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.
(10/04/2026)
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
“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
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, 10/04/2026)
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
Transport of microplastic debris in estuaries
This Chapter provides insight into the physical, hydrodynamic and biochemical processes governing the transport of microplastics in estuarine environments. The focus is mainly on the physical and hydrodynamical processes that control microplastic transport, although the role of biochemical processes on their dynamical behaviour is discussed. The chapter begins by describing the microplastic physical properties and their variability with the time spent in the environment due to weathering, biofouling, and flocculation. This variability makes them different from other suspended particulate matter and critically affects their buoyancy, deposition and erosion rates. The more prominent hydrodynamic processes driving the transport of microplastics are then discussed. Next, four case studies are presented to illustrate microplastic dynamics in different types of estuaries, from well-mixed to strongly stratified. Finally, sampling and numerical approaches for analysing the dispersion of microplastics in estuaries are reviewed.
(. vol. 2, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UGR
Potential impacts of cable bacteria activity on hard-shelled benthic foraminifera: implications for their interpretation as bioindicators or paleoproxies
Hard-shelled foraminifera are protists able to build a calcareous or agglutinated shell (called a “test”). Here we study the impact of sediment acidification on calcareous test preservation. For this study, sediment cores were sampled in the macrotidal Auray estuary located on the French Atlantic coast. Living and dead foraminifera were quantified until 5 cm depth and discriminated using the Cell-Tracker™ Green vital marker. The pH and oxygen profiles combined with quantitative polymerase chain reaction (qPCR) suggested that cable bacteria were most likely to cause the acidifying process. Cable bacteria (CB) are filamentous bacteria coupling sulfide oxidation to oxygen reduction over centimetre distances, generating a strong pH gradient within the first few centimetres of the sediment that could affect the microhabitats occupied by benthic foraminifera. On two different intertidal mudflats, volumetric filament densities have been estimated. They were comparable to those observed in the literature for coastal environments, with 7.4 ± 0.4 and 74.4 ± 5.0 m cm−3 per bulk sediment, respectively. Highly contrasting sediment acidification (from low to very intense) was described from 1.0 to 2.4 ΔpH. This seems to lead to various dissolution stages of the foraminiferal calcareous test from intact to fully dissolved tests revealing the organic lining. The dissolution scale is based on observations of living Ammonia spp. and Haynesina germanica specimens under a scanning electronic microscope. Furthermore, dead foraminiferal assemblages showed a strong calcareous test loss and an organic lining accumulation throughout depth under low pH, hampering the test preservation in deep sediment. These changes in both living and dead foraminiferal assemblages suggest that cable bacteria must be considered in ecological monitoring and historical studies using foraminifera as bioindicators and paleoenvironmental proxies.
(Biogeosciences. vol. 21, n° 1726-4170, pp. 911-928, 10/04/2026)
LPG-ANGERS, LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Sedimentology of Modern Bahamian Carbonate Slopes: Summary and Update
Slopes adjacent to the Bahamian carbonate platform revealed a large variety of depositional processes. In this study, we present a synthesis summarizing 109,000 km2 of bathymetric and reflectivity data with ∼7,900 km of seismic lines and 311 m of sediment cores that were obtained over the last 50 years. These data are used to develop a conceptual model of sedimentation patterns on Quaternary carbonate slope systems and their interaction with the adjacent shallow-water carbonate platforms. Our data highlight that during the Quaternary, factors controlling large-scale sedimentation on Bahamian slopes have numerous similarities as they have higher sedimentation rates during interglacials. At a small scale, every slope has its own characteristics that are contemporary controlled by two main characteristics: (a) facies on the adjacent shallow-water platform, and (b) the impact of shallow- and deep-water currents. Large-scale tectonics influence sediment deposition as it determines the position of the islands and impacts platform facies distribution.
(Geochemistry, Geophysics, Geosystems. vol. 25, pp. 6, pp. 265-290, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OSU PYTHEAS, IRD, AMU, INSU - CNRS, CNRS, INRAE, [Total Energies. Anciennement : Total, TotalFina, TotalFinaElf], CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE
Modélisation à complexité réduite de l’impact du phénomène de bypass sédimentaire sur la dynamique des plages de poche
Le phénomène de bypass sédimentaire peut considérablement influencer la dynamique des plages de poche à moyen et long terme. Cependant, il n’est encore que partiellement inclus dans les modèles d’évolution du trait de côte à complexité réduite. Ici, une paramétrisation du flux de sédiments qui contournent (« bypass ») un obstacle rocheux est implémentée dans le modèle LX-Shore. Les simulations effectuées sur le cas académique d’une plage initialement rectiligne bordée par deux épis rocheux montrent que le transport des sédiments autour de l’obstacle dans la colonne d’eau (ou « full bypassing », FB) impacte significativement la forme moyenne et la variabilité spatiale du trait de côte par rapport au bypass se produisant uniquement lorsque le trait de côte franchit la pointe de l’ouvrage (ou « shoreline bypassing », SB). L’angle de rotation de la plage est réduit d’environ 1/3, en particulier en cas de climat de vagues peu obliques et asymétriques. La courbure de la plage est également significativement réduite, surtout en cas de forçage très oblique et asymétrique. Enfin, le maximum d’érosion en amont de l’ouvrage est surestimé jusqu’à 30% en configuration SB par rapport à FB. Ces résultats soulignent l’importance de l’influence du bypass sédimentaire sur la dynamique des plages de poche et la nécessité d’intégrer des paramétrisations de ce phénomène dans les modèles à complexité réduite.
(pp. 303-310, 10/04/2026)
BW-CGC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM
Incisocalliope aestuarius (Crustacea: Amphipoda: Pleustidae), an old introduced species in the Gironde Estuary (SW France)
The amphipod Incisocalliope aestuarius was recently collected since 2015 in the mesohaline part of the Gironde Estuary (SW France) with a van Veen grab and in the lower intertidal part in oyster bed by hand-picking. A look back at past studies showed that this species was present in this estuary since 1976, whereas the original description of this amphipod comes from Watling and Maurer in 1973, from the East coast of America. The validity of the Incisocalliope genus is herein questioned, and it is proposed to transfer species of the genus Inciscalliope to Parapleustes genus.
(Journal of the Marine Biological Association of the United Kingdom. vol. 104, n° 0025-3154, pp. e116, 10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISYEB, MNHN, EPHE, PSL, SU, CNRS, UA, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE
Comparing the evolution of debris-free and debris-covered glaciers during the end of the Lateglacial and the Holocene in Dudh Koshi basin, Everest region, Nepal
Debris-covered glaciers are very frequent geomorphological features in Khumbu Himal (Nepal). Rock debris on the glacier surface play a significant role in glacier-climate relationships and glacier dynamics. These effects may cause an asynchronous evolution of debris-covered glaciers compared to debris-free glaciers at a multicentennial to millennial scale. Here, we explore this hypothesis by documenting and comparing the multi-millennial Holocene evolution of a debris-free glacier, Sabai glacier, and two debris-covered glaciers, Dig and Huuku glaciers, from adjacent catchments in Dudh Koshi basin (Everest region, Nepal). To do so, we dated rock samples collected from moraine boulders on both debris-covered and debris-free glaciers using the 10Be cosmic ray exposure (CRE) dating method. 10Be CRE ages obtained from 41 moraine boulder samples provide time constraints from ∼13.5 ka to 0.1 ka. While at Dig (debris-covered) and Sabai (debris-free) glaciers, no moraines from the Lateglacial and the Early Holocene are preserved, debris-covered Huuku glacier evidenced a large glacier extent during the Bølling-Allerød and Early Holocene with two moraines dated respectively to ∼13.5 ka and 11 ka, synchronously with most debris-free and debris-covered glaciers in this region. These two glacier advances are concomitant with enhanced monsoon precipitation supporting a qualitative relationship. The absence of debris landforms in the main valley question the nature of Huuku glacier during the Bølling-Allerød and Early Holocene, which could have been either debris-free or covered by a thin debris layer only. During the Mid Holocene, significant differences are observed in the evolution of the two glacier types. The two debris-covered glaciers recorded a significant advance at ∼4.8 ka, synchronous with that observed on other debris-covered glaciers in Khumbu valley. However, such glacier advance during the Mid Holocene was not evidenced on debris-free glaciers in the Dudh Koshi valley. Such a Mid Holocene glacier advance may have a spatial signature with frequent cases reported from both types of glaciers in the western part of High Mountain Asia, which are however infrequent in the arid and semi-arid southern and north-eastern Tibet. During the Late Holocene, both types of glaciers evolved similarly again, with moraines spanning the last two millennia, including the Little Ice Age, concomitant with enhanced monsoon precipitation.
(Quaternary Science Reviews. vol. 344, n° 0277-3791, pp. 108994, 10/04/2026)
CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, IGE, IRD, INSU - CNRS, CNRS, INRAE, Fédération OSUG, UGA, Grenoble INP, UGA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Observation et modélisation de la dynamique pluriannuelle des cordons dunaires en Gironde
Considérées comme des réservoirs de biodiversité, les dunes côtières représentent également des barrières naturelles contre la submersion marine et de larges sources de sable modérant l'érosion du trait de côte. Leur évolution dépend de nombreuses interactions complexes entre des processus marins, éoliens et biologiques. L'analyse de données d'observation collectées le long de cordons dunaires à une échelle pluriannuelle, et leur utilisation pour calibrer et valider des modèles numériques, permettent de mieux comprendre ces interactions. Cette étude a montré que le modèle AeoLiS était capable de reproduire, de manière satisfaisante, la migration pluriannuelle de deux cordons dunaires peu végétalisés sur de la côte girondine. En revanche, la végétation joue un rôle prépondérant dans l'évolution de cordons dunaires et sera intégrée dans le cadre du modèle lors de futurs travaux.
(10/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, BRGM