Trace elements and persistent organic pollutants in chicks of 13 seabird species from Antarctica to the subtropics
Seabirds from remote regions are mainly exposed to environmental contaminants from non-point contamination of their food webs. Pre-fledging seabird chicks are fed by their parents with marine prey captured in the vicinity of breeding colonies. Contaminant concentrations in tissues of pre-fledging chicks can thus be mostly related to local dietary sources, and have the potential to unravel spatial patterns of environmental contamination in marine ecosystems. Here, mercury (Hg), 13 other trace elements, and 18 persistent organic pollutants (POPs) were quantified in blood of chicks across four breeding locations that encompass a large latitudinal range in the southern Indian Ocean (from Antarctica, through subantarctic areas, to the subtropics), over a single breeding season. Thirteen species of penguins, albatrosses and petrels were studied, including endangered and near-threatened species, such as Amsterdam albatrosses and emperor penguins. Blood Hg burdens varied widely between species, with a factor of ~50 between the lowest and highest concentrations (mean ± SD, 0.05 ± 0.01 and 2.66 ± 0.81 µg g−1 dry weight, in thin-billed prions and Amsterdam albatrosses, respectively). Species relying on Antarctic waters for feeding had low Hg exposure. Concentrations of POPs were low in chicks, with the exception of hexachlorobenzene. Contaminant concentrations were mainly explained by species differences, but feeding habitat (inferred from δ13C values) and chicks’ body mass also contributed to explain variation. Collectively, our findings call for further toxicological investigations in Amsterdam albatrosses and small petrel species, because they were exposed to high and diverse sources of contaminants, and in macaroni penguins, which specifically showed very high selenium concentrations. Capsule: Seabird chicks from four distant sites in the southern Indian Ocean had contrasted blood metallic and organic contaminant patterns depending on species, feeding habitat and body mass.
(Environment International. vol. 134, n° 0160-4120, pp. 105225, 01/01/2020)
LIENSs, INSU - CNRS, ULR, CNRS, CEBC, ULR, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sea surface temperature in the Indian sector of the Southern Ocean over the Late Glacial and Holocene
Centennial-and millennial-scale variability of Southern Ocean temperature over the Holocene is poorly known, due to both short instrumental records and sparsely distributed high-resolution temperature reconstructions, with evidence for past temperature variations in the region coming mainly from ice core records. Here we present a high-resolution (∼ 60 year), diatom-based sea surface temperature (SST) reconstruction from the western Indian sector of the Southern Ocean that spans the interval 14.2 to 1.0 ka (cal-ibrated kiloyears before present). During the late deglacia-tion, the new SST record shows cool temperatures at 14.2-12.9 ka and gradual warming between 12.9 and 11.6 ka in phase with atmospheric temperature evolution. This supports the evolution of the Southern Ocean SST during the deglacia-tion being linked with a complex combination of processes and drivers associated with reorganisations of atmospheric and oceanic circulation patterns. Specifically, we suggest that Southern Ocean surface warming coincided, within the dating uncertainties, with the reconstructed slowdown of the Atlantic Meridional Overturning Circulation (AMOC), rising atmospheric CO 2 levels, changes in the southern westerly winds and enhanced upwelling. During the Holocene the record shows warm and stable temperatures from 11.6 to 8.7 ka followed by a slight cooling and greater variability from 8.7 to 1 ka, with a quasi-periodic variability of 200-260 years identified by spectral analysis. We suggest that the increased variability during the mid-to late Holocene reflects the establishment of centennial variability in SST connected with changes in the high-latitude atmospheric circulation and Southern Ocean convection.
(Climate of the Past. vol. 16, n° 1814-9324, pp. 1451-1467, 26/04/2026)
Maynooth University, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ETH Zürich
Video Depth Inversion at a Microtidal Site Exposed to Prevailing Low-energy Short-period Waves and Episodic Severe Storms
Bouvier, C., Balouin Y., Castelle B. and Valentini N., 2020. Video depth inversion at a microtidal site exposed to prevailing low-energy short-period waves and episodic severe storms. Over the last decades, a wide range of depth inversion algorithms have been developed, which aim to infer local water depth from remotely-sensed wave parameters based on physical relations. Particularly, the depth inversion algorithm named cBathy (Holman et al., 2013) showed good results for a range of wave conditions and environments but the method was only applied to beaches exposed to moderate or highly energetic wave climate, with wave peak period often larger than 8 s. This paper applies the cBathy algorithm for the very first time on a Mediterranean Sea beach, Sète, southeast France, a semidiurnal microtidal environment exposed to a moderate-energy modal wave climate and episodic severe storms. The objective of the paper is to assess the ability of the cBathy algorithm to estimate the nearshore bathymetry for waves with large energy spread in both direction and frequency. After a comparison between the remotely sensed bathymetry and a ground truth bathymetric survey, we use a non-linear, depth-averaged morphodynamic model, 2DBeach (Dubarbier et al., 2017), on remotely sensed bathymetries to determine the sensitivity of nearshore waves and horizontal circulations to the estimated morphology. The depth inversion technique estimates the nearshore bathymetry with good accuracy (RMSE = 0.39 m) for a beach area extending respectively 1600 m and 600 m in the longshore and cross-shore directions, respectively, suggesting the technical feasibility of coupling remotely-sensed bathymetry to 2DH numerical model, even at short-waves exposed Mediterranean beaches.
(Journal of Coastal Research, n° 0749-0208, 26/04/2026)
BRGM, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Rhythms during the polar night: evidence of clock-gene oscillations in the Arctic scallop Chlamys islandica
Arctic regions are highly impacted by climate change and are characterized by drastic seasonal changes in light intensity and duration with extended periods of permanent light or darkness. Organisms use cyclic variations in light to synchronize daily and seasonal biological rhythms to anticipate cyclic variations in the environment, to control phenology and to maintain fitness. In this study, we investigated the diel biological rhythms of the Arctic scallop, Chlamys islandica, during the autumnal equinox and polar night. Putative circadian clock genes and putative light perception genes were identified in the Arctic scallop. Clock gene expression oscillated in the three tissues studied (gills, muscle, mantle edge). The oscillation of some genes in some tissues shifted from daily to tidal periodicity between the equinox and polar night periods and was associated with valve behaviour. These results are the first evidence of the persistence of clock gene expression oscillations during the polar night and might suggest that functional clockwork could entrain rhythmic behaviours in polar environments.
(Proceedings of the Royal Society B: Biological Sciences. vol. 287, n° 0962-8452, pp. 20201001, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Parasitism in ecosystem engineer species: A key factor controlling marine ecosystem functioning
Although parasites represent a substantial part of marine communities’ biomass and diversity, their influence on ecosystem functioning, especially via the modification of host behaviour, remains largely unknown. Here, we explored the effects of the bopyrid ectoparasite Gyge branchialis on the engineering activities of the thalassinid crustacean Upogebia pusilla and the cascading effects on intertidal ecosystem processes (e.g. sediment bioturbation) and functions (e.g. nutrient regeneration). Laboratory experiments revealed that the overall activity level of parasitized mud shrimp is reduced by a factor 3.3 due to a decrease in time allocated to burrowing and ventilating activities (by factors 1.9 and 2.9, respectively). Decrease in activity level led to strong reductions of bioturbation rates and biogeochemical fluxes at the sediment–water interface. Given the world-wide distribution of mud shrimp and their key role in biogeochemical processes, parasite-mediated alteration of their engineering behaviour has undoubtedly broad ecological impacts on marine coastal systems functioning. Our results illustrate further the need to consider host–parasite interactions (including trait-mediated indirect effects) when assessing the contribution of species to ecosystem properties, functions and services.
(Journal of Animal Ecology. vol. 89, n° 0021-8790, pp. 2192-2205, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Local and regional controls on Holocene sea ice dynamics and oceanography in Nares Strait, Northwest Greenland
Nares Strait is one of three channels that connect the Arctic Ocean to Baffin Bay. Unique sea-ice conditions in the strait lead to the formation of landfast ice arches at its northern and southern ends. These ice arches regulate Arctic sea-ice and freshwater export through the strait and promote the opening of the North Water polynya. The present study addresses the paucity of pre-satellite records of environmental conditions in the Nares Strait area, and aims at reconstructing Holocene sea-ice conditions and ocean circulation in the strait. The investigation is based on a marine sediment core strategically retrieved from under the current ice arch in Kane Basin to the south of Nares Strait, and provides a continuous record spanning the past ca 9 kyrs. We use benthic foraminiferal assemblages and sea-ice biomarkers to infer changes in Holocene ocean circulation and sea-ice conditions in Kane Basin. The establishment of the modern ocean circulation in Kane Basin is related to ice sheet retreat and postglacial rebound, while changes in sea-ice cover concur with major shifts in the Arctic Oscillation (AO). Our results suggest that sea-ice cover in Kane Basin was highly variable between ca 9.0 and 8.3 cal. ka BP, before increasing, probably in link with the 8.2 cold event and the opening of Nares Strait. A short period of minimum sea-ice cover and maximum Atlantic bottom water influence occurred between ca 8.1 and 7.5 cal. ka BP, when Kane Basin was deeper than for the remaining of the Holocene. As atmospheric temperatures dropped, sea-ice cover intensified in Kane Basin between ca 7.5 and 5.5 cal. ka BP, but strong winds under prevailing positive-like AO conditions likely prevented the formation of ice arches in Nares Strait. During this time, our micro-paleontological data show that Atlantic water was progressively excluded from Kane Basin by the postglacial isostatic rebound. Increasingly cooler atmospheric temperatures and a shift towards more negative phases of the AO may have promoted the establishment of ice arches in Nares Strait between ca 5.5 and 3.0 cal. ka BP. Instabilities in the Kane Basin ice arch ca 3.0 cal. ka BP coincide with a shift towards prevailing positive phases of the AO, while a brief recovery of the ice arch occurred during more negative-like AO conditions between ca 1.2 and 0.2 cal. ka BP.
(Marine Geology. vol. 422, n° 0025-3227, pp. 106115, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INSTAAR, UNB, GEUS, ULaval, INSU - CNRS, CNRS
Shut down of the South American summer monsoon during the penultimate glacial
We analysed changes in mean annual air temperature (MAAt), vegetation and biomass burning on a long and continuous lake-peat sediment record from the colônia basin, southeastern Brazil, examining the responses of a wet tropical rainforest over the last 180 ka. Stronger southern atmospheric circulation up to the latitude of colônia was found for the penultimate glacial with lower temperatures than during the last glacial, while strengthening of the South American summer monsoon (SASM) circulation started during the last interglacial and progressively enhanced a longer wet summer season from 95 ka until the present. Past MAAT variations and fire history were possibly modulated by eccentricity, although with signatures which differ in average and in amplitude between the last 180 ka. Vegetation responses were driven by the interplay between the SASM and southern circulation linked to Antarctic ice volume, inferred by the presence of a cool mixed evergreen forest from 180 to 45 ka progressively replaced by a rainforest. We report cooler temperatures during the marine isotope stage 3 (MIS 3: 57-29 ka) than during the Last Glacial Maximum (LGM: 23–19 ka). Our findings show that tropical forest dynamics display different patterns than mid-latitude during the last 180 ka.
(Scientific Reports. vol. 10, n° 2045-2322, pp. 6275, 26/04/2026)
UMR ISEM, Cirad, EPHE, PSL, UM, CNRS, IRD, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, UNICAMP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, USP
The Eurasian Modern Pollen Database (EMPD), Version 2
(Earth System Science Data. vol. 12, n° 1866-3508, pp. 2423-2445, 26/04/2026)
UNIL, UMR ISEM, Cirad, EPHE, PSL, UM, CNRS, UK, MSU, OCCR, UNIBE, HNHP, MNHN, UPVD, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMBE, AU, AMU, CNRS, BIK-F, SGN, UAM, AWI, UiB, RAS, UGR, UAM, UG, Lares-Las, UR2, UNIROMA, ARC, UAM, IMEP, AU, CNRS, LISTIC, USMB [Université de Savoie] [Université de Chambéry], UNIMIB
On the natural and anthropogenic drivers of the Senegalese (West Africa) low coast evolution: Saint Louis Beach 2016 COASTVAR experiment and 3D modeling of short term coastal protection measures
West Africa's low and densely populated coasts crystallize most of the environmental and societal problems and resulting vulnerability. It is becoming urgent to document this coast and the natural and anthropogenic forces to understand its evolution. Saint Louis is a historic (World Heritage) city located on the Langue de Barbarie, a 10 km sandspit at the mouth of the Senegal River. Because of its location, it is vulnerable (erosion, flooding) to river and ocean variability. This intermediate barred microtidal beach is located in a storm-free intertropical environment, but is exposed to distant oblique energetic waves from high latitudes, causing one of the highest coastal drifts in the world (∼800,000 m3/year). As part of the COASTVAR project, an intensive international field experiment was conducted in Saint Louis from 4 to 13 December 2016 to quantify the natural protective role played by the sandbar, coastal currents and transient exchanges with the inner shelf. Many instruments have been deployed to measure waves, currents, bathymetry and topography. This article provides an overview on the objectives of the experiment, the deployment and the first results of the modeling of coastal protection strategy
(Journal of Coastal Research. vol. 95, n° 0749-0208, pp. 583-587, 26/04/2026)
UCAD, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DAMCP, LGO, UBS, IFREMER, UBO EPE, CNRS, LGL-TPE, ENS de Lyon, UCBL, INSU - CNRS, UJM, CNRS, SHOM, UAC, LOCEAN-PROTEO, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, ECOLA, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, CNES, IRD, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, UGB
Poly-phased fluid flow in the giant fossil pockmark of Beauvoisin, SE basin of France
The giant Jurassic-aged pockmark field of Beauvoisin developed in a 800 m wide depression for over 3.4 Ma during the Oxfordian; it formed below about 600 m water depth. It is composed of sub-sites organized in clusters and forming vertically stacked carbonate lenses encased in marls . This fine-scale study is focused on a detailed analysis of petrographical organization and geochemical signatures of crystals that grew up in early to late fractures of carbonate lenses, surrounding nodules, and tubes that fed them. The isotopic signature (C, O and Sr) shows that at least three different episodes of fluid migration participated to the mineralization processes. Most of the carbonates precipitated when biogenic seepage was active in the shallow subsurface during the Oxfordian. The second phase occurred relatively soon after burial during early Cretaceous and thermogenic fluids came probably from underlying Pliensbachian, Late Toarcian or Bajocian levels. The third phase is a bitumen-rich fluid probably related to these levels reaching the oil window during Mio-Pliocene. The fluids migrated through faults induced by the emplacement of Triassic-salt diapir of Propiac during the Late Jurassic and that remained polyphased drain structures over time.
(Bulletin de la Société Géologique de France. vol. 191, n° 0037-9409, pp. 35, 26/04/2026)
INSU - CNRS, UM, CNRS, UA, GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], UniCA, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS, UB