Publications de Damien Bouffard

Combined Earth observations reveal the sequence of conditions leading to a large algal bloom in Lake Geneva

Damien Bouffard, Abolfazl Irani Rahaghi, Marco Toffolon, Oscar Rodrigo Sepúlveda Steiner, Rafael Sebastian Reiss, Frédéric Charles Soulignac

Freshwater algae exhibit complex dynamics, particularly in meso-oligotrophic lakes with sudden and dramatic increases in algal biomass following long periods of low background concentration. While the fundamental prerequisites for algal blooms, namely ligh ...

Springernature2024

Lake surface cooling drives littoral-pelagic exchange of dissolved gases

Alfred Johny Wüest, Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Cintia Luz Ramon Casanas

The extent of littoral influence on lake gas dynamics remains debated in the aquatic science community due to the lack of direct quantification of lateral gas transport. The prevalent assumption of diffusive horizontal transport in gas budgets fails to exp ...

Amer Assoc Advancement Science2024

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

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

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

Spatial Variability of Turbulent Mixing From an Underwater Glider in a Large, Deep, Stratified Lake

Alfred Johny Wüest, Sébastien Lavanchy, Damien Bouffard, Bieito Fernandez Castro, Oscar Rodrigo Sepúlveda Steiner, Alexander Lebaron Forrest

Recent efforts using microstructure turbulence measurements have contributed to our understanding of the overall energy budget in lakes and linkages to vertical fluxes. A paucity of lake-wide turbulence measurements hinders our ability to assess how repres ...

AMER GEOPHYSICAL UNION2023

Convective regimes induced by surface cooling and topography in stratified waterbodies

Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Cintia Luz Ramon Casanas

Gravitational convection plays a significant role in the ventilation, heat and mass distribution of aquatic systems. This study investigates thermally driven convection resulting from heat loss at the air-water interface during cooling periods in freshwate ...

Iahr-Int Assoc Hydro-Environment Engineering Research2022

A Bayesian data assimilation framework for lake 3D hydrodynamic models with a physics-preserving particle filtering method using SPUX-MITgcm v1

Damien Bouffard, Firat Ozdemir, Cintia Luz Ramon Casanas, Camille Roland Marie Minaudo

We present a Bayesian inference for a three-dimensional hydrodynamic model of Lake Geneva with stochastic weather forcing and high-frequency observational datasets. This is achieved by coupling a Bayesian inference package, SPUX, with a hydrodynamics packa ...

COPERNICUS GESELLSCHAFT MBH2022

Detritus-hosted methanogenesis sustains the methane paradox in an alpine lake

Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

Accumulation of methane in oxic waters of lakes and the ocean has been widely reported. Despite the importance for the greenhouse gas budget, mechanistic controls of such "methane paradox" remain elusive. Here, we use a combination of CH4 concentration and ...

American Society of Limnology and Oceanography2022

Flushing the Lake Littoral Region: The Interaction of Differential Cooling and Mild Winds

Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Cintia Luz Ramon Casanas

The interaction of a uniform cooling rate at the lake surface with sloping bathymetry efficiently drives cross-shore water exchanges between the shallow littoral and deep interior regions. The faster cooling rate of the shallows results in the formation of ...

AMER GEOPHYSICAL UNION2022

Seasonality of density currents induced by differential cooling

Alfred Johny Wüest, Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez

When lakes experience surface cooling, the shallow littoral region cools faster than the deep pelagic waters. The lateral density gradient resulting from this differential cooling can trigger a cold downslope density current that intrudes at the base of th ...

2022

Coupling remote sensing and particle tracking to estimate trajectories in large water bodies

Alfred Johny Wüest, Damien Bouffard, Tamar Kohn, Chaojie Li

Propelled by the rapid development of equipment, technology and computational power, the monitoring and simulation of the hydrodynamics in lakes have steadily advanced. In contrast, water quality simulations are more difficult to implement, due to the diff ...

Elsevier2022

Integrating Inland and Coastal Water Quality Data for Actionable Knowledge

Damien Bouffard, Theo Baracchini, Camille Roland Marie Minaudo

Water quality measures for inland and coastal waters are available as discrete samples from professional and volunteer water quality monitoring programs and higher-frequency, near-continuous data from automated in situ sensors. Water quality parameters als ...

MDPI2021

Development of overturning circulation in sloping waterbodies due to surface cooling

Alfred Johny Wüest, Damien Bouffard, Tomy Doda, Hugo Nicolás Ulloa Sánchez, Cintia Luz Ramon Casanas

Cooling the surface of freshwater bodies, whose temperatures are above the temperature of maximum density, can generate differential cooling between shallow and deep regions. When surface cooling occurs over a long enough period, the thermally induced cros ...

Cambridge University Press2021

Inhibited vertical mixing and seasonal persistence of a thin cyanobacterial layer in a stratified lake

Alfred Johny Wüest, Damien Bouffard, Bieito Fernandez Castro, Oscar Rodrigo Sepúlveda Steiner

Harmful blooms of the filamentous cyanobacteria Planktothrix rubescens have become common in many lakes as they have recovered from eutrophication over the last decades. These cyanobacteria, capable of regulating their vertical position, often flourish at ...

2021

LeXPLORE: A floating laboratory on Lake Geneva offering unique lake research opportunities

Natacha Tofield-Pasche, Alfred Johny Wüest, Sébastien Lavanchy, Damien Bouffard

Environmental sciences depend heavily on observational data. Successful studies of ecological processes in lakes require in-situ data that cover the relevant temporal scales from milliseconds to entire seasons. Temporal and spatial coverage requirements re ...

2021

The value of human data annotation for machine learning based anomaly detection in environmental systems

Damien Bouffard, Camille Roland Marie Minaudo

Anomaly detection is the process of identifying unexpected data samples in datasets. Automated anomaly detection is either performed using supervised machine learning models, which require a labelled dataset for their calibration, or unsupervised models, w ...

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

Evolution of stream and lake water temperature under climate change

Bettina Schaefli, Alfred Johny Wüest, Damien Bouffard, Wolf Hendrik Huwald, Carl Love Mikael Råman Vinnå, Martin Schmid, Adrien Michel

This report presents past observations and projects the future development of water temperature in Swiss lakes and rivers. Projections are made until the end of the 21st century using the CH2018 climate scenarios. Besides climate change effects on temperat ...

Federal Office for the Environment (FOEN)2021

Meteolakes: An operational online three-dimensional forecasting platform for lake hydrodynamics

Alfred Johny Wüest, Damien Bouffard, Theo Baracchini

Environmental management depends on high-quality monitoring and its meaningful interpretation. The combination of local weather dynamics, regional anthropogenic stresses and global environmental changes make the evaluation of monitoring information in dyna ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Assessing Subaquatic Mass Movement Hazards: an Integrated Observational and Hydrodynamic Modelling Approach

Alfred Johny Wüest, Damien Bouffard, Nathalie Dubois, Carl Love Mikael Råman Vinnå

High-resolution lake and reservoir bathymetric surveys can pinpoint locations that may experience underwater landslides (subaquatic sedimentary mass movements). These can pose a risk to underwater and shoreline infrastructure. This paper outlines an approa ...

2020

Data assimilation of in situ and satellite remote sensing data to 3D hydrodynamic lake models: a case study using Delft3D-FLOW v4.03 and OpenDA v2.4

Alfred Johny Wüest, Damien Bouffard, Theo Baracchini

The understanding of physical dynamics is crucial to provide scientifically credible information on lake ecosystem management. We show how the combination of in situ observations, remote sensing data, and three-dimensional hydrodynamic (3D) numerical simul ...

2020