The Sao Tomé deep-sea turbidite system (Southern Brazil Basin): Cenozoic seismic stratigraphy and sedimentary processes
The Sao Tomé deep-sea turbidite system, elongated parallel to the rise of the south Brazilian continental margin, was first interpreted as a channel-levee system resulting from contour-current activity. Study of new seismic data permits the proposal of a stratigraphy for the system and a new interpretation of depositional processes. Three major depositional units have been recognized that are separated by major erosive discontinuities. The basal unit seems to be Paleocene to lower or middle Eocene, and the second one, subdivided into two subunits, is probably upper Oligocene to middle Miocene. Both units show superimposed north-to-south-channelized turbidite systems, with supply provided directly from a channel network that crosses the upper margin in the north. The third unit is upper Miocene(?) to Pliocene or Quaternary and is still under predominantly gravity processes: turbidite processes in the lower and upper subunits, and major mass-flow processes in the median subunit. The sediment sources are located either in the north or in the south, with sediment provided by major deep-sea channels. The base of the upper subunit is well marked by an erosive discontinuity (late Pliocene or Pliocene-Quaternary boundary). Impact of the contour currents is mainly recorded as widespread erosive surfaces (seismic discontinuities) correlated to global hydrological events and transparent or wavy deposits. Because this system contains a significant amount of upper Quaternary sands, it suggests the occurrence of petroleum reservoirs along the rise and the Sao Paulo Plateau in the lower continental slope.
(AAPG Bulletin. vol. 87, n° 0149-1423, pp. 873-894, 01/05/2003)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The key role of metallothioneins in the bivalve Corbicula Fliuminea during the depuration phase after in situ exposure to Cd and Zn
(Aquatic Toxicology. vol. 63, n° 0166-445X, pp. 89-102, 10/04/2003)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LMBA, UBS, UBO EPE, CNRS
Estimation of potential and limits of bivalve closure response to detect contaminants: a new approach applied to cadmium
(Environmental Toxicology and Chemistry. vol. 22, n° 0730-7268, pp. 914-920, 01/04/2003)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LMBA, UBS, UBO EPE, CNRS
Digenean trematodes moderately alter Hydrobia ulvae population size structure
The mudsnail Hydrobia ulvae, primary host to a number of digeneans, was studied to check whether parasite effects on individual hosts could have repercussion on population size structure and dynamics. Three different mudsnail populations were monitored monthly in Arcachon Bay, south-west France. Arguin is a moderately sheltered oceanic sandflat and a bird reserve, La Canelette is a sheltered sandflat near a harbour and Lette Douce is a sheltered salt marsh. Parasite prevalence differed among the three stations, with no obvious seasonal pattern: 0–16% at Arguin, 0–6% at La Canelette and 1–5% at Lette Douce. Between four and five digenean species were identified, with Haploporidae dominating at Arguin and Notocotylidae dominating at Lette Douce. Prevalence increased with snail shell height. Large snails from Arguin were heavily parasitized, but suddenly disappeared between December 1998 and January 1999. The snail size distribution was consequently modified. To test whether digenean-induced mortality could be involved, a 50-d laboratory experiment was performed. Mudsnails hosting digeneans with rediae (as Haploporidae or Heterophyidae) displayed significantly higher mortality rates than mudsnails hosting sporocysts (as Microphallidae) or healthy mudsnails. The present study demonstrates that digenean parasites induce population structure changes and shorten lifespan of mudsnails, through increasing size-dependent mortality.
(Journal of the Marine Biological Association of the United Kingdom. vol. 83, n° 0025-3154, pp. 297-305, 20/03/2003)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Toward a Better Determination of Turbulent Air–Sea Fluxes from Several Experiments
An accurate determination of turbulent exchanges between the ocean and the atmosphere is a prerequisite to identify and assess the mechanisms of interaction that control part of the variability in the two media over a wide range of spatial and temporal scales. An extended dataset for estimating air-sea fluxes (representing nearly 5700 h of turbulence measurements) has been collected since 1992 during six dedicated experiments performed in the Atlantic Ocean and the Mediterranean Sea. This paper presents the methodology used through the successive experiments to progress in this field. The major developments concern (i) flux instrumentation, with the deployment of a microwave refractometer to get the latent heat flux in most meteorological conditions; (ii) the analysis of airflow distortion effects around the ship structure and sensors through both computational fluid dynamics and physical simulations in a water tank, then the derivation of correction for these effects; (iii) the application of both inertial dissipation and eddy-correlation methods from the various experiments, allowing the authors to assess and discuss flux-determination methods on ships, and particularly bulk parameterization; (iv) the validation and analysis of mesoscale surface flux fields from models and satellites by using ship data, showing some deficiencies in operational model fields from ECMWF, the need of high-quality fluxes to interpret ocean-atmosphere exchanges, and the potential advantage of satellite retrieval methods. Further analysis of these datasets is being performed in a unique database (the ALBATROS project, open to the international scientific community). It will include refinement of airflow distortion correction and reprocessing of earlier datasets, the investigation of fluxes under specific conditions (low wind), and the effect of sea state among others. It will also contribute to further validation and improvements of satellite retrievals in various climatic/meteorological conditions.
(Journal of Climate. vol. 16, n° 0894-8755, pp. 600 - 618, 01/02/2003)
CETP, UVSQ, INSU - CNRS, CNRS, DIRSE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CREATIS, UCBL, CPE, INSA Lyon, INSA, INSERM, CNRS, DGO, UB, JPL, CALTECH, CNRM, INSU - CNRS, CNRS, Comue de Toulouse
Bacterial diversity of epilithic biofilm assemblages of an anthropised river section, assessed by DGGE analysis of a 16S rDNA fragment
(Aquatic Microbial Ecology. vol. 33, n° 0948-3055, pp. 217-224, 08/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A tentative reconstruction of the last interglacial and glacial inception in Greenland based on new gas measurements in the Greenland Ice Core Project (GRIP) ice core
The disturbed stratigraphy of the ice in the lowest 10% of the Greenland GRIP ice core prevents direct access to climatic information older than 110 kyr. This is especially regretful since this period covers the previous interglacial corresponding to marine isotopic stage 5e (MIS 5e, 130-120 kyr B.P.). Here we present a tentative reconstruction of the disturbed GRIP chronology based on the succession of globally well mixed gas parameters. The GRIP d 18 O ice chronological sequence is obtained by comparing a new set of d 18 O of atmospheric O 2 and CH 4 measurements from the bottom section of the GRIP core with their counterpart in the Vostok Antarctic profiles. This comparison clearly identifies ice from the penultimate glacial maximum (MIS 6, 190-130 kyr B.P.) in the GRIP core. Further it allows rough reconstruction of the last interglacial period and of the last glacial inception in Greenland which appears to lay its Antarctic counterpart. Our data suggest that while Antarctica is already entering into a glaciation, Greenland is still experiencing a warm maximum during MIS 5e.
(Journal of Geophysical Research. vol. 108, n° 0148-0227, 08/04/2026)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LGGE, OSUG, UJF, Grenoble INP, INSU - CNRS, IRSTEA, USMB [Université de Savoie] [Université de Chambéry], CNRS, INSU - CNRS, CNRS, ICOS-RAMCES, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CEP, UNIBE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UCPH
Organic-rich sediments in ventilated deep-sea environments: Relationship to climate, sea level, and trophic changes
Sediments on the Namibian Margin in the SE Atlantic between water depths of ∼1000 and ∼3600 m are highly enriched in hydrocarbon-prone organic matter. Such sedimentation has occurred for more than 2 million years and is geographically distributed over hundreds of kilometers along the margin, so that the sediments of this region contain a huge concentrated stock of organic carbon. It is shown here that most of the variability in organic content is due to relative dilution by buried carbonates. This reflects both export productivity and diagenetic dissolution, not differences in either water column or bottom water anoxia and related enhanced preservation of organic matter. These observations offer a new mechanism for the formation of potential source rocks in a well-ventilated open ocean, in this case the South Atlantic. The organic richness is discussed in terms of a suite of probable controls including local wind-driven productivity (upwelling), trophic conditions, transfer efficiency, diagenetic processes, and climate-related sea level and deep circulation. The probability of past occurrences of such organic-rich facies in equivalent oceanographic settings at the edge of large oceanic basins should be carefully considered in deep offshore exploration.
(Journal of Geophysical Research. vol. 108, n° 0148-0227, pp. 3045, 08/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBC EOAS, UBC, ISTO, INSU - CNRS, UO, CNRS, PBDS, INSU - CNRS, CNRS, IFPEN, LODYC, IRD, UPMC, CNRS, LMMNHN, MNHN, CNRS
Interpretation of the nitrogen isotopic signal variations in the Mauritanian upwelling with a 2D physical-biogeochemical model
A physical-biogeochemical model is used to simulate the evolution of the δ15N signal during the last glacial-interglacial transition in sedimentary cores offshore from the Mauritanian upwelling. The biological model is a classical nitrogen-based trophic chain model, which also computes the nitrogen isotope fractionation. The 2D physical primitive equation model simulates the coastal upwelling circulation and is applied for different sea level scenarios. The effect of the sea level rise, inducing the shelf immersion, seems to be a main factor explaining the organic nitrogen flux and isotopic signal variations along the last deglaciation. This effect is modulated by an upwelling seasonality that may have been much longer at the Last Glacial Maximum, around 10-11 months instead of 4-5 months at present. Between 15 and 5.5 kyr ago, 60% of the sedimentary δ15N variations could be explained by this local shelf immersion effect. This reconstruction also reproduces the strong isotopic fall occurring between 5.5 kyr and the present.
(Global Biogeochemical Cycles. vol. 17, n° 0886-6236, 08/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, TBL, UT3, Comue de Toulouse, CNRS
Massive flank failures and tsunamis in the Canary Islands: past, present, future
(pp. 132, 08/04/2026)
GEOLAB, UBP, IR SHS UNILIM, UNILIM, UCA [2017-2020], CNRS, UCA, ULPGC, CSIC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LGP, UP1, UPEC UP12, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA