{"id":25485,"date":"2026-03-06T14:00:41","date_gmt":"2026-03-06T13:00:41","guid":{"rendered":"https:\/\/www.mio.osupytheas.fr\/?p=25485"},"modified":"2026-03-06T14:09:05","modified_gmt":"2026-03-06T13:09:05","slug":"arthur-coet-will-present-his-thesis-on-wednesday-18-march-2026-at-2-00-pm-at-lhexagone-luminy","status":"publish","type":"post","link":"https:\/\/www.mio.osupytheas.fr\/en\/arthur-coet-soutiendra-sa-these-le-mercredi-18-mars-2026-a-14h00-a-lhexagone-luminy\/","title":{"rendered":"Arthur Co\u00ebt will present his thesis on Wednesday 18 March 2026 at 2pm at the Hexagone (Luminy)."},"content":{"rendered":"<div data-elementor-type=\"wp-post\" data-elementor-id=\"25485\" class=\"elementor elementor-25485\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-85a7d7d e-flex e-con-boxed e-con e-parent\" data-id=\"85a7d7d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-1fe8cae elementor-widget elementor-widget-text-editor\" data-id=\"1fe8cae\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p style=\"text-align: justify;\"><strong>Arthur Co\u00ebt<\/strong> (MIO Biogeochemistry) will submit his doctoral thesis on <strong>wednesday 18 march 2026<\/strong> \u00e0 <strong>14h00<\/strong>, at l'Hexagone (Luminy, Marseille) on the following topic: <em>Dynamics and architecture of diazotrophs particle colonization. <\/em>You are warmly invited to attend the defence and the thesis reception that will follow.<\/p><h4>\u00a0<\/h4><h4 style=\"text-align: justify;\"><strong>Abstract<\/strong><\/h4><p style=\"text-align: justify;\">The ocean plays a central role in global carbon and nitrogen cycling, largely driven by microbial activity. Among these processes, nitrogen fixation converts inert N\u2082 into bioavailable forms that sustain marine food webs. While cyanobacterial diazotrophs have long been studied, non-cyanobacterial diazotrophs (NCDs) are now recognized as widespread and potentially major contributors to the marine nitrogen cycle.<br \/>This thesis investigates the hypothesis that NCDs exploit marine particles as microhabitats that protect nitrogenase from oxygen. Combining in situ chemotaxis assays in the Arctic Ocean, quantitative cell tracking, and high-resolution imaging of aggregates, this work reveals how microbial behavior, spatial organization, and metabolism interact.<br \/>Together, the results demonstrate that marine particles act as dynamic hotspots supporting non-cyanobacterial N\u2082 fixation in the ocean.<\/p><h4>\u00a0<\/h4><h4 style=\"text-align: justify;\"><strong>Composition of the jury\u00a0<\/strong><\/h4><ul style=\"text-align: justify;\"><li style=\"text-align: justify;\">Leila TIRICHINE - Nantes University, CNRS - Reviewer<\/li><li style=\"text-align: justify;\">Josep M\u00aa GASOL PIQU\u00c9 - ICM, CSIC, Barcelona - Reviewer<\/li><li style=\"text-align: justify;\">Lasse RIEMANN - University of Copenhagen - Examiner<\/li><li style=\"text-align: justify;\">Hans-Peter GROSSART - IGB, Berlin - Examiner<\/li><li style=\"text-align: justify;\">Jean-Christophe POGGIALE - MIO, CNRS, Marseille - Jury President<\/li><li style=\"text-align: justify;\">Mar BENAVIDES - MIO, IRD, Marseille - Supervisor<\/li><li style=\"text-align: justify;\">Pierre RONCERAY - CINaM, CNRS, Marseille - Co-supervisor<\/li><\/ul><h4>\u00a0<\/h4><h4 style=\"text-align: justify;\"><a href=\"https:\/\/univ-amu-fr.zoom.us\/j\/3724097500\" target=\"_blank\" rel=\"noopener\"><strong>Zoom link<\/strong><\/a><\/h4><p style=\"text-align: justify;\">Meeting ID: 372 409 7500<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-62ce63d e-flex e-con-boxed e-con e-parent\" data-id=\"62ce63d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-d0f57fc elementor-widget elementor-widget-image\" data-id=\"d0f57fc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1536\" height=\"1004\" src=\"https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-1536x1004.jpg\" class=\"attachment-1536x1536 size-1536x1536 wp-image-25487\" alt=\"\" srcset=\"https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-1536x1004.jpg 1536w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-300x196.jpg 300w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-1024x669.jpg 1024w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-768x502.jpg 768w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-2048x1338.jpg 2048w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-18x12.jpg 18w, https:\/\/www.mio.osupytheas.fr\/wp-content\/uploads\/2026\/03\/schemabio-copie_page-0001-1320x863.jpg 1320w\" sizes=\"(max-width: 1536px) 100vw, 1536px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"<p>Arthur Co\u00ebt (MIO Biog\u00e9ochimie) soutiendra sa th\u00e8se de doctorat le mercredi 18 mars 2026 \u00e0 14h00, \u00e0 l&#8217;Hexagone (Luminy, Marseille) sur le sujet suivant : Dynamics and architecture of diazotrophs [&hellip;]<\/p>\n","protected":false},"author":319,"featured_media":25487,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[17,1,26],"tags":[],"class_list":["post-25485","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-a-la-une","category-actualites","category-theses"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts\/25485","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/users\/319"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/comments?post=25485"}],"version-history":[{"count":14,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts\/25485\/revisions"}],"predecessor-version":[{"id":25653,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts\/25485\/revisions\/25653"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/media\/25487"}],"wp:attachment":[{"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/media?parent=25485"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/categories?post=25485"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/tags?post=25485"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}