Résumé
Abstract
Turbulent mixing controls the vertical transfer of heat, gases and nutrients in stratified water bodies, shaping their response to environmental forcing. Nevertheless, due to technical limitations, the redistribution of wind-derived energy fuelling turbulence within stratified lakes has only been mapped over short (sub-annual) timescales. Here we present a year-round observational record of energy fluxes in the large Lake Geneva. Contrary to the standing view, we show that the benthic layers are the main locus for turbulent mixing only during winter. Instead, most turbulent mixing occurs in the water-column interior during the stratified summer season, when the co-occurrence of thermal stability and lighter winds weakens near-sediment currents. Since stratified conditions are becoming more prevalent –possibly reducing turbulent fluxes in deep benthic environments–, these results contribute to the ongoing efforts to anticipate the effects of climate change on freshwater quality and ecosystem services in large lakes.
Auteurs, date et publication :
Auteurs Bieito Fernández Castro , Damien Bouffard , Cary Troy , Hugo N. Ulloa , Sebastiano Piccolroaz , Oscar Sepúlveda Steiner , Hannah E. Chmiel , Lucas Serra Moncadas , Sébastien Lavanchy , Alfred Wüest
Publication : Communications Earth & Environment
Date : 2025
Volume : 2
Issue : 1
Pages : 215
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Stefania Russo , Michael D. Besmer , Frank Blumensaat , Damien Bouffard , Andy Disch , Frederik Hammes , Angelika Hess , Moritz Lürig , Blake Matthews , Camille Minaudo , Eberhard Morgenroth , Viet Tran-Khac , Kris Villez
Publication : Water Research
Date : 2025
Volume : 206
Pages : 117695
Catégorie(s)
#INRAE #OLARésumé
According to biogeography studies, the abundance and richness of soil microorganisms vary across multiple spatial scales according to soil properties and farming practices. However, soil microorganisms also exhibit poorly understood temporal variations. This study aimed at better understanding how soil microbial communities respond to changes in farming practices at a landscape scale over time. A regular grid of 269 sites was set up across a 1,200 ha farming landscape, and soil samples were characterized for their molecular microbial biomass and bacterial richness at two dates (2011 and 2016). A mapping approach highlighted that spatial microbial patterns were stable over time, while abundance and richness levels were modified. The drivers of these changes were investigated though a PLS-PM (partial least square path-modeling) approach. Soil properties were stable over time, but farming practices changed. Molecular microbial biomass was mainly driven by soil resources, whereas bacterial richness depended on both farming practices and ecological parameters. Previous-crop and management effects and a temporal dependence of the microbial community on the historical farming management were also highlighted.
Auteurs, date et publication :
Auteurs Laurie Dunn , Christophe Lang , Nicolas Marilleau , Sébastien Terrat , Luc Biju-Duval , Mélanie Lelièvre , Solène Perrin , Nicolas Chemidlin Prévost-Bouré
Publication : PLOS ONE
Date : 2025
Volume : 16
Issue : 6
Pages : e0252216
Catégorie(s)
#Genosol #INRAERésumé
Abstract
A dramatic slowing down of acoustic wave transport in dense fish shoals is observed in open-sea fish cages. By employing a multi-beam ultrasonic antenna, we observe the coherent backscattering phenomenon. We extract key parameters of wave transport such as the transport mean free path and the energy transport velocity of diffusive waves from diffusion theory fits to the experimental data. The energy transport velocity is found to be about 10 times smaller than the speed of sound in water, a value that is exceptionally low compared with most observations in acoustics. By studying different models of the fish body, we explain the basic mechanism responsible for the observed very slow transport of ultrasonic waves in dense fish shoals. Our results show that, while the fish swim bladder plays an important role in wave scattering, other organs have to be considered to explain ultra-low energy transport velocities.
Auteurs, date et publication :
Auteurs Benoit Tallon , Philippe Roux , Guillaume Matte , Jean Guillard , John H. Page , Sergey E. Skipetrov
Publication : Scientific Reports
Date : 2025
Volume : 11
Issue : 1
Pages : 17541
Catégorie(s)
#INRAE #OLARésumé
Accurate and continuous measurement of the subsoil CO2 is critical to better understand the terrestrial and atmosphere gas transfer process. This work aims to develop and field test a specific flow system to continuously measure the soil gas concentration (χc) and understand its main physical drivers. Hourly data measured in situ were collected through two dedicated wells at 1 m and 6 m depth coupled with micrometeorological measurement. Our study shows that χc at -1 m was at the lowest in winter and highest in summer. Meanwhile, the seasonal variation of χc at -6 m is somewhat unclear. While it is inevitable that temperature plays a significant role, this factor related to biological activity cannot fully explain the variation. The decrease in χc at both depths in summer coincides with an increase of friction velocity, especially during dry periods with R2 of 0.68, which shows strong empirical evidence that wind turbulence plays a significant role in driving the deep soil CO2. A monitoring strategy for gas measurement combining borehole and micrometeorological measurement offers excellent long-term monitoring possibilities to derive the vertical distribution of CO2 and better understand the main physical drivers of gas exchange.
Auteurs, date et publication :
Auteurs Didi Adisaputro , Philippe De Donato , Laurent Saint-Andre , Odile Barres , Catherine Galy , Gilles Nourrisson , Médéric Piedevache , Marion Derrien
Publication : Applied Sciences
Date : 2021
Volume : 11
Issue : 4
Pages : 1753
Catégorie(s)
#FORET Montiers #INRAERésumé
Data description : Data are temperature profiles recorded in Lakes Geneva, Bourget and Annecy during the summer period of strong thermal stratific...
Auteurs, date et publication :
Auteurs Rachel Pilla , Orlane Anneville
Date : 2021
Catégorie(s)
#INRAE #OLAAuteurs, date et publication :
Auteurs Emilie Lyautey , Elodie Billard , Nathalie Tissot , Stéphan Jacquet , Isabelle Domaizon
Publication : Microbial Ecology
Date : 2021
Catégorie(s)
#INRAE #OLARésumé
Data description : Data are in situ profiles of dissolved oxygen concentrations, water temperature, Secchi depths and total phosphorus concentratio...
Auteurs, date et publication :
Auteurs Jean-Philippe Jenny
Date : 2021
Catégorie(s)
#INRAE #OLARésumé
Soil amendments with organic waste products (OWPs) have been widely supported in Europe to improve soil fertility, causing wide changes in the microbial community structure and diversity, especially in the short-term period. Those changes are known to affect the volatile organic compound (VOC) emissions by soil. This work aimed to characterize, in terms of quantity and composition, the effect of green waste and sludge (GWS) application on soil VOC emissions and microbial community 49 h after the last GWS application. Two different soil samples were compared to test the effect of the soil history on VOC emissions and microbial communities. For this reason, we chose a soil that received GWS input for 20 years (GWS sample) and one that did not receive any organic input during the same period (CN sample). Furthermore, samples were manipulated to generate three microbial dilution diversity gradients (low, medium, and high). Results showed that Bacteroidetes phyla took advantage of the GWS application in all samples, increasing their relative abundance by 22% after 49 h, while the Proteobacteria phylum was penalized by the GWS amendment, passing from 58% to 49% relative abundance 49 h after the GWS application. Microbial structure differences between microbial diversity dilution levels remained even after the GWS application. GWS amendment induced a change in the emitted VOC profiles, especially in samples used to receiving GWS. GWS amendment doubled the VOC emissions from samples used to receiving GWS after 49 h. Finally, the microbial community was strongly correlated to the VOC emissions. Firmicutes, Proteobacteria, Actinobacteria, and Crenarchaeota were positively correlated (Pearson coefficient > 0.6), while other phyla, such as Bacteroidetes and Verrucomicrobia, were found to be negatively correlated (Pearson coefficient < −0.6) to the VOC emissions. After the addition of GWS, these correlations shifted from positive to negative and from negative to positive.
Auteurs, date et publication :
Auteurs Letizia Abis , Sophie Sadet-Bourgeteau , Benjamin Lebrun , Raluca Ciuraru , Florence Lafouge , Virginie Nowak , Julie Tripied , Sabine Houot , Pierre Alain Maron , Benjamin Loubet
Publication : Applied Microbiology
Date : 2021
Volume : 1
Issue : 1
Pages : 123-141
Catégorie(s)
#INRAE #PRO #PRO QualiAgroAuteurs, date et publication :
Auteurs Christian Pichot , Damien Maurice , Ghislaine Monet , Rachid Yahiaoui , Philippe Clastre , Benjamin Jaillet
Date : 2021