{"id":29214,"date":"2026-07-17T17:15:41","date_gmt":"2026-07-17T15:15:41","guid":{"rendered":"https:\/\/www.mio.osupytheas.fr\/?p=29214"},"modified":"2026-07-24T10:23:01","modified_gmt":"2026-07-24T08:23:01","slug":"thesis-by-eleonord-mayissah-moungues","status":"publish","type":"post","link":"https:\/\/www.mio.osupytheas.fr\/en\/these-eleonord-mayissah-moungues\/","title":{"rendered":"Congratulations to Eleonord Mayissah Moungues, who defended his thesis on Friday 17 July 2026 at the University of Toulon"},"content":{"rendered":"
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Eleonord Mayissah Moungues<\/strong> (Masuku University of Science and Technology (USTM Gabo) \u2013 MIO University of Toulon) defended his doctoral thesis on Friday 17 July 2026<\/strong> \u00e0 14h00<\/strong> at the University of Toulon \u2013 La Garde Campus, on the following topic: Chemical and microbiological inputs from the Ogoou\u00e9 River into its mangroves. <\/em><\/p>

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Abstract<\/strong><\/h4>

Sediments in rivers and mangroves act as an ecological reservoir, accumulating metals resulting from human activity (mining, industry, agriculture, towns and cities). But this sequestration is not permanent. When conditions change \u2013 such as climate, tides or dredging \u2013 these metals can be released into the water, contaminating fish and, ultimately, finding their way onto our plates.<\/p>

In Gabon, the Ogoou\u00e9 River is precisely in this kind of situation: it rises in a mining area (manganese, gold), flows through rural and urban areas, and then empties into the Atlantic Ocean, feeding one of the largest mangrove forests in Central Africa. Throughout its course, human pressures vary and the river carries numerous sediment particles, which may be contaminated. However, whilst useful, the existing environmental monitoring relies mainly on satellite imagery and one-off chemical measurements, which only flag up damage once it is already visible.<\/p>

This thesis proposes an alternative approach combining traditional geochemical indicators with the microbial communities living in sediments (bacteria, archaea); invisible to the naked eye, they are present in their billions in every gram of silt. These microorganisms react very quickly to changes in their environment: for example, if the concentration of a contaminant \u2013 particularly a metal \u2013 increases, some microorganisms disappear whilst others proliferate. Monitoring these changes in microbial communities would provide managers with an additional monitoring tool.
By studying three areas along the Ogoou\u00e9 River \u2013 the Franceville-Moanda mining region upstream, the main course of the Ogoou\u00e9, and the mangroves of Port-Gentil on the coast, this study shows that combining geochemical and microbial indicators provides a much more detailed and earlier picture of the state of the ecosystems.<\/p>

This thesis proposes practical tools for environmental managers, enabling them to anticipate environmental degradation rather than simply observing it. This approach can be applied to other countries facing the same challenges: reconciling economic development, resource extraction and the protection of natural heritage.<\/p>

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Key words<\/strong><\/h4>

Ogoou\u00e9 River, Sediment, Trace metals, Geochemical indicators, Microbial biodiversity, Mangroves.<\/p>

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Composition of the jury\u00a0<\/strong><\/h4>

  • Mr Nicolas Marmier<\/strong>, University Professor, Universit\u00e9 C\u00f4te d\u2019Azur (France), Rapporteur,<\/p><\/li>

  • Mr Olivier Gros<\/strong>, University Professor, University of the Antilles (France), Rapporteur,<\/p><\/li>

  • Mr Alain Dolla<\/strong>, Research Director, CNRS (France), Examiner,<\/p><\/li>

  • Mr Louis-Cl\u00e9ment Obame Engonga<\/strong>, University Professor, Masuku University of Science and Technology (Gabon), Examiner,<\/p><\/li>

  • Ms Isabelle Navarro<\/strong>, Research Fellow, IRD (France), Examiner,<\/p><\/li>

  • Ms Estelle Dumont<\/strong>, Assistant Lecturer at the University of Science and Technology of Masuku (Gabon), Co-supervisor of a PhD thesis,<\/p><\/li>

  • Mr Joseph Privat Ondo<\/strong>, Senior Lecturer (HDR), Masuku University of Science and Technology (Gabon), Co-supervisor of a PhD thesis,<\/p><\/li>

  • Mr St\u00e9phane Mounier<\/strong>, Senior Lecturer (HDR), University of Toulon (France), PhD supervisor.<\/p><\/li><\/ul>\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

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    Photo credit: St\u00e9phane Mounier<\/em><\/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\t\t<\/div>","protected":false},"excerpt":{"rendered":"

    Eleonord Mayissah Moungues (Universit\u00e9 des Sciences et Techniques de Masuku USTM Gabo – MIO Universit\u00e9 de Toulon) a soutenu sa th\u00e8se de doctorat le Vendredi 17 juillet 2026 \u00e0 14h00 […]<\/p>\n","protected":false},"author":319,"featured_media":29279,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[17,1,26],"tags":[],"class_list":["post-29214","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\/29214","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=29214"}],"version-history":[{"count":22,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts\/29214\/revisions"}],"predecessor-version":[{"id":29285,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/posts\/29214\/revisions\/29285"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/media\/29279"}],"wp:attachment":[{"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/media?parent=29214"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/categories?post=29214"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mio.osupytheas.fr\/en\/wp-json\/wp\/v2\/tags?post=29214"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}