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Detailed geochemical and mineralogical insights into some of the richest rare earth elements and yttrium (REY)-containing bioapatites from ocean-floor sediments have been provided by combining laser ablation inductively coupled plasma diffraction analysis, and Ce L3-edge high energy-resolution X-ray absorption near edge structure (HR-XANES) spectroscopy. Bioapatites at 1.94 and 4.70 m below the seafloor (mbsf) of the Clarion-Clipperton Zone (CCZ) of the Pacific Ocean have 26,600 (RSD = 15.7%, n = 20) and 30,300 (RSD = 14.6%, n = 10) mg/kg (mg/kg) total REY, respectively, and bioapatites at 2.28 and 6.95 mbsf of the Peru Basin have 15,500 (RSD = 15.6%, n = 20) and 15,700 (RSD = 17.8%, n = 29) mg/kg total REY, respectively. All bioapatite specimens have a variety of isomorphic substitutions in all atomic positions of the crystallographic structure. The average crystallochemical formula of bioapatites at 6.95 mbsf of the Peru Basin is [(PO4)2.71(SiO4)0.04(CO3,SO4)0.25][Ca4.57Na0.29Y0.04][F0.87Cl0.21]. All other substituents are below 0.04 atoms per formula unit. HR-XANES provides the first direct evidence for trivalent Ce in sediment apatites. The strong negative geochemical anomaly of Ce in fossil bioapatites is well explained by the occurrence of four valent Ce-MnO2 and CeO2 within the sediment and in seafloor ferromanganese nodules.

International audience; Our understanding of the up to seven orders of magnitude partitioning of thallium (Tl) between seawater and ferromanganese (FeMn) deposits rests upon two foundations: (1) being able to quantify the Tl(I)/Tl(III) ratio that reflects the extent of the oxidative scavenging of Tl by vernadite (δ-MnO2), the principle manganate mineral in oxic and suboxic environments, and (2) being able to determine the sorption sites and bonding environments of the Tl(I) and Tl(III) complexes on vernadite. We investigated these foundations by determining the oxidation state and chemical form of Tl in FeMn crusts and nodules from the global oceans at a Tl concentration ranging from several hundreds ppm (mg/kg) down to the low ppm level. Seventeen hydrogenetic crusts and eleven nodules from the Pacific, Atlantic, and Indian oceans and Baltic Sea were characterized by chemical analysis, X-ray diffraction, Raman spectroscopy, Mn K-edge X-ray absorption near-edge structure (XANES) spectroscopy, and Tl L3-edge high energy-resolution XANES (HR-XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The Tl concentration increases linearly from 1.5 to 319 ppm with the Mn/Fe ratio in Fe-vernadite from hydrogenetic crusts, whereas the percentage of Tl(III) to total Tl varies between 62% and 100% independent of both the Mn/Fe and Mn(III)/Mn(IV) 2 ratios. The data, complemented by molecular modeling of the Tl(III) coordination and by XANES calculations, suggest that the enrichment of Tl in Fe-vernadite is driven by (1) the oxidative uptake of octahedrally coordinated Tl(III) above the vacant Mn(IV) sites and on the layer edges of the vernadite layers, and (2) the sorption of Tl(I) on the crystallographic site of Ba at the surface of the vernadite layers, which is analog to the surface site of K. Thus, Tl has a high affinity for vernadite regardless of its oxidation state, and the lack of correlation between Tl(III) and the Mn/Fe ratio in FeMn crusts is explained by the affinity of Tl(I) for the Ba site. The Tl concentration varies between 2 and 112 ppm in surface and buried nodules independent of the Mn/Fe ratio, and the percentage of Tl(III) varies between 0% and 100%. Nodules subjected to sediment diagenesis with replacement of layered vernadite by tunneled todorokite are depleted in Tl and have more reduced thallium. Knowledge of the complex interplay of mineralogy, surface chemical processes, and crystallographic siting are required to understand the variability of Tl concentrations, redox state, and acquisition processes by marine FeMn deposits.

Informing the data subject in the procedure required by Regulation (EU) 2016/679 on the protection of personal data is often confused by practitioners in GDPR with the process of obtaining informed consent. Apart from this, which gives rise to discussions on the necessity of requiring specialists in GDPR to do courses dedicated to the field, the issue of information raises a number of issues in practice, marked by blurring, non-uniform interpretations or even a void of interpretation, much as the current legal doctrine and not only is relatively poor in materials that concern the field of personal data protection, and the practice of the National Supervisory Authority for Personal Data Processing under the new EU Regulation is still in its infancy. This article aims to address a series of dilemmas encountered in the GDPR practice by providing theoretical explanations and examples to facilitate the access of practitioners to the essence of institutions that inform the target person.

Calcareous nannofossils are micrometric calcite platelets secreted by the photosynthetic algae named coccolithophores and incertae sedis. Calcareous nannoplankton inhabit the photic zone from coast to open-ocean and have left an abundant fossil record since the Triassic. Therefore, they constitute an interesting material for geochemical studies although they have been overlooked in comparison to foraminifera. We have analyzed manganese distribution and valence in six calcareous nannofossil species representing different ages (Recent to Jurassic) and geological settings (land sections and deep ocean core-tops) and with different structures to assess the potential of Mn as a paleobiological or paleoenvironmental proxy. Nano x -Ray Fluorescence ( xrf ) maps were established at the esrf id 22 ni and id 21 beamlines and Mn k -edge x -Ray Absorption Near Edge Structure ( xanes ) at id 21. Mn is more abundant in nannofossils from pre-Quaternary rock samples than from core-top samples. In nannofossil rock samples, Mn nano xrf maps show distributions correlated with primary crystalline organization whereas in nannofossil core-top samples, Mn is either absent or does not follow the crystal organization. X anes analyses show that Mn is in the form of MnCO3. All these observations argue for Mn incorporation within calcareous nannofossils controlled by diagenesis through overgrowth of secondary calcite (Ca, Mn)CO3. Crusts grew along the original crystal growth directions. The incorporation of Mn in some core-top samples highlights potential early diagenesis input when the detached platelet lies on the seafloor or is still in the water column. Mn should therefore be considered a critical tool to identify diagenetic overgrowth rather than primary environmental conditions.

International audience; Metals are pre-requisites for life, fingerprints of life and tracers of metabolic processes of biomineralisation in living organisms. To study metals at macromolecular interaction scales requires state of the art analytical capabilities down to trace element levels and nanometer spatial resolutions. Fortunately, in the last decade, highly sensitive X-ray probes have been developed at worldwide 3rd generation synchrotron facilities. To date, a limited number of these highly specific nanoimaging probes have been deployed, and the ESRF ID16A/B and ID21 ones are among the leaders. X-rays are non (or least) destructive, noninvasive, penetrative and highly sensitive probes of solid samples and metals are their ideal targets. X-ray fluorescence has reached few tens of nm resolutions and a world record for absolute mass of e.g. 50 zg for Fe, whichcan be recognized as only about 600 atoms. Over the past decade, we have developed a multi-analyses methodology of nanoimaging mid-Z elements in low-Z matrices as a direct application to Life and/or Planetary Sciences of trace metals in biological matrices or in C/Si-based ones.X-ray fluorescence and absorption spectroscopies, deployed at the few nanometer scales, are sensitive probes but they require a re-assessment of the analytical requirements previously established at the few micron levels [1]. We will present some specific analytical developments and methodologies optimized for such applications. They are centered onto absolute quantification of metals using both the Fundamental Parameter Approximation and reference materials, after spectra analysis using the PyMCA package [2] coupled to Monte-Carlo simulations of sample compositions [3] and geometries, prerequisites for 2D/3D elemental imaging. Examples based on metal detection were applied to either environmental key organisms such as foraminifers or coccolithofores [4, 5] but also to the oldest living organisms tracedback to life's origins on Earth [1]. Finally, our search for life being also aimed at planetary and astronomical scales on exoplanets, we will present our patented methodology and sample holder [6] for Quarantine Extraterrestrial Sample Analyses (QESA) for the upcoming Returned Sample Missions from Mars and asteroids [7].[1] – L. Lemelle, A. Simionovici et al., Trends Anal. Chem. 91, 104–111, 2017.[2] – Solé, V.A., Papillon, et al., Spectrochim. Acta B, 62, 63-68, 2006.[3] – T. Schoonjans, L. Vincze, V.A. Sol_e, et al., Spectrochim. Acta B 70, 10-23, 2012.[4] – L. Lemelle, A. Bartolini, A. Simionovici, et al., Nature Comm., (in review) 2019.[5] – B. Suchéras-Marx, F. Giraud, A. Simionovici et al., Geobiology 14, 390-403, 2016.[6] – A. Simionovici and CNES, European Patent Office # EP2411791A1, 2010.[7] – A. Simionovici, L Lemelle et al., Proc. of the EAS Annual Meeting, EWASS, 2019

Paleoceanographical reconstructions are often based on microfossil geochemical analyses. Coccoliths are the most ancient, abundant and continuous record of pelagic photic zone calcite producer organisms. Hence, they could be valuable substrates for geochemically based paleoenvironmental reconstructions but only Sr/Ca is exploited even if it remains poorly understood. For example, some murolith coccoliths species have very high Sr/Ca compared to the common 1-4 mmol/mol recorded in placolith coccoliths. In this study, we analyzed the elemental composition of the Middle Jurassic murolith Crepidolithus crassus by synchrotron-based nanoXRF (X-ray Fluorescence Spectroscopy) mapping focusing on Sr/Ca and compared the record to two placolith species, namely Watznaueria contracta and Discorhabdus striatus. In C. crassus, Sr/Ca is more than ten times higher than in both placoliths and seems higher in the proximal cycle. By comparison with the placoliths analyzed in the same analytical set-up and from the same sample, we exclude the impact of the diagenesis and seawater Sr/Ca to explain the high Sr/Ca in C. crassus. Based on comparisons to Pontosphaera discopora and Scyphosphaera apsteinii which also have high Sr/Ca, it seems more likely that high Sr/Ca in C. crassus is either due to the vertical elongation of the R-units of the proximal cycle or related to the action of the special polysaccharide controlling the growth of those vertically elongated R-units that may have affinities to Sr2+ . In order to apply the Sr/Ca proxy to muroliths, further investigations are needed on cultured coccoliths.