Publications associées à Glaciations quaternaires

Near-bed stratification controls bottom hypoxia in ice-covered alpine lakes

Damien Bouffard, Camille Roland Marie Minaudo, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Hannah Elisa Chmiel, Janine Rüegg, Nicolas Thomas Georges Escoffier, Pascal Perolo

In ice-covered lakes, near-bottom oxygen concentration decreases for most of the wintertime, sometimes down to the point that bottom waters become hypoxic. Studies insofar have reached divergent conclusions on whether climate change limits or reinforces th ...

American Society of Limnology and Oceanography2023

Physicochemical characterization and source apportionment of Arctic ice-nucleating particles observed in Ny-Alesund in autumn 2019

Athanasios Nenes, Ghislain Gilles Jean-Michel Motos, Jörg Wieder, Guangyu Li

Ice-nucleating particles (INPs) initiate primary ice formation in Arctic mixed-phase clouds (MPCs), altering cloud radiative properties and modulating precipitation. For atmospheric INPs, the complexity of their spatiotemporal variations, heterogeneous sou ...

Copernicus GmbH2023

The Biogeochemical Legacy of Arctic Subglacial Sediments Exposed by Glacier Retreat

Tyler Joe Kohler

During past periods of advance, Arctic glaciers and ice sheets overrode soil, sediments, and vegetation and buried significant stores of organic matter (OM); these glaciers are now shrinking rapidly due to climate warming. Little is known about the biogeoc ...

2022

Unexpected post‐glacial colonisation route explains the white colour of barn owls ( Tyto alba ) from the British Isles

Nicolas Jean Philippe Guex, Christian Iseli

The climate fluctuations of the Quaternary shaped the movement of species in and out of glacial refugia. In Europe, the majority of species followed one of the described traditional postglacial recolonization routes from the southern peninsulas towards the ...

2022

Ice multiplication from ice-ice collisions in the high Arctic: sensitivity to ice habit, rimed fraction, ice type and uncertainties in the numerical description of the process

Athanasios Nenes, Georgia Sotiropoulou

Atmospheric models often fail to correctly reproduce the microphysical structure of Arctic mixed-phase clouds and underpredict ice water content even when the simulations are constrained by observed levels of ice nucleating particles. In this study we inve ...

Copernicus GmbH2021

Snowfall and snow accumulation processes during the MOSAiC winter and spring season

Michael Lehning, Marc Schneebeli Zeugin, David Nicholas Wagner, Markus Frey, Marc Oggier

Data from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition allowed us to investigate the temporal dynamics of snowfall, snow accumulation, and erosion in great detail for almost the whole accumulation season (N ...

2021

Seascape Genomics of the Sugar Kelp Saccharina latissima along the North Eastern Atlantic Latitudinal Gradient

Chloé Christiane Laurence Jollivet, Stéphane Mauger

Temperature is one of the most important range-limiting factors for many seaweeds. Driven by the recent climatic changes, rapid northward shifts of species' distribution ranges can potentially modify the phylogeographic signature of Last Glacial Maximum. W ...

MDPI2020

Snapshots of mean ocean temperature over the last 700,000 yr using noble gases in the EPICA Dome C ice core

Adrien Michel

Together with the latent heat stored in glacial ice sheets the ocean heat uptake carries the lion’s share of glacial/interglacial changes in the planetary heat content but little direct information on the global mean ocean temperature (MOT) is available to ...

2021

Enhanced trace element mobilization by Earth's ice sheets

Tyler Joe Kohler

Trace elements sustain biological productivity, yet the significance of trace element mobilization and export in subglacial runoff from ice sheets is poorly constrained at present. Here, we present size-fractionated (0.02, 0.22, and 0.45 mu m) concentratio ...

National Academy of Sciences2020

Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists

Edward Mitchell, Luca Bragazza, Mariusz Lamentowicz, Enrique Lara, Bertrand Fournier

Recent studies show that soil eukaryotic diversity is immense and dominated by micro-organisms. However, it is unclear to what extent the processes that shape the distribution of diversity in plants and animals also apply to micro-organisms. Major diversif ...

WILEY2019

Silicon isotopes in Arctic and sub-Arctic glacial meltwaters: the role of subglacial weathering in the silicon cycle

Tyler Joe Kohler

Glacial environments play an important role in high-latitude marine nutrient cycling, potentially contributing significant fluxes of silicon (Si) to the polar oceans, either as dissolved silicon (DSi) or as dissolvable amorphous silica (ASi). Silicon is a ...

2019

Implications of river intrusion and convective mixing on the spatial and temporal variability of under-ice CO2

Damien Bouffard, Natacha Tofield-Pasche

Ice-covered periods might significantly contribute to lake emissions at ice-melt, yet a comprehensive understanding of under-ice carbon dioxide (CO2) dynamics is still lacking. This study investigated the processes driving spatiotemporal patterns of under- ...

2019

Importance of the advection scheme for the simulation of water isotopes over Antarctica by atmospheric general circulation models: A case study for present-day and Last Glacial Maximum with LMDZ-iso

Etienne Gabriel Henri Vignon

Atmospheric general circulation models (AGCMs) are known to have a warm and isotopically enriched bias over Antarctica. We test here the hypothesis that these biases are partly consequences of a too diffusive advection. Exploiting the LMDZ-iso model, we sh ...

2019

Where does the river end? Drivers of spatiotemporal variability in CO2 concentration and flux in the inflow area of a large boreal lake

Natacha Tofield-Pasche, Hannah Elisa Chmiel

River inflow affects the spatiotemporal variability of carbon dioxide (CO2) in the water column of lakes and may locally influence CO2 gas exchange with the atmosphere. However, spatiotemporal CO2 variability at river inflow sites is often unknown leaving ...

American Society of Limnology and Oceanography2020

Energetics of Radiatively Heated Ice-Covered Lakes

Alfred Johny Wüest, Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Kraig Bates Winters

We derive the mechanical energy budget for shallow, ice-covered lakes energized by penetrative solar radiation. Radiation increases the available and background components of the potential energy at different rates. Available potential energy drives under- ...

2019

Effects of Atmospheric Processing on the Oxidative Potential of Biomass Burning Organic Aerosols

Athanasios Nenes, Kalliopi Violaki

Oxidative potential (OP), which is the ability of certain components in atmospheric particles to generate reactive oxidative species (ROS) and deplete antioxidants in vivo, is a prevailing toxicological mechanism underlying the adverse health effects assoc ...

AMER CHEMICAL SOC2019

A model of the western Laurentide Ice Sheet, using observations of glacial isostatic adjustment

Jean-Philippe Lucien Montillet

We present the results of a new numerical model of the late glacial western Laurentide Ice Sheet, constrained by observations of glacial isostatic adjustment (GIA), including relative sea level indicators, uplift rates from permanent GPS stations, contempo ...

Elsevier2016

Mobile Riverbed Scour Downstream of a Piano Key Weir

Anton Schleiss, Michael Pfister, Stefan Jüstrich

In parallel to their most frequent application as an auxiliary dam spillway, piano key weirs (PKWs) are also installed on low-head barrages in combination with run-off-the-river power plants. Their efficient rating curve, advantageous behavior under driftw ...

Asce-Amer Soc Civil Engineers2016

The Genomic Signature of Population Reconnection Following Isolation: From Theory to HIV

Amalio Telenti, Jeffrey David Jensen, Séverine Vuilleumier Varisco

Ease of worldwide travel provides increased opportunities for organisms not only to colonize new environments but also to encounter related but diverged populations. Such events of reconnection and secondary contact of previously isolated populations are w ...

Genetics Society of America2015

Uncertainties in isoprene photochemistry and emissions: implications for the oxidative capacity of past and present atmospheres and for climate forcing agents

Jed Oliver Kaplan

Isoprene and its oxidation products are major players in the oxidative chemistry of the troposphere. Current understanding of the factors controlling biogenic isoprene emissions and of the fate of isoprene oxidation products in the atmosphere has been evol ...

Copernicus GmbH2015