Publications de Oscar Rodrigo Sepúlveda Steiner

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

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

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

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

Seasonality modulates wind-driven mixing pathways in a large lake

Alfred Johny Wüest, Bieito Fernandez Castro, Oscar Rodrigo Sepúlveda Steiner, Hugo Nicolás Ulloa Sánchez, Sebastiano Piccolroaz

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 turbule ...

SPRINGERNATURE2021

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

Correction to: Inhibited vertical mixing and seasonal persistence of a thin cyanobacterial layer in a stratified lake (vol 83, 38, 2021)

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

2021

Mixing processes and their ecological implications: From vertical to lateral variability in stratified lakes

Oscar Rodrigo Sepúlveda Steiner

The physical environment of natural waters influences biogeochemical processes to generate specific ecological niches, promoting biophysical interactions. Bacteria and phytoplankton communities can form spatial structures, such as layers and patches. The p ...

EPFL2020

Convection‐Diffusion Competition Within Mixed Layers of Stratified Natural Waters

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner

In stratified natural waters, convective processes tend to form nearly homogeneous mixed layers. However, shear‐driven turbulence generated by large‐scale background flow often rapidly smooths them through mixing with the stratified surroundings. Here we s ...

2019

Hydrodynamics of a periodically wind‑forced small and narrow stratified basin: a large‑eddy simulation experiment

Alfred Johny Wüest, Damien Bouffard, Oscar Rodrigo Sepúlveda Steiner, Serban George Constantinescu, Kyoung Sik Chang, Hugo Nicolás Ulloa Sánchez

We report novel results of a numerical experiment designed for examining the basin-scale hydrodynamics that control the mass, momentum, and energy distribution in a daily wind-forced, small thermally-stratified basin. For this purpose, the 3-D Boussinesq e ...

2018