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4. Microbial shift in the enteric bacteriome of coral reef fish following climate-driven regime shifts

Author

Cheutin, M.-C., Villéger, S., Hicks, C.C., Robinson, J.P.W., Graham, N.A.J., Marconnet, C., Restrepo, C.X.O., Bettarel, Y., Bouvier, T., Auguet, J.-C., Cheutin, M.-C., Villéger, S., Hicks, C.C., Robinson, J.P.W., Graham, N.A.J., Marconnet, C., Restrepo, C.X.O., Bettarel, Y., Bouvier, T., and Auguet, J.-C.

Abstract

Replacement of coral by macroalgae in post-disturbance reefs, also called a “coral-macroalgal regime shift”, is increasing in response to climate-driven ocean warming. Such ecosystem change is known to impact planktonic and benthic reef microbial communities but few studies have examined the effect on animal microbiota. In order to understand the consequence of coral-macroalgal shifts on the coral reef fish enteric bacteriome, we used a metabarcoding approach to examine the gut bacteriomes of 99 individual fish representing 36 species collected on reefs of the Inner Seychelles islands that, following bleaching, had either recovered to coral domination, or shifted to macroalgae. While the coral-macroalgal shift did not influence the diversity, richness or variability of fish gut bacteriomes, we observed a significant effect on the composition (R2 = 0.02; p = 0.001), especially in herbivorous fishes (R2 = 0.07; p = 0.001). This change is accompanied by a significant increase in the proportion of fermentative bacteria (Rikenella, Akkermensia, Desulfovibrio, Brachyspira) and associated metabolisms (carbohydrates metabolism, DNA replication, and nitrogen metabolism) in relation to the strong turnover of Scarinae and Siganidae fishes. Predominance of fermentative metabolisms in fish found on macroalgal dominated reefs indicates that regime shifts not only affect the taxonomic composition of fish bacteriomes, but also have the potential to affect ecosystem functioning through microbial functions.

Published
2021

5. Souterrain et habitat rural du Moyen Âge

Author

Bonnamour, Gerald, Arles, Adrien, Marconnet, C., Coutelas, Arnaud, Tomas, E., Université d'Orléans, SCD, Amélie Laurent ( CG45) (Coord.), Laurent Fournier (INRAP) (Coord.), and Christophe Marconnet (Arkemine) (Coord.)

Subjects
[SHS.ARCHEO] Humanities and Social Sciences/Archaeology and Prehistory, [SHS] Humanities and Social Sciences, ComputingMilieux_MISCELLANEOUS
Published
2013

6. Fouille archéologique préventive ' Le Cerisier ', commune du Bonhomme (Haut-Rhin, avril 2006)

Author

Bonnamour , G., Camizuli , Estelle, Marconnet , C., Archéologie, Terre, Histoire, Sociétés [Dijon] ( ARTeHiS ), Ministère de la Culture et de la Communication ( MCC ) -Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Archéologie, Terre, Histoire, Sociétés [Dijon] (ARTeHiS), and Ministère de la Culture et de la Communication (MCC)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
métallurgie, Archéologie préventive, scorie, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, metallurgy, recyclage, argent, recycling, slag, Archéologie, [ SHS.ARCHEO ] Humanities and Social Sciences/Archaeology and Prehistory, mechanical process, Haut-Rhin, silver, traitement mécanique
Abstract

Les procédés liés à la métallurgie de l’argent sont évoqués dans un certain nombre de traités anciens. Au xvie siècle, les illustrations devenues célèbres de Heinrich Groff représentent une mine d’argent et ses structures de traitements situées dans la région (La Croix-aux-Mines).L’opération d’archéologie préventive a eu pour objet la fouille de vestiges liés à la métallurgie de l’argent dans les environs de Sainte-Marie-aux-Mines (Haut Rhin, France). Elle fait suite à un diagnostic réalisé par Patrick Clerc1 (INRAP) en Juin 2004. Une fouille programmée organisée dans une parcelle voisine par Pierre Fluck2 dans les années 19903 avait permis de mettre au jour des vestiges de fours métallurgiques du xvie siècle.La fouille a mis en évidence des amas de résidus métallurgiques. Le site ayant été perturbé par la guerre de 1914-1918, il a été indispensable de distinguer les dépôts liés au fonctionnement d’un atelier métallurgique de ceux vraisemblablement remaniés.L’étude approfondie de la stratification a permis d’identifier différentes phases de dépôts. Certaines unités stratigraphiques sont notamment constituées de scories concassées et calibrées, preuves d’un traitement mécanique. Une sole de bocard témoigne entre autres de la présence de l’installation de broyage à proximité immédiate de la fonderie.En termes de structures et hormis les tranchées de la Grande Guerre, seuls des restes d’un dispositif en bois associé aux sables de scories concassées et daté du xvie siècle, ont été découverts.A défaut de structures de chauffe, une grande quantité de scories, de résidus et de restes de fours a été échantillonnée. Des analyses ont été réalisées afin d’apprécier les processus de la métallurgie de l’époque. Several ancient treaties mention the silver metallurgical techniques. The famous drawings of Heinrich Groff, dated from the 16th century, describe a silver mine – located in the Vosges mountains (La-Croix-aux-Mines) – and all the infrastructures related to the extraction of this precious metal.Thanks to its rich industrial heritage, the area of Sainte-Marie-aux-Mines (Vosges Mountains – North East of France) is an exceptional place to study the ancient production of silver mainly for money manufacturing.The object of the excavation presented in this paper was the study of silver metallurgy remains, located near Sainte-Marie-aux-Mines. It was performed soon after the trenches survey lead by Patrick Clerc (INRAP) in the same area. In the nineties, Pierre Fluck had indeed discovered in the neighbourhood some former melting furnaces dated from the 16th century. Our excavation, performed in 2006, has shown high amount of metallurgical wastes (slags, mattes, speisses…) but as the site was disturbed by the First World War, it was necessary to identify the undisturbed layers where the workshop could have taken place.A precise stratigraphic study has explained the organisation of the complex deposit phases. Several layers were composed of crushed and calibrated slags, attesting the occurrence of a mechanical process. Moreover an anvil of stamp-mill was found and might corroborate the hypothesis of a crushing workshop near the smelting one.Except the WWI trenches, a nice wood structure in relation with the crushed slag sands was discovered and dated from the 16th c. Even if no particular furnace structures were detected, the high amount of metallurgical wastes sampled, help to understand the different stages of the smelting process. In particular, it gives us access to the ore used.

Published
2011

11. Corrosion of stainless steels induced by manganese oxidizing micro-organisms

Author

Marconnet, C., Landoulsi, J., Dagbert, C., Richard, C., and Pulvin, S.

Abstract

One of the most studied processes leading to cases of Microbiologically Influenced Corrosion (MIC) of stainless steels immersed in natural waters deals with micro-organisms able to precipitate manganese oxides/hydroxides on the surface of the material. The aim of this paper is to present a state-of-the-art on the different mechanisms, found in the literature, likely to explain the biooxidation of Mn?(II) and the influence of biodeposited manganese oxides on the electrochemical behaviour of stainless steels. The role of the enzymatic activity of these micro-organisms is emphasized. En corrosion a?robie, un des m?canismes les plus fr?quemment cit?s pour expliquer certains cas de corrosion microbienne en eaux naturelles est li? ? la pr?sence de micro-organismes capables de pr?cipiter des oxydes/hydroxydes de mangan?se sur la surface des m?taux et alliages pr?sents dans leur environnement. L'objectif de cet article est de pr?senter les diff?rents m?canismes, cit?s dans la litt?rature, qui sont ? l'origine de la corrosion microbienne induite par les micro-organismes mangano-oxydants. Les m?canismes d?crits sont de nature ?lectrochimique?; en effet, ces micro-organismes peuvent, par leur m?tabolisme, exercer une influence sur le comportement ?lectrochimique et par cons?quent sur la r?sistance ? la corrosion des aciers inoxydables. L'influence de l'activit? enzymatique de ces micro-organismes est d?velopp?e.

Published
2006

12. Enzymatic mechanism in low chloride medias : Influence of glucose oxidase on the electrochemical behaviour of AISI 316L stainless steel

Author

Landoulsi, J., Marconnet, C., Dagbert, C., Pulvin, S., Richard, C., and F?ron, D.

Abstract

The open circuit potential (OCP) of stainless steels immersed in natural waters generally increases with time. This phenomenon is strongly linked to the formation of a biofilm on the surface. Several studies have proved that the biofilm modifies the reaction of reduction of dissolved oxygen and that it acts mainly on the cathodic processes. One of the hypotheses explaining the action of the biofilm involves certain bacteria which use dissolved oxygen and extracellular enzymes to produce reactive oxygen species. Among this kind of metabolites is hydrogen peroxide H2O2. This compound interacts with the passive layer of stainless steels and affects their electrochemical behaviour, even when the chloride concentration is low. The aim of this work is to study the influence of an enzymatic reaction (of the oxydoreductase type) on anodic and cathodic processes on AISI 316L stainless steel. Experiments are carried out in two artificial electrolytes simulating natural freshwaters, with two different chloride concentrations. The role of enzymatically-produced hydrogen peroxide is shown by OCP measurements and voltamperometric methods. Le comportement ?lectrochimique des aciers inoxydables en eaux naturelles a ?t? caract?ris? par une augmentation de leur potentiel de corrosion libre. Ce ph?nom?ne est fortement li? ? la formation d'un biofilm ? leur surface. Plusieurs ?tudes ont montr? que le biofilm modifie la r?action de r?duction de l'oxyg?ne et qu'il agit principalement sur les processus cathodiques. L'une des hypoth?ses qui explique le mode d'action du biofilm met en jeu le r?le de certaines bact?ries qui utilisent l'oxyg?ne pour former des interm?diaires r?actifs. En r?alit?, ces bact?ries s?cr?tent des enzymes extracellulaires responsables de la formation de ces esp?ces r?actives. Certaines r?actions enzymatiques consistent ? r?duire l'oxyg?ne de l'air pour former du peroxyde d'hydrog?ne (H2O2). Ce produit interagit avec la couche passive des aciers inoxydables et affecte fortement leur comportement ?lectrochimique, m?me dans les milieux faiblement chlorur?s. L'objectif de ce travail est d'?tudier l'influence d'une r?action enzymatique (type oxydor?ductase) sur les processus anodiques et cathodiques sur acier inoxydable AISI?316L. L'?tude a ?t? men?e dans deux milieux artificiels, simulant les eaux douces naturelles, avec des concentrations diff?rentes en chlorures. Des suivis du potentiel de corrosion libre ainsi que des m?thodes voltamp?rom?triques ont ?t? utilis?s pour mettre en ?vidence le r?le du peroxyde d'hydrog?ne bioform?.

Published
2006

13. Behaviour of stainless steels immersed in natural waters: Electrochemistry and bacterial adhesion

Author

Marconnet, C., Dagbert, C., Roy, M., and F?ron, D.

Abstract

The free corrosion potential of a stainless steel immersed in natural seawater rises quickly until it reaches values ranging between +100 and +350 mV/SCE, which increases the risk of initiation of pitting corrosion. According to litterature this phenomenon also occurs in fresh waters. The aim of this study is to confirm or to invalidate this trend; the electrochemical behaviour of samples of stainless steels immersed in river water and the influence of the biofilm formed on the surface of the samples are studied. The free corrosion potentials of three different stainless steels (S30403 or AISI 304L, S31603 or AISI 316L, S31254 or 254SMO) have been measured continuously during their immersion in the Seine river. SEM observations of the samples surface show the presence of a biofilm on the three kinds of stainless steel. The free corrosion potentials increase and end up between +100 and +300 mV/SCE. This increase is not immediate, the latency time being around 20 days. This could be related to an effect of the low temperature of the water during the immersion (8?10 ?C) and/or to an effect of the Total Organic Carbon (TOC), which would limit the growth rate of the biofilm, hence its influence on the evolution of the free corrosion potential.Un acier inoxydable immerg? dans de l?eau de mer naturelle voit son potentiel de corrosion libre Ecorr augmenter rapidement jusqu?? atteindre des valeurs comprises entre +100 et +350 mV/ECS, ce qui augmente le risque d?initiation de la corrosion par piq?res. D?apr?s la litt?rature, il semblerait que le m?me ph?nom?ne ait lieu en eaux douces naturelles. Le but de cette ?tude est de confirmer ou infirmer cette tendance en ?tudiant le comportement ?lectrochimique d??chantillons d?aciers inoxydables immerg?s dans une eau de rivi?re et en examinant l?influence du biofilm form? sur la surface de l?acier inoxydable. Pour cela, un suivi du potentiel de corrosion libre d??chantillons d?aciers inoxydables S30403 (AISI 304L), S31603 (AISI 316L) et S31254 (254SMO) a ?t? effectu? durant leur immersion dans la Seine. Des observations de la surface des ?chantillons ont ?t? pratiqu?es au MEB et ont montr? la pr?sence d?un biofilm sur les trois nuances d?acier inoxydable. L?augmentation du potentiel de corrosion libre a bien eu lieu et a atteint les m?mes valeurs que celles de la litt?rature (entre +100 et +300 mV/ECS). Par contre, cette augmentation n?est apparue qu?apr?s un temps de latence d?environ 20 jours. L?explication de ce retard peut provenir de la faible temp?rature de l?eau (8?10 ?C) et de sa faible teneur en carbone organique total (COT) qui limiteraient la vitesse de d?veloppement du biofilm et donc son impact sur l??volution de Ecorr.

Published
2005

14. Microbial Shift in the Enteric Bacteriome of Coral Reef Fish Following Climate-Driven Regime Shifts.

Author

Cheutin MC, Villéger S, Hicks CC, Robinson JPW, Graham NAJ, Marconnet C, Restrepo CXO, Bettarel Y, Bouvier T, and Auguet JC

Abstract

Replacement of coral by macroalgae in post-disturbance reefs, also called a "coral-macroalgal regime shift", is increasing in response to climate-driven ocean warming. Such ecosystem change is known to impact planktonic and benthic reef microbial communities but few studies have examined the effect on animal microbiota. In order to understand the consequence of coral-macroalgal shifts on the coral reef fish enteric bacteriome, we used a metabarcoding approach to examine the gut bacteriomes of 99 individual fish representing 36 species collected on reefs of the Inner Seychelles islands that, following bleaching, had either recovered to coral domination, or shifted to macroalgae. While the coral-macroalgal shift did not influence the diversity, richness or variability of fish gut bacteriomes, we observed a significant effect on the composition (R2 = 0.02; p = 0.001), especially in herbivorous fishes (R2 = 0.07; p = 0.001). This change is accompanied by a significant increase in the proportion of fermentative bacteria ( Rikenella, Akkermensia , Desulfovibrio , Brachyspira ) and associated metabolisms (carbohydrates metabolism, DNA replication, and nitrogen metabolism) in relation to the strong turnover of Scarinae and Siganidae fishes. Predominance of fermentative metabolisms in fish found on macroalgal dominated reefs indicates that regime shifts not only affect the taxonomic composition of fish bacteriomes, but also have the potential to affect ecosystem functioning through microbial functions.

Published
2021
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