and the effect of environmental factors on genomic differentiation using the metagenomic dataset generated by the Tara Oceans expeditions with a particular focus on the Arctic Ocean. A second part of my work aims as characterizing diatom interactions with other members of the plankton using the Tara Oceans network of interactions.

I previously worked on deciphering interactions between B12-dependent microalgae and B12-producing bacteria. Vitamin B12 is an enzymatic cofactor exclusively synthesized by some archaea and bacteria. This work led to major results such as the first publication about the repartition of B12 dependency in haptophytes, suggesting that all haptophyte species would require the vitamin for their growth, being the first microalgal group gathering exclusively B12 auxotrophs. This would mean that haptophytes would have benefited from a constant B12 source in their surrounding environment during their evolution, potentially by obtaining B12 from prokaryotes.

Besides research, I like to be involved in scientific education. I have supervised MSc and advanced technician students in the Faculty of Sciences and Techniques at Nantes University (France) and contributed to different events during which I communicated with the general public.

Institutional and outreach
Co-organizer of the Tara Oceans Seminar Series (TOSS) September 2020 – present. This event aims at gathering members of the Tara Oceans consortium on a regular basis to reinforce collaborations between groups.
Contribution to a scientific stand for “La Mer XXL” July 2019, Nantes, France
Participation to “La fête de la science” October 2018, Nantes, France
Presentation at the “Journées Scientifiques” of Nantes University, open to the general public, June 2018, Nantes, France
Co-organizer of the IFREMER PhD days, October 2017, Nantes, France

Selected publications
. Bulánková P, Sekulić M, Jallet D, Nef C, van Oosterhout C, Delmont T, I Vercauteren, Maria Osuna-Cruz C, Vancaester E, Mock T, Sabbe K, Daboussi F, Bowler C, Vyverman W, Vandepoele K and De Veylder L. Mitotic interhomolog recombination between homologous chromosomes drives genomic diversity in diatoms. Current Biology (2020). DOI : 10.1016/j.cub.2021.05.013

. Chaffron S, Delage E, Budinich M, Vintache D, Henry N, Nef C, Ardyna M, Zayed AA, Junger PC, Galand PE, Lovejoy C, Murray A, Sarmento H, Tara Oceans coordinators, Acinas S, Babin M, Iudicone D, Jaillon O, Karsenti E, Wincker P, Karp-Boss L, Sullivan MB, Bowler C, de Vargas C and Eveillard D. Environmental vulnerability of the global plankton community interactome. bioRxiv (2020). DOI : 10.1101/2020.11.09.375295

. Nef C, Henry C, Nicolau É, Bérard J-B, Hervé F, Caruana AMN, Kaas R, Mairet F and Garnier M. Cobalamin scarcity modifies carbon allocation and impairs DMSP production through methionine metabolism in the haptophyte microalgae Tisochrysis lutea. Frontiers in Marine Science 7:569560 (2020). DOI : 10.3389/fmars.2020.56956

. Nef C, Jung S, Mairet F, Kaas R, Grizeau G and Garnier M. How haptophytes microalgae mitigate vitamin B12 limitation. Scientific Reports 9, 8417 (2019). DOI : 10.1038/s41598-019-44797-w