Impacts of AMOC Collapse on Monsoon Rainfall: A Multi-Model Comparison
A collapse of the Atlantic Meridional Overturning Circulation (AMOC) would have substantial impacts on global precipitation patterns, especially in the vulnerable tropical monsoon regions. We assess these impacts in experiments that apply the same freshwater hosing to four state-of-the-art climate models with bistable AMOC. As opposed to previous results, we find that the spatial and seasonal patterns of precipitation change are remarkably consistent across models. We focus on the South American Monsoon (SAM), the West African Monsoon (WAM), the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM). Models consistently suggest substantial disruptions for WAM, ISM, and EASM with shorter wet and longer dry seasons (−29.07%, −18.76%, and −3.78% ensemble mean annual rainfall change, respectively). Models also agree on changes for the SAM, suggesting rainfall increases overall, in contrast to previous studies. These are more pronounced in the southern Amazon (+43.79%), accompanied by decreasing dry-season length. Consistently across models, our results suggest a robust and major rearranging of all tropical monsoon systems in response to an AMOC collapse.
(Earth's Future. vol. 12, n° 2328-4277, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Gestion quantitative de l’eau et usages agricoles sous contrainte climatique
Plus grande région agricole de France et d’Europe, la Nouvelle-Aquitaine subit comme l’ensemble du territoire national, les conséquences du changement climatique et notamment des sécheresses. L’eau et son accès sont des enjeux cruciaux pour une partie des agriculteurs mais une part de la population est inquiète des possibles conséquences environnementales. La question de la gestion de l’eau est donc au cœur de controverses publiques depuis quelques années. C’est dans ce contexte qu’ AcclimaTerra s’est proposé d’apporter une contribution au débat dans le but de réintroduire des données et des résultats scientifiques sur la ressource en eau.
(pp. 68, 14/10/2026)
BRGM, Bordeaux Sciences Agro, CED, IEP Bordeaux, UB, CNRS, AGIR, Toulouse INP, Comue de Toulouse, INP - PURPAN, Toulouse INP, Comue de Toulouse, INRAE, UMR G-EAU, Cirad, BRGM, IRD, INRAE, Institut Agro, UP, HydrASA, IC2MP [Poitiers], UP, INC-CNRS, CNRS, UMR EGFV, UB, Bordeaux Sciences Agro, INRAE, UMLP, UP, Solagro, ISVV, UB, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
New insights into the impact of leachates from in-field collected plastics on aquatic invertebrates and vertebrates.
The impact of leachates from micronized beached plastics of the Mediterranean Sea and Atlantic Ocean on coastal marine ecosystems was investigated by using a multidisciplinary approach. Chemical analysis and ecotoxicological tests on phylogenetically distant species were performed on leachates from the following plastic categories: bottles, pellets, hard plastic (HP) containers, fishing nets (FN) and rapido trawling rubber (RTR). The bacteria Alivibrio fischeri, the nauplii of the crustaceans Amphibalanus amphitrite and Acartia tonsa, the rotifer Brachionus plicatilis, the embryos of the sea urchin Paracentrotus lividus, the ephyrae of the jellyfish Aurelia sp. and the larvae of the medaka Oryzias latipes were exposed to different concentrations of leachates to evaluate lethal and sub-lethal effects. Thirty-one additives were identified in the plastic leachates; benzophenone, benzyl butyl phthalate and ethylparaben were present in all leachates. Ecotoxicity of leachates varied among plastic categories and areas, being RTR, HP and FN more toxic than plastic bottles and pellets to several marine invertebrates. The ecotoxicological results based on 13 endpoints were elaborated within a quantitative weight of evidence (WOE) model, providing a synthetic hazard index for each data typology, before their integrations in an environmental risk index. The WOE assigned a moderate and slight hazard to organisms exposed to leachates of FN and HP collected in the Mediterranean Sea respectively, and a moderate hazard to leachates of HP from the Atlantic Ocean. No hazard was found for pellet, bottles and RTR. These findings suggest that an integrated approach based on WOE on a large set of bioassays is recommended to get a more reliable assessment of the ecotoxicity of beached-plastic leachates. In addition, the additives leached from FN and HP should be further investigated to reduce high concentrations and additive types that could impact marine ecosystem health.
(Environmental Pollution. vol. 355, n° 0269-7491, pp. 124233, 14/10/2026)
IAS, CNR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NEOLAiA, UNIVPM, ULPGC, LCPO, UB, ENSCBP, INC-CNRS, CNRS
Factors Controlling Mud Floc Settling Velocity in a Highly Turbid Macrotidal Fluvial‐Estuarine System
This study assesses the settling dynamics of suspended sediments along the hyper‐turbid Gironde Garonne fluvial‐estuarine system, with an innovative optical SCAF instrument (System of Characterization of Aggregates and Flocs). Two fields campaigns were carried out to determine the settling velocity and properties of suspended sediments during a semi‐diurnal tidal cycle, as well as hydrodynamic conditions and water properties. The two sampling stations were representative of two regions: a tidal river dominated by fresh water and an estuary affected by salty or brackish waters. A high spatial variability of the settling velocity was observed along the fluvial‐estuarine system and vertically along the water column. Settling velocities ranged from 0.02 to 0.4 mm/s. This study confirms that in hyper‐turbid systems, the suspended sediment concentration (SSC) is predominantly driving the settling dynamics of suspended sediment. Threshold concentrations have been defined for the flocculation and hindered regimes where the settling velocity may vary by one order of magnitude. Although in natural environments it is difficult to distinguish between the effects of SSC and turbulence (as they are correlated), in the Gironde‐Garonne system the turbulent shear G seems to affect the settling of suspended sediment to a lower extent. Settling velocity variations cannot be directly correlated to salinity or organic matter content. Despite differences in hydrodynamic and environmental conditions in fluvial and estuarine regions, a common prediction law has been found to estimate settling velocity of suspended sediment as a function of suspended sediment concentration.
(Journal of Geophysical Research. Oceans. vol. 129, n° 2169-9275, pp. e2024JC021558, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, RHITME, Cerema, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, IGE, IRD, INSU - CNRS, CNRS, INRAE, Fédération OSUG, UGA, Grenoble INP, UGA, Fédération OSUG
El Niño-like tropical Pacific ocean cooling pattern during the Last Glacial Maximum
Many state-of-the-art climate models are unable to reproduce the observed 20th century surface warming pattern in the tropical Pacific Ocean, casting doubt on the robustness of future projections. Here, we examine past changes in the tropical Pacific upper ocean spatial pattern using paleoclimate reconstructions from proxies and simulations from a multi-model ensemble. The proxy results demonstrate that during the Last Glacial Maximum, when atmospheric carbon dioxide concentrations were lower than present, temperatures in the western tropical Pacific Ocean decreased more than in the east, leading to an El Niño-like cooling pattern. This result contrasts with the zonally uniform cooling pattern observed in model simulations, highlighting the common issue of models overestimating the sensitivity of eastern tropical Pacific sea surface temperatures to greenhouse forcing. Our proxy results imply that the western Pacific may warm more than the east in response to future climate change, producing a La Niña-like surface warming pattern.
(Communications Earth & Environment. vol. 5, n° 2662-4435, pp. 587, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MARUM, QMUL, NTU
Constraining Plio‐Pleistocene Shifts in Northwest African Hydroclimate, Ecosystem Distributions, and Marine Productivity: New Paleo‐Records Across the Mid‐Pleistocene Transition
AbstractNorthwest Africa transitioned from a wet/vegetated landscape toward drier/sparser conditions sometime between the late‐Pliocene and the late‐Pleistocene. However, our understanding of the precise timing and nature of this transition is hampered by a paucity of paleo‐records which bridge these two intervals. Here we report new plant‐wax isotope as well as dust and opal flux records from the relatively brief interval ∼1.1–1.0 million years ago (Ma) to evaluate the astronomical timescale controls of Northwest African hydroclimate and vegetation during the Mid‐Pleistocene Transition (MPT) and, in context with published records, the drivers of long‐term climate and ecological trends over the Plio‐Pleistocene. The tempo and amplitude of the Northwest African monsoon rainfall swings closely track low latitude insolation forcings over the last 5 Ma. However, we demonstrate that a pronounced mean state decline in monsoon strength likely occurred following the MPT most likely instigated by increasing Atlantic meridional sea surface temperature gradients or declines in the strength of the meridional overturning circulation. The northward extent of vegetation does not track changes in monsoon strength over the Plio‐Pleistocene and thus may be more strongly influenced by changes in monsoon rainfall extent or ecosystem disturbances. Progressively diminished dust fluxes following a decline in monsoon strength after 1.0 Ma is consistent with reduced production and subsequent depletion of fine‐grained sediments in the Sahara. Synchroneity between dust and opal fluxes across timescales suggests nutrient delivery to the surface ocean via dust plays a key role in marine primary productivity off the coast of Northwest Africa.
(Paleoceanography and Paleoclimatology. vol. 39, n° 2572-4525, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
L'impact du numérique. Avis CTES sur les actions menées en 2023-2024
Cet avis porte sur l’impact du numérique en lien avec les activités de l’université. Il évalue les actions mises en place par l’université dans le cadre des engagements décrits dans la Feuille de route des transitions environnementales et sociétales de l’université (Feuille de route), notamment l’engagement 15.
(pp. 10 p., 14/10/2026)
BSE, UB, CNRS, INRAE, LOMA, UB, CNRS, ImmunoConcept, UB, INSERM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A new species of Malacoceros (Annelida, Polychaeta, Canalipalpata, Spionidae) from urban waters in Gabon
A new species of Malacoceros is described from estuarine equatorial waters in Libreville (Gabon, West Africa). During a recent environmental study aimed to assess the urban impact on an estuarine ecosystem near Libreville, the collection of sediment samples from the area was undertaken. The local invertebrate macrofauna had not been previously well studied, and to document the biodiversity, specimens were examined in more detail. A new species of Malacoceros was discovered, occurring in mangrove areas. The new species is described and illustrated in detail, and information on three molecular markers was retrieved and partially used for species delimitation analysis. The new species resembles Malacoceros indicus (Fauvel 1928) described from India but is easily distinguished by a very conspicuous morphological character, the presence of 7–11 large tubercles along the anterior margin of the prostomium. The presence of such conspicuous tubercles has never been observed before in Malacoceros. Maximum likelihood trees for species of Malacoceros and the close genera of Rhynchospio, for which we have data, are also provided. The suitability of characters used for species delimitation in Malacoceros is discussed.
(African Zoology, n° 1562-7020, pp. 1--16, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Revealing the profound influence of diapause on gene expression: Insights from the annual transcriptome of the copepod Calanus finmarchicus
Abstract Annual rhythms are observed in living organisms with numerous ecological implications. In the zooplanktonic copepod Calanus finmarchicus , such rhythms are crucial regarding its phenology, body lipid accumulation, and global carbon storage. Climate change drives annual biological rhythms out of phase with the prevailing environmental conditions with yet unknown but potentially catastrophic consequences. However, the molecular dynamics underlying phenology are still poorly described. In a rhythmic analysis of C. finmarchicus annual gene expression, results reveal that more than 90% of the transcriptome shows significant annual rhythms, with abrupt and dramatic upheaval between the active and diapause life cycle states. This work explores the implication of the circadian clock in the annual timing, which may control epigenetic mechanisms to profoundly modulate gene expression in response to calendar time. Results also suggest an increased light sensitivity during diapause that would ensure the photoperiodic entrainment of the endogenous annual clock.
(Molecular Ecology. vol. 33, n° 0962-1083, 14/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SAMS, MIAT INRAE, INRAE, JMU, AWI, HIFMB, OFFIS
“Hidden” biodiversity: a new amphipod genus dominates epifauna in association with a mesophotic black coral forest
Black corals are important components of mesophotic and deep-water marine habitats. Their presence at great depths (e.g., 50 to 200 m) makes accessibility difficult, limiting our understanding of the associated biodiversity. Amphipods dominate vagile epifauna in marine habitats around the world, fulfilling important ecosystem functions. However, there are no studies on amphipods exclusively associated with black corals, including relationships between their ecological patterns (e.g., abundances) and the size of coral colonies. We investigated the epifaunal composition and abundance associated with black coral colonies of Antipathella wollastoni in the subtropical eastern Atlantic Ocean. In total, 1,736 epifaunal individuals were identified, of which 1,706 (98.27%) were amphipods, belonging to 6 taxa. We identified and described a new amphipod genus and species within the Stenothoidae family, Wollastenothoe minuta gen. nov., sp. nov., which outnumbered the amphipod assemblage (86.15%) and provided a complete taxonomic key of Stenothoidae family including this new finding. For the first time, the association between an amphipod species and a black coral was described, including a strong correlation between coral colony size and amphipod abundances. This study demonstrates that epifauna associated with mesophotic black corals remains largely undescribed.
(Coral Reefs. vol. 43, n° 0722-4028, pp. 655–672, 14/10/2026)
ULPGC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULB, LECOB, SU, CNRS, OOB, SU, CNRS