The Bengal fan: external controls on the Holocene Active Channel turbidite activity
The eastern levee of the Active Channel in the Bengal fan has been investigated in order to better understand the history of turbidite activity in this channel during the Holocene in the context of Ganges-Brahmaputra source-to-sink' system. A robust C-14-based chronostratigraphy provides high temporal resolution for reconstructing sediment accumulation history on the eastern levee of the Active Channel. Integration of this study with previous work in the area suggests that the Bengal fan has remained continually connected with the Ganges-Brahmaputra fluvial system through the Holocene, feeding through the main canyon, the Swatch of No Ground (SoNG). An intense turbidite activity occurred during a transgressive wet period from 14.5 to 9.2 ka cal. BP, followed by an abrupt shift in sedimentation at 9.2 ka cal. BP, probably due to the high sea level leading to a partial disconnection between massive river discharges and the deep turbidite system. During the last 9.2 ka cal. BP, turbidite activity is still present but irregular, likely modulated by a combination of various forcings such as monsoon variability and river migration. In total, three phases are distinguishable during this period: 9.2-5.5, 5.5-4, and 4 ka cal. BP to modern, according to the turbidite record. Unexpectedly, the Indo-Asian monsoon does not appear to be the only predominant forcing on the establishment of the Bengal fan during the Holocene because of the combination of different forcings directly affecting transfers between the Ganges-Brahmaputra and the Bengal fan as well as river migrations, delta construction, and potentially anthropogenic impact.
(The Holocene. vol. 27, n° 0959-6836, pp. 900-913, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SCTA, UQAM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOPS, UP11, CNRS, EMBS, iSTeP, UPMC, CNRS
A DEB-IB model to test trophic and ontogenic triggers on the downstream migration of juvenile European sturgeon
Our objective was to integrate the fish physiology within a rigorous conceptual framework to coherently simulate the different biological processes constrained by possible environmental and anthropogenic pressures on individuals.
(pp. 1, 21/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Is apparent low productivity of the invasive marine mollusc Crepidula fornicata Linnaeus, 1758 related to biased age determination?
The slipper limpet Crepidula fornicata Linnaeus, 1758 is a major exotic invader of East North Atlantic coasts. Individuals live on top of each other and form stacks with the youngest on the top. Earlier studies reported that one individual typically settles per year. If true, it is a simplified means to provide a “shell length-age” relationship for population dynamics studies, especially Production/Biomass ratio (P/B) assessment. However, estimated P/B ranges between 0.15 and 0.45 yr-1 seem low compared to those of closely-related marine invertebrates and considering the invasiveness of C. fornicata in coastal habitats. In this study, we placed artificial substrates (“tiles”) for one year in the middle of a C. fornicata colony and measured settlement. We sometimes observed more than one individual settling per stack in a year: 4% of stacks were composed by 3 individuals, 27% by 2 individuals and 69% were single specimen. On this basis, we formulated a model to better link the position of each C. fornicata within a stack to its age. In addition, the C. fornicata population was annually sampled for 5 years. Then, population dynamics parameters, density at recruitment, mortality rate, growth performance, production and P/B were estimated. We compared two cases: (i) individual age was defined by its position in stacks; (ii) individual age was corrected by the model. Recalculation moderately increased growth performance expectation (+2 to 8% per year) but greatly enhanced production and P/B (ca. 1.2 to 2.6-fold per year). Recalculated P/B values ranged from 0.55 to 0.72 yr-1. While still low, they were more consistent with published values for similar large marine invertebrates, in particular for invasive species.
(Aquatic Invasions. vol. 12, n° 1798-6540, pp. 459-468, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact de 3 pesticides sur les acides gras de la diatomée d'eau douce Gomphonema gracile
Depuis plusieurs années, l'usage intensif de pesticides a causé de nombreux problèmes à l'environnement, faisant des pesticides des polluants majeurs des écosystèmes aquatiques (Aydinalp & Porca 2004). Parmi les indicateurs biologiques, les biomarqueurs doivent être développés en raison de leur capacité à révéler précocement des effets toxiques sur les organismes vivants. Le but de cette étude est d'évaluer les spécificités/sensibilités des profils d'acides gras (composition en acides gras saturés, insaturés et polyinsaturés par chromatographie gazeuse couplée à un détecteur à ionisation de flamme) des diatomées en comparaison avec des descripteurs d'effet « classiques » (inhibition de la photosynthèse, croissance, analyses génétiques). Des cultures de la diatomée d'eau douce Gomphonema gracile sont soumises séparément à 3 pesticides ayant des cibles cellulaires différentes, à une concentration environnementale et une concentration plus élevée (diuron et Smétolachlore, C1= 1 µg/L et C2= 10 µg/L ; glyphosate, C1= 5 µg/L and C2= 50 µg/L). Les diatomées sont exposées durant leur phase de croissance exponentielle à une température et une intensité lumineuse respectivement de 17°C et 67 µmol.m-2.s-1. Après une semaine d'exposition, la composition des diatomées en acides gras est déterminée en parallèle des descripteurs « classiques ». Tandis que les effets des pesticides sur les descripteurs « classiques » sont pas ou peu sensibles, notamment aux plus faibles concentrations d'exposition, certains profils d'acides gras semblent être spécifiques à la nature de la contamination chimique. A l'heure actuelle des analyses approfondies des acides gras sont encore en cours. Finalement, cette étude fournit une base pour l'utilisation de la composition en acides gras des diatomées comme biomarqueur de la contamination toxique des eaux douces.
(pp. 18-18, 21/06/2026)
UR EABX, IRSTEA, INRA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Changes in Holocene meridional circulation and poleward Atlantic flow: the Bay of Biscay as a nodal point
This paper documents the last 10 ka evolution of one of the key parameters of climate: sea-surface temperatures (SST) in the subpolar North Atlantic. We focus on the southern Bay of Biscay, a highly sensitive oceanographic area because of its strategic and nodal position regarding the dynamics of the North Atlantic subpolar and subtropical gyres. This site furthermore offers unique sedimentary environments characterized by exceptional accumulation rates, enabling the study of Holocene archives at (infra)centennial scales. Our results mainly derive from planktonic foraminiferal association analysis on two cores from the southern Landes plateau. These associations were used as quantitative tools (thanks to the Modern Analog Technique) to track past hydrographical changes. SST reconstructions were thus obtained at an unprecedented resolution and compared to a compilation of Holocene records from the northern North Atlantic. From this regional perspective are shown fundamental timing differences between the gyre dynamics, nuancing classical views of a simple meridional overturning cell.
(Climate of the Past. vol. 13, n° 1814-9324, pp. 201-216, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOPS, UP11, CNRS, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Selective pressure of fishways upon morphological and muscle enzymatic traits of migrating glass eels
Fishways are built on obstacles to restore the connectivity between aquatic habitats. Our study investigated how species-specific fishways interact with interindividual trait differences among fish. We compared several groups of glass eels (Anguilla anguilla) climbing two types of fishways with those remaining below the water impoundments. We analyzed relative body condition factor, body length, mass, and in vitro activities and gene transcription levels of several enzymes involved in the energy metabolism (LDH, CS, CCO, PK). Differences among groups indicated that glass eel fish ladders can be size-specific, according to the type of substrate covering the surface of apparatus. Moreover, we found that climbing specific glass eel ladders can require higher endurance-related metabolic traits, triggering increased aerobic capacities. Increased aerobic efforts together with potential size selectivity of fishways should be taken into account when designing such devices and choosing appropriate location on eel migratory pathways.
(Canadian Journal of Fisheries and Aquatic Sciences. vol. 74, n° 0706-652X, pp. 445-451, 21/06/2026)
UR EABX, IRSTEA, EDF [E.D.F.], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The climate of the Common Era off the Iberian Peninsula
The Mediterranean region is a climate hot spot, sensitive not only to global warming but also to water availability. In this work we document major temperature and precipitation changes in the Iberian Peninsula and margin during the last 2000 years and propose an interplay of the North Atlantic internal variability with the three atmospheric circulation modes (ACMs), (North Atlantic Oscillation (NAO), east atlantic (EA) and Scandinavia (SCAND)) to explain the detected climate variability. We present reconstructions of sea surface temperature (SST derived from alkenones) and on-land precipitation (estimated from higher plant n-alkanes and pollen data) in sedimentary sequences recovered along the Iberian Margin between the south of Portugal (Algarve) and the northwest of Spain (Galiza) (36 to 42° N). A clear long-term cooling trend, from 0 CE to the beginning of the 20th century, emerges in all SST records and is considered to be a reflection of the decrease in the Northern Hemisphere summer insolation that began after the Holocene optimum. Multi-decadal/centennial SST variability follows other records from Spain, Europe and the Northern Hemisphere. Warm SSTs throughout the first 1300 years encompass the Roman period (RP), the Dark Ages (DA) and the Medieval Climate Anomaly (MCA). A cooling initiated at 1300 CE leads to 4 centuries of colder SSTs contemporary with the Little Ice Age (LIA), while a climate warming at 1800 CE marks the beginning of the modern/Industrial Era. Novel results include two distinct phases in the MCA: an early period (900-1100 years) characterized by intense precipitation/flooding and warm winters but a cooler spring-fall season attributed to the interplay of internal oceanic variability with a positive phase in the three modes of atmospheric circulation (NAO, EA and SCAND). The late MCA is marked by cooler and relatively drier winters and a warmer spring-fall season consistent with a shift to a negative mode of the SCAND. The Industrial Era reveals a clear difference between the NW Iberia and the Algarve records. While off NW Iberia variability is low, the Algarve shows large-amplitude decadal variability with an inverse relationship between SST and river input. Such conditions suggest a shift in the EA mode, from negative between 1900 and 1970 CE to positive after 1970, while NAO and SCAND remain in a positive phase. The particularly noticeable rise in SST at the Algarve site by the mid-20th century (±1970), provides evidence for a regional response to the ongoing climate warming. The reported findings have implications for decadal-scale predictions of future climate change in the Iberian Peninsula.
(Climate of the Past. vol. 13, n° 1814-9324, pp. 1901-1918, 21/06/2026)
IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of explosive volcanic eruptions on the main climate variability modes
(Global and Planetary Change. vol. 150, n° 0921-8181, pp. 24 - 45, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEP, UNIBE, OCCR, UNIBE, PARVATI, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, UOR, BSC-CNS, CERFACS
Migratory behavior, metabolism, oxidative stress and mercury concentrations in marine and estuarine European glass eels (Anguilla anguilla)
The relationships between the migratory behavior, methylmercury (MeHg) concentrations, oxidative stress response and detoxification processes were investigated in glass eels collected in marine (Molliets) and estuarine (Urt) waters (Adour estuary, South West France) at the end of the fishing season (April). Glass eel migratory behavior was investigated in an experimental flume according to their response to dusk. Fish responding to the decrease in light intensity by ascending in the water column and moving with or against the flow were considered as having a high propensity to migrate (migrant). Glass eels still sheltering at the end of the 24 h catching period were considered as having a low propensity to migrate and were called non-migrant. Our results provide some evidence that estuarine glass eels were bigger, presented a higher propensity to migrate and a lower oxidative stress response than marine glass eels. This might reflect a selection process, some marine glass eels progressively settling or dying before reaching Urt and/or a change in feeding behavior. In April, glass eels restart feeding in the Adour estuary which might decrease the oxidative stress possibly related to starvation, and enhance migration. MeHg concentrations was significantly higher in non-migrant than in migrant glass eels and it is suggested that non-migrant glass eels might present a higher vulnerability to stress (at least contamination and/or starvation), although the underlying mechanisms remain to be elucidated. © 2016 Elsevier Inc.
(Physiology & behavior. vol. 169, n° 0031-9384, pp. 33--40, 21/06/2026)
ECOBIOP, INRA, UPPA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS
Signification environnementale de guano de salanganes et de chiroptères de Nouvelle-Calédonie. Premiers résultats
L'intérêt est grandissant pour le potentiel présenté par les acccumulations cavernicoles de guano de chauves-souris et d'oiseaux en tant qu'enregistrements stratigraphiques continentaux, complémentaires voire alternatifs aux archives étudiées générale-ment (sédiments lacustres, palustres, tourbeux, etc.). Ces dépôts permettent des reconstructions de la variabilité climatique à haute résolution pour des échelles de temps récentes à plus anciennes, grâce à la calibration de nouveaux proxies susceptibles d'enregistrer ces variations. Ainsi la comparaison du contenu pollinique et des traceurs isotopiques δ13 C et δD des n-alcanes du guano de différents animaux insectivores, les salanganes diurnes (Collocalia spodiopygia) et les chiroptères nocturnes (Micropterus robustior) cohabitant dans de nombreuses grottes de Nouvelle-Calédonie, met en évidence une grande variabilité. Celle-ci est à l'image des cibles de nourrissage des proies appétées et de leur interaction avec les composantes de l'écosystème, en particulier les plantes. La grande richesse du contenu pollinique observée dans les deux types de guano, bien que présentant 50 % de taxons communs, souligne des aires de nourrissage préférentielles. Elle montre aussi des fluctuations interannuelles, marqueurs probables de changements environnementaux, sinon climatiques. Cet article présente des premiers résultats obtenus sur le sondage HAK1 prélévé dans un amas de guano de salanganes de la grotte Hama sur l'île de Lifou, l'une des îles Loyautés. La comparaison entre les données de géochimie isotopique moléculaire (isotopes du carbone δ13C et de l'hydrogène δD du n-alcane C29) et les données pluviométriques met en évidence une bonne covariation interprétée comme marqueur du signal climatique ENSO contemporain des dépôts de guano analysés. Ce travail préliminaire confirme le fort potentiel des amas de guano cavernicoles pour étudier à haute résolution les changements paléo-environnementaux.
(Quaternaire. vol. 28, n° 1142-2904, pp. 401-412, 21/06/2026)
BTP, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IAC