Publications de Alfred Johny Wüest

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

Penetrative Convection Modifies the Dynamics of Downslope Gravity Currents

Alfred Johny Wüest, Tomy Doda, Hugo Nicolás Ulloa Sánchez

Gravity currents contribute to the transport of heat and mass in atmospheric and aquatic environments. In aquatic systems subject to daily surface cooling, gravity currents propagate through turbulent convective surroundings. Yet, the effects of thermal co ...

AMER GEOPHYSICAL UNION2023

Disentangling the effects of climate change and reoligotrophication on primary production in a large lake

Alfred Johny Wüest, Emile Barbe, Hugo Nicolás Ulloa Sánchez, Shubham Krishna

Climate change and reduction in nutrient loads have significant effects on primary production and phytoplankton growth dynamics. Since in the last few decades in many regions, nutrients in lakes were reduced simultaneously as the climate changed. Yet, it r ...

SPRINGER BASEL AG2023

Fish Diversity in Relation to Littoral Habitats in Three Basins of Lake Kivu (East Africa)

Alfred Johny Wüest

In total, 28 of the 29 fish species reported from the Lake Kivu basin occur in the littoral zone of the lake, but information about their structure, occurrence, and the habitats affecting their distribution is largely lacking. The lake's inshore area is po ...

MDPI2023

Current status and strategic way forward for long-term management of Lake Kivu (East Africa)

Natacha Tofield-Pasche, Alfred Johny Wüest

Lake Kivu is one of the African Great Lakes lying in the Albertine Rift. It provides livelihoods to 5.7 million people living in the two riparian countries of the Democratic Republic of the Congo and the Republic of Rwanda. Lake Kivu is currently experienc ...

Elsevier Sci Ltd2023

Effects of Bubble Plumes on Lake Dynamics, Near-Bottom Turbulence, and Transfer of Dissolved Oxygen at the Sediment-Water Interface

Alfred Johny Wüest

We quantify the lake dynamics, near-bottom turbulence, flux of dissolved oxygen (DO) across the sediment-water interface (SWI) and their interactions during oxygenation in two lakes. Field observations show that the lake dynamics were modified by the bubbl ...

AMER GEOPHYSICAL UNION2023

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

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

The entire lifetime of a distinct double‑diffusive staircase in crater Lake Nyos, Cameroon

Alfred Johny Wüest

Lake Nyos, a deep crater lake, located in the north-west of Cameroon, was permanently stratified below 50 m depth due to subaquatic sources supplying warm, salty and CO2- enriched water into the deepest reaches. The high CO2 content in these source waters ...

2022

The Land-Water-Energy Nexus of Ruzizi River Dams (Lake Kivu Outflow, African Great Lakes Region): Status, Challenges, and Perspectives

Alfred Johny Wüest

Hydroelectric power (HP) represents the main source of electricity in Africa, including the Democratic Republic of Congo. The demand for new dam construction is high, and major projects are currently progressing through planning and implementation stages. ...

FRONTIERS MEDIA SA2022

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

Netto- Ökosystemproduktion in Seen - Bestimmung aus Monitoringdaten

Alfred Johny Wüest, Isabel Blanca Sophie Kiefer

PRODUCTION NETTE DE L’ÉCOSYSTÈME DANS LES LACS – DÉTERMINATION GRÂCE AUX DONNÉES DE MONITORING Les algues et les cyanobactéries se développent dans la couche de surface productive des lacs par l’absorption de CO2, de lumière et de nutriments. Malgré sa réu ...

2021

Primary and Net Ecosystem Production in a Large Lake Diagnosed From High-Resolution Oxygen Measurements

Alfred Johny Wüest, Bieito Fernandez Castro, Pascal Perolo, Hannah Elisa Chmiel, Shubham Krishna, Camille Roland Marie Minaudo

The rates of gross primary production (GPP), ecosystem respiration (R), and net ecosystem production (NEP) provide quantitative information about the cycling of carbon and energy in aquatic ecosystems. In lakes, metabolic rates are often diagnosed from die ...

American Geophysical Union2021

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

Anleitung zur Analyse von Sauerstoffzehrung und Netto-Ökosystemproduktion in Seen. Arbeitshilfe zur Ermittlung relevanter Grössen der Trophie von Seen

Alfred Johny Wüest, Isabel Blanca Sophie Kiefer

Diese Arbeitsanleitung bietet einen Leitfaden zur Analyse der Sauerstoffzehrung und der Netto-Ökosystemproduktion in Seen. Diese beiden Grössen bilden wichtige Grundlagen zur Bestimmung der See-Gesundheit und ermöglichen, deren zeitliche Entwicklung zu unt ...

Eawag2021

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

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

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