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, 27/04/2026)
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
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, 27/04/2026)
UR EABX, IRSTEA, EDF [E.D.F.], 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, 27/04/2026)
UR EABX, IRSTEA, INRA, 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, 27/04/2026)
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
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, 27/04/2026)
IFREMER, 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, 27/04/2026)
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
Benthic foraminiferal response to sedimentary disturbance in the Capbreton canyon (Bay of Biscay, NE Atlantic)
Living (Rose Bengal stained) and dead benthic foraminifera were investigated at 6 deep-sea sites sampled in the Capbreton canyon area (Bay of Biscay, France). Three sites were located along the canyon axis at 301 m, 983 m and 1478 m and 3 stations were positioned on adjacent terraces at 251 m, 894 m and 1454 m. Sedimentary features indicate that frequent sedimentary disturbances of different magnitudes occur along the Capbreton canyon axis and adjacent terraces. Such environmental conditions cause the presence of very particular benthic environments. Along the 6 studied sites, different foraminiferal responses to various sedimentary patterns are observed revealing the complexity of this canyon environment. Some sites (Gitan 3 (canyon axis), Gitan 5 (canyon axis) and Gitan 6 (terrace)) are characterized by moderate to low standing stocks and low diversity and are mainly dominated by pioneer taxa such as Fursenkoina brady, Reophax dentaliniformis and Technitella melo suggesting a recent response to turbidite deposits recorded at these sites. Others sites (Gitan 1 and Gitan 2) show extremely high standing stocks and are mainly dominated by the opportunistic Bolivina subaenariensis and Bulimina marginata. Such faunal characteristics belonging to a more advanced stage of ecosystem colonization indicates strongly food-enriched sediment but extremely unstable conditions. Moderate standing stocks and diverse assemblage composed of species such as Uvigerina mediterranea and U. peregrina has only been observed at the terrace site Gitan 4. More stable sedimentary conditions recorded at this terrace seem to be suitable to the development of a dense and diverse foraminiferal community. Numerous neritic allochtonous species were observed in the dead foraminiferal fauna. These allochthonous species mainly originate from shelf areas (<60 m).
(Deep Sea Research Part I: Oceanographic Research Papers. vol. 120, n° 0967-0637, pp. 61-75, 27/04/2026)
LDO, INSU - CNRS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Per- and poly-fluoroalkyl compounds in freshwater fish from the Rhône River: Influence of fish size, diet, prey contamination and biotransformation
(Science of the Total Environment. vol. 605-606, n° 0048-9697, pp. 38--47, 27/04/2026)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EAWAG, EPFL, ISM, UB, INC-CNRS, CNRS
Drug residues in urban water: A database for ecotoxicological risk management
Human-use drug residues (DR) are only partially eliminated by waste water treatment plants (WWTPs), so that residual amounts can reach natural waters and cause environmental hazards. In order to properly manage these hazards in the aquatic environment, a database is made available that integrates the concentration ranges for DR, which cause adverse effects for aquatic organisms, and the temporal variations of the ecotoxicological risks. To implement this database for the ecotoxicological risk assessment (ERA database), the required information for each DR is the predicted no effect concentrations (PNECs), along with the predicted environmental concentrations (PECs). The risk assessment is based on the ratio between the PNECs and the PECs. Adverse effect data or PNECs have been found in the publicly available literature for 45 substances. These ecotoxicity test data have been extracted from 125 different sources. This ERA database contains 1157 adverse effect data and 287 PNECs. The efficiency of this ERA database was tested with a data set coming from a simultaneous survey of WWTPs and the natural environment. In this data set, 26 DR were searched for in two WWTPs and in the river. On five sampling dates, concentrations measured in the river for 10 DR could pose environmental problems of which 7 were measured only downstream of WWTP outlets. From scientific literature and measurements, data implementation with unit homogenisation in a single database facilitates the actual ecotoxicological risk assessment, and may be useful for further risk coming from data arising from the future field survey. Moreover, the accumulation of a large ecotoxicity data set in a single database should not only improve knowledge of higher risk molecules but also supply an objective tool to help the rapid and efficient evaluation of the risk.
(Science of the Total Environment. vol. 609, n° 0048-9697, pp. 927-941, 27/04/2026)
ToxAlim-MeX, ToxAlim, INRA, UT3, Comue de Toulouse, ENVT, Toulouse INP, Toulouse INP, Comue de Toulouse, INP - PURPAN, Toulouse INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse
The historical demise of Pinus nigra forests in the Northern Iberian Plateau (south-western Europe)
Pinus nigra Arn. forests dominated over extensive areas of the Northern Iberian Plateau (Spain) during the Holocene, but a strong decline during the historical period (c. 1300-700 cal. BP) led to the present fragmented populations. This demise has been generally attributed to land-use changes or climate, but the specific roles of disturbance regimes such as fire variability and grazing on the long-term are not fully understood yet. We combine multi-proxy palaeoecological data (fossil pollen, spores, conifer stomata, microscopic and macroscopic charcoal) together with quantitative analyses (ordination and peak detection) from a high-resolution sedimentary sequence (Tubilla del Lago, 900 m a.s.l.) to assess the causes of pine forests demise. A new microscopic charcoal record from an additional sequence (Espinosa de Cerrato, 885 m a.s.l.) is used to assess burning and pine decline at a more regional (100 km radius) scale. Pinus nigra forests could cope with drought and fire regime variability (FRI = 110-500 years), with forest recovery taking c. 100-200 years after fires. Only at 1300-1200 cal. BP a long-lasting irrecoverable demise of P. nigra forests occurred when human-induced fires together with arable and pastoral farming became widespread in the area. Subsequently, Quercus woodlands expanded in the remnant patchy pinewoods. This vegetation shift was primarily caused by three particularly important fire episodes in less than a century (c. 1300-1200 cal. BP). Synthesis: Pinus nigra forests have shown a millennial resilience to the natural fire regime of the Northern Iberian Plateau, that was characterized by relatively frequent small-moderate fires and rare high-intensity fires. However, frequent human-caused crown fires and the onset of intensive farming caused their demise over an extensive area. Ongoing land-use abandonment in the Iberian mountains could promote the occurrence of high-intensity, severe fires due to the rapid build-up of high fuel loads. Forest management could mimic the natural fire regime by periodically reducing fuel loads for a transitional period until natural disturbance variability is fully restored, thus preserving these relict native plant communities.
(Journal of Ecology. vol. 105, n° 0022-0477, pp. 634-646, 27/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OCCR, UNIBE, UAM