Ultra-trace interference-free analysis of palladium in natural waters by ICP-MS after on-line matrix separation and pre-concentration
The determination of palladium (Pd) in environmental samples by ICP-MS is challenging as all its isotopes are extensively interfered due to isobaric (e.g. 110Cd on 110Pd, 106Cd on 106Pd), polyatomic (e.g. 92Mo16O on 108Pd, 89Y16O on 105Pd) and doubly-charged (e.g. 208Pb2+ on 104Pd) species formed in the plasma from elements usually present at concentrations several orders of magnitude higher. As a result, the determination of Pd in natural waters is extremely scarce despite is has been proven that this metal is subject to a significant anthropogenic impact mainly linked to its use in catalytic converters in motor vehicles. In order to overcome this situation, we have developed an ultra-trace interference-free methodology for the determination of Pd in natural waters by ICP-MS after on-line matrix separation and preconcentration. The method is based on the strong affinity of Pd towards a commercially-available carboxymethylated polyethylenimine resin, which also has the ability to retain most of the transition metals. However, Pd is not eluted from the resin at typical elution conditions (e.g. 2 M HNO3, which removes all the interference-forming metals), but this can be attained by passing a diluted thiourea solution (10−3 M). Therefore, the interference-free on-line determination of Pd in natural waters was successfully achieved using a two-step elution procedure. Procedural blank values were 0.012 ± 0.003 ng kg−1 (n = 6), which results in a detection limit of 0.010 ng kg−1, allowing the determination of dissolved Pd in natural samples at low, ambient concentrations. The optimized methodology was applied to determine the concentrations of Pd in the Gironde estuary, which represents the first dissolved Pd profile along an estuarine salinity gradient and one of the first dataset of Pd concentrations in natural waters at ambient levels in almost 4 decades. The simplicity of the preconcentration setup and the possibility for its automation offers new analytical opportunities, which will be useful for future studies aiming to improve our understanding of the behavior of Pd in natural waters.
(Talanta. vol. 232, n° 0039-9140, pp. 122289, 01/09/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Presentation and evaluation of the IPSL‐CM6A‐LR ensemble of extended historical simulations
The Institut Pierre-Simon Laplace Climate Modeling Center has produced an ensemble of extended historical simulations using the IPSL-CM6A-LR climate model. This ensemble (referred to as IPSL-EHS) is composed of 32 members over the 1850–2059 period that share the same external forcings but differ in their initial conditions. In this study, we assess the simulated decadal to multidecadal climate variability in the IPSL-EHS. In particular, we examine the global temperature evolution and recent warming trends, and their consistency with ocean heat content and sea ice cover. The model exhibits a large low-frequency internal climate variability. In particular, a quasi-bicentennial mode of internal climate variability is present in the model and is associated with the Atlantic Meridional Overturning Circulation. Such variability modulates the global mean surface air temperature changes over the historical period by about $\sim$0.1K. This modulation is found to be linked to the phase present in the initial condition state of each member. This variability appears to decrease during the 1850–2018 period in response to external forcings. The analysis of the ocean heat content reveals furthermore an overestimation of the ocean stratification, which likely leads to an overestimation of the recent warming rate on average
(Journal of Advances in Modeling Earth Systems. vol. 13, n° 1942-2466, pp. e2021MS002565, 01/09/2021)
IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, LOCEAN-NEMO R&D, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, LMD, INSU - CNRS, X, IP Paris, ENPC, SU, CNRS, ENS-PSL, PSL, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Eocene-Oligocene paleoenvironmental changes in the South Orkney Microcontinent (Antarctica) linked to the opening of Powell Basin
(Global and Planetary Change. vol. 204, n° 0921-8181, pp. 103581, 01/09/2021)
IACT, CSIC, UGR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UGR, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, IGME, LOCEAN-VOG, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité
Development in the European flounder (Platichthys flesus) of a q-PCR assay for the measurement of telomere length, a potential biomarker of pollutant effects for biomonitoring studies
Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been proposed as a biomarker of cellular aging, cumulative stress exposure and life-span in humans. With the aim to propose new biomarkers, a q-PCR protocol was adapted for the measurement of TL in the European flounder Platichthys flesus. The protocol was then applied in 2-year-old flounders from the Seine Estuary. The absolute TL in the flounder is 54 ± 13 kbp per genome (mean ± standard error). Considering relative or absolute TL, no correlation was observed with DNA damage and any of the measured contaminant concentrations (trace elements, metabolites of polycyclic aromatic hydrocarbons, polychlorobiphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, perfluoroalkyl substances). Because sampling was limited, further investigations are required to state a possible impact of chemical pollution on flatfish telomeres. This is motivated by correlations observed with organochlorinated compounds when decreasing statistical significance (p ≤ 0.10)
(Marine Pollution Bulletin. vol. 170, n° 0025-326X, pp. 112610, 01/09/2021)
BE, IFREMER, LRHBL, HMMN, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
High-resolution marine data and transient simulations support orbital forcing of ENSO amplitude since the mid-Holocene
Lack of constraint on spatial and long-term temporal variability of the El Niño southern Oscillation (ENSO) and its sensitivity to external forcing limit our ability to evaluate climate models and ENSO future projections. Current knowledge of Holocene ENSO variability derived from paleoclimate reconstructions does not separate the role of insolation forcing from internal climate variability. Using an updated synthesis of coral and bivalve monthly resolved records, we build composite records of seasonality and interannual variability in four regions of the tropical Pacific: Eastern Pacific (EP), Central Pacific (CP), Western Pacific (WP) and South West Pacific (SWP). An analysis of the uncertainties due to the sampling of chaotic multidecadal to centennial variability by short records allows for an objective comparison with transient simulations (mid-Holocene to present) performed using four different Earth System models. Sea surface temperature and pseudo-δ18O are used in model-data comparisons to assess the potential influence of hydroclimate change on records. We confirm the significance of the Holocene ENSO minimum (HEM) 3-6ka compared to low frequency unforced modulation of ENSO, with a reduction of ENSO variance of ∼50 % in EP and ∼80 % in CP. The approach suggests that the increasing trend of ENSO since 6ka can be attributed to insolation, while models underestimate ENSO sensitivity to orbital forcing by a factor of 4.7 compared to data, even when accounting for the large multidecadal variability. Precession-induced change in seasonal temperature range is positively linked to ENSO variance in EP and to a lesser extent in other regions, in both models and observations. Our regional approach yields insights into the past spatial expression of ENSO across the tropical Pacific. In the SWP, today under the influence of the South Pacific Convergence Zone (SPCZ), interannual variability was increased by ∼200 % during the HEM, indicating that SPCZ variability is independent from ENSO on millennial time scales.
(Quaternary Science Reviews. vol. 268, n° 0277-3791, pp. 107125, 01/09/2021)
LOCEAN-VALCO, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, UPCH, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, MPI-M, AWI, MARUM, UMR ISEM, Cirad, EPHE, PSL, UM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UOR
Modern relationships between microscopic charcoal in marine sediments and fire regimes on adjacent landmasses to refine the interpretation of marine paleofire records: An Iberian case study
Marine microcharcoal records provide invaluable information to understand changes in biomass burning and its drivers over multiple glacial and interglacial cycles and to evaluate fire models under warmer climates than today. However, quantitative reconstructions of burnt area, fire intensity and frequency from these records need calibration studies of the current fire-microcharcoal relationship. Here, we present the analysis of microcharcoal concentration and morphology in 102 core-top sediment samples collected in the Iberian margin and the Gulf of C adiz. We show that microcharcoal concentrations are influenced by the water depth or the distance from the river mouth. At regional scale, the mean microcharcoal concentrations and microcharcoal elongation (length to width ratio) show a marked latitudinal variation in their distribution, primarily controlled by the type of burnt vegetation in the adjacent continent. High microcharcoal concentrations in marine sediments represent rare, large and intense fires in open Mediterranean woodlands. Based on these results, the increasing trend of microcharcoal concentrations recorded since 8 ka in the well-known marine sedimentary core MD95-2042 off the Iberian margin indicates the occurrence of large and infrequent fires of high intensity due to the progressive degradation of the Mediterranean forest and the expansion of shrublands.
(Quaternary Science Reviews. vol. 270, n° 0277-3791, pp. 107148, 30/08/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFE, UPVM, EPHE, PSL, UM, CNRS, IRD [Occitanie], INRAE, Institut Agro, IPMA, CCMAR, UAlg, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GM, IFREMER, CAM, UCL, EPHE, PSL
Evaporation of biogenic organic particle using acoustic levitation
(30/08/2021)
ISM, UB, INC-CNRS, CNRS, LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The Blue Supergiant Progenitor of the Supernova Imposter AT 2019krl
Extensive archival Hubble Space Telescope, Spitzer Space Telescope, and Large Binocular Telescope imaging of the recent intermediate-luminosity transient, AT 2019krl in M74, reveal a bright optical and mid-infrared progenitor star. While the optical peak of the event was missed, a peak was detected in the infrared with an absolute magnitude of M 4.5 μm = -18.4 mag, leading us to infer a visual-wavelength peak absolute magnitude of -13.5 to -14.5. The pre-discovery light curve indicated no outbursts over the previous 16 yr. The colors, magnitudes, and inferred temperatures of the progenitor best match a 13-14 M e yellow or blue supergiant (BSG) if only foreground extinction is taken into account, or a hotter and more massive star if any additional local extinction is included. A pre-eruption spectrum of the star reveals strong Hα and [N II] emission with wings extending to ±2000 km s -1 . The post-eruption spectrum is fairly flat and featureless with only Hα, Na I D, [Ca II], and the Ca II triplet in emission. As in many previous intermediate-luminosity transients, AT 2019krl shows remarkable observational similarities to luminous blue variable (LBV) giant eruptions, SN 2008S-like events, and massive-star mergers. However, the information about the pre-eruption star favors either a relatively unobscured BSG or a more extinguished LBV with M > 20 M e likely viewed pole-on.
Unified Astronomy Thesaurus concepts: Massive stars (732); Supergiant stars (1661); Evolved stars (481); Eruptive variable stars (476); Luminous blue variable stars (944)
(The Astrophysical Journal. vol. 917, n° 0004-637X, pp. 63, 17/08/2021)
MPIA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRAL, ENS de Lyon, UCBL, INSU - CNRS, CNRS, UCBL, OSUL, ENS de Lyon, UCBL, INSU - CNRS, CNRS, UTIAS | Kavli IPMU, UTokyo | UTIAS, UTokyo, IPCF, CNR
Ancient Faunal History Revealed by Interdisciplinary Biomolecular Approaches
Starting four decades ago, studies have examined the ecology and evolutionary dynamics of populations and species using short mitochondrial DNA fragments and stable isotopes. Through technological and analytical advances, the methods and biomolecules at our disposal have increased significantly to now include lipids, whole genomes, proteomes, and even epigenomes. At an unprecedented resolution, the study of ancient biomolecules has made it possible for us to disentangle the complex processes that shaped the ancient faunal diversity across millennia, with the potential to aid in implicating probable causes of species extinction and how humans impacted the genetics and ecology of wild and domestic species. However, even now, few studies explore interdisciplinary biomolecular approaches to reveal ancient faunal diversity dynamics in relation to environmental and anthropogenic impact. This review will approach how biomolecules have been implemented in a broad variety of topics and species, from the extinct Pleistocene megafauna to ancient wild and domestic stocks, as well as how their future use has the potential to offer an enhanced understanding of drivers of past faunal diversity on Earth.
(Diversity. vol. 13, n° 1424-2818, 10/08/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Preservation and distribution of detrital clay coats in a modern estuarine heterolithic point bar in the Gironde estuary (Bordeaux, France)
Estuaries provide an excellent depositional environment to study the interaction between minerals (clays, quartz sands…) and biofilms. The estuary bottom is largely covered by biofilms that impact sediment stability, the mud and clay-coat content in sands, and sedimentary-structure stability, thus influencing sandstone properties during burial. Although numerous oil, gas, and geothermal reservoirs are exploited in estuarine heterolithic point bars, many questions remain about the origin of reservoir properties and heterogeneities in these sedimentary bodies. In order to better understand the sedimentary and microbiologic processes in estuarine systems and to better predict the reservoir quality of estuarine sandstones, this study characterizes a modern heterolithic point bar located in the Garonne estuarine channel at various scales, ranging from the microscopic (thin section) to the macroscopic (core) scale. Three piston cores 4.5 to 6.8 m long were drilled in the Bordeaux North Point Bar. Three main facies were identified in these cores: 1) sandy gravel, 2) heterolithic, medium-grained sand dunes, and 3) thin heterolithic, fine-grained sand beds with mud drapes. The sands are classified as lithic arkoses to feldspathic litharenites. Detrital clay grain coats, which at deep burial depths are transformed to permeability preserving authigenic chlorite coatings, are observed from the base to the top of the point bar. These detrital clay grain coats are mainly composed of smectite, illite, kaolinite, and chlorite, intermixed with other components, such as diatoms or pyrite. Biofilms of exopolymeric substances (EPSs), mostly produced by diatoms, are believed to control the adhesion of the clay coats to the surface of sand grains. Quantification by thin section shows that on average about 30% of the sands are coated in the point bar. The proportion of clay-coated grains appears to be independent of facies. Radiocarbon age dating measured on organic matter points to significant vertical mixing, highlighting the significance of erosion and redeposition. The activities of 137Cs and 210Pb indicate a vertical sedimentation rate of ca. 0.02 m.yr–1 in the muddy chute channel. These ages, coupled to historical maps, suggest that the present-day point bar has developed over the last 300 years with a vertical sedimentation rate ranging from 0.015 to 0.036 m.y–1 and a lateral migration rate of about 1 m.y–1. The combination of sedimentary geology, thin-section petrography, and mineralogy at high spatial and temporal resolutions highlights the potential of this study area as a modern analogue for ancient tidally influenced point-bar deposits associated with clay coatings.
(Journal of Sedimentary Research. vol. 91, n° 1527-1404, pp. 812-832, 09/08/2021)
GEOPS, INSU - CNRS, CNRS, Bordeaux INP, UBM, IC2MP [Poitiers], UP, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS