Publications associées à Non-crystalline tetravalent uranium species in the subsurface: formation and stability

The isotopic signature of U(V) during bacterial reduction

Marinella Mazzanti, Rizlan Bernier-Latmani, Radmila Faizova, Margaux Camille Andréa Molinas, Ashley Richards Brown

The two-step electron transfer during bacterial reduction of UVI to UIV is typically accompanied by mass-independent fractionation of the 238U and 235U isotopes, whereby the heavy isotope accumulates in the reduced product. However, the role of the UV inte ...

2024

Reproductive isolation arises during laboratory adaptation to a novel hot environment

Ana Marija Jaksic

Background: Reproductive isolation can result from adaptive processes (e.g., ecological speciation and mutation-order speciation) or stochastic processes such as "system drift" model. Ecological speciation predicts barriers to gene flow between populations ...

BMC2024

Diagenetic isotope exchange in biocalcites for paleoclimate reconstruction

Deyanira Graciela Cisneros Lazaro

The oxygen isotope compositions of fossil biocalcites, such as foraminifera, bivalves, brachiopods, and belemnites have allowed for reconstructions of sea surface and deep ocean temperatures throughout the Phanerozoic and constitute the most important reco ...

EPFL2024

Atomic level insight into irradiation effects in nuclear fuel materials

Shaileyee Bhattacharya

Microstructural evolution during in-pile irradiation, radiation damage effects and fission products behavior in UO2 nuclear fuel are key issues in understanding and for the modeling of the performance as well as safety characteristics of nuclear fuels in t ...

EPFL2024

Organic matters, but inorganic matters too: column examination of elevated mercury sorption on low organic matter aquifer material using concentrations and stable isotope ratios

Lorenz Schwab

Sorption of mercury (Hg) in soils is suggested to be predominantly associated with organic matter (OM). However, there is a growing collection of research that suggests that clay minerals and oxides are also important solid phases for the sorption of solu ...

2024

From roots to canopy: Unraveling the influence of species diversity on tree water relations under warmer and drier climates

Eugénie Isabelle Mas

The worsening of drought events with rising air temperature alters tree water relations causing severe hydraulic impairments and widespread forest mortality. Mixing tree species with contrasting hydraulic traits could reduce forest vulnerability to extreme ...

EPFL2024

Tree diversity reduces variability in sapling survival under drought

Charlotte Grossiord, Xiaojuan Liu, Jingjing Liang

Enhancing tree diversity may be important to fostering resilience to drought-related climate extremes. So far, little attention has been given to whether tree diversity can increase the survival of trees and reduce its variability in young forest plantatio ...

Wiley2024

Organ-specific biotransformation in salmonids: Insight into intrinsic enzyme activity and biotransformation of three micropollutants

Kristin Schirmer, Juliane Hollender

Aquatic ecosystems continue to be threatened by chemical pollution. To what extent organisms are able to cope with chemical exposure depends on their ability to display mechanisms of defense across different organs. Among these mechanisms, biotransformatio ...

Elsevier2024

Invasive palms have more efficient and prolonged CO2 assimilation compared to native sub-Mediterranean vegetation

Marco Conedera, Thibaut Michel Georges Juillard, Charlotte Grossiord, Christoph Bachofen, Janisse Deluigi

In sub-Mediterranean ecosystems, shade-tolerant broadleaf evergreens, especially the invasive Trachycarpus fortunei, are spreading uncontrollably in the forest understorey, impeding the regeneration of the native deciduous woody vegetation. Most invasive s ...

Elsevier2024

Multi-year time series of daily solute and isotope measurements from three Swiss pre-Alpine catchments

Jana Freiin von Freyberg

Time series analyses of solute concentrations in streamwater and precipitation are powerful tools for unraveling the interplay of hydrological and biogeochemical processes at the catchment scale. While such datasets are available for many sites around the ...

Nature Portfolio2024

Technical note: Two-component electrical-conductivity-based hydrograph separation employing an exponential mixing model (EXPECT) provides reliable high-temporal-resolution young water fraction estimates in three small Swiss catchments

Davide Canone, Jana Freiin von Freyberg

The young water fraction represents the portion of water molecules in a stream that have entered the catchment relatively recently, typically within 2-3 months. It can be reliably estimated in spatially heterogeneous and nonstationary catchments from the a ...

Copernicus Gesellschaft Mbh2024

Implementing Multi-Electron Transfer Strategies in Uranium Chemistry

Dieuwertje Katelijn Modder

In the last decades, the activation of small molecules has attracted increasing attention for their use as cheap and abundant feedstock. Low-oxidation state uranium complexes have displayed high reactivity towards small molecules thanks to their unique pro ...

EPFL2023

Iron Reduction in Profundal Sediments of Ultraoligotrophic Lake Tahoe under Oxygen-Limited Conditions

Meret Aeppli

Increased periods of bottom water anoxia in deep temperate lakes due to decreasing frequency and depth of water column mixing in a warming climate may result in the reductive dissolution of iron minerals and increased flux of nutrients from the sediment in ...

2023

Mercury Isotope Fractionation during Dark Abiotic Reduction of Hg(II) by Dissolved, Surface-Bound, and Structural Fe(II)

Lorenz Schwab

Stable mercury (Hg) isotope ratios are an emerging tracer for biogeochemical transformations in environmental systems, but their application requires knowledge of isotopic enrichment factors for individual processes. We investigated Hg isotope fractionatio ...

Amer Chemical Soc2023

Using continuous electrical conductivity measurements to derive major solute concentrations in karst systems

Paolo Benettin

Hydrochemical data of karst springs provide valuable insights into the internal hydrodynamical functioning of karst systems and support model structure identification. However, the collection of high-frequency time series of major solute species is limited ...

WILEY2023

A Route to Stabilize Uranium(II) and Uranium(I) Synthons in Multimetallic Complexes

Rosario Scopelliti, Marinella Mazzanti, Ivica Zivkovic, Dieuwertje Katelijn Modder

Herein, we report the redox reactivity of a multimetallic uranium complex supported by triphenylsiloxide (−OSiPh3) ligands, where we show that low valent synthons can be stabilized via an unprecedented mechanism involving intramolecular ligand migration. T ...

Wiley-VCH Verlag GmbH2023

Characterization of Thruster-Induced Turbulence for Fine Sediment Suspension

Giovanni De Cesare, Azin Amini, Montana Marshall, Andre Luis Stakowian

Reservoir sedimentation is a key challenge for storage sustainability because it causes volume loss, affecting hydropower production capacity, dam safety, and flood management. A preliminary EPFL study proposed and studied an innovative device (called SEDM ...

2023

Experimental modeling of fine sediment routing: SEDMIX device with thrusters

Giovanni De Cesare, Azin Amini, Montana Marshall

Reservoir sedimentation is a key challenge for storage sustainability because it causes volume loss, affecting hydropower production capacity, dam safety, and flood management. A preliminary EPFL study proposed and studied an innovative device (called SEDM ...

CRC Press/Balkema2023

Fish Diversity in Relation to Littoral Habitats in Three Basins of Lake Kivu (East Africa)

Alfred Johny Wüest

In total, 28 of the 29 fish species reported from the Lake Kivu basin occur in the littoral zone of the lake, but information about their structure, occurrence, and the habitats affecting their distribution is largely lacking. The lake's inshore area is po ...

MDPI2023

Reliable uncertainties: Error correlation, rotated error bars, and linear regressions in three-isotope plots and beyond

Reto Georg Trappitsch

Correlated errors of experimental data are a common but often neglected problem in physical sciences. Various tools are provided here for thorough propagation of uncertainties in cases of correlated errors. Discussed are techniques especially applicable to ...

ELSEVIER2023