Environmental samples of microplastics induce significant toxic effects in fish larvae.
Microplastics (MPs) are present throughout aquatic ecosystems, and can be ingested by a wide variety of organisms. At present, the physical and chemical effects of environmental MPs on aquatic organisms are poorly documented. This study aims to examine the physiological and behavioral effects caused by fish consuming environmental microplastics at different life stages. MP samples were collected from beaches on three islands (Easter Island, Guam and Hawaii) located near the North and South gyres of the Pacific Ocean. Larvae and juveniles of Japanese Medaka were fed for 30days with three doses of MPs (0.01, 0.1 and 1% w/w in fish food) approximate to the concentrations measured in moderately and heavily contaminated ocean areas. Ingestion of MPs by medaka larvae caused (variously) death, decreased head/body ratios, increased EROD activity and DNA breaks and, alterations to swimming behavior. A diet of 0.1% MPs was the most toxic. Two-month-old juveniles fed with 0.01% MPs did not exhibit any symptoms except an increase in DNA breaks. Our results demonstrate ingestion and mainly sublethal effects of environmental MPs in early life stages of fish at realistic MP concentrations. The toxicity of microplastics varies from one sample to another, depending on polymer composition, weathering and pollutant content. This study examines the ecological consequences microplastic build-up in aquatic ecosystems, more particularly in coastal marine areas, which serve as breeding and growing grounds for a number of aquatic species.
(Environment International. vol. 134, n° 0160-4120, pp. 105047, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS, PAnTher, ONIRIS, INRAE, APEX, PAnTher, ONIRIS, INRAE, ANSES
Field Observations of Wave-induced Headland Rips
Most of rip-current field experiments have focused on persistent rips along rip-channeled sandy beaches or transient rips along reasonably alongshore-uniform surf-zone morphology, while experiments on rip flowing against structures are scarce. In October 2018, a 3-week field experiment was performed at Anglet beach, SW France, aiming at examining the dynamics of high-energy rip currents in complex settings. The beach is barred with prominent inherited geology, characterized by the presence of a 500-m headland and a natural submerged reef. A large array of in-situ instruments was deployed to capture the temporal and spatial variability of rip flow circulations, including ADCPs, surf-zone drifters and video monitoring. The latter allowed to identify a wide range of rip-flow patterns. Among these patterns, a high-intensity rip current flowing against the headland was a dominant feature for obliquely incident waves. Such a boundary rip current was driven by the deflection of the longshore current against the headland, peaking at 0.7 m/s (5-min time-and depth-averaged) 800-m offshore in 12-m depth for a moderate storm event with 4-m obliquely incident waves. Very-lowfrequency (O(1h) and O(30min)) fluctuations of this rip current were observed around low tide. Measurements of the vertical structure of the rip reveal that the deflection rip was more vertically-sheared as the water depth increases, with higher velocities near the surface, which is typical of a theoretical rip head structure.
(Journal of Coastal Research. vol. 95, n° 0749-0208, pp. 578, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SIAME, UPPA, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS
Reconstructing climatic modes of variability from proxy records using ClimIndRec version 1.0
Modes of climate variability strongly impact our climate and thus human society. Nevertheless, the statistical properties of these modes remain poorly known due to the short time frame of instrumental measurements. Reconstructing these modes further back in time using statistical learning methods applied to proxy records is useful for improving our understanding of their behaviour. For doing so, several statistical methods exist, among which principal component regression is one of the most widely used in paleoclimatology. Here, we provide the software ClimIndRec to the climate community; it is based on four regression methods (principal component regression, PCR; partial least squares, PLS; elastic net, Enet; random forest, RF) and cross-validation (CV) algorithms, and enables the systematic reconstruction of a given climate index. A prerequisite is that there are proxy records in the database that overlap in time with its observed variations. The relative efficiency of the methods can vary, according to the statistical properties of the mode and the proxy records used. Here, we assess the sensitivity to the reconstruction technique. ClimIndRec is modular as it allows different inputs like the proxy database or the regression method. As an example, it is here applied to the reconstruction of the North Atlantic Oscillation by using the PAGES 2k database. In order to identify the most reliable reconstruction among those given by the different methods, we use the modularity of ClimIndRec to investigate the sensitivity of the methodological setup to other properties such as the number and the nature of the proxy records used as predictors or the targeted reconstruction period. We obtain the best reconstruction of the North Atlantic Oscillation (NAO) using the random forest approach. It shows significant correlation with former reconstructions, but exhibits higher validation scores.
(Geoscientific Model Development. vol. 13, n° 1991-9603, pp. 841 - 858, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CQFD, IMB, UB, Bordeaux INP, CNRS, Inria, UOR, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité
Bounding Global Aerosol Radiative Forcing of Climate Change
Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol-radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol-driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed-phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of -1.6 to -0.6 W m-2, or -2.0 to -0.4 W m-2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial-era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.
(Reviews of Geophysics. vol. 58, n° 8755-1209, 26/04/2026)
IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LMD, INSU - CNRS, X, IP Paris, ENPC, SU, CNRS, ENS-PSL, PSL
Hygroscopic behavior of aerosols generated from solutions of 3-methyl-1,2,3-butanetricarboxylic acid, its sodium salts, and its mixtures with NaCl
Secondary organic aerosols (SOAs), which are formed and transformed through complex physicochemical processes in the atmosphere, have attracted considerable attention over the past decades because of their impacts on both climate change and human health. Recently, 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a low volatile, highly oxidized, secondary generation product of monoterpenes, is one of the most relevant tracer compounds for biogenic SOAs. Therefore, MBTCA was selected to understand its hygroscopic properties better. In addition, interactions between the organic acid and inorganic components have been reported, which may alter their hygroscopic properties mutually. In this study, laboratory-generated, micrometer-sized, pure MBTCA, mono-/di-/tri-sodium MBTCA salts, and MBTCA-NaCl mixture aerosol particles of four mixing ratios (molar ratios = 1 : 1, 1 : 2, 1 : 3, and 2 : 1) were examined systematically to observe their hygroscopic behavior by varying the relative humidity (RH) from RH = ~95 % to ~1 % through a dehydration process, followed by a humidification process from RH = ~1 % to ~95 %, using in-situ Raman microspectrometry (RMS) assembled with a see-through impactor where the particles were deposited on a Si wafer. The hygroscopic behavior of pure MBTCA and MBTCA-NaCl mixture aerosol particles of three mixing ratios (molar ratios = 1 : 1, 1 : 2, and 1 : 3) were also examined using a levitation system mounted on in-situ RMS through a humidification process from RH = ~10 % to ~80 % after a quenching process from droplets, followed by dehydration from RH = ~80 % to ~10 %. The pure MBTCA droplets effloresced at RH = ~30–57.8 % and did not dissolve until RH > 95 %. The mono- and di-sodium MBTCA salt aerosols did not show clear efflorescence RH (ERH) and deliquescence RH (DRH). In contrast, the tri-sodium MBTCA salt exhibited ERH = ~44.4–46.8 % and DRH = ~53.1 %, during the hygroscopic experiment cycle. The mixture aerosols generated from solutions of MBTCA : NaCl = 1 : 1 and 2 : 1 showed no visible ERH and DRH in the see-through impactor because of the partial and total consumption of NaCl, respectively, through chemical reactions during the dehydration process. The mixture particles with a 1 : 1 molar ratio in the levitation system exhibited a clear DRH at ~71 % and ERH at ~50 %. This suggests less reaction between the mixtures and a larger portion of NaCl remaining in the levitation system. The other mixtures of MBTCA : NaCl = 1 : 2 and 1 : 3 displayed single-stage efflorescence and deliquescence at ERH = ~45–50 % and DRH = ~74 %, respectively, because of the considerable amount of NaCl present in the mixture aerosols in both systems. Observations and Raman analyses indicated that only monosodium MBTCA salt aerosols could be formed through a reaction between MBTCA and NaCl. The reaction occurred more rapidly with a more elevated concentration of either MBTCA or NaCl, and the controlling factor for the reactivity of the mixtures depended mostly on the availability of H+ dissociated from the MBTCA tricarboxylic acid. The lower degree of reaction of the mixture particles in the levitation system might be caused by the relatively airtight circumstance inside, i.e., the less release of HCl. In addition, the quenching process, i.e., the starting point of the hygroscopicity experiments, induced the solidification of MBTCA, and further, a slow reaction between MBTCA and NaCl. The study revealed that the interactions between the MBTCA and NaCl could modify the properties of the organic acid in the atmosphere, leading to enhanced capability of the probable heterogeneous chemistry in the aqueous aerosols.
(Atmospheric Chemistry and Physics. vol. 20, n° 1680-7316, pp. 14103–14122, 26/04/2026)
ISM, UB, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The contribution of short-wave breaking to storm surges: The case Klaus in the Southern Bay of Biscay
This study investigates the contribution of shortwave breaking to storm surges through a high-resolution hindcast of the sea state and storm surge associated with the extra-tropical storm Klaus. This storm made landfall in January 2009 in the Southern Bay of Biscay and produced the largest storm surges observed in this region over the last 20 years, with 1.70 m in the Arcachon Lagoon and 1.10 m in the Adour Estuary. A fully-coupled 3D modelling system, which uses a vortex force formalism to represent wave-current interactions, is applied with a spatial resolution down to 35 m in the surf zones in order to properly compute the wave-induced setup. Modelling results reveal that the wave setup contributes by up to 40% and 23% to the storm surge peak in the Adour Estuary and the Arcachon Lagoon respectively. Accounting for wave forces in the circulation model improves storm surge predictions by 50 to 60%. This is explained by the dominant role played by wave forces in the momentum balance at the inlets under storm waves. Numerical experiments further reveal that the wave-induced setup can be tidally-modulated, although this phenomenon seems to be site-specific. Finally, a sensitivity analysis highlights the importance of the model grid resolution in the surf zones to correctly resolve the wave setup along open-ocean coasts. Inside the lagoon, the storm surge and wave setup are less sensitive to the grid resolution while tidal propagation cannot be accurately represented with a resolution of 1000 m, which is typically used in operational storm surge forecast.
(Ocean Modelling. vol. 156, n° 1463-5003, pp. 101710, 26/04/2026)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOPS, IRD, IFREMER, INSU - CNRS, UBO EPE, CNRS, CNRM, INSU - CNRS, CNRS, Comue de Toulouse
Assessment of swimming behavior of the Pacific oyster D-larvae (Crassostrea gigas) following exposure to model pollutants
This study describes an image analysis method that has been used to analyze the swimming behavior of native oyster D-larvae (Crassostrea gigas) from the Arcachon Bay (SW, France). In a second time, this study evaluated the impact of copper and S-metolachlor pollutants on D-larvae swimming activity and the possible relationship between developmental malformations and abnormal swimming behavior. Analyses in wild and cultivated oyster D-larvae were investigated during two breeding-seasons (2014 and 2015) at different sampling sites and dates. In controlled conditions, the average speed of larvae was 144 µm s '1 and the maximum speed was 297 µm s '1 while the trajectory is mainly rectilinear. In the presence of environmental concentration of copper or S-metolachlor, no significant difference in maximum or average larval speed was observed compared to the control condition but the percentage of circular trajectory increased significantly while the rectilinear swimming larvae significantly declined. The current study demonstrates that rectilinear trajectories are positively correlated to normal larvae while larvae with shell anomalies are positively correlated to circular trajectories. This abnormal behavior could affect the survival and spread of larvae, and consequently, the recruitment and colonization of new habitats. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
(Environmental Science and Pollution Research. vol. 27, n° 0944-1344, pp. 3675-3685, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, INRAE
Glacier and ocean variability in Ata Sund, west Greenland, since 1400 CE
To improve knowledge of marine-terminating glaciers in western Greenland, marine sediment cores from the Ata Sund fjord system, hosting two outlet glaciers, Eqip Sermia and Kangilerngata Sermia, were investigated. The main objective was to reconstruct glacial activity and paleoceanographic conditions during the past 600 years. Ice-rafted debris (IRD) was quantified by wet-sieving sediment samples and by using a computed tomography scan. Variability in relative bottom water temperatures in the fjord was reconstructed using foraminiferal analysis. On the basis of this, three periods of distinct glacial regimes were identified: Period 1 (1380–1810 CE), which covers the culmination of the Little Ice Age (LIA) and is interpreted as having advanced glaciers with high IRD content. Period 2 (1810–1920 CE), the end of the LIA, which was characterised by a lowering of the glaciers’ calving flux in response to climate cooling. During Period 3 (1920–2014 CE), both glaciers retreated substantially to their present-day extent. The bottom water temperature started to decrease just before Period 2 and remained relatively low until just before the end of Period 3. This is interpreted as a local response to increased glacial meltwater input. Our study was compared with a study in Disko Bay, nearby Jakobshavn Glacier and the result shows that both of these Greenlandic marine-terminating glaciers are responding to large-scale climate change. However, the specific imprint on the glaciers and the different fjord waters in front of them result in contrasting glacial responses and sediment archives in their respective fjords.
(The Holocene, n° 0959-6836, pp. 095968362095043, 26/04/2026)
GEUS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Microbial Communities of the Shallow-Water Hydrothermal Vent Near Naples, Italy, and Chemosynthetic Symbionts Associated With a Free-Living Marine Nematode
Shallow-water hydrothermal vents are widespread, especially in the Mediterranean Sea, owing to the active volcanism of the area. Apart free microbial communities’ investigations, few biological studies have been leaded yet. Investigations of microbial communities associated with Nematoda, an ecologically important group in sediments, can help to improve our overall understanding of these ecosystems. We used a multidisciplinary-approach, based on microscopic observations (scanning electron microscopy: SEM and Fluorescence In Situ Hybridization: FISH) coupled with a molecular diversity analysis using metabarcoding, based on the 16S rRNA gene (V3-V4 region), to characterize the bacterial community of a free-living marine nematode and its environment, the shallow hydrothermal vent near Naples (Italy). Observations of living bacteria in the intestine (FISH), molecular and phylogenetic analyses showed that this species of nematode harbors its own bacterial community, distinct from the surrounding sediment and water. Metabarcoding results revealed the specific microbiomes of the sediment from three sites of this hydrothermal area to be composed mainly of sulfur oxidizing and reducing related bacteria.
(Frontiers in Microbiology. vol. 11, n° 1664-302X, pp. 2023, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LM2E, IFREMER, UBO EPE, CNRS, LEP, EEP, IFREMER, PARTHENOPE
Short-term variations of platinum concentrations in contrasting coastal environments: The role of primary producers
Short-term variations of Pt concentrations and primary production indicators were compared in three contrasting coastal sites during spring bloom: (i) the Gironde Estuary mouth (SW France), (ii) the semi-enclosed Arcachon Bay (SW France), and (iii) the urbanized Genoa Harbor (NW Italy). At each site, surface seawater sampling and physical-chemical measurements were combined to study diel cycles (over 25 h) of dissolved Pt concentrations in seawater (PtD) and master variables reflecting primary production activity (chlorophyll-a, phaeopigments, and particulate organic carbon, POC concentrations). Plankton nets were used in all sites, providing for the first time plankton Pt concentrations (PtPK) over a whole diel cycle (Gironde Estuary mouth) and spot sampling (Arcachon Bay and Genoa Harbor) in the coastal zone. Bivalves (wild oysters or mussels), reflecting organisms at higher trophic levels, were also collected at all sites. The POC/Chl-a ratios in the collected particulate material suggested high contribution of phytoplankton to the particulate matter in the productive Gironde Estuary mouth. At this site, phytoplankton activity partly controlled Pt cycling and particle/dissolved Pt partitioning during daytime. During the night, zooplankton grazing may release Pt into the dissolved phase. These processes are partly masked by external factors such as tide or local Pt sources, especially in more confined and/or urbanized coastal water bodies such as the Arcachon Bay and the Genoa Harbor. Platinum levels in plankton and bivalves from these contrasting sites along the Atlantic and Mediterranean coasts tended to reflect the general Pt levels in seawater. These results clearly suggest that (i) Pt contamination of coastal waters and marine organisms has become a common feature in urbanized sites and (ii) Pt transfer to the marine food chain starts at the basic level of primary producers. By concentrating Pt (Bioconcentration Factor: BCF ~ 104), phytoplankton may serve as a biomonitor to assess Pt contamination in coastal environments.
(Marine Chemistry. vol. 222, n° 0304-4203, pp. 103782, 26/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIGE, IIM, CSIC, UniGe