Late Glacial to Preboreal sea-level rise recorded by the Rhône deltaic system (NW Mediterranean)

International audienceA unique late Glacial–Preboreal record of changes in sea-level and sediment fluxes originating from the Alps is recorded in the Rhône subaqueous delta in the Western Mediterranean Sea. The compilation of detailed bathymetric charts, together with high-resolution seismic profiles and long cores, reveals the detailed architecture of several sediment lobes, related to periods of decreased sea-level rise and/or increased sediment flux. They are situated along the retreat path of the Rhône distributaries, from the shelf edge and canyon heads up to the modern coastline. They form transgressive backstepping parasequences across the shelf, the late Holocene (highstand) deltas being confined to the inner shelf. The most prominent feature is an elongated paleo-shoreface/deltaic system, with an uppermost sandy fraction remolded into subaqueous dunes. A long piston core into the bottomsets of this prograding unit allows precise dating of this ancient deltaic system. In seismic data, it displays aggradation, starting at not, vert, similar 15 cal kyr BP, followed by progradation initiated during the first phase of the Younger Dryas, a period of reduced sea-level rise or stillstand. The delta kept pace with resumed sea-level rise during the Preboreal (which is estimated at about 1 cm/yr), as a result of increased sediment supply from the Alps (melting of glaciers and more humid climate “flushing” the sediment down to the sea). Abandonment of the delta occurred around 10,500 cal yr BP, that is to say about 1000 yr after the end of the Younger Dryas, probably because of decreased sediment flux

Variability in intermediate water circulation of the western Tyrrhenian margin (NE Corsica) over the past 56 kyr

The Marion Dufrene core MD01-2472 made of hemipelagic fine-grained sediments (silt and clays) was collected at 501 m depth on the East Corsica continental slope in 2001 and studied in detail in its 12 uppermost meters. The correlation between sedimentological parameters (Sortable Silt), isotopic data and 14C dating allowed to establish the chronology of main climate events (Younger Dryas/YD, Bölling-Alleröd/B-A, Heinrich events/HS) on this record and to evaluate the impact of major climate oscillations on bottom water condition variability. The sea temperature changes are identified thanks to the planktonic foraminifera assemblages. HS are marked by planktonic foraminifers with peaks of the polar species N. pachyderma (left-coiling), whilst interstadials are marked by warm planktonics that become very abundant during the B-A and Holocene. The occurrence of reworked ostracod species (originating from the continental shelf) and the presence of shallow water Elphidium/Ammonia benthic foraminifera are used to estimate the degree of along-slope transport at the core site. This has revealed two intervals of along-slope transport also associated with coarse-grained contourites, deposited during the YD and HS2 episodes. Intervals with Krithe spp. (ostracod), C. wuellerstorfi (benthic foraminifera) indicate bottom water oxygenation during stadials, whereas interstadials are typified by A. acuminata and Paracypris sp (ostracods) indicating low oxygenated environments. The Last Glacial Maximum is dominated by the planktonic foraminifer T. quinqueloba suggesting high surface primary productivity associated with the establishment of mestrophic bottom conditions. During the Holocene, benthic assemblages indicate oligo-mesotrophic conditions and weak hydrodynamic bottom regime. We hypothesize that there is relationship between the Levantine Intermediate Water (LIW) intensification during cold rapid climate events and benthic fauna assemblages due to changes in: 1) bottom water ventilation, corresponding to a significant reinforcement of the LIW velocity, and 2) the export of nutrients (generating changes in trophic conditions) and/or sediment particles by bottom currents (contributing to the formation of contourites)

Deltaic and Coastal Sediments as Recorders of Mediterranean Regional Climate and Human Impact Over the Past Three Millennia

This work was financially supported by the MISTRALS/PaleoMex program and by the Project of Strategic Interest NextData PNR 2011–2013 (www. nextdataproject.it). Lionel Savignan is thanked for his participation in the biomarker analysis. Radiocarbon datings for core KESC9-14 have been funded by Institut Carnot Ifremer-EDROME (grant A0811101). We also thank the Holocene North-Atlantic Gyres and Mediterranean Overturning dynamic through Climate Changes (HAMOC) project for financial support. The biomarker data presented here are available in the supporting information.Peer reviewedPublisher PD

Deltaic and Coastal Sediments as Recorders of Mediterranean Regional Climate and Human Impact Over the Past Three Millennia

International audienc

Ceftolozane/Tazobactam for Treatment of Severe ESBL-Producing Enterobacterales Infections: A Multicenter Nationwide Clinical Experience (CEFTABUSE II Study)

Background. Few data are reported in the literature about the outcome of patients with severe extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) infections treated with ceftolozane/tazobactam (C/T), in empiric or definitive therapy.Methods. A multicenter retrospective study was performed in Italy (June 2016-June 2019). Successful clinical outcome was defined as complete resolution of clinical signs/symptoms related to ESBL-E infection and lack of microbiological evidence of infection. The primary end point was to identify predictors of clinical failure of C/T therapy.Results. C/T treatment was documented in 153 patients: pneumonia was the most common diagnosis (n = 46, 30%), followed by 34 cases of complicated urinary tract infections (22.2%). Septic shock was observed in 42 (27.5%) patients. C/T was used as empiric therapy in 46 (30%) patients and as monotherapy in 127 (83%) patients. Favorable clinical outcome was observed in 128 (83.7%) patients; 25 patients were considered to have failed C/T therapy. Overall, 30-day mortality was reported for 15 (9.8%) patients. At multivariate analysis, Charlson comorbidity index >4 (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.9-3.5; P = .02), septic shock (OR, 6.2; 95% CI, 3.8-7.9; P < .001), and continuous renal replacement therapy (OR, 3.1; 95% CI, 1.9-5.3; P = .001) were independently associated with clinical failure, whereas empiric therapy displaying in vitro activity (OR, 0.12; 95% CI, 0.01-0.34; P < .001) and adequate source control of infection (OR, 0.42; 95% CI, 0.14-0.55; P < .001) were associated with clinical success.Conclusions. Data show that C/T could be a valid option in empiric and/or targeted therapy in patients with severe infections caused by ESBL-producing Enterobacterales. Clinicians should be aware of the risk of clinical failure with standard-dose C/T therapy in septic patients receiving CRRT

Risk Factors and Outcomes of Candidemia Caused by Biofilm-Forming Isolates in a Tertiary Care Hospital

Very few data exist on risk factors for developing biofilm-forming Candida bloodstream infection (CBSI) or on variables associated with the outcome of patients treated for this infection. METHODS AND FINDINGS: We identified 207 patients with CBSI, from whom 84 biofilm-forming and 123 non biofilm-forming Candida isolates were recovered. A case-case-control study to identify risk factors and a cohort study to analyze outcomes were conducted. In addition, two sub-groups of case patients were analyzed after matching for age, sex, APACHE III score, and receipt of adequate antifungal therapy. Independent predictors of biofilm-forming CBSI were presence of central venous catheter (odds ratio [OR], 6.44; 95% confidence interval [95% CI], 3.21-12.92) or urinary catheter (OR, 2.40; 95% CI, 1.18-4.91), use of total parenteral nutrition (OR, 5.21; 95% CI, 2.59-10.48), and diabetes mellitus (OR, 4.47; 95% CI, 2.03-9.83). Hospital mortality, post-CBSI hospital length of stay (LOS) (calculated only among survivors), and costs of antifungal therapy were significantly greater among patients infected by biofilm-forming isolates than those infected by non-biofilm-forming isolates. Among biofilm-forming CBSI patients receiving adequate antifungal therapy, those treated with highly active anti-biofilm (HAAB) agents (e.g., caspofungin) had significantly shorter post-CBSI hospital LOS than those treated with non-HAAB antifungal agents (e.g., fluconazole); this difference was confirmed when this analysis was conducted only among survivors. After matching, all the outcomes were still favorable for patients with non-biofilm-forming CBSI. Furthermore, the biofilm-forming CBSI was significantly associated with a matched excess risk for hospital death of 1.77 compared to non-biofilm-forming CBSI. CONCLUSIONS: Our data show that biofilm growth by Candida has an adverse impact on clinical and economic outcomes of CBSI. Of note, better outcomes were seen for those CBSI patients who received HAAB antifungal therapy

Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)

International audienceSea surface temperatures (SSTs) and land-derived input time series were generated from the Gulf of Lions inner-shelf sediments (NW Mediterranean Sea) using alkenones and high-molecular-weight odd-carbon numbered n-alkanes (TERR-alkanes), respectively. The SST record depicts three main phases: a warm Early Holocene (∼ 18 ± 0.4 °C) followed by a cooling of ∼ 3 °C between 7000 and 1000 BP, and rapid warming from ∼ 1850 AD onwards. Several superimposed multi-decadal to centennial-scale cold events of ∼ 1 °C amplitude were also identified. TERR-alkanes were quantified in the same sedimentary horizons to identify periods of high Rhone River discharge and compare them with regional flood reconstructions. Concentrations show a broad increase from the Early Holocene towards the present with a pronounced minimum around 2500 BP and large fluctuations during the Late Holocene. Comparison with Holocene flood activity reconstructions across the Alps region suggests that sediments of the inner shelf originate mainly from the Upper Rhone River catchment basin and that they are primarily delivered during positive North Atlantic Oscillation (NAO)

Epi-bathyal ostracod assemblage in Holocene Rhone deltaic sediments (Gulf of Lions, NW Mediterranean) and their palaeoecological implications

Since the Last Glacial Maximum, the Rhone River, which is the most important source of freshwater and sediment to the western Mediterranean Sea, migrated in a north-westward direction during the rapid Deglacial and Early Holocene sea-level rise. During the phase of global high sea-level (Middle and Late Holocene), an overall eastward migration of the Rhone outlet, under natural and/or human influence, is recorded through several sediment accumulations confined along the inner shelf in the form of deltaic lobes. These lobes that make up the whole Rhone subaqueous delta represent very expanded sedimentary archives of the Rhone Holocene history. In this paper, using three long piston cores retrieved from the most recent Bras de Fer (RHS-KS55) and Roustan (RHS-KS22 and RHS-KS57) deltaic lobes, at water depth ranging from 43 m to 79 m, we analyze the distribution of the Rhone ostracod assemblages during the Holocene. Our study highlighted the presence of epi-bathyal ostracods belonging to the genus Argilloecia, Cytheropteron and Krithe in shallow water deltaic sediments. Close to the Rhone River mouth, the presence of these full-marine ostracods is limited because of well-marked fluvial influence, whereas the occurrence of Argilloecia spp., C. rotundatum, K. compressa and K. pernoides increases with increasing distance from the river mouth. Thus, we hypothesize that C. rotundatum, K. compressa, and especially Argilloecia spp. might be more tolerant to higher fluvial influence than K. pernoides, which is only observed in the distal part of the Rhone River influence. Environment-related parameters (such as fresh-water and sediment input from the Rhone River, food supply, and dissolved oxygen) other than bathymetry are thought to have a major role in the development of these full-marine ostracods at the studied site.Depuis le Dernier Maximum Glaciaire, le Rhône, qui représente la source la plus importante d’eau douce et de sédiments en Méditerranée occidentale, a migré progressivement vers le nord-ouest en réponse à la remontée rapide du niveau de la mer au cours de la déglaciation et de l’Holocène inférieur. Suite à la stabilisation du niveau de la mer et à l’établissement d’un haut niveau marin au cours de l’Holocène moyen et supérieur, la migration naturelle et/ou anthropique de l’embouchure du Rhône vers l’est a conduit à l’accumulation de plusieurs unités sédimentaires confinées au niveau de la plateforme interne sous la forme de lobes deltaïques. Ces lobes, constitutifs du delta sous-marin du Rhône, donnent accès à d’épaisses séries sédimentaires renfermant l’histoire holocène du Rhône. A travers l’étude de trois carottes sédimentaires prélevées à des profondeurs d’eau comprises entre 43 m et 79 m au niveau des lobes deltaïques récents du Bras de Fer (RHS-KS55) et de Roustan (RHS-KS22 et RHS-KS57), nous analysons, dans ce papier, la distribution des assemblages d’ostracodes au cours de l’Holocène. Notre étude permet de mettre en avant la présence d’ostracodes caractéristiques du domaine épi-bathyal et appartenant aux genres Argilloecia, Cytheropteron et Krithe au sein de sédiments deltaïques peu profonds. A proximité de l’embouchure du Rhône, la présence de ces ostracodes de mer ouverte est restreinte par une influence fluviatile fortement marquée. En s’éloignant de l’embouchure du Rhône, nous notons l’apparition de Argilloecia spp., C. rotundatum, K. compressa et K. pernoides. Nous soulignons également que C. rotundatum, K. compressa et surtout Argilloecia spp. semblent tolérer une plus forte influence fluviatile que K. pernoides qui est uniquement rencontrée dans la partie distale de l’influence du Rhône. Ces différentes observations nous conduisent à émettre l’hypothèse que les paramètres environnementaux (tels que les apports d’eau douce et de sédiments par le Rhône, la nourriture disponible ou la teneur en oxygène dissous) autre que la bathymétrie jouent un rôle important dans le développement des ces ostracodes de mer ouverte au niveau de notre site d’étude