{"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-soutiendra-sa-these-le-mercredi-18-mars-2026-a-14h00-a-lhexagone-luminy","status":"publish","type":"post","link":"https:\/\/www.mio.osupytheas.fr\/fr\/arthur-coet-soutiendra-sa-these-le-mercredi-18-mars-2026-a-14h00-a-lhexagone-luminy\/","title":{"rendered":"Arthur Co\u00ebt soutiendra sa th\u00e8se le mercredi 18 mars 2026 \u00e0 14h00 \u00e0 l&#8217;Hexagone (Luminy)"},"content":{"rendered":"\t\t<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 Biog\u00e9ochimie) soutiendra sa th\u00e8se de doctorat le <strong>mercredi 18 mars 2026<\/strong> \u00e0 <strong>14h00<\/strong>, \u00e0 l&#8217;Hexagone (Luminy, Marseille) sur le sujet suivant : <em>Dynamics and architecture of diazotrophs particle colonization. <\/em>Vous \u00eates chaleureusement invit\u00e9s \u00e0 assister \u00e0 la soutenance ainsi qu&#8217;au pot de th\u00e8se qui suivra.<\/p><h4>\u00a0<\/h4><h4 style=\"text-align: justify;\"><strong>R\u00e9sum\u00e9<\/strong><\/h4><p style=\"text-align: justify;\">L\u2019oc\u00e9an joue un r\u00f4le central dans les cycles biog\u00e9ochimiques du carbone et de l\u2019azote, largement r\u00e9gul\u00e9s par l\u2019activit\u00e9 microbienne. Parmi ces processus, la fixation du N\u2082 convertit le diazote atmosph\u00e9rique en azote biodisponible, soutenant les r\u00e9seaux trophiques marins. Si les cyanobact\u00e9ries ont longtemps concentr\u00e9 l\u2019attention, les diazotrophes non-cyanobact\u00e9riens (NCDs) apparaissent aujourd\u2019hui comme largement r\u00e9pandus et potentiellement majeurs dans le cycle global de l\u2019azote.<br \/>Cette th\u00e8se teste l\u2019hypoth\u00e8se selon laquelle les NCDs exploitent les particules marines comme microhabitats protecteurs contre l\u2019oxyg\u00e8ne. En combinant un essai de chimiotaxie in situ en Arctique, le suivi quantitatif de trajectoires cellulaires et l\u2019imagerie haute r\u00e9solution d\u2019agr\u00e9gats, ce travail met en \u00e9vidence le lien entre comportement microbien, organisation spatiale et activit\u00e9 m\u00e9tabolique.<br \/>Les r\u00e9sultats montrent que les particules marines constituent des hotspots dynamiques et transitoires de fixation du N\u2082 dans l\u2019oc\u00e9an.<\/p><h4>\u00a0<\/h4><h4 style=\"text-align: justify;\"><strong>Composition du jury\u00a0<\/strong><\/h4><ul style=\"text-align: justify;\"><li style=\"text-align: justify;\">Leila TIRICHINE &#8211; Nantes Universit\u00e9, CNRS \u2013 Rapporteuse<\/li><li style=\"text-align: justify;\">Josep M\u00aa GASOL PIQU\u00c9 &#8211; ICM, CSIC, Barcelona \u2013 Rapporteur<\/li><li style=\"text-align: justify;\">Lasse RIEMANN \u2013 University of Copenhagen \u2013 Examinateur<\/li><li style=\"text-align: justify;\">Hans-Peter GROSSART \u2013 IGB, Berlin \u2013 Examinateur<\/li><li style=\"text-align: justify;\">Jean-Christophe POGGIALE \u2013 MIO, CNRS, Marseille \u2013 Pr\u00e9sident du jury<\/li><li style=\"text-align: justify;\">Mar BENAVIDES \u2013 MIO, IRD, Marseille \u2013 Supervisor<\/li><li style=\"text-align: justify;\">Pierre RONCERAY \u2013 CINaM, CNRS, Marseille \u2013 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>Lien Zoom<\/strong><\/a><\/h4><p style=\"text-align: justify;\">ID de r\u00e9union : 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>\n\t\t","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\/fr\/wp-json\/wp\/v2\/posts\/25485","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/users\/319"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/comments?post=25485"}],"version-history":[{"count":14,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/posts\/25485\/revisions"}],"predecessor-version":[{"id":25653,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/posts\/25485\/revisions\/25653"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/media\/25487"}],"wp:attachment":[{"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/media?parent=25485"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/categories?post=25485"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/fr\/wp-json\/wp\/v2\/tags?post=25485"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}