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, 02/09/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Temperature variations in caves induced by atmospheric pressure variations-Part 2: Unveiling hidden thermal signals
In underground cavities, temperature variations of the order of 10-3 °C are permanently induced by the variations of atmospheric pressure, even at great depths, with couplings of the order of 0.2 to 20 × 10-3 °C/hPa depending on frequency. In the first part of this study, we established the atmospheric pressure to temperature transfer function (TF) as a function of frequency from 8 × 10-7 to 8 × 10-4 Hz. Here, we use this TF to calculate the expected PIT variations, which, after being subtracted from the observed time-series, provide residual temperature time-series. We calculated such temperature residuals in four natural caves in France: Esparros, Aven d'Orgnac, Pech Merle and Chauvet-Pont d'Arc Caves, the last two containing unique prehistoric wall paintings. Temperature signals, as small as a few 10-3 °C, due to human presence, are then conspicuous, with evidence of relaxation longer than several days and long-term cumulative effects. In addition, we observe temperature signals suggesting non-stationary states characterized by several processes which are not necessarily easy to separate, such as transient air currents, due to barometric winds or locally semi-confined convection cells, transient infiltration, or energy dissipation by evaporation-condensation at the rock surface. This background thermal agitation displays a scale-free amplitude spectrum, from 2 × 10-5 to 4 × 10-4 Hz, of the form f-α, with α varying from 0.1 to 0.6 depending on the site. Furthermore, at the Chauvet Cave, a weak but unambiguous peak emerges during some months at a period of about 82.2 ± 0.8 minutes, suggesting a Helmholtz-type resonance. Small but significant temperature signals are therefore detected in underground cavities once the effect of atmospheric pressure variations is corrected for. These signals reveal subtle coupled processes whose knowledge is essential to evaluate preservation strategies and to establish conditions for resilience of underground systems under artificial or natural influence including climate change.
(Geosystems and Geoenvironment. vol. 2, 02/09/2026)
IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Contribution des méthodes d'imagerie drone à l'étude des bassins fracturés : application à la plate-forme mésozoïque nord-Aquitaine.
Dans les bassins sédimentaires, la connaissance du réseau de fractures et de la manière dont il s'est développé au cours du temps permettent de mieux contraindre les conditions actuelles de migration des fluides (eaux, saumures, hydrocarbures, CO2). Bien que souvent associés aux données de reconnaissances (sismique 3D, forages...), ces réseaux peuvent également être observés et caractérisés à partir d'affleurements sur le terrain. Les surfaces stratigraphiques, en particulier, font l'objet d'un nombre croissant d'études avec le développement de l'imagerie à haute résolution à partir de drone. L'objectif de cette étude est de caractériser le réseau de fracturation de la partie nord du bassin Aquitain afin de reconnaître les principaux épisodes de fracturations. Pour cela, des ortho-images drone ont été acquises sur le littoral Atlantique entre la Vendée et la Charente Maritime. L'âge des terrains varient depuis l'Hettangien au nord jusqu'au Tithonien au sud. Cet enregistrement sédimentaire permet potentiellement d'estimer l'âge des déformations sur l'intervalle 200-150 Ma à l'aide des critères de chronologie relative. Cette approche est complétée par datation U/Pb sur cristaux de calcite qui remplissent certaines populations de fractures. Les premiers résultats mettent en évidence une période de calme tectonique entre 200 et 150 Ma, suivie par deux phases d'ouverture de fractures orientées E-W à la fin du Jurassique et au milieu du Crétacé supérieur. Localement, une reprise en compression selon une direction NNW-SSE recoupe l'ensemble des fractures en ouverture et est attribuée à la propagation en champ lointain de contraintes Pyrénéennes.
(02/09/2026)
LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST, Nantes Univ, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS
Tour d’horizon du bassin stéphano-permien de Graissessac-Lodève
Fin mai 2023, l’Association des Géologues du Permien et du Trias (AGPT) a consacré en grande partie son excursion annuelle au bassin stéphano-permien de Graissessac-Lodève. Cet article, extrait principalement du livret-guide, récapitule l’histoire tectono-sédimentaire du bassin à partir d’une sélection de sites et de panoramas remarquables
(Géochronique. vol. 168, n° 0292-8477, pp. 56-67, 02/09/2026)
INSU - CNRS, CNRS, UA, UM, UMR AMAP, Cirad, CNRS, IRD [Occitanie], IRD, INRAE, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS
Behavioral and Ecological Responses of an Invasive Freshwater Mussel to Noise Pollution
Biological invasions and anthropogenic noise represent two major threats to fresh water ecosystems but the response of invasive species to noise and how it can modulate their behavior and ecological impact have received scant attention. In this study, we conducted a two-phase laboratory experiment to investigate the effect of motorboat noise on the quagga mussel Dreissena bugensis, one of the world's most invasive species causing detrimental ecological and economic impacts. We first measured aggregation patterns during a 14 to 18day rearing phase where the mussels experienced laboratory background noise supplemented or not with motorboat sounds that mimic nautical activity during summmer. Afterwards, we monitored the valve activity and estimated the filtration rate of mussels from both rearing conditions in the presence or absence of motorboat noise for 12 hours. Our results showed that aggregation rate and mean aggregate size were higher with motorboat noise. Conversely, valve activity did not differ between the two noise conditions but was significantly increased by the previous repeated exposure to noise during the rearing phase. The relationship between valve activity and filtration rate was positive for the mussels not exposed to boat noise, positive but weaker for the mussels that experienced boat noise during one of the two experiment and not significant for those under boat noise during the whole investigation.
Further research is needed to understand the physiological origins of the response to noise and the consequences on life-history traits and mussel-based ecosystem processes such as phytoplanktonic primary production, benthification and biofouling.
(02/09/2026)
CRNL-ENES, CRNL, UCBL, UJM, UJM EPE, INSERM, CNRS, BVPAM, UJM, UJM EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CARRTEL, USMB [Université de Savoie] [Université de Chambéry], INRAE, Fédération OSUG
A protocol for lixiviation of micronized plastics for aquatic toxicity testing.
Plastics contain various types and amounts of additives that can leach into the water column when entering aquatic ecosystems. Some leached plastic additives are hazardous to marine biota at environmentally relevant concentrations. Disparate methodological approaches have been adopted for toxicity testing of plastic leachates, making comparison difficult. Here we propose a protocol to standardize the methodology to obtain leachates from microplastics (MPs) for aquatic toxicity testing. Literature reviewing and toxicity tests using marine model organisms and different types of MPs were conducted to define the main methodological aspects of the protocol. Acute exposure to leachates from the studied plastics caused negative effects on the early life stages of sea urchins and marine bacteria. We provide recommendations of key factors influencing lixiviation of MPs , such as particle size (<250 μm), solid-to-liquid ratio (1-10 g/L), mixing conditions (1-60 rpm), and lixiviation time (72 h). The proposed methodology was successful to determine the toxicity of leachates from different micronized plastics on marine biota. Our recommendations balance sensitivity, feasibility and environmental relevance, and their use would help ensure comparability amongst studies for a better assessment of the toxicity of plastic leachates on aquatic biota.
(Chemosphere. vol. 333, n° 0045-6535, pp. 138894, 02/09/2026)
ULPGC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DTU
LA SÉCHERESSE FLUVIALE ET SES IMPACTS SOCIO-ENVIRONNEMENTAUX : CAS DE LA VALLÉE DE MANOMBO, SUD-OUEST DE MADAGASCAR
Le fleuve Manombo, avec la baisse de son débit ces dernières années, est révélateur du dérèglement climatique qui affecte le Sud-ouest de Madagascar. Or, la présence de ce cours d'eau demeure un des piliers majeurs sur lesquelles reposent les activités socio-économiques des populations riveraines. Notre recherche a pour objectif d'évaluer les impacts socio-environnementaux de cette diminution de la ressource en eau, à partir d'observations directes et d'enquêtes auprès des utilisateurs de la basse vallée du Manombo. Les premiers résultats montrent l'asséchement et l'ensablement de nombreuses terres agricoles situées en contexte fluvial (Baiboho) ou en parcelle irriguée (Tanety) ; les formations de mangroves sont également affectées. Ces changements se traduisent par : (i)une déstabilisation des sociétés en place en raison de pratiques agricoles devenues inadaptées mais également (ii) une dégradation des écosystèmes forestiers qui résulte de ponctions accrues de la part de populations devenues vulnérables en quête de nouvelles ressources.
(02/09/2026)
LAM, IEP Bordeaux, IRD, UBM, CNRS, UBM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Temperature variations in caves induced by atmospheric pressure variations-Part 1: Transfer functions and their interpretation
According to thermodynamics, atmospheric pressure variations (APV) cause temperature variations in air. However, such variations are difficult to observe, except in thermally stable environments such as underground cavities. We have studied the properties of these temperature variations in four natural caves in France, where continuous time-series have been collected since 1998: Esparros, Aven d'Orgnac, Pech Merle and Chauvet-Pont d'Arc Caves, the last two containing unique prehistoric wall paintings. The pressure to air temperature transfer function (TF), evaluated from 8 × 10-7 to 8 × 10-4 Hz, strongly depends on frequency; its modulus, at the barometric tide S2 (12 h), varies from 2 to 14 × 10-3 °C/hPa. While the TFs show pluriannual stability, seasonal variations are observed when sufficiently long data sets are available. Rock surface temperature is also affected by APV and we extract the air to rock surface temperature TF at Esparros, Chauvet and Pech Merle Caves. The observed TFs are accounted for by an improved analytical model including gas adiabatic compressibility, heat exchange with the rock, heat diffusion in the rock, phase changes of water at the rock surface and an advective term due to barometric pumping motion in the air volume. This model has three free parameters: the effective rock surface to air volume ratio, the time constant of heat exchanges and the effective adiabatic coefficient of cavity air. It is sufficient to account for the various situations observed in natural caves. Using this model, the observed TFs can be interpreted; they reflect the type of thermodynamics active at a given location, in particular the presence of barometric winds, but the actual values of parameters remain difficult to predict. Thus, temperature variations induced by APV emerge as a fundamental tool to characterize underground environments, relevant in some cases for cave heritage preservation, illustrating the coupled processes active in the Critical Zone.
(Geosystems and Geoenvironment. vol. 2, 02/09/2026)
IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
Sea-level fluctuations control the distribution of highly liquefaction-prone layers on volcanic-carbonate slopes
Understanding and quantifying the hazards related to earthquake-induced submarine liquefaction and landslides are particularly significant offshore of tropical volcanic-carbonate islands, where carbonate production competes with volcanism to create highly contrasted lithological successions. To improve the detection of liquefaction-prone layers, we analyzed physical properties and mineralogy and performed 70 dynamic triaxial tests on 25 sediment cores offshore of the eastern side of Mayotte (Comoros archipelago in the western Indian Ocean) in an area that has experienced significant seismicity since 2018. We found that the main parameter controlling the liquefaction potential offshore of Mayotte is the presence of low-density layers with high calcite content accumulating along the slope during lowstands. This phasing with sea-level fluctuations implies a significant recurrent geohazard for tropical volcanic-carbonate islands worldwide. Furthermore, the relationship we found between the cyclic resistance of sediment and its density and magnetic susceptibility represents a time-effective approach for identifying the hazards related to earthquake-induced liquefaction.
(Geology. vol. 51, n° 0091-7613, pp. 402-407, 02/09/2026)
GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Global coastal groundwater and subterranean estuary nutrients
These data were compiled from original and published datasets of coastal groundwater / subterranean estuary research efforts along global coastline (sites within 1km of shoreline). The dataset includes sampling site names, locations, original sample information, sample depth, temperature, salinity, dissolved nitrogen concentrations, and dissolved phosphorus concentrations. The data source or curator is also included in the dataset.
(PANGAEA, 02/09/2026)
USM, GU, UiB, OSU, SC State, OUC, AU, UC, ZMT, SYSU, OFFIS, SNU, WHOI, WHOI, IIMyC, CONICET, UNMdP, UQAR, HU, UAB, UA, ECNU, UFZ, AIMS, CSIRO, CENPAT, SCU, ODU, SBU, SUNY, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NCESS, IO-PAN, PAN, UNSW, UNSW, UFRN, SJSU, UCONN, VIMS, GU