Des biofilms témoins et acteurs du fonctionnement de la rivière
Des biofilms phototrophes complexes (multi espèces) se développent dans certains tronçons de rivière. Ils participent au fonctionnement de la rivière et peuvent être utilisés comme bioindicateurs pour la gestion des cours d'eau.
(pp. 3, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS, UR REBX, CEMAGREF
Holocene glacier and deep water dynamics, Adélie Land region, East Antarctica
This study presents a high-resolution multi-proxy investigation of sediment core MD03-2601 and documents major glacier oscillations and deep water activity during the Holocene in the Adé lie Land region, East Antarctica. A comparison with surface ocean conditions reveals synchronous changes of glaciers, sea ice and deep water formation at Milankovitch and sub-Milankovitch time scales. We report (1) a deglaciation of the Adé lie Land continental shelf from 11 to 8.5 cal ka BP, which occurred in two phases of effective glacier grounding-line retreat at 10.6 and 9 cal ka BP, associated with active deep water formation; (2) a rapid glacier and sea ice readvance centred around 7.7 cal ka BP; and (3) five rapid expansions of the glacier-sea ice systems, during the Mid to Late Holocene, associated to a long-term increase of deep water formation. At Milankovich time scales, we show that the precessionnal component of insolation at high and low latitudes explains the major trend of the glacier-sea ice-ocean system throughout the Holocene, in the Adé lie Land region. In addition, the orbitally-forced seasonality seems to control the coastal deep water formation via the sea ice-ocean coupling, which could lead to opposite patterns between north and south high latitudes during the Mid to Late Holocene. At sub-Milankovitch time scales, there are eight events of glacier-sea ice retreat and expansion that occurred during atmospheric cooling events over East Antarctica. Comparisons of our results with other peri-Antarctic records and model simulations from high southern latitudes may suggest that our interpretation on glacier-sea ice-ocean interactions and their Holocene evolutions reflect a more global Antarctic Holocene pattern.
(Quaternary Science Reviews. vol. 28, n° 0277-3791, pp. 1291-1303, 23/02/2026)
UP1, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, VU, PBDS, INSU - CNRS, CNRS, LMGM, CNRS, CBI, UT3, Comue de Toulouse, CNRS
Antarctic climate change and the environment
The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (, the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.
(Antarctic Science. vol. 21, n° 0954-1020, pp. 541, 23/02/2026)
BAS, NERC, GSFC, CNR, AWI, SCAR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Treatment of topographic and bathymetric data acquired at the Truc-Vert Beach (SW France) during the ECORS field experiment
(. vol. special issue 56, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, L3AB, UB, INSU - CNRS, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LAB, UB, INSU - CNRS, CNRS, UB
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, 23/02/2026)
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
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, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CRC, UB, 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, 23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, 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, 23/02/2026)
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.
(23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMB, UB, Bordeaux INP, CNRS
Effects of tidal forcing on biogeochemical processes in intertidal permeable sandy sediments
(23/02/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPGN, UN, CNRS