Pseudopolydora kempi japonica Imajima & Hartman, 1964 (Polychaeta: Spionidae): a controversial subspecies long overlooked in European waters
Recently, using morphological and molecular analyses, several Pseudopolydora specimens (Polychaeta: Spionidae) from French coastal waters were identified as Pseudopolydora kempi ssp. japonica Imajima and Hartman, 1964. According to the samples examined, P. kempi ssp. japonica has been present in European waters since 2004. Previous misidentifications in France are likely due to its resemblance to the indigenous species Pseudopolydora pulchra (Carazzi, 1893), and to the status of P. kempi ssp. japonica which is still controversial. Material was collected from Arcachon Bay, Morbihan Bay, Aiguillon Bay, and in the Gironde estuary (Bay of Biscay, France). All these areas have extensive shellfish industries, especially the farming of the Japanese oyster Magallana gigas (Thunberg, 1793). The importation of these live oysters from Japan has often included other species including polychaete worms, indicating a major vector of exotic species.
(BioInvasions Records. vol. 32, n° 2242-1300, pp. 403-418, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMS POREA, INSU - CNRS, CNRS, INRAE, LIENSs, INSU - CNRS, ULR, CNRS
Wave input reduction approach to compute the alongshore distribution of breaking wave conditions along the North Médoc coast
This study introduce an input reduction (IR) methodology that we developed specifically to enhance computational efficiency in nearshore wave modeling for the complex area of the Nord Médoc coast, adjacent to one of the margest estuary in Europe (Gironde). This methodology combines simulated annealing optimization with wave modeling. We apply it to an extensive 15-year offshore wave time series obtained from MARC's WavevatchIII-based simulaton and prediction system (LOPS). The IR effectiveness is assessed by comparinf the original and simplified offshore wave time series, simulated with the spectral wave model SWAN, at three nearshore locations in our study zone. Results indicate a strong agreement nearshore between the original and simplified offshore wave time series, with mean absolute errors ranging from 8 to 20 cm for the significant wave height, 0.7 to 1 s for peak wave period and 1.2 to 3.8° for wave direction. Using an optimal number of 30 clusters, the simulated annealing optimization affectively clusters wave data. Further validation of this IR-method involves analyzing its impact on long-term sediment transport using a reduced complexity shoreline model (LX-shore). This study lays the groundwork for the set-up of the reduced-complexity shoreline model to be applied in this intricate hydro-morphodynamic zone.
(pp. 121-130, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM
Observations of Tide- and Wave-Driven Groundwater Dynamics in Meso-Tidal Sandy Beach
This study focuses on the non-hydrostatic groundwater dynamics of a meso-tidal sandy beach under the influence of tides and waves. A field campaign was conducted at Lacanau Beach, France, during four consecutive tide cycles in March 2022. Groundwater dynamics was monitored based on a network of buried pressure sensors. The data analysis revealed the combined influences of waves and tides on the groundwater circulation. Tidal-scale groundwater flows are predominantly seaward, primarily controlled by the head gradient resulting from a high coastal aquifer. A circulation cell develops under the swash zone and moves across the beachface following the tidal oscillations. On a daily scale per alongshore and vertical units, the observed flow is 2.5 m$^3$ .m$^{-2}$ .day$^{-1}$, i.e., 912.5 m$^3$.m$^{-2}$.year$^{-1}$. Extrapolating the present dataset, it may be expected that combined events, such as drought-induced aquifer depletion with high tides, could lead to beach-scale gradient reversal, potentially causing salinisation of the continental aquifer.
(Water. vol. 16, n° 2073-4441, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, SIAME, UPPA
Changes in taxonomic and functional composition of subalpine plant communities in response to climate change under contrasting conditions of bedrock and snow cover duration
Questions: We assessed interactions between climate change, bedrock types and snow cover duration on the trajectories of taxonomic and functional composition of subalpine plant communities. We predict (i) an increase in species richness on siliceous bedrock due to a reduced competition and a decrease in richness on calcareous bedrock due to increasing drought stress; (ii) decreasing snow cover duration should induce a higher shrub encroachment in hollows as compared to ridges; and (iii) increasing growing season temperature should induce taller sizes and more conservative growth traits, in particular in hollows. Location: Subalpine belt of the Grandes Rousses mountain range, southwestern Alps (France). Methods: 189 vegetation plots were sampled in 1997 and 2017-2018. The duration of snow cover was assessed during two years in 1995-1997 and five functional traits were measured on 108 species in 2021. We performed multivariate analyses, quantified community-weighted means (CWM) of traits and used ANOVAs to detect responses to local-scale factors and changes in snow cover, temperature and precipitation since 1997 according to a nearby meteorological station. Results: Overall, taxonomic composition weakly changed and changes were more dependent on the position of communities along the snow cover duration gradient than on their bedrock type. The abundance of drought-tolerant species increased at the border of hollows and there was, over all communities, a slight increase in the abundance of dwarf shrubs and tall herbaceous species, a strong decrease in short herbaceous species and, thus, an overall decrease in species richness. There were important overall changes in CWM of size traits, in particular leaf area which increased the most in hollows irrespective of bedrock types. Conclusion: In this subalpine site the effects of decreasing snow cover duration overwhelmed the effects of bedrocks, which may explain the overall increase in competitive species and decrease in species richness
(Journal of Vegetation Science. vol. 35, n° 1100-9233, pp. e13253, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LECA, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, UGA, UR LESSEM, INRAE, Fédération OSUG, UGA
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, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MARUM, QMUL, NTU
Caractérisation des réservoirs silicoclastiques du Trias inférieur à la méso-échelle, un aquifère aux enjeux locaux, nationaux et européens
(. vol. 83, pp. 118, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS
“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, 10/04/2026)
ULPGC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULB, LECOB, SU, CNRS, OOB, SU, 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, 10/04/2026)
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, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SAMS, MIAT INRAE, INRAE, JMU, HIFMB, OFFIS
Influence de la morphologie dunaire sur les flux éoliens et le transport sédimentaire : Exemple sur la côte Aquitaine
L'évolution des dunes côtières est d'une importance stratégique vis-à-vis du risque de submersion dans un contexte d'érosion de nombreux littoraux sableux. Leur dynamique est contrôlée par les interactions complexes entre les facteurs biotiques et abiotiques, notamment le vent incident, la morphologie de la dune et la densité de végétation. La littérature décrit les caractéristiques du vent lors du franchissement d'un système plagedune ainsi que du transport sédimentaire associé pour de nombreux environnements. Toutefois, il n'est pas documenté à ce jour, comment deux systèmes à la morphologie contrastée répondent à une même tempête. Dans ce cadre, une campagne de terrain de 3 jours a été réalisée sur deux sites voisins de la côte Aquitaine (La Teste-de-Buch (S1) et Biscarrosse (S2)) en simultanée. Ils présentent des morphologies contrastées avec une dune fixée par la végétation au front dunaire abrupte (36°) en S1 et une dune libre, au profil doux (11°) en S2. L'étude repose sur l'acquisition de données de vent à l'aide de 21 anémomètres répartis sur les deux sites d'étude, complétée en plusieurs endroits par l'analyse qualitative de panaches de fumigènes capturés par vidéo. Enfin, des mesures de transport sédimentaire ont également été réalisées en différentes positions sur le long des profils. Les résultats mettent en évidence le rôle de la morphologie sur le comportement du vent lors du franchissement de la dune favorisant en S2 un transport sédimentaire pouvant atteindre 200 kg/m²/h au niveau de la crête. Les sédiments transportés proviennent de la plage et de l'érosion de la face marine de la dune. A contrario, l'impact de la face très abrupte de la dune de S1 sur le vent limite très fortement le transport sédimentaire de la plage vers le haut de la dune. Ainsi, la morphologie de S2 favorise le transfert sédimentaire de la plage vers les terres permettant sur des secteurs en érosion le maintien d'un milieu dunaire dans le temps.
(10/04/2026)
UPVD, CEFREM, UPVD, INSU - CNRS, CNRS, ISMO, CNRS, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF