Updated calibration of the clumped isotope thermometer in planktonic and benthic foraminifera
Accurate reconstruction of past ocean temperatures is of critical importance to paleoclimatology. Carbonate clumped isotope thermometry (“Δ47 ”) is a relatively recent technique based on the strong relationship between calcification temperature and the statistical excess of 13C–18O bonds in carbonates. Its application to foraminifera holds great scientific potential, particularly because Δ47 paleotemperature reconstructions do not require assumptions regarding the 18O composition of seawater. However there are still relatively few published observations investigating the potential influence of parameters such as salinity or foraminiferal size and species. We present a new calibration data set based on 234 replicate analyses of 9 planktonic and 2 benthic species of foraminifera collected from recent core-top sediments, with calcification temperatures ranging from −2 to 25 °C. We observe a strong relationship between Δ47 values and independent, oxygen-18 estimates of calcification temperatures:
Δ47 = 41.63 × 103/T2 + 0.2056
The formal precision of this regression (± 0.7–1.0 °C at 95 % confidence level) is much smaller than typical analytical errors. Our observations confirm the absence of significant species-specific biases or salinity effects. We also investigate potential foraminifer size effects between 200 and > 560 μm in 6 species, and conclude that all size fractions from a given core-top location and species display statistically undistinguishable Δ47 values. These findings provide a robust foundation for future inter-laboratories comparisons and paleoceanographic applications.
(Geochimica et Cosmochimica Acta. vol. 239, n° 0016-7037, pp. 1-16, 20/06/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, CLIMAG, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
A comparison between water circulation and terrestrially-driven dissolved silica fluxes to the Mediterranean Sea traced using radium isotopes
The circulation of seawater through permeable coastal sediments is increasingly recognized as an important source of nutrients, including dissolved silica (DSi), to the coastal ocean. Here, we utilized a Ra isotope (223 Ra, 224 Ra ex , 228 Ra) mass balance to quantify DSi fluxes driven by water circulation to a small shallow coastal lagoon (La Palme; French Mediter-ranean) during June 2016, as compared to karstic groundwater spring inputs. The DSi flux driven by lagoon water circulation (derived from 224 Ra ex) was approximately one order of magnitude greater (1900 ± 1700 mol d À1) than the DSi load of the karstic groundwater spring (250 ± 50 mol d À1) and greater than molecular diffusion (970 ± 750 mol d À1). Lagoon water circulation was a negligible source of 228 Ra, indicating that circulation-driven DSi inputs occur over a timescale of days. Offshore transects were studied to quantify fluxes of marine-derived submarine groundwater discharge (SGD) from the permeable sandy coastline adjacent to the lagoon, into the Mediterranean Sea. Surface water transects revealed near-shore enrichments of Ra and DSi, attributed to wave-setup and water exchange through the permeable beach between the lagoon and the sea. Upscaling over the 9.5 km stretch of sandy beaches results in a marine SGD-driven DSi flux of 2.3 ± 1.3 Â 10 4 mol d À1 , similar in magnitude to the Têt river during November 2016 (3.3 ± 2.4 Â 10 4 mol d À1), the largest river in the region. A positive relationship between DSi and 224 Ra ex in lagoon water and seawater, but not 228 Ra, suggests that 224 Ra ex and DSi enrichments are derived from a similar source, the sediment (i.e. lithogenic particle dissolution), operating on short timescales. A marine SGD-driven DSi flux to the Gulf of Lions (3.8 ± 2.2 Â 10 5 mol d À1) is likely continuous over time. The relatively constant DSi inputs from water circulation for the shallow lagoons and beaches along the French Mediterranean Sea
(Geochimica et Cosmochimica Acta. vol. 238, n° 0016-7037, pp. 496-515, 20/06/2026)
LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UAB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOMIC, INSU - CNRS, SU, CNRS, OOB, SU, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, JCU, VUB
Whole-transcriptome response to wastewater treatment plant and stormwater effluents in the Asian clam, Corbicula fluminea
The increase in human population and urbanization are resulting in an increase in the volume of wastewater and urban runoff effluents entering natural ecosystems. These effluents may contain multiple pollutants to which the biological response of aquatic organisms is still poorly understood mainly due to mixture toxicity and interactions with other environmental factors. In this context, RNA sequencing was used to assess the impact of a chronic exposure to wastewater treatment plant and stormwater effluents at the whole-transcriptome level and evaluate the potential physiological outcomes in the Asian clam Corbicula fluminea. We de-novo assembled a transcriptome from C. fluminea digestive gland and identified a set of 3,181 transcripts with altered abundance in response to water quality. The largest differences in transcriptomic profiles were observed between C. fluminea from the reference site and those exposed to wastewater treatment plant effluents. On both anthropogenically impacted sites, most differentially expressed transcripts were involved in signaling pathways in relation to energy metabolism such as mTOR and FoxO, suggesting an energy/nutrient deficit and hypoxic conditions. These conditions were likely responsible for damages to proteins and transcripts in response to wastewater treatment effluents whereas exposure to urban runoff might result in immune and endocrine disruptions. In absence of comprehensive chemical characterization, the RNAseq approach could provide information regarding the mode of action of pollutants and then be useful for the identification of which parameters must be studied at higher integration level in order to diagnose sites where the presence of complex and variable mixtures of chemicals is suspected.
(Ecotoxicology and Environmental Safety. vol. 165, n° 0147-6513, pp. 96-106, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GENOTOUL, UT3, Comue de Toulouse, ENVT, Toulouse INP, INSERM, CNRS, Toulouse INP, Comue de Toulouse, INRAE, MIAT INRAE, INRAE, INRAE
Towards the Development of a Storm Erosion EWS for the French Aquitaine Coast
Towards the development of a storm erosion EWS for the French Aquitanian coast. The 230-km long Aquitaine sandy coast, SW France, is vulnerable to erosion hazards owing to its full exposure to Atlantic storm waves. Since 2015, the Observatory of the Aquitaine Coast and several academic and local partners have developed a network to better survey and forecast storm-driven morphological changes at regional scale. This paper presents the implementation of an early warning system (EWS) with the primary objective to alert the network members 2-3 days ahead in order to perform pre-storm and post-storm surveys. Regional bulletins are edited to identify the most exposed coastal sections. At local scale, tests are realized on two morphological indicators used to forecast qualitatively and quantitatively the likelihood of beach and dune erosion. The two indicators (namely the Collision Regime Indicator, CRI, and the Eroded Volume Indicator, EVI, were calibrated and further validated at two nearby beaches where extensive morphological data are collected regularly: bimonthly surveys from 2009 to 2015 at Truc Vert beach and surveys every 2 to 7 days during the winters since 2015 at Biscarrosse beach. Results indicate promising performance, with the CRI predicting collision regime when front dune erosion was indeed observed, and the EVI predicting fairly accurate eroded sediment volume on cross shore beach profile. Nevertheless, more extensive validation of the CRI and EVI is needed to extend the indicators to the entire Aquitaine coast and for a wide range single storms and storm clusters.
(Journal of Coastal Research. vol. SI 85, n° 0749-0208, pp. 5 p., 20/06/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Influence des conditions édaphiques sur la réponse des communautés alpines au changement global
Les effets du réchauffement climatique et de l'augmentation de la sécheresse estivale sur la composition et la diversité des communautés alpines ont été largement étudiés. Cependant le rôle modulateur des facteurs locaux tels que la roche mère, la mésotopographie et l'enneigement, est encore mal connu. Dans cette étude nous ré-échantillonnons la végétation d'un site de l'alpin inférieur des Alpes dauphinoises (France) étudié en 1997 et où se juxtaposent des variations importantes de roches mères (calcaire et siliceuse), de mésotopographie et d'enneigement susceptibles de moduler la réponse des communautés alpine au changement climatique. 112 relevés effectués en 1997 et 2017 et précisément géo-référencés, sont analysés par Analyse Factorielle des Correspondances. La végétation a très sensiblement évolué en 20 ans et montre une tendance vers la xérophilisation et l'oligotrophisation. La xérophilisation s'observe le long de l'axe 1 de l'AFC par déplacement de la position des relevés vers un pôle caractérisé par des sols superficiels calcaires à disponibilité en eau réduite, qui s'oppose à un autre pôle représenté par des sols acides développés sur roche siliceuse ou sur matériau mixte. Cet effet est particulièrement sensible au milieu du gradient de disponibilité en eau, en bordure de combes à neige. L'oligotrophisation, est probablement due à une baisse du pâturage et s'observe principalement le long de l'axe 2 de l'AFC, par déplacement de la position des relevés vers un pôle caractérisé par des sites exposés à déneigement précoce (mésotopographie convexe) sur sols siliceux. La richesse spécifique de l'ensemble des communautés décroit en moyenne de 15%, très probablement sous l'effet de l'augmentation de la compétition par les ligneux induite par la baisse du pâturage. Nos résultats montrent que les facteurs édaphiques locaux peuvent limiter la remontée altitudinale des espèces telle qu'elle est prédite par les principaux modèles de niche, la plupart des espèces pouvant trouver à la même altitude des refuges microclimatiques leur permettant d'éviter les effets du changement climatique.
(Botany / Botanique. vol. 4, n° 1916-2790, pp. 81-91, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, UR LESSEM, IRSTEA, UGA [2016-2019], Fédération OSUG, UGA [2016-2019], LECA, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019]
The influence of natural dissolved organic matter on herbicide toxicity to marine microalgae is species-dependent
Microalgae, which are the foundation of aquatic food webs, may be the indirect target of herbicides used for agricultural and urban applications. Microalgae also interact with other compounds from their environment, such as natural dissolved organic matter (DOM), which can itself interact with herbicides. This study aimed to evaluate the influence of natural DOM on the toxicity of three herbicides (diuron, irgarol and S-metolachlor), singly and in ternary mixtures, to two marine microalgae, Chaetoceros calcitrans and Tetraselmis suecica, in monospecific, non-axenic cultures. Effects on growth, photosynthetic efficiency (Ф’M) and relative lipid content were evaluated. The chemical environment (herbicide and nutrient concentrations, dissolved organic carbon and DOM optical properties) was also monitored to assess any changes during the experiments. The results show that, without DOM, the highest irgarol concentration (I0.5: 0.5 mg.L−1) and the strongest mixture (M2: irgarol 0.5 μg.L−1 + diuron 0.5 μg.L−1 + S-metolachlor 5.0 μg.L−1) significantly decreased all parameters for both species. Similar impacts were induced by I0.5 and M2 in C. calcitrans (around −56% for growth, −50% for relative lipid content and −28% for Ф’M), but a significantly higher toxicity of M2 was observed in T. suecica (−56% and −62% with I0.5 and M2 for growth, respectively), suggesting a possible interaction between molecules. With DOM added to the culture media, a significant inhibition of these three parameters was also observed with I0.5 and M2 for both species. Furthermore, DOM modulated herbicide toxicity, which was decreased for C. calcitrans (−51% growth at I0.5 and M2) and increased for T. suecica (-64% and −75% growth at I0.5 and M2, respectively). In addition to the direct and/or indirect (via their associated bacteria) use of molecules present in natural DOM, the characterization of the chemical environment showed that the toxic effects observed on microalgae were accompanied by modifications of DOM composition and the quantity of dissolved organic carbon excreted and/or secreted by microorganisms. This toxicity modulation in presence of DOM could be explained by (i) the modification of herbicide bioavailability, (ii) a difference in cell wall composition between the two species, and/or (iii) a higher detoxification capacity of C. calcitrans by the use of molecules contained in DOM. This study therefore demonstrated, for the first time, the major modulating role of natural DOM on the toxicity of herbicides to marine microalgae.
(Aquatic Toxicology. vol. 198, n° 0166-445X, pp. 103-117, 20/06/2026)
UR EABX, IRSTEA, BE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPM
Influence of recent climatic events on the surface water storage of the Tonle Sap Lake
Lakes and reservoirs have been identified as sentinels of climate change. Tonle Sap is the largest lake in both the Mekong Basin and Southeast Asia and because of the importance of its ecosystem, it is has been described as the “heart of the lower Mekong”. Its seasonal cycle depends on the annual flood pulse governed by the flow of the Mekong River. This study provides an impact analysis of recent climatic events from El Niño 1997/1998 to El Niño 2015/2016 on surface storage variations in the Tonle Sap watershed determined by combining remotely sensed observations, multispectral images and radar altimetry from 1993 to 2017. The Lake's surface water volume variations are highly correlated with rainy season rainfall in the whole Mekong River Basin (R = 0.84) at interannual time-scale. Extreme droughts and floods can be observed when precipitation deficit and excess is recorded in both the Tonle Sap watershed and the Mekong River Basin during moderate to very strong El Niño/La Niña events (R = −0.70) enhanced by the Pacific Decadal Oscillation (R = −0.68). Indian and Western North Pacific Monsoons were identified as having almost equal influence. Below normal vegetation activity was observed during the first semester of 2016 due to the extreme drought in 2015.
(Science of the Total Environment. vol. 636, n° 0048-9697, pp. 1520-1533, 20/06/2026)
GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CESBIO, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, INRAE, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], LMTG, UT3, Comue de Toulouse, CNRS
Quantitative biostratigraphical ranges of some late Cenozoic species of the dinoflagellate genusSpiniferitesand taxonomic considerations
A new quantitative biostratigraphical method, based on an ‘index of stratigraphical abundance’ (ISA), has been used to refine the stratigraphical range of 50 dinoflagellate cyst taxa. Most of these correspond to Quaternary representatives of Achomosphaera or Spiniferites. Some extinct taxa are also discussed when their morphology is close to that of recent species (e.g. Spiniferites lenzii, S. twistringiensis and S. pseudofurcatus), as well as some species possibly related to the motile Gonyaulax spinifera complex. The ISAs of S. mirabilis and S. hyperacanthus are similar, as well as for S. elongatus and S. sphaericum. Although initially presumed as indicating morphotypes of a same taxon, it seems rather that the ISAs similarites must be interpreted as an indication of close ecological preferences. The emergence of forms of Spiniferites with low to absent septa appears relatively late (compared to the range of the genus), but the first occurrence of intergonal processes is relatively early, indicating that it is probably a character deeply rooted into the generic genome. The previously calculated phylogeny of some Gonyaulax motile cells shows a different tree pattern than the stratigraphical first appearance succession of their presumed cyst equivalents.
(Palynology. vol. 42, n° 0191-6122, pp. 203-220, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Taxonomy and operational identification of Quaternary species of Spiniferites and related genera
In this article, we are proposing an Identification Key for recognition of Quaternary Spiniferites species and some morphologically close Quaternary taxa of some related genera. We summarize the morphological features of 43 taxa (including three subspecies and one variety) based on the original description of the holotypes and sometimes supplemented by our observations. In addition to the Identification Key, we refer to published illustrations that feature both typical and atypical specimens for each taxon. The compilation of this key gave us the opportunity to reconsider some taxonomic concepts, which resulted in two new combinations and an emendation: Hafniasphaera granulata (Mao 1989) comb. nov., emend. and Hafniasphaera multisphaera (Price and Pospelova 2014) comb. nov. In addition, we recommend that the names Spiniferites nodosus and Spiniferites pseudofurcatus subsp. obliquus be restricted to their holotype.
(Palynology. vol. 42, n° 0191-6122, pp. 45-71, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CR2P, MNHN, SU, CNRS
Contamination of soils by metals and organic micropollutants: case study of the Parisian conurbation
Soils are playing a central role in the transfer and accumulation of anthropogenic pollutants in urbanized regions. Hence, this study aimed at examining the contamination levels of selected soils collected within and around the Paris conurbation (France). This also evaluated factors controlling contamination. Twenty-three trace and major elements as well as 82 organic micropollutants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalates (PAEs), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), and perfluoroalkylated substances (PFASs) were analyzed. Results reinforced the concern raised by the occurrence and levels of metals such as Zn, Pb, Cu, and Hg, identified as metallic markers of anthropogenic activities, but also pointed out the ubiquitous contamination of soils by organic micropollutants in the 0.2–55,000-μg/kg dw range. For well-documented compounds like PAHs, PCBs, and to a lesser extent PBDEs, contents were in the range of background levels worldwide. The pollutant stock in tested soil was compared to the annual atmospheric input. For PAHs; Pb; and to a lesser extent Zn, Cu, Cd, Hg, Sb, PAEs, and APs, a significant stock was observed, far more important than the recent annual atmospheric fluxes. This resulted from both (i) the persistence of a fraction of pollutants in surface soils and (ii) the cumulative atmospheric inputs over several decades. Regarding PBDEs and PFASs, stronger atmospheric input contributions were observed, thereby highlighting their recent dispersal into the environment.
(Environmental Science and Pollution Research. vol. 25, n° 0944-1344, pp. 23559–23573, 20/06/2026)
LEESU, ENPC, UPEC UP12, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEDI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, METIS, UPMC, EPHE, PSL, CNRS, EPHE, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS