New outcomes from spatial remote sensing during the ECORS experiment : towards validation of ocean color products and large-scale bathymetry mapping in a coastal zone
(Journal of Coastal Research, n° 0749-0208, pp. SI56(2), 1756-1760, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRC, UB, CNRS
Millennial-scale climatic variability between 340 000 and 270 000 years ago in SW Europe: evidence from a NW Iberian margin pollen sequence
We present a new high-resolution marine pollen record from NW Iberian margin sediments (core MD03-2697) covering the interval between 340 000 and 270 000 years ago, a time period centred on Marine Isotope Stage (MIS) 9 and characterized by particular baseline climate states. This study enables the documentation of vegetation changes in the northwestern Iberian Peninsula and therefore the terrestrial climatic variability at orbital and in particular at millennial scales during MIS 9, directly on a marine stratigraphy. Suborbital vegetation changes in NW Iberia in response to cool/cold events are detected throughout the studied interval even during MIS 9e ice volume minimum. However, they appear more frequent and of higher amplitude during the 30 000 years following the MIS 9e in-terglacial period and during the MIS 9a-8 transition, which correspond to intervals of an intermediate to high ice volume and mainly periods of ice growth. Each suborbital cold event detected in NW Iberia has a counterpart in the Southern Iberian margin SST record. High to moderate amplitude cold episodes detected on land and in the ocean appear to be related to changes in deep water circulation and probably to iceberg discharges at least during MIS 9d, the mid-MIS 9c cold event and MIS 9b. This work provides therefore additional evidence of pervasive millennial-scale climatic variability in the North Atlantic borderlands throughout past climatic cycles of the Late Pleistocene, regardless of glacial state. However, ice volume might have an indirect influence on the amplitude of the millennial climatic changes in Southern Europe.
(Climate of the Past. vol. 5, n° 1814-9324, pp. 53-72, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, WHOI, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Effects of tidal forcing on biogeochemical processes in intertidal permeable sandy sediments
(26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGN, UN, CNRS
Pocket beach hydrodynamics : the example of four macrotidal beaches, Brittany, France
During several field experiments, measurements of waves and currents as well as topographic surveys were conducted on four morphologically-contrasted macrotidal beaches along the rocky Iroise coastline in Brittany (France). These datasets provide new insight on the hydrodynamics of pocket beaches, which are rather poorly documented compared to wide and open beaches. The results notably highlight a cross-shore gradient in the magnitude of tidal currents which are relatively strong offshore of the beaches but are insignificant inshore. Despite the macrotidal setting, the hydrodynamics of these beaches are thus totally wave-driven in the intertidal zone. The crucial role of wind forcing is emphasized for both moderately and highly protected beaches, as this mechanism drives mean currents two to three times stronger than those due to more energetic swells when winds blow nearly parallel to the shoreline. Moreover, the mean alongshore current appears to be essentially wind-driven, wind waves being superimposed on shore-normal oceanic swells during storms, and variations in their magnitude being coherent with those of the wind direction. We also found evidence for the contribution of infragravity waves to the formation of an intertidal sand bar (through prolonged duration of swash processes at the same beach level) and to the development of beach cusps (but not to their initiation), for which the observed standing edge wave pattern may have been enhanced by the enclosed pocket-beach setting. The paper highlights some of the specificities of pocket beach with regards to their hydrodynamics and morphodynamics. More detailed observations would be needed, however, prior to a more comprehensive review.
(Marine Geology. vol. 266, n° 0025-3227, pp. 1-17, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN
Comparaison d'estimateurs de régression non paramétriques : application en valvométrie
La mesure de l'activité de mollusques bivalves est un moyen d'enregistrer le comportement de bivalves in situ et donc d'évaluer des changements de la qualité de l'eau. Nous proposons un modèle de régression non paramétrique et comparons trois estimateurs non paramétriques, récursifs ou non, de la fonction de lien sur les données acquises en Nouvelle Calédonie.
(26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMB, UB, Bordeaux INP, CNRS
Holocene size variations in two diatom species off East Antarctica: Productivity vs environmental conditions
I here present a biometric investigation on two diatom species, Fragilariopsis kerguelensis (O’Meara) Hustedt and Fragilariopsis curta (Van Heurck) Hustedt, in Holocene samples from sediment core MD03-2601 from the Antarctic Continental Shelf off Adélie Land, East Antarctica. Apical valve length measurements of the two species are compared to their respective absolute and relative abundances as a proxy for the species productivity. Fragilariopsis kerguelensis valves were longer and more abundant during the warmer Mid-Holocene period and smaller and less abundant during the colder Late-Holocene period. Conversely, F. curta valves were smaller and less abundant during the warmer Mid-Holocene period and longer and more abundant during the colder Late-Holocene period. Mean apical valve length variations even follow centennial-to-millennial oscillations in the species abundances. Maximal valve length and minimal valve length were also larger during the warmer Mid-Holocene period and during the colder Late-Holocene period for F. keguelensis and F. curta, respectively. The observed positive size-abundance relationships are linked to the environmental conditions at the core location that stands today at the lower ecological limit for F. kerguelensis and upper ecological limit for F. curta. More favourable environmental conditions (warmer, less icy for F. kerguelensis and colder, icier for F. curta) allowed for sexual reproduction at the upper range of the sexually inducible size window and subsequent restoration of larger initial cells which, in turn, resulted in overall bigger size of the species populations, though vegetative multiplication was more frequent.
(Deep Sea Research Part I: Oceanographic Research Papers. vol. 56, n° 0967-0637, pp. 1983-1993, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Approche de l’évolution contemporaine (-50 ans à nos jours) de l’estuaire de la Gironde sous modifications des forçages hydro-climatiques et des contraintes anthropiques : Projet 2009-2011 – Réseau de recherche littoral aquitain - Atelier Gironde
Les propositions présentées ci-après pour la période 2009-2011 s'inscrivent dans le prolongement de celles proposées précédemment (2007-2008) et elles constituent ainsi les "briques" d'un projet plus vaste de moyen terme, visant une meilleure compréhension du système girondin : "Fonctionnement, évolution et trajectoire de l'écosystème estuarien sous contraintes naturelles et anthropiques.
(pp. 86, 26/10/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, CEMAGREF
The euthycarcinoid arthropods from Montceau-les-Mines, France: functional morphology and affinities
New three-dimensionally preserved specimens of two euthycarcinoid arthropods, namely Schramixerxes gerem and Sottyxerxes multiplex, allow complete description of both the dorsal and ventral sides of the exoskeleton. The functional morphology is tentatively interpreted for the first time. In S. gerem, the ‘thirteenth somite', or ‘monosomite' is fully described and re-interpreted as the main articulatory process of the body, between the cephalic region and the preabdomen. The morphology and arrangement of the two parts of the process clearly indicate that the anterior cephalic region of the body could move laterally and bend ventrally, while posterior somites could only move ventrally. Unlike several other euthycarcinoid species, the ventral side of the head area exhibits one or two plates instead of mandibles; such distinct morphologies are indicative of different feeding mechanisms and behaviours among euthycarcinoid arthropods. Possible homologies with the labrum of Hexapoda support the hypothesis that euthycarcinoids have hexapod affinities.
(Earth and Environmental Science Transactions of the Royal Society of Edinburgh. vol. 99, n° 1755-6910, pp. 11-25, 02/12/2008)
LDO, INSU - CNRS, UBO EPE, CNRS, PEPS, UCBL, INSU - CNRS, CNRS
Late Quaternary history of the Nouméa lagoon (New Caledonia, South West Pacific) as depicted by seismic stratigraphy and multibeam bathymetry A modern model of tropical rimmed shelf
The barrier reef tract of New Caledonia is the second largest in the world enclosing lagoons of variable width. The Late Quaternary evolution of these barrier reefs and lagoons is poorly known. A recent high resolution seismic and multibeam bathymetry survey was carried out in the south-western lagoon from shoreline to open ocean across the barrier reef pass systems to perform sequence stratigraphy and to better understand the Quaternary evolution of the lagoon. Two depositional sequences bounded by type-1 erosional surfaces can be identified. The bounding surfaces delineate the bottom of two generations of incised valleys. System tracts comprising a complete succession of regressive, lowstand, transgressive and highstand tracts were observed only in the upper sequence. Chronostratigraphic and sedimentological interpretations of the seismic data are based on correlations with the chronology defined in the nearby cores drilled through the reefs and in the gravity cores previously recovered in the inner lagoon. Interpretation of seismic data is also carried out on the basis of correlation with multibeam bathymetric data. Our results indicate that the history of the New Caledonian lagoon probably does not exceed 200ka marked by two or three brief episodes each of immersion of about ten thousand years. The bathymetric data reveal that during successive low sea level stands, the lagoon was dependent upon erosional fluvial networks. The deep fluvial valleys were connected to the continental slope through the passes. Seismic records reveal that upstream palaeo-channels are not connected to the modern coastal rivers. In contrast, many aggrading deposits, including numerous stacking channels, and extending across the proximal part of the outer lagoon, can be identified. Examination of drainage network morphology suggests a progressive tilt of the outer lagoon. Such evolution reveals that the Nouméa lagoon which is one of the widest in the world is an exceptional modern example of a rimmed shelf providing data to analyze the past counterparts.
(Palaeogeography, Palaeoclimatology, Palaeoecology. vol. 270, n° 0031-0182, pp. 29-45, 01/12/2008)
LDO, INSU - CNRS, UBO EPE, CNRS, UEB, PALEOTROPIQUE, IPRA, UPPA, CNRS, LDL, UM2, INSU - CNRS, CNRS, GEOAZUR 6526, IRD, UPMC, UNS, INSU - CNRS, UniCA, CNRS
Production of marine trematode cercariae: A potentially overlooked path of energy flow in benthic systems
Parasites, in particular trematodes, are unseen but ubiquitous components of marine intertidal ecosystems. Although parasites are known to affect population dynamics and food web structure, their potential function as an unrecognized path of energy flow in these ecosystems is yet to be quantified. We use published data on rates at which trematodes produce free-swimming infective larvae (cercariae) that are released from their gastropod intermediate hosts to investigate patterns in cercarial output as a function of different variables, and to calculate the annual production of cercariae in different marine benthic systems. Across 18 trematode species, cercarial output (no. cercariae shed snail–1 d–1) ranged over 4 orders of magnitude and was positively correlated with snail host species size. While cercarial output did not correlate with latitude, it did correlate negatively with the size of cercariae, and was influenced by the type of downstream host sought by cercariae, being highest when this host was a vertebrate. Our estimates of annual cercarial production (kJ m–2 yr–1), which take into account the density of infected snails in the habitat, were within the range of production values reported for free-living invertebrates inhabiting benthic ecosystems. These estimates would be much higher if they included all trematode species in an ecosystem, and not just single-species values. Overall, results suggest that trematode cercariae represent potentially important paths of energy flow in benthic systems as well as a potentially important food supply to benthic organisms.
(Marine Ecology Progress Series. vol. 372, n° 0171-8630, pp. 147-155, 01/12/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UTPA