Vegetation Increases CH4 Emissions and Methanotroph Diversity in Marine Sediments
Seagrass meadows are key blue carbon (C) ecosystems, storing large amounts of organic C over centuries. Their climate benefits may be reduced by methane (CH 4 ) emissions, whose microbial and environmental descriptors in Zostera noltii meadows, dominant seagrass in North‐Western Europe, remain poorly understood. We studied CH 4 fluxes, CH 4 ‐producing and consuming microbial communities and sediment physicochemical parameters in Z. noltii meadows and adjacent bare sediments across seven sites in Arcachon Bay, France. In situ CH 4 fluxes were measured at low tide during daytime conditions, providing standardized estimates of peak emissions. Microbial communities were characterized using targeted metagenomics of three functional genes ( mcrA , mmoX , pmoA ) and quantitative PCR. CH 4 fluxes were higher in vegetated than bare sediments (24.4 ± 2.6 vs. 9.4 ± 0.7 μmol m −2 day −1 ). Mixed linear models and random forest analyses identified C accumulation rate and CO 2 flux as the strongest positive descriptors of CH 4 fluxes. Vegetated sediments hosted more diverse methanotrophs, while methanogens showed no habitat differences. Four genera ( mcrA–Methanolobus , mmoX–Methylocella , pmoA–Methylococcus , Methyloglobulus ) emerged as abundant, seagrass‐associated, correlated with CH 4 fluxes, and highlighted by models. Functional diversity, especially pmoA richness, was a stronger microbial descriptor of CH 4 fluxes than gene abundance or a specific genus. Findings indicate Z. noltii meadows enhance C burial and CH 4 emission, with methanotroph diversity potentially mitigating CH 4 emissions. Our results provide the first integrated assessment of CH 4 fluxes and their descriptors in Z. noltii meadows, based on limited temporal coverage capturing the daytime peak emission conditions, highlighting the intertwined nature of C burial and CH 4 emissions and the need to account for both in blue C climate assessments.
(Global Change Biology. vol. 32, n° 1354-1013, pp. e70989, 01/07/2026)
LEM, UCBL, ENVL, VAS, CNRS, INRAE, CEAB, CSIC, UEF, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Bordeaux INP, IFPEN, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, UM, UNIMI
Effect of the microparasite Perkinsus olseni on the bioturbation activity and engineering potential of the Manila clam Ruditapes philippinarum
Host behavioral modifications induced by parasites can have profound ecological consequences, especially when they affect ecosystem engineers such as bioturbators. While the influence of macroparasites on host behavior and, by extension, on ecosystem functioning is documented in the marine realm, the role of microparasites remains unexplored. The association between Perkinsus olseni, a widespread microeukaryotic parasite, and the Manila clam Ruditapes philippinarum, an abundant bioturbator in many coastal soft-bottom environments, is an interesting model for investigating this overlooked aspect. Infection by P. olseni has been shown to alter various physiological parameters in clams, such as immune response, metabolic activity, and reproductive performance. However, whether these internal disruptions translate into behavioral changes, such as modifications in sediment particle transports initiated by clams, remains an open question. In this study, we explore whether infection by P. olseni influences the bioturbation activity of the Manila clam, a process with significant implications for ecosystem processes, such as nutrient fluxes, in coastal environments. We did not report major changes in the engineering potential of the Manila clam when infected with non-lethal doses of Perkinsus olseni. However, we noticed a subtle increase in the magnitude of sediment transport activities, which may reflect behavioral adaptations. Given the ecological role of R. philippinarum as a driver of benthic processes, even little parasiteinduced behavioral shifts could cascade down to affect ecosystem processes such as sediment dynamics and benthic community structure. Exploring such interactions opens new perspectives on how microparasites may influence ecosystem functioning, not only through physiological disturbances but also via changes in host functional traits.
(Journal of Invertebrate Pathology. vol. 217, n° 0022-2011, pp. 108605, 01/07/2026)
ECOMAP, AD2M, SU, CNRS, SBR, SU, CNRS, EDYMAR, AD2M, SU, CNRS, SBR, SU, CNRS, AD2M, SU, CNRS, SBR, SU, CNRS, SBR, SU, CNRS, CNRS, STAMAR, INSU - CNRS, SU, CNRS, ISTerre, IRD, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, UGA, FR2424, SBR, SU, CNRS, UB, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CENAREST
DroneSCAT: A Drone-Borne and Low-Cost Microwave Scatterometer for Subsurface Imaging
Using low cost and commercial elements, we designed and realized a drone-borne microwave scatterometer in the 1-6 GHz range for subsurface imaging applications. The core of the instrument of a portable vector network analyzer associated to lightweight horn antennas produced using 3D printing. It is carried by DJI drones and accurate positioning is performed with the help of the free Centipede GNSS system. We validated our DroneSCAT instrument over a coastal parabolic sand dune, allowing the detection of buried paleosols down to 3 meters. We then tested it for archeological prospecting and detect a strong reflector buried 1 meter deep. The DroneSCAT instrument allows the detection of subsurface structures, with the benefit of a very agile system and without need for contact with the ground.
(Drone Systems and Applications. vol. 14, n° 2564-4939, 25/06/2026)
OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LAB, UB, INSU - CNRS, CNRS, PACEA, UB, CNRS, UBM, CNRS, UB, UBM, CNRS, UB, UBM, CNRS, CNRS, UBM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Protracted ocean circulation slowdown drove exceptional ice-sheet melting during ice age termination IV
Glacial terminations stand out for their high rates of sea-level rise, particularly during meltwater pulses. Termination IV (T-IV; ~340,000 years before present) is a prominent example, with sea level rising at up to ~5 m per century. Due to sparse absolute age constraints on marine records, the causes for the high rates of sea-level rise at T-IV remain elusive. In this work, we provide a speleothem chronology from northern Italy, which we transpose to North Atlantic marine records. We infer that the high T-IV sea-level rise rate likely relates to a feedback whereby protracted meltwater release caused enhanced ocean heat storage, followed by heat release upon circulation recovery, driving additional ice-sheet collapse. This analysis highlights the critical role of oceanic feedbacks in driving exceptional rates of sea-level rise during terminations.
Middle to Late Pleistocene climate records feature sharp transitions between maximum glacial and interglacial climate conditions, referred to as glacial terminations 1-3 . Terminations were first identified in benthic foraminiferal stable oxygen isotope (δ 18 O b ) records from deepocean sediment cores 4,5 , where negative δ 18 O b shifts were ascribed to ice-volume reduction and associated release of 18 O-depleted meltwater to the ocean 6,7 . Independent sea-level reconstructions 8-11 have corroborated this picture and provided quantitative insights, showing strong agreement with individual and stacked benthic δ 18 O b time series that reflect both deep-ocean temperature and ice volume changes 12,13 . Detailed inspection of terminations reveals that ice-sheet retreat is not gradual; instead, there were times of accelerated collapse that led to meltwater pulses and remarkably high rates of sea-level rise 10,14 . Glacial terminations are also punctuated by millennial-scale climate perturbations, with abrupt shifts in oceanic and atmospheric temperatures and ocean circulation 15,16 that likely reflect bi-stability of the Atlantic
(Nature Communications. vol. 17, n° 2041-1723, pp. 5675, 16/06/2026)
NTU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMPA, CCMAR, UAlg, IGEC, Xjtu, CEPAM, UNS, CNRS, UniCA, GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], IRD, UniCA, HNHP, MNHN, UPVD, CNRS
Coastal ecosystem degradation driven by decades of unregulated terrestrial mining
Anthropogenic land-based disturbances can cascade into the sea, altering coastal ecosystems over long timescales. Mining exemplifies this land-sea connectivity, yet its full environmental footprint is underestimated when marine impacts are overlooked. Here, we investigate long-term coastal changes associated with nickel mining using a paleoecological approach in New Caledonia. A 226-cm sediment core spanning ~1000 years was analysed, combining ancient sedimentary DNA, foraminifera, and geochemistry. Since its onset in 1875, mining has modified sediment run-off and microbial assemblages. The most pronounced changes occurred in the 1960s after the mechanisation of extraction tools, which intensified soil erosion and increased sediment run-off, altering the richness and structure of both microeukaryotic and foraminiferal communities. Although post-1975 regulations mitigated nickel-rich run-off, persistent ecological disturbances remain. These findings highlight how terrestrial disturbances can induce long-term changes in coastal ecosystems, emphasising that land and sea should be studied and managed as a connected continuum.
(Communications Earth & Environment. vol. 7, n° 2662-4435, pp. 494, 16/06/2026)
DYNECO, IFREMER, ENTROPIE [Nouvelle-Calédonie], IRD [Nouvelle-Calédonie], IFREMER, UNC, CNRS, CCEM, IFREMER, LOCEAN-VALCO, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, GEO-OCEAN, UBS, IFREMER, INSU - CNRS, UBO EPE, CNRS, ENTROPIE [Réunion], IRD, UR, CNRS, IMPMC, MNHN, SU, CNRS, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Assessment of open science practices in marine sciences: results of the ANR SODIO project The projects
Assessing the impacts of human activities and climate change on biogeochemical cycles and marine ecosystems, as well as ensuring sustainable management of coastal and ocean water quality, constitute major challenges for scientists and policymakers. However, identifying these impacts is challenging due to the high variability of environmental conditions and limited data availability. To address this issue, French research funding agencies have been promoting open science, the unhindered dissemination of research outputs, methods and data, for several years. This initiative is based on the development of a national research infrastructure dedicated to Earth data, Data Terra, with ODATIS forming the pole dedicated to French coastal and marine data. This infrastructure is designed to assist the research community in complying with the EU INSPIRE Directive. However, open science practices within the French marine community, particularly with regard to data sharing and management, remain inconsistent and are not yet fully systematic. The ANR RESO SODIO project aims to enhance awareness of the current state of open science practices within the French marine research community. Specifically, it targets scientific projects funded by the INSU LEFE CYBER call, which supports multidisciplinary research projects at deepening our understanding of biogeochemical cycles and how marine ecosystems function, in order to improve our assessment of their past and future changes. Some of these projects focused on the Bay of Biscay, such as VOG, which was dedicated to studying the biological and geochemical processes of the western Gironde salt marsh, or DYCIDEMAIN, which investigated carbon dynamics at the exchange interfaces of temperate tidal marshes in the Île de Ré area. The primary objectives of SODIO are threefold: firstly, to understand the data sharing practices in place for these projects; secondly, to identify any barriers to open data sharing; and thirdly, to propose tools to help the community. Since 2014, LEFE CYBER has supported over 130 projects led by 96 principal investigators (PIs). A survey was conducted among project leaders (PIs) to assess their data storage and sharing practices, as well as their needs. The first requests to complete the questionnaire were sent out in June 2025. It took up to four reminders to obtain a significant number of responses by February 2026. PIs were also asked to provide any additional information or feedback they thought would be helpful, if necessary. Twenty-nine PIs agreed to be interviewed. This was carried out between September 2025 and March 2026. The results, based on a good response rate (75%), reveal that fewer than half of the respondents actively encourage their partners to archive their data, and some believe it is not their responsibility. The most commonly cited benefits of data archiving include data reuse, transparency and reproducibility, scientific valorisation, institutional mandates, data producer protection and journal editorial requirements. The most frequently reported obstacles include a lack of knowledge about data repositories and the need for technical support to prepare data, including metadata, documentation and format selection for handling diverse data types. There is also limited awareness of existing platforms, particularly for certain data types such as codes and model outputs, and for large datasets, such as images. The PIs also highlight challenges related to the interoperability of multi-source data and the absence (or knowledge) of a common nomenclature, particularly for biological data. The heterogeneity and diversity of national, European and international platforms also makes selecting the most suitable solution difficult. Furthermore, feedback suggests that colleagues may not be fully engaged, particularly in collaborative projects, or that they may not fully apprehend the importance of data archiving in comparison to only publication in journals. Furthermore, some researchers have emphasised that the two-year archiving period after the project ends is insufficient for preserving the scientific value of the data. Many continue to store their data locally (on personal computers or external hard drives), which increases the risk of data loss due to hardware failure or staff turnover. In light of these outcomes, the ANR RESO SODIO project, along with the help of the projet SO’ODATIS, will now develop a series of tutorials and practical guides to encourage good practices in data management within the French marine research community. The purpose of this presentation is to share these findings with a broader audience and encourage discussion on data opening and management practices
(16/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], OSU ECCE TERRA, ENS-PSL, PSL, INSU - CNRS, SU, CNRS, IRD, IFREMER, INSU - CNRS, IGN, CNRS, CNES, INRAE
Reconstructing the Exhumation and Paleo‐Earthquake History of a Submarine Normal Fault From Preserved Markers at the Seafloor (Roseau Fault, Lesser Antilles, France)
Assessing seismic and tsunami hazards along coastlines requires understanding past earthquakes and their recurrence along active submarine faults. Subaqueous paleoseismology commonly relies on sediment cores and seismic reflection data, but these methods may be limited by local site conditions or data quality. To overcome these limitations, a new approach using submersible‐based optical imagery can provide valuable insights into the paleoseismic history of submarine faults. In this study, we conducted a near‐bottom geological survey using submersibles along the Roseau normal fault (Lesser Antilles, France). This fault can host a M7 event if broken entirely. In 2004, it generated the Mw6.3 Les Saintes earthquake that produced a prominent coseismic ribbon at its base. High‐resolution submersible observations of the fault free face allowed mapping and characterizing detailed fault scarp morphologies, including new deformation markers such as abrasion bands, notches, roughness variations, dark bands, and uplifted sediments. These geomorphic markers form on the seafloor and are interpreted as records of fault scarp exhumation linked to changes in base level driven by sedimentation and tectonic activity. At one site, the observed morphology can be explained by three distinct earthquakes combined with episodes of rapid sedimentation. The penultimate earthquake produced a minimum vertical offset of 3 m, exceeding the 1.4 m slip associated with the 2004 event, indicating that it was at least as energetic. Sedimentation rates from nearby cores indicate that this penultimate event occurred much more recently than 2.8 kyr. These results demonstrate the value of submersible‐based offshore fault studies for reconstructing seismic histories.
(Geochemistry, Geophysics, Geosystems. vol. 27, pp. e2026GC012905, 11/06/2026)
GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], IRD, UniCA, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, GFZ, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, iSTeP, INSU - CNRS, SU, CNRS, CY
Modélisation morphodynamique de cordons dunaires en remobilisation sur le littoral de Nouvelle-Aquitaine
À la suite de l'hiver 2013-2014, les cordons dunaires de la côte aquitaine, fortement impactés par l'érosion marine, évoluent principalement sous l'effet des processus éoliens. Sur plusieurs kilomètres, des systèmes historiquement fixés par la végétation ont progressivement migré vers l'intérieur des terres sous forme de dunes aérodynamiques. Ces dynamiques offrent l'opportunité d'étudier les processus de remobilisation dunaire. Les modèles morphodynamiques éoliens constituent des outils prometteurs pour simuler ces processus, mais peu d'études ont évalué leur capacité à reproduire les observations in situ. À partir de données de vent, transport sédimentaire et topographie collectées lors de la campagne AEOLEX-1 sur le site de La Teste, cette étude évalue les performances du modèle DUNA. Les résultats montrent une bonne reproduction des processus physiques : le vent est correctement simulé (R² > 0,7 pour l'intensité, R² > 0,91 pour la direction) et, moyennant une calibration du paramètre separation angle, l'évolution morphologique présentent des erreurs centimétriques sur une année pour une dune de 25 m de hauteur. DUNA constitue ainsi un outil adapté pour l'étude de l'évolution des dunes peu végétalisées et offre des perspectives pour l'appui à la gestion des cordons dunaires remobilisés.
(Revue Paralia, n° 1760-8716, 09/06/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS
L'hydrosystème dunaire littoral dans un contexte de changement global : prémices d'une étude hydrogéologique du continuum océan-dunes-lac en Nouvelle-Aquitaine
(09/06/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Travaux exploratoires du GT Immunomarquage
(01/06/2026)
Glyco-MEV, UNIROUEN, NU, HeRacLeS, UNIROUEN, NU, IRIB, UNIROUEN, NU, INSERM, CNRS, INSERM, INC-CNRS, CNRS, IBS - UMR 5075, CNRS, IRIG, DRF (CEA), CEA, UGA, IBGC, UB, CNRS, CMEAB, TRI-Genotoul, INSERM, CNRS, INRAE, EPE UT, Comue de Toulouse, BIC, UB, INSERM, CNRS, SBR, SU, CNRS, IBS, CHU Angers, IGDR, UR, CNRS, Biosit : Biologie - Santé - Innovation Technologique, PF I2BC, I2BC, CEA, CNRS, IBDM, AMU, CdF (institution), CNRS, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CICS, UdA