Mass wasting processes along the Owen Ridge (Northwest Indian Ocean)
The Owen Ridge is a prominent relief that runs parallel to the coast of Oman in the NW Indian Ocean and is closely linked to the Owen Fracture Zone, an 800-km- long active fault system that accommodates today the Arabia-India strike-slip motion. Several types of mass failures mobilizing the pelagic cover have been mapped in details along the ridge using multibeam bathymetry and sediment echosounder. Here we present a synthetic map of the different types of mass wasting features observed along the ridge and we further establish a morphometric analysis of submarine landslides. The spatial variation of failure morphology is strongly related to the topography of the basement. The highest volumes of multi-events generated slides are mobilized along the southern portion of the ridge. There, the estimated volume of evacuated material during a slide is up to 45 km3. Combining these new observations with re-interpreted ODP seismic lines (Leg 117) documents sporadic mass wasting events through time along the southern segment of the ridge since its uplift in the Early Miocene, with a typical recurrence rate of the order of 105-106 years. Although seismicity may still be the final triggering process, mass wasting frequency is mainly controlled by the slow pelagic sedimentation rates and hence, time needed to build up the 40-80 m thick pelagic cover required to return to a mechanically unstable pelagic cover .
(Marine Geology, n° 0025-3227, pp. 1-21, 13/04/2026)
iSTeP, UPMC, CNRS, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, 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) : Rapport de synthèse année 1 Avril 2010 - Mars 2011
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 pour l’année 1, couvrant la période Avril 2010 – Mars 2011.
(pp. 36, 13/04/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Agulhas leakage as a key process in the modes of Quaternary climate changes
Heat and salt transfer from the Indian Ocean to the Atlantic Ocean (Agulhas leakage) has an important effect on the global thermo-haline circulation and climate. The lack of long transfer record prevents elucidation of its role on climate changes throughout the Quaternary. Here, we present a 1,350-ka accumulation rate record of the planktic foraminiferal species Globorotalia menardii. We demonstrate that, according to previous assumptions, the presence and reseeding of this fauna in the subtropical southeast Atlantic was driven by interocean exchange south of Africa. The Agulhas transfer strengthened at glacial ice-volume maxima for every glacial-interglacial transition, with maximum reinforcements organized according to a 400-ka periodicity. The long-term dynamics of Agulhas leakage may have played a crucial role in regulating meridional overturning circulation and global climate changes during the Mid-Brunhes event and the Mid-Pleistocene transition, and could also play an important role in the near future.
(Proceedings of the National Academy of Sciences of the United States of America. vol. 109, n° 0027-8424, pp. 6835-6839, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS
Evaluation of advanced tertiary treatments for the reduction of refractory micropollutants in treated wastewater
Some refractory micropollutants remain in treated wastewater after secondary treatments. In order to reduce their concentration in treated water, tertiary treatments can be used such as advanced oxidation processes and activated carbon. The efficiency of granular activated carbon in a long term is not well known and advanced oxidation processes have mostly been studied at laboratory scale. Advanced oxidation processes and granular activated carbon pilots were studied in two different wastewater treatment plants in order to determine their efficiency on numerous micropollutants. Both processes were efficient (>90%) on beta blockers and other drugs. The removal of alkylphenols was not complete with UV and hydrogen peroxide. Activated carbon was still efficient after six months functioning 24/24.
(pp. 4, 13/04/2026)
IRSTEA, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Occurrence and fate of relevant substances in wastewater treatment plants regarding Water Framework Directive and future legislations
The next challenge of wastewater treatment is to reliably remove micropollutants at the microgram per litre range. During the present work more than 100 substances were analysed through on-site mass balances over 19 municipal wastewater treatment lines. The most relevant substances according to their occurrence in raw wastewater, in treated wastewater and in sludge were identified, and their fate in wastewater treatment processes was assessed. About half of priority substances of WFD were found at concentrations higher than 0.1 μg/L in wastewater. For 26 substances, potential non-compliance with Environmental Quality Standard of Water FrameworK Directive has been identified in treated wastewater, depending on river flow. Main concerns are for Cd, DEHP, diuron, alkylphenols, and chloroform. Emerging substances of particular concern are by-products, organic chemicals (e.g. triclosan, benzothiazole) and pharmaceuticals (e.g. ketoprofen, diclofenac, sulfamethoxazole, carbamazepine). About 80% of the load of micropollutants was removed by conventional activated sludge plants, but about two-thirds of removed substances were mainly transferred to sludge.
(Water Science and Technology. vol. 65, n° 0273-1223, pp. 1179-1189, 13/04/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A new insight for micropollutants in activated sludge: variability of influent concentrations and effects of operating parameters on removal performances
We investigated how variable were concentrations in raw wastewater for 6 beta-blockers and 10 metals. Measured concentrations suggested a different consumption of 4 beta-blockers according to the season. We observed the same variability for metals. During a day, influent concentrations were not constant. However, daily concentrations seemed to be similar for consecutive days. So a robust understanding of a treatment process implied the knowledge of influent concentrations. We studied also the influence of operating conditions on micropollutant removal. We observed that a higher temperature, a lower MLSS concentration and a higher ammonium oxidation promoted micropollutant removal.
(pp. 5, 13/04/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR Qualisud, Cirad, UM1, UM2, Montpellier SupAgro, AU, UR, UM, Montpellier SupAgro
Comparison of kernel density estimators with assumption on number of modes
(13/04/2026)
LMBA, UBS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CQFD, IMB, UB, Bordeaux INP, CNRS, Inria, IMB, UB, Bordeaux INP, CNRS
Biogeochemical dynamics related to seasonal changes and biomass-density patterns in rhyzosphere sediments of a Zostera noltii meadow
(13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, CJB, UA, IRD, UB
Tracking atmospheric and riverine terrigenous supplies variability during the last glacial and the Holocene in central Mediterranean
The objectives were to retrace the eolian and fluvial terrigenous supplies in a sediment core from the Sicilian-Tunisian Strait by coupling mineralogical, grain-size and geochemical approaches, in order to get informations on the atmospheric versus riverine 5 contributions to sedimentation on the southern side of central Mediterranean since the last glacial. The eolian supply is dominant over the whole interval, excepted during the sapropel S1 when riverine contribution apparently became significant, and particles provenance has been modified since Last Glacial. Saharan contribution increased during the Bølling-Allerød, evidencing the persistence of aridity over North Africa although the northern Mediterranean already experienced moister and warmer conditions. The Younger Dryas is marked by proximal dust inputs highlighting intense regional eolian activity. A southward migration of dust provenance toward Sahel occurred at the onset of the Holocene, likely resulting from a southward position of the Inter Tropical Convergence Zone, probably associated with a large-scale atmospheric reorganization. Finally, a peculiar high terrigenous flux associated with drastic modifications of the mineralogical and geochemical sediment signature occurred during the sapropel S1, suggesting the propagation of fine-particles derived from major floodings of the Nile River – resulting from enhanced rainfall on northeastern Africa – and their transportation across the Sicilian-Tunisian Strait by intermediate water-masses.
(pp. 2921–2968, 13/04/2026)
LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOPS, UP11, CNRS
Development of q-PCR approaches to assess water quality: Effects of cadmium on gene expression of the diatom Eolimna minima
This study was undertaken to develop molecular tools to assess water quality using diatoms as the biological model. Molecular approaches were designed following the development of a rapid and easy RNA extraction method suited to diatoms and the sequencing of genes involved in mitochondrial and photosystem metabolism. Secondly the impact of cadmium was evaluated at the genetic level by q-PCR on 9 genes of interest after exposure of Eolimna minima diatom populations cultured in suspension under controlled laboratory conditions. Their growth kinetics and Cd bioaccumulation were followed.Population growth rates revealed the high impact of Cd at 100μg/L with total inhibition of growth. These results are linked to the high bioaccumulation values calculated after 14 days of exposure, 57.0±6.3μg. Cd/g. dw and 734.1±70μg. Cd/g. dw for exposures of 10 and 100μg. Cd/L respectively.Genetic responses revealed the impact of Cd on the mitochondrial metabolism and the chloroplast photosystem of E. minima exposed to 10 and 100μg. Cd/L with induction of cox1, 12S, d1 and psaA after 7 days of exposure for the concentration of 100μg. Cd/L and of nad5, d1 and psaA after 14 days of exposure for both conditions.This is the first reported use of q-PCR for the assessment of toxic pollution on benthic river diatoms. The results obtained presage interesting perspectives, but the techniques developed need to be optimized before the design of new water quality diagnosis tools for use on natural biofilms.
(Water Research. vol. 46, n° 0043-1354, pp. 934-942, 13/04/2026)
UR REBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS