Publications by authors named "Germain Bayon"

10 Publications

  • Page 1 of 1

A Multi-Elements Isotope Approach to Assess the Geographic Provenance of Manila Clams () via Recombining Appropriate Elements.

Foods 2021 Mar 18;10(3). Epub 2021 Mar 18.

Department of Marine Sciences and Convergent Technology, Hanyang University, Ansan 15588, Korea.

The increasing global consumption of seafood has led to increased trade among nations, accompanied by mislabeling and fraudulent practices that have rendered authentication crucial. The multi-isotope ratio analysis is considered as applicable tool for evaluating geographical authentications but requires information and experience to select target elements such as isotopes, through a distinction method based on differences in habitat and physiology due to origin. The present study examined recombination conditions of multi-elements that facilitated geographically distinct classifications of the clams to sort out appropriate elements. Briefly, linear discriminant analysis (LDA) analysis was performed according to several combinations of five stable isotopes (carbon (δC), nitrogen (δN), oxygen (δO), hydrogen (δD), and sulfur (δS)) and two radiogenic elements (strontium (Sr/Sr) and neodymium (Nd/Nd)), and the geographical classification results of the Manila clam from Democratic People's Republic of Korea (DPR Korea), Korea and China were compared. In conclusion, linear discriminant analysis (LDA) with at least four elements (C, N, O, and S) including S revealed a remarkable cluster distribution of the clams. These findings expanded the application of systematic multi-elements analyses, including stable and radiogenic isotopes, to trace the origins of collected from the Korea, China, and DPR Korea.
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http://dx.doi.org/10.3390/foods10030646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003290PMC
March 2021

A new chemical separation procedure for the determination of rare earth elements and yttrium abundances in carbonates by ICP-MS.

Talanta 2020 Nov 13;219:121244. Epub 2020 Jun 13.

LaTIM (INSERM UMR 1101) Université de Bretagne Occidentale, 22, Avenue C. Desmoulins, 29238, Brest Cedex 3, France.

The determination of rare earth elements (REEs) and Y in carbonates can be complicated by low REE abundances and the presence of significant amounts of Ba resulting in problematic interferences when analysed by ICP-MS. We describe here a novel ion-exchange method using the DGA resin (TODGA), combined with addition of a Tm spike, which allows the separation of the REEs+Y as a whole prior to analysis using an Element XR ICP-MS. This method was validated with results obtained on three different reference carbonate materials (CAL-S, JLs-1 and BEAN, an in-house standard), yielding reproducibility levels better than 3% (RSD) in most cases. This new separation scheme is particularly well suited for carbonate samples having very low REE contents, but could be equally applied to various rock types and organic-rich sample matrices whenever quantitative Ba removal is required.
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http://dx.doi.org/10.1016/j.talanta.2020.121244DOI Listing
November 2020

Abrupt response of chemical weathering to Late Quaternary hydroclimate changes in northeast Africa.

Sci Rep 2017 03 14;7:44231. Epub 2017 Mar 14.

Laboratoire Océanographique de Villefranche sur Mer (LOV, OOV), CNRS, UPMC Univ Paris 06, 181 chemin du Lazaret, 06230, Villefranche sur Mer, France.

Chemical weathering of silicate rocks on continents acts as a major sink for atmospheric carbon dioxide and has played an important role in the evolution of the Earth's climate. However, the magnitude and the nature of the links between weathering and climate are still under debate. In particular, the timescale over which chemical weathering may respond to climate change is yet to be constrained at the continental scale. Here we reconstruct the relationships between rainfall and chemical weathering in northeast Africa for the last 32,000 years. Using lithium isotopes and other geochemical proxies in the clay-size fraction of a marine sediment core from the Eastern Mediterranean Sea, we show that chemical weathering in the Nile Basin fluctuated in parallel with the monsoon-related climatic evolution of northeast Africa. We also evidence strongly reduced mineral alteration during centennial-scale regional drought episodes. Our findings indicate that silicate weathering may respond as quickly as physical erosion to abrupt hydroclimate reorganization on continents. Consequently, we anticipate that the forthcoming hydrological disturbances predicted for northeast Africa may have a major impact on chemical weathering patterns and soil resources in this region.
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http://dx.doi.org/10.1038/srep44231DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349522PMC
March 2017

Extensive wet episodes in Late Glacial Australia resulting from high-latitude forcings.

Sci Rep 2017 Mar 8;7:44054. Epub 2017 Mar 8.

The Australian National University, Research School of Earth Sciences, Canberra, Australia.

Millennial-scale cooling events termed Heinrich Stadials punctuated Northern Hemisphere climate during the last glacial period. Latitudinal shifts of the intertropical convergence zone (ITCZ) are thought to have rapidly propagated these abrupt climatic signals southward, influencing the evolution of Southern Hemisphere climates and contributing to major reorganisation of the global ocean-atmosphere system. Here, we use neodymium isotopes from a marine sediment core to reconstruct the hydroclimatic evolution of subtropical Australia between 90 to 20 thousand years ago. We find a strong correlation between our sediment provenance proxy data and records for western Pacific tropical precipitations and Australian palaeolakes, which indicates that Northern Hemisphere cooling phases were accompanied by pronounced excursions of the ITCZ and associated rainfall as far south as about 32°S. Comparatively, however, each of these humid periods lasted substantially longer than the mean duration of Heinrich Stadials, overlapping with subsequent warming phases of the southern high-latitudes recorded in Antarctic ice cores. In addition to ITCZ-driven hydroclimate forcing, we infer that changes in Southern Ocean climate also played an important role in regulating late glacial atmospheric patterns of the Southern Hemisphere subtropical regions.
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http://dx.doi.org/10.1038/srep44054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5341032PMC
March 2017

Seep-carbonate lamination controlled by cyclic particle flux.

Sci Rep 2016 11 23;6:37439. Epub 2016 Nov 23.

MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany.

Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U-Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes.
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http://dx.doi.org/10.1038/srep37439DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5120270PMC
November 2016

North Atlantic Deep Water Production during the Last Glacial Maximum.

Nat Commun 2016 06 3;7:11765. Epub 2016 Jun 3.

Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité de Recherche Géosciences Marines, F-29280 Plouzané, France.

Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ(13)C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.
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http://dx.doi.org/10.1038/ncomms11765DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895795PMC
June 2016

Abrupt drainage cycles of the Fennoscandian Ice Sheet.

Proc Natl Acad Sci U S A 2013 Apr 8;110(17):6682-7. Epub 2013 Apr 8.

Aix Marseille Université, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, Collège de France, 13545 Aix-en-Provence Cedex 04, France.

Continental ice sheets are a key component of the Earth's climate system, but their internal dynamics need to be further studied. Since the last deglaciation, the northern Eurasian Fennoscandian Ice Sheet (FIS) has been connected to the Black Sea (BS) watershed, making this basin a suitable location to investigate former ice-sheet dynamics. Here, from a core retrieved in the BS, we combine the use of neodymium isotopes, high-resolution elemental analysis, and biomarkers to trace changes in sediment provenance and river runoff. We reveal cyclic releases of meltwater originating from Lake Disna, a proglacial lake linked to the FIS during Heinrich Stadial 1. Regional interactions within the climate-lake-FIS system, linked to changes in the availability of subglacial water, led to abrupt drainage cycles of the FIS into the BS watershed. This phenomenon raised the BS water level by ∼100 m until the sill of the Bosphorus Strait was reached, flooding the vast northwestern BS shelf and deeply affecting the hydrology and circulation of the BS and, probably, of the Marmara and Aegean Seas.
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http://dx.doi.org/10.1073/pnas.1214676110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3637780PMC
April 2013

Intensifying weathering and land use in Iron Age Central Africa.

Science 2012 Mar 9;335(6073):1219-22. Epub 2012 Feb 9.

Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Unité de Recherche Géosciences Marines, F-29280 Plouzané, France.

About 3000 years ago, a major vegetation change occurred in Central Africa, when rainforest trees were abruptly replaced by savannas. Up to this point, the consensus of the scientific community has been that the forest disturbance was caused by climate change. We show here that chemical weathering in Central Africa, reconstructed from geochemical analyses of a marine sediment core, intensified abruptly at the same period, departing substantially from the long-term weathering fluctuations related to the Late Quaternary climate. Evidence that this weathering event was also contemporaneous with the migration of Bantu-speaking farmers across Central Africa suggests that human land-use intensification at that time had already made a major impact on the rainforest.
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http://dx.doi.org/10.1126/science.1215400DOI Listing
March 2012

Determination of rare earth elements and other trace elements (Y, Mn, Co, Cr) in seawater using Tm addition and Mg(OH)₂ co-precipitation.

Talanta 2011 Jul 5;85(1):582-7. Epub 2011 May 5.

Département Géosciences Marines, IFREMER, 29280 Plouzané, France.

This paper reports on a novel procedure for determining trace element abundances (REE and Y, Cr, Mn, Co) in seawater by inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The procedure uses a combination of pre-concentration using co-precipitation onto magnesium hydroxides and addition of thulium spike. The validity of the method was assessed onto 25 ml volumes of certified reference materials (NASS- and CASS-4) and in house seawater standard. Procedural blanks were determined by applying the same procedure to aliquots of seawater previously depleted in trace elements by successive Mg(OH)(2) co-precipitations, yielding estimated contributions to the studied samples better than 1.1% for all elements, with the exception of Cr (<3.3%) and Co (up to 8%). The reproducibility of the method over the six month duration of the study was smaller than 11% RSD for all the studied elements. Results obtained for NASS-5 and CASS-4 agree well with published working values for trace elements.
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http://dx.doi.org/10.1016/j.talanta.2011.04.023DOI Listing
July 2011

Fossil evidence for serpentinization fluids fueling chemosynthetic assemblages.

Proc Natl Acad Sci U S A 2011 May 25;108(19):7698-703. Epub 2011 Apr 25.

Laboratoire d'Ecogéochimie des Environnements Benthiques, Centre National de la Recherche Scientifique, Laboratoire Arago, Université Pierre et Marie Curie-Paris 6, 66650 Banyuls-sur-Mer, France.

Among the deep-sea hydrothermal vent sites discovered in the past 30 years, Lost City on the Mid-Atlantic Ridge (MAR) is remarkable both for its alkaline fluids derived from mantle rock serpentinization and the spectacular seafloor carbonate chimneys precipitated from these fluids. Despite high concentrations of reduced chemicals in the fluids, this unique example of a serpentinite-hosted hydrothermal system currently lacks chemosynthetic assemblages dominated by large animals typical of high-temperature vent sites. Here we report abundant specimens of chemosymbiotic mussels, associated with gastropods and chemosymbiotic clams, in approximately 100 kyr old Lost City-like carbonates from the MAR close to the Rainbow site (36 °N). Our finding shows that serpentinization-related fluids, unaffected by high-temperature hydrothermal circulation, can occur on-axis and are able to sustain high-biomass communities. The widespread occurrence of seafloor ultramafic rocks linked to likely long-range dispersion of vent species therefore offers considerably more ecospace for chemosynthetic fauna in the oceans than previously supposed.
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http://dx.doi.org/10.1073/pnas.1009383108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3093485PMC
May 2011