Benthic and Planktic Foraminifera as Indicators of Late Glacial to Holocene Paleoclimatic Changes in a Marginal Environment: An Example from the Southeastern Bay of Biscay.
Benthic and planktic foraminiferal assemblages from two sediment cores (2,000 m depth, 44 degrees 33'N, 2 degrees 45'W) were analyzed to first compare modern and dead faunas and next to study changes in the hydrology of the southeastern Bay of Biscay (SE BoB) over the last 12.8 cal ka BP. Considering benthic ecosystem characteristics, the first part of the paleorecord (12.8-7.6 cal ka BP) is composed of laminated sediments that may have resulted from turbiditic overflow events, whereas occurrences of transported species (e. g. Nonionella sp., Cassidulina carinata) attest of continental influence at the core location. After 7.6 cal ka BP, the sediment becomes bioturbated concomitantly to the stabilization of the sea-level. The benthic foraminiferal fauna is largely dominated by Uvigerina peregrina suggesting a high seasonality with seasonal pulsed organic matter fluxes to the seafloor. On the other hand, the planktic foraminiferal composition indicates that surface water masses were under the influence of the polar front in the early record, which retreated at about 11.5 cal ka BP. The early Holocene is characterized by relatively warm and stratified water masses at 8.4-4.8 cal ka BP. The last 4.8 cal ka BP records a gradual sea surface water cooling trend and enhanced foraminiferal production from similar to 2.6 cal ka BP until present. The early (12.8-10.5 cal ka BP) and late (2.3-1.7 cal ka BP) Holocene are characterized by the presence of the planktic species Globigerinoides ruber probably caused by intrusions of the Iberian Poleward Current (IPC), and a negative state of the North Atlantic Oscillation (NAO).
(Acta Protozoologica. vol. 52, n° 0065-1583, pp. 161-180, 19/04/2026)
BIAF, UA, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Addendum année 2 Avril 2011 - Mars 2012
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe.
(pp. 172, 19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, IRSTEA
France National Report 2012, ICES Working Group on Introduction and Transfers of Marine Organisms
(19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNICAEN, NU, IFREMER, LIENSs, INSU - CNRS, ULR, CNRS, SBR, UPMC, CNRS
Global biomass burning : a synthesis and review of Holocene paleofire records and their controls
(Quaternary Science Reviews. vol. 65, n° 0277-3791, pp. 5-25, 19/04/2026)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SAGES, UOR, CPCC, UOR, OCCR, UNIBE, UNIBE, LCE, CNRS, UFC, UBFC
Biodiversité marine : chapitre 6
A l'échelle du golfe de Gascogne et de ses zones côtières et littorales, les suivis de la biodiversité montrent d'importantes variations annuelles d'abondance e de répartition géographique des espèces en relation avec le climat. Les tendances actuelles montrent que la biodiversité va évoluer vers une augmentation de représentativité des espèces tempérées chaudes, une modification de la phénologies des espèces et de la productivité des écosystèmes.
(pp. 173-188, 19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, IRSTEA, LERAR, COAST, IFREMER, IRSTEA, IFREMER, MNHN, UPMC
Long term effects of polycyclic aromatic hydrocarbons on zebrafish behavioral and reproduction responses
(19/04/2026)
BE, IFREMER, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LRHLR, HGS, IFREMER, LPGP, INRA, Biosit : Biologie - Santé - Innovation Technologique
Carbon and suspended sediment transport in an impounded alpine river (Isère, France)
Carbon and total suspended sediment (TSS) loads were investigated from April 2006 to March 2008 in the mountainous watershed of the Isère River, French Alps (5570 km2). The river bed has been highly impounded for hydroelectricity production during the last century. Hydraulic flushes are managed every year to prevent TSS storage within upstream dams. The Isère River has been instrumented for high-frequency monitoring of water, TSS by turbidity and carbon (organic, inorganic, dissolved and particulate) in order to evaluate the impact of natural floods and hydraulic flushes on annual loads. Annual TSS load which was estimated between 1.3 and 2.3 MT y−1 (i.e. 233 to 413 T km−2 y−1) highlighted the high erodibility of the Isère watershed. Annual carbon load was estimated between 173 103 T y−1 and 199 103 T y−1 (i.e 31 to 36 T km−2 y−1). About 80% of the annual carbon loads were inorganic. The impact of hydraulic flushes on annual loads appeared limited (less than 3% for annual TSS load and about 1.5% for annual carbon load), whereas the most important natural flood event contributed to 20% of the annual TSS load and 10% of the annual carbon load.
(Hydrological Processes. vol. 27, n° 0885-6087, pp. 2498-2508, 19/04/2026)
LTHE, OSUG, UJF, Grenoble INP, INSU - CNRS, IRSTEA, USMB [Université de Savoie] [Université de Chambéry], CNRS, IRD, INSU - CNRS, INPG, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISTO, BRGM, INSU - CNRS, UO, CNRS, SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, EDF [E.D.F.]
Zebrafish: A model animal for analyzing the impact of environmental pollutants on muscle and brain mitochondrial bioenergetics.
Mercury, anthropogenic release of uranium (U), and nanoparticles constitute hazardous environmental pollutants able to accumulate along the aquatic food chain with severe risk for animal and human health. The impact of such pollutants on living organisms has been up to now approached by classical toxicology in which huge doses of toxic compounds, environmentally irrelevant, are displayed through routes that never occur in the lifespan of organisms (for instance injecting a bolus of mercury to an animal although the main route is through prey and fish eating). We wanted to address the effect of such pollutants on the muscle and brain mitochondrial bioenergetics under realistic conditions, at unprecedented low doses, using an aquatic model animal, the zebrafish Danio rerio. We developed an original method to measure brain mitochondrial respiration: a single brain was put in 1.5mL conical tube containing a respiratory buffer. Brains were gently homogenized by 13 strokes with a conical plastic pestle, and the homogenates were immediately used for respiration measurements. Skinned muscle fibers were prepared by saponin permeabilization. Zebrafish were contaminated with food containing 13μg of methylmercury (MeHg)/g, an environmentally relevant dose. In permeabilized muscle fibers, we observed a strong inhibition of both state 3 mitochondrial respiration and cytochrome c oxidase activity after 49 days of MeHg exposure. We measured a dramatic decrease in the rate of ATP release by skinned muscle fibers. Contrarily to muscles, brain mitochondrial respiration was not modified by MeHg exposure although brain accumulated twice as much MeHg than muscles. When zebrafish were exposed to 30μg/L of waterborne U, the basal mitochondrial respiratory control ratio was decreased in muscles after 28 days of exposure. This was due to an increase of the inner mitochondrial membrane permeability. The impact of a daily ration of food containing gold nanoparticles of two sizes (12 and 50nm) was investigated at a very low dose for 60 days (40ng gold/fish/day). Mitochondrial dysfunctions appeared in brain and muscle for both tested sizes. In conclusion, at low environmental doses, dietary or waterborne heavy metals impinged on zebrafish tissue mitochondrial respiration. Due to its incredible simplicity avoiding tedious and time-consuming mitochondria isolation, our one-pot method allowing brain respiratory analysis should give colleagues the incentive to use zebrafish brain as a model in bioenergetics. This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy.
(International Journal of Biochemistry and Cell Biology. vol. 45, n° 1357-2725, pp. 16-22, 19/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IBGC, UB, CNRS
A note about the critical bandwidth for a kernel density estimator with the uniform kernel
Among available bandwidths for kernel density estimators, the critical bandwidth is a data-driven one, which satisfies a constraint on the number of modes of the estimated density. When using a random bandwidth, it is of particular interest to show that it goes toward 0 in probability when the sample size goes to infinity. Such a property is important to prove satisfying asymptotic results about the corresponding kernel density estimator. It is shown here that this property is not true for the uniform kernel.
(17/12/2012)
IMB, UB, Bordeaux INP, CNRS, CQFD, IMB, UB, Bordeaux INP, CNRS, Inria, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LMBA, UBS, UBO EPE, CNRS
High-resolution architecture of a polygonal fault interval inferred from geomodel applied to 3D seismic data from the Gjallar Ridge, Vøring Basin, Offshore Norway
3D seismic data located in the Gjallar Ridge (Vøring Basin, offshore Norway) reveals a closely-spaced polygonal fault system affecting more than 800 m of homogeneous mud-dominated Quaternary and Tertiary sequences. As some faults reach the modern seafloor, they represent an active polygonal fault system at present day. Even if the processes remain unclear and are still under debate, it is generally agreed that the initiation of polygonal faults is the result of shallow burial dewatering of fine-grained unconsolidated sediments by volumetric compaction. 3D seismic data are commonly interpreted by propagating horizons automatically and by picking faults manually. However, in the case of polygonal fault intervals, this approach is time consuming due to the huge number of faults and because automatic propagation can be misleading. In this study, we applied a new technique of 3D seismic interpretation based on a sequential stratigraphy analysis, using the new PaleoScan© software (Eliis Company). It allowed us to build a 3D geological model computing more than 300 horizons within the faulted intervals. We then used the coherency attribute, depicting anomalies in the shape of seismic waveform like faults, in order to constrain a possible link between fault distribution and stratigraphic levels. Our approach allows fault throws to be calculated in milliseconds on any polygonal fault plane. The result shows that fault segments have been reactivated by dip-linkage. Distribution of faults depends on mechanical units, intervals characterized by different petrophysical properties, which are independent from lithological and diagenetic changes. According to these results, we propose a model showing the evolution of polygonal fault intervals in which faulting stages are separated by a quiescence phase during burial. A first tier of polygonal faults is initiated at a specific depth, according to the Cam-clay model. Then, following a period of quiescence during which mud-rich sediments continued to accumulate, new fault segments are initiated above the first mechanical unit and within this undeformed interval. New nucleated faults then connect downward to pre-existing underlying polygonal fault system, thus progressively increasing the thickness of the faulted interval.
(Marine Geology. vol. 332-334, n° 0025-3227, pp. 134-161, 01/12/2012)
UAG, INSU - CNRS, UM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NOC, Géosciences Montpellier, UAG, INSU - CNRS, UM, CNRS, UiO, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS