Inverse Modeling Applications to Coastal Marine Ecosystems
Quantitative estimates of energy or material flows within food webs are increasingly viewed as essential to progress on a number of questions in ecosystem science. Inverse analysis has been used since the 1980s to estimate all flows within plankton food webs originally based on incomplete information. Its application to many aquatic environments, including the coastal zone, has led to a variety of methodological improvements. This chapter explains the methodology of inverse modeling and dynamic modeling that derived from this method and illustrates different application in ecosystems ecology. This approach also provides rigorous statistical comparisons of food web properties across ecosystems using indices from Ecological Network Analysis. Various methodological developments are currently underway and some of them are presented here, with a special focus on the link between static and dynamic modeling.
(pp. 96-121, 21/06/2026)
M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, BOREA, MNHN, IRD, SU, CNRS, UA, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, ULaval, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NIOZ, UKZN, UMR MARBEC, IRD, IFREMER, CNRS, UM, IMR, IMR, UiB, UR EABX, INRAE, MIAME, UPPA, INRAE, OFB, Institut Agro
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, 21/06/2026)
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, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
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.
(21/06/2026)
UPVD, CEFREM, UPVD, INSU - CNRS, CNRS, ISMO, CNRS, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF
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, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Caractérisation des réservoirs silicoclastiques du Trias inférieur à la méso-échelle, un aquifère aux enjeux locaux, nationaux et européens
(. vol. 83, pp. 118, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS
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, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SAMS, MIAT INRAE, INRAE, JMU, AWI, HIFMB, OFFIS
Plant detection from ultra high resolution remote sensing images: A Semantic Segmentation approach based on fuzzy loss
In this study, we tackle the challenge of identifying plant species from ultra high resolution (UHR) remote sensing images. Our approach involves introducing an RGB remote sensing dataset, characterized by millimeter-level spatial resolution, meticulously curated through several field expeditions across a mountainous region in France covering various landscapes. The task of plant species identification is framed as a semantic segmentation problem for its practical and efficient implementation across vast geographical areas. However, when dealing with segmentation masks, we confront instances where distinguishing boundaries between plant species and their background is challenging. We tackle this issue by introducing a fuzzy loss within the segmentation model. Instead of utilizing one-hot encoded ground truth (GT), our model incorporates Gaussian filter refined GT, introducing stochasticity during training. First experimental results obtained on both our UHR dataset and a public dataset are presented, showing the relevance of the proposed methodology, as well as the need for future improvement.
(21/06/2026)
OBELIX, IRISA-D6, IRISA, UR, INSA Rennes, UBS, ENS Rennes, Inria, CNRS, IMT Atlantique, LETG - Rennes, UBO EPE, UR2, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
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, 21/06/2026)
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
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., 21/06/2026)
BSE, UB, CNRS, INRAE, LOMA, UB, CNRS, ImmunoConcept, UB, INSERM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS