The effects of artificial light at night on behavioral rhythm and related gene expression are wavelength dependent in the oyster Crassostrea gigas
Artificial light at night (ALAN) constitutes a growing threat to coastal ecosystems by altering natural light cycles, which could impair organisms’ biological rhythms, with resulting physiological and ecological consequences. Coastal ecosystems are strongly exposed to ALAN, but its effects on coastal organisms are poorly studied. Besides ALAN’s intensity, ALAN’s quality exposure may change the impacts on organisms. This study aims to characterize the effects of different ALAN’s spectral compositions (monochromatic wavelength lights in red (peak at 626 nm), green (peak at 515 nm), blue (peak at 467 nm), and white (410–680 nm) light) at low and realistic intensity (1 lx) on the oyster Crassostrea gigas daily rhythm. Results reveal that all ALAN’s treatments affect the oysters’ daily valve activity rhythm in different manners and the overall expression of the 13 studied genes. Eight of these genes are involved in the oyster’s circadian clock, 2 are clock-associated genes, and 3 are light perception genes. The blue light has the most important effects on oysters’ valve behavior and clock and clock-associated gene expression. Interestingly, red and green lights also show significant impacts on the daily rhythm, while the lowest impacts are shown with the green light. Finally, ALAN white light shows the same impact as the blue one in terms of loss of rhythmic oysters’ percentage, but the chronobiological parameters of the remaining rhythmic oysters are less disrupted than when exposed to each of the monochromatic light’s treatments alone. We conclude that ALAN’s spectral composition does influence its effect on oysters’ daily rhythm, which could give clues to limit physiological and ecological impacts on coastal environments.
(Environmental Science and Pollution Research. vol. 30, n° 0944-1344, pp. 120375-120386, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Image analysis and benthic ecology: Proceedings to analyze in situ long‐term image series
Long time series of underwater images have become a tool widely used within the benthic ecology research community. The development of new acquisition systems with bigger storing capacities lead researchers and scientists to deploy them for longer periods resulting in large amounts of data. This paper focuses on the first steps of analyzing large numbers of underwater images, which involves assessing the amount of valid data while assuming no technical problems. The question here addressed is how many of the in situ images can reliably be really used for benthic ecology purposes. To answer this question, we propose a method to eliminate nonvalid images and use it with four different sets of time-lapsed images acquired for long periods ranging from 73 to 371 ds in a row. The results show that elimination of between 8% and 22% of the images is possible depending on the data set. The main advantage of the method is easing and accelerating automation of subsequent analysis.
(Limnology and Oceanography: Methods. vol. 21, n° 1541-5856, pp. 169-177, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IO-PAN, PAN
Morphodynamics of wave-dominated beaches
Abstract Wave-dominated sandy beaches are highly valued by societies and are amongst the world’s most energetic and dynamic environments. On wave-dominated beaches with unlimited sand supply and limited influence of tide and geology, beach change has long been conceptualised in the morphodynamic framework of Wright and Short (1984). Such framework describes the occurrence of beach types based on wave conditions and sediment characteristics across the complete reflective–dissipative spectrum. Building on theoretical work, field/laboratory measurements and monitoring programmes, the physical mechanisms underpinning this morphodynamic framework have been progressively unravelled. Cross-shore morphological changes are primarily controlled by equilibrium and beach memory principles with below (above) average wave conditions driving down-state (up-state) transitions associated with onshore (offshore) sediment transport. Such cross-shore behaviour mostly reflects the imbalance between the onshore-directed sediment transport driven by wave nonlinearities and the offshore-directed sediment transport driven by the undertow. Self-organised morphological instabilities resulting from different positive feedback mechanisms are primarily responsible for alongshore morphological variability and the generation of rhythmic morphological features, such as crescentic bars, rip channels and beach cusps. Critically, wave climate and changes in wave regimes are key in driving the coupled cross-shore and longshore behaviour that ultimately explains modal beach state and frequency-response characteristics of beach morphological time series.
(Cambridge Prisms: Coastal Futures. vol. 1, pp. e1, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Storm response and multi-annual recovery of eight coastal dunes spread along the Atlantic coast of Europe
Coastal dunes are natural barriers against coastal flooding, and represent large sources of sediment to mitigate coastal erosion, besides being a natural habitat for many living beings. Yet, these complex environments are threatened by sea level rise and possibly enhanced storminess in the future. Most of the studies on coastal dune erosion and recovery from storms are either site specific or focus on a short-time scale, from months to a couple of years. Here, airborne LiDAR data collected from 2011 to 2020 at eight diverse coastal dunes, spread from NW England to SW France, were analysed to study their response, and recovery from the most energetic extreme storms wave conditions since at least 1948. Results show that the 2013/14 winter was the first or second largest erosive event (from −14 to −290 m3/m dune volume loss) from 2011 to 2020 at all sites. The magnitude of storm-driven sand volume loss was mainly controlled by dune face slope (r = 0.84). Dunes with steeper pre-storm slopes lost the largest volumes of sand. At a dune scale, the scarping height was also well correlated to the dune face slope at sites where storm response was characterized by limited alongshore variability. Dune recovery was site specific (no recovery, partial, complete, excess), with dunes that either progressively returned to their pre-storm morphology or were reshaped while recovering. Percentage of dune sand volume recovery was well correlated to the local and long-term satellite-derived shoreline change rate computed from 1984 to 2021 (r = 0.81), suggesting that dune recovery is mainly controlled by the local coastal sediment budget. The rate of dune crest elevation increase (from 4.2 to 12 cm/year) at four of the study sites from 2011 to 2020, largely exceeded sea level rise rate over the past decade (3.3 ± 0.7 mm/year). These results provide key insight into the contrasting resilience of some of the most exposed coastal dunes along the Atlantic coast that recover at different rates following the same sequence of extreme storms
(Geomorphology. vol. 435, n° 0169-555X, pp. 108735, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Settling dynamics of cohesive sediments in a highly turbid tidal river
An optical settling column was used in the Garonne Tidal River to estimate the settling velocity of suspended matter in surface waters over a period characterized by contrasting hydrological conditions. A time and space variability of settling velocity was observed during this study. The settling velocities of surface suspended matter ranged from 0.018 to 0.268 mm.s −1 , and the median diameter of dispersed particles varied from 4.74 to 14.38 µm. The data revealed the physical processes influencing the sediment settling dynamics throughout different time scales in a highly turbid tidal river. On tidal and fortnightly time scales, resuspension, deposition and advection mechanisms were the major drivers of the settling velocity variability, while it is likely that the estuarine turbidity maxima (ETM) was responsible for seasonal variations. The findings of this work suggest that in tidal rivers, salinity is too low to promote flocculation, whereas ETM can play a key role in enhancing this process. The stronger variability in settling velocity occurs on a tidal timescale, with median values up to four times higher at the end of the ebb tide than at high water. These variations cannot be correlated to salinity or sediment concentration. On a seasonal timescale, flocculation appears to be strongly correlated with the presence of the ETM and associated fluid mud layer. A simple correlation based on tidal variations seems to be a better predictor than the relationships based on the sediment concentration.
(Marine Geology. vol. 457, n° 0025-3227, pp. 106995, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IGE, IRD, INSU - CNRS, CNRS, INRAE, Fédération OSUG, UGA, Grenoble INP, UGA
Holocene hydroclimate variability along the Southern Patagonian margin (Chile) reconstructed from Cueva Chica speleothems
Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to itssoutherly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strengthand latitudinal position changed during the Holocene, leading thus to different responses of the vegetation topast climate changes along the Chilean continental margin. A new speleothem record from Cueva Chica (51◦S) isinvestigated to reconstruct past climatic changes throughout the Holocene in conjunction with other marine andpaleoenvironmental records of the region and better constrain the regional paleoclimatic evolutions of SWWs.Samples comprising both a flowstone core and a stalagmite were radiometrically dated (U–Th & 14C) toconstruct age-depth models for the highly-resolved proxy profiles (δ13C, δ18O, chemical composition). TheCueva Chica record provides a highly-resolved isotopic and elemental curves for the last 12 ka, albeit with ahiatus from 5.8 to 4 ka BP. The multi-proxy analysis suggests three climatic regimes throughout the Holocene inSouthern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene. Theglobal drivers for these tri-phased climatic regimes are likely related to oceanic and South polar feedbacks. Theearly Holocene was the warmest period and might be attributable to changes in global ocean circulation whichinvolved a rise in air T◦ and a strength in SWW from 50◦S, and therefore higher precipitations over landmass.After 9 ka BP, an intensified deglaciation dynamic along the Antarctic Peninsula is concordant with increasingsummer insolation in the Southern hemisphere, leading to a poleward shift of the SWWs in response to globalwarming and thus to a reduction in moisture supply from the Pacific onto the Patagonian shore. After 5 ka BP, agradual SST decline is consistent with an equatorward shift of the SWWs in response to a cooling Southernhemisphere. The SWW storm tracks extended to lower latitudes, inducing a return to wetter conditions withhighly variable moisture patterns along the Patagonian landmass. Clumped isotope (Δ 47) analyses at lowerresolution reflect the degree of kinetic isotope fractionation at the time of carbonate deposition, especially duringthe dry interval around 8.5–5.5 ka BP. Reduced kinetic isotope fractionation is observed since at least 2.6 ka BP,a period marked by (slightly) wetter conditions.
(Global and Planetary Change. vol. 222, n° 0921-8181, pp. 104050, 24/02/2026)
IDEES, UNICAEN, NU, ULH, NU, UNIROUEN, NU, CNRS, IRIHS, UNIROUEN, NU, VUB, EDYTEM, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, VUB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MPIC, GFZ, UBA, UMAG
Deformation bands and alteration in porous glass-rich volcaniclastics: Insights from Milos, Greece
Deformation bands in porous volcaniclastics are little studied structural heterogeneities despite their relevance for constraining the modalities of deformation development and related fluid-rock interactions in volcanic areas. We document a dense network of normal-sense Deformation Bands (Normal-sense Compactional Shear Bands (NCSBs) affecting upper Pliocene felsic glassy tuffites in Milos, Greece. NCSBs probably formed between 300 and 500 m of burial depth, in response to NE-SW directed extension which is related to volcanic rift development in the area. They accommodate mm-to m-shear-offsets, trend either N105 ± 10° or N070 ± 10°, and show mutual cross-cutting relations. The NCSB fault rock is made of ultracataclasite in which the cataclastic mechanisms have affected both the mineral fraction and the volcanic glass. Minerals are fractured along their cleavages whereas pumices are interestingly fractured along their vesicles. The development of chemical alteration (dissolution and cementation) essentially into the ultracataclasite is expressed through glass-hosted corrosion gulfs and smectites filling the intergranular porosity. These observations support that NCSBs preferentially retained water, have been the seat of greater fluid flow, and are the locus of ongoing phyllosilicate self-sealing in the vadose zone. A significant decrease (up to one order of magnitude) in porosity is measured within the studied NCSBs
(Journal of Structural Geology. vol. 177, n° 0191-8141, pp. 104982, 24/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, I2M-BX, UB, CNRS, INRAE, INSU - CNRS, CNRS, UA, UM, UiB, UiB
Le GIS Sol dans les départements et régions d’Outre-mer français
Cet article présente les axes des travaux pédologiques effectués dans les régions ultramarines françaises dans le cadre du Groupement d’Intérêt Scientifique Sol. Ces travaux concernent les programmes « Réseau de mesures de la qualité des sols » (RMQS) et « Inventaire, Gestion et Conservation des Sols » (IGCS), conduits aux Petites Antilles, Martinique et Guadeloupe, à La Réunion et Mayotte, et en Guyane. Ces travaux revêtent un caractère particulier du fait que les territoires concernés sont soumis à des climats variés dans la bande intertropicale et des conditions de développement des sols contrastées sur des lithologies continentales du socle et insulaires volcaniques. Dans le cadre du programme IGCS, les travaux se sont axés dans un premier temps sur l’inventaire et la sauvegarde numérique des connaissances de la distribution des sols acquises dans ces territoires depuis les années 1950. Dans un second temps, des synthèses morpho-pédologiques ont été réalisées grâce à ces données pédologiques numérisées et intégrées à une base de données, complétées par des données géologiques et géomorphologiques. Ces travaux sont illustrés dans cet article à travers le cas de la Guadeloupe. La première campagne du programme RMQS, qui s’est déroulée entre 2006 et 2015, a porté sur 67 sites dans les mêmes territoires. La mise en place de ce programme en Outre-mer s’est faite avec quelques adaptations par rapport au dispositif mis en place dans l’Hexagone, et qui concernent l’implantation des sites, les analyses de sols réalisées et la gestion des échantillons de sols. Quelques résultats de ce programme sont discutés, concernant les stocks de carbone du sol en Guyane, et les teneurs en éléments traces métalliques et hydrocarbures aromatiques polycycliques dans les territoires insulaires. Enfin, les pistes d’évolution du programme sont discutées, afin d’améliorer le suivi des propriétés des sols dans ces territoires.
(Étude et Gestion des Sols. vol. 30, n° 1252-6851, pp. 145-168, 24/02/2026)
UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, Info&Sols, INRAE, PNRL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRD, iEES Paris, IRD, SU, UPEC UP12, CNRS, INRAE
Unraveling the climate control on debris-free glacier evolution in the Everest region (Nepal, central Himalaya) during the Holocene
Current mass balance and meteorological surveys of Mera glacier located about 30 km south of Mount Everest in Nepal show the dominant role of Asian monsoon precipitation on interannual mass balance variability while temperature controls the altitude of snow-rain threshold. As these observations on mass balance variability only explore the recent decades, studies on paleo glacial extents are useful to investigate the long-term climate forcing on glacier evolution. To do so, we investigated the long-term evolution of the debris-free Mera glacier and a neighbouring small debris-free South Khare glacier. Fifty-one 10Be CRE ages were obtained from samples collected on moraine boulders and roches moutonnées. 10Be CRE ages of the boulders span from the end of the Lateglacial (19.0–11.7 ka) to the Little Ice Age (∼0.6–0.1 ka). The oldest dated moraine in this study was observed at the base of South Khare glacier with an age of 13.6 ± 0.5 ka. The two glaciers subsequently experienced their largest Holocene extent in the Early Holocene with moraines dated to 11.0 ± 0.3 ka at the base of Mera glacier and 10.8 ± 0.5 ka at the base of South Khare glacier. We did not observe any moraine from the Mid-Holocene. During the Late Holocene several glacier advances were recorded around 2.3 ± 0.2 ka, 1.5 ka and then during the last centuries at Mera glacier and around 2.8 ± 0.6 ka, and during the Little Ice Age at South Khare glacier. To explore the links between long-term Nepalese glacier changes and climate, we used oceanic and terrestrial Indian Summer monsoon reconstructions and temperature and precipitation output from two transient global climate models TraCE and LOVECLIM. These climate data outputs were corrected by a reconstruction of the Atlantic Meridional Overturning Circulation (AMOC) over the Holocene and its associated climatic impacts. We also used sensitivity experiments from the IPSL (Institut Pierre Simon Laplace) model to discuss the possible influence of horizontal resolution, land hydrology, vegetation and runoff on changes in Asian summer monsoon. Importantly, we show this long-term Nepalese glacier pattern does not perfectly conform neither to the Indian monsoon precipitation that is documented from terrestrial and marine records nor to temperature and precipitation changes simulated by the models. While the maximum glacier extent in the Early Holocene corresponds to enhanced precipitation documented by proxies and models, the Late Holocene glacier advance remains puzzling. We claim that new paleo glacier records and improved climate simulations are necessary to get a better understanding of past glacier changes and the associated climate dynamics, which might be crucial to gain confidence in both glacier and climate future evolutions.
(Quaternary Science Reviews. vol. 310, n° 0277-3791, pp. 108109, 24/02/2026)
CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, IRD, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IGE, IRD, INSU - CNRS, CNRS, INRAE, Fédération OSUG, UGA, Grenoble INP, UGA, GEOPS, INSU - CNRS, CNRS
Toxicity assessment of environmental MPs and NPs and polystyrene NPs on the bivalve Corbicula fluminea using a multi-marker approach
Small plastic particles, microplastics (MPs) and nanoplastics (NPs) represent a major threat in aquatic environments. Freshwater organisms are exposed to MPs and NPs, particularly in industrial and urban areas. The present study aimed to compare the toxicity between polystyrene NPs (PS NPs) and environmental microplastics (ENV MPs) and nanoplastics (ENV NPs) generated from macro-sized debris collected in the Garonne River on the freshwater bivalve C. fluminea. The organisms were exposed to the different plastic particles at three environmentally relevant concentrations: 0.008, 10, and 100 μg L−1 for 21 days. The biological responses of organisms were assessed using a multi-biomarker approach from the sub-individual to the individual level. The results demonstrated that: i) ENV NPs triggered more effects on detoxification processes and immune response, confirming that using manufactured NPs for laboratory exposure can lead to misleading conclusions on the risks posed by plastic particles; ii) effects of ENV MPs were less marked than ENV NPs, emphasizing the importance of testing a size continuum of plastic particles from NPs to MPs; iii) some effects were only observed for the low and/or intermediate concentrations tested, underlining the importance of using environmentally relevant concentrations. In light of these results, laboratory studies should be continued by exposing aquatic species to environmental MPs and NPs. The properties of these particles have to be characterized for a better risk assessment of environmental plastic particles.
(Comparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology. vol. 273, n° 1532-0456, pp. 109714, 24/02/2026)
BIOSSE, UCO, BiOSSE, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS, ULaval, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité