Publications associées à Événement anoxique océanique

Metabolic Performance and Fate of Electrons during Nitrate-Reducing Fe(II) Oxidation by the Autotrophic Enrichment Culture KS Grown at Different Initial Fe/N Ratios

Autotrophic nitrate-reducing Fe(II)-oxidizing (NRFeOx) microorganisms fix CO2 and oxidize Fe(II) coupled to denitrification, influencing carbon, iron, and nitrogen cycles in pH-neutral, anoxic environments. However, the distribution of electrons from Fe(II ...

AMER SOC MICROBIOLOGY2023

Rapid grain boundary diffusion in foraminifera tests biases paleotemperature records

Anders Meibom, Jaroslaw Hubert Stolarski, Arthur Adams, Deyanira Graciela Cisneros Lazaro, Jinming Guo, Lukas Baumgartner

The paleoseawater temperature record from the oxygen isotope compositions of fossil foraminifera tests may be biased by up to about 1 degrees C due to grain-boundary diffusion alone, according to isotope exchange experiments on foraminifera tests. The oxyg ...

2023

Spatially Explicit Linkages Between Redox Potential Cycles and Soil Moisture Fluctuations

Andrea Rinaldo, Rizlan Bernier-Latmani, Paolo Benettin, Manon Frutschi, Simiao Wang, Filippo Miele, Mitra Asadollahi

Reduction-oxidation cycles measured through soil redox potential (Eh) are associated with dynamic soil microbial activity. Understanding changes in the composition of, and resource use by, soil microbial communities requires Eh predictability under shiftin ...

American Geophysical Union2023

Arctic tropospheric ozone: assessment of current knowledge and model performance

Jakob Boyd Pernov, Ilann Ernest Valentin Bourgeois, Luca Pozzoli

As the third most important greenhouse gas (GHG) after carbon dioxide (CO2) and methane (CH4), tropospheric ozone (O3) is also an air pollutant causing damage to human health and ecosystems. This study brings together recent research on observations and mo ...

Copernicus Publications2023

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

Catalytic effects of photogenerated Fe(II) on the ligand-controlled dissolution of Iron(hydr)oxides by EDTA and DFOB

Janet Gordon Hering

Low bioavailability of iron due to poor solubility of iron(hydr)oxides limits the growth of microorganisms and plants in soils and aquatic environments. Previous studies described accelerated dissolution of iron(hydr)oxides under continuous illumination, b ...

Pergamon-Elsevier Science Ltd2021

Persistence of bioconvection-induced mixed layers in a stratified lake

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

In situ observations of biophysical interactions in natural waters typically focus on physical mechanisms influencing biological activity. Yet, biological activity can also drive physical processes in aquatic environments. A community of photoautotrophic, ...

American Society of Limnology and Oceanography2021

Direct-write laser-induced self-organization and metallization beyond the focal volume in tellurite glass

Yves Bellouard, Gözden Torun

We report on a self-organized process initiated on a potassium-tungsten-tellurite glass surface under repetitive femtosecond laser irradiation in a regime where cumulative effects lead to a localized melting. Specifically, we show that self-organized perio ...

2021

Effect of Aging on the Stability of Microbially Reduced Uranium in Natural Sediment

Rizlan Bernier-Latmani, Barbora Bártová, Yuheng Wang, Luca Loreggian, Sophie Louise Bretagne, Agnès Novotny

Reductive immobilization of uranium has been explored as a remediation strategy for the U-contaminated subsurface. Via the in situ biostimulation of microbial processes, hexavalent U is reduced to less soluble tetravalent species, which are immobilized wit ...

2019

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

Luca Loreggian

Uranium (U) contamination of ground and surface waters poses an acute hazard on the ecosystem and human health. Since the discovery of microbial U(VI) reduction, U bioremediation has been explored as a promising and cost-effective method compared to tradit ...

EPFL2019

Interplay of S and As in Mekong Delta sediments during redox oscillations

Rizlan Bernier-Latmani, Laurent Louis José Charlet

The cumulative effects of periodic redox cycling on the mobility of As, Fe, and S from alluvial sediment to groundwater were investigated in bioreactor experiments. Two particular sediments from the alluvial floodplain of the Mekong Delta River were invest ...

2019

Fe(II)-Catalyzed Ligand-Controlled Dissolution of Iron(hydr)oxides

Janet Gordon Hering

Dissolution of iron(III)phases is a key process in soils, surface waters, and the ocean. Previous studies found that traces of Fe(II) can greatly increase ligand controlled dissolution rates at acidic pH, but the extent that this also occurs at circumneutr ...

AMER CHEMICAL SOC2019

Fast Potentiometric CO2 Sensor for High-Resolution in Situ Measurements in Fresh Water Systems

Nadezda Pankratova, Bernhard Wehrli

We present a new potentiometric sensor principle and a calibration protocol for in situ profiling of dissolved CO2 with high temporal and spatial resolution in fresh water lakes. The sensor system is based on the measurement of EMF between two solid-contac ...

AMER CHEMICAL SOC2018

Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

Anders Meibom, Stéphane Laurent Escrig, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna ...

Public Library of Science2017

Correlated TEM-NanoSIMS investigation of foraminiferal metabolism

Charlotte Madeleine Nicole Lekieffre

Foraminifera are ubiquitous eukaryotic protists inhabiting all types of marine environments. The chemical and isotopic compositions of their carbonate tests are commonly used as proxies for paleo-environmental conditions. However, while foraminifera repres ...

EPFL2017

Burial-induced oxygen-isotope re-equilibration of fossil foraminifera explains ocean paleotemperature paradoxes

Anders Meibom

Oxygen-isotope compositions of fossilised planktonic and benthic foraminifera tests are used as proxies for surface-and deep-ocean paleotemperatures, providing a continuous benthic record for the past 115 Ma. However, visually imperceptible processes can a ...

Springer Nature2017

Oxygen depletion in stratified lakes - why shallow and deep lakes react differently

Alfred Johny Wüest, Robert Vincent Schwefel

Oxygen is the most important element in natural waters for any higher aquatic life, such as fish. As with humans, almost all members of aquatic ecosystems need oxygen to breathe. Building on this, treatment of drinking water is easier for oxic than for ano ...

2016

Uranium Isotopes Fingerprint Biotic Reduction

Rizlan Bernier-Latmani, Yuheng Wang, Malgorzata Alicja Stylo

Knowledge of paleo-redox conditions in the Earth's history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic ...

Natl Acad Sciences2015

Redox variations and bioproductivity in the Ediacaran: Evidence from inorganic and organic geochemistry of the Corumba Group, Brazil

Mariluz Bagnoud

Stable isotope ratios combined with elemental compositions and molecular biomass data provide a powerful tool in Neoproterozoic palaeoenvironmental interpretations. Here, we report the results of an extensive organic and inorganic geochemical study perform ...

Elsevier2014