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Alfred Johny Wüest

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Related publications (118)

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Diffusive-type of double diffusion in lakes - a review

Alfred Johny Wüest

This chapter is a contribution in honour of Gerhard H Jirka, who has been fascinated by the amazing variety of small-scale structures that nature surprises us with, particularly in stratified natural waters. Here, we focus on the diffusive regime of double ...

CRC Press2012

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

Using small-scale measurements to estimate hypolimnetic oxygen depletion in a deep lake

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Low oxygen concentrations in lakes and reservoirs are an ongoing environmental concern, particularly in light of increasing anthropogenic activity and climate change. Oxygen depletion processes in lakes are still not completely understood and a variety of ...

American Society of Limnology and Oceanography2018

Oxygen depletion in stratified lakes - why shallow and deep lakes react differently

Alfred Johny Wüest, Robert Vincent Schwefel

Oxygen is the most important element in natural waters for any higher aquatic life, such as fish. As with humans, almost all members of aquatic ecosystems need oxygen to breathe. Building on this, treatment of drinking water is easier for oxic than for ano ...

2016

Simulations of a double-diffusive interface in the diffusive convection regime

Alfred Johny Wüest

Three-dimensional direct numerical simulations are performed that give us an in-depth account of the evolution and structure of the double-diffusive interface. We examine the diffusive convection regime, which, in the oceanographically relevant case, consi ...

Cambridge University Press2012

Present and past bio-available phosphorus budget in the ultra-oligotrophic Lake Brienz

Alfred Johny Wüest, Beat Mueller

A detailed budget of the fluxes of bio-available phosphorus (bio-P) was established for the ultra-oligotrophic Lake Brienz (Switzerland) and its catchment. Lake Brienz is a cold, deep oligotrophic peri-alpine lake that receives an annual load of approximat ...

Birkhauser Verlag Ag2007

A new robust oxygen-temperature sensor for aquatic eddy covariance measurements

Alfred Johny Wüest

The fragility of thin Clark-type glass microelectrodes used in aquatic eddy covariance measurements of benthic oxygen fluxes is a challenge when using this powerful technique. This study presents a new fast-responding dual oxygen-temperature sensor for edd ...

Association for the Sciences of Limnology and Oceanography (ASLO)2016

Shear-induced convective mixing in bottom boundary layers on slopes

Alfred Johny Wüest

Field data from a stratified lake demonstrate that buoyancy-driven convective mixing can be an important mechanism for the formation of well-mixed bottom boundary layers (BBLs) on slopes. Convective turbulence is caused by differential transport of stratif ...

American Society of Limnology and Oceanography2005

Measurements of eddy correlation oxygen fluxes in shallow freshwaters: Towards routine applications and analysis

Alfred Johny Wüest

Benthic fluxes of dissolved oxygen are measured in a shallow reservoir using the eddy correlation technique. Flux variations depict the diurnal production-consumption cycle, with daytime oxygen release following the solar radiation trend. The average night ...

Amer Geophysical Union2008

Trend-oriented sampling strategy and estimation of soluble reactive phosphorus loads in streams

Alfred Johny Wüest

[1] Nutrient transfer from soils to surface waters is associated with large, hydrologically induced fluctuations. Consequently, stream-based estimation of long-term changes in nutrient leaching is masked by variations of stream discharge. Using high-resolu ...

Amer Geophysical Union2005

Are surface temperature and chlorophyll in a large deep lake related? An analysis based on satellite observations in synergy with hydrodynamic modelling and in-situ data

Alfred Johny Wüest, Damien Bouffard, Isabel Blanca Sophie Kiefer

2018

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

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

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

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

Comment on An additional challenge of Lake Kivu in Central Africa - upward movement of the chemoclines by Finn Hirslund

Alfred Johny Wüest

In a paper published earlier this year, Finn Hirslund suggested to release degassed deepwater from methane harvesting to the surface layer of Lake Kiwi in order to counteract an observed slow rising of the chemoclines in the lake. In this comment, we prese ...

Pagepress Publ2012

Impact of deepwater mixing on hypoxia in Lake Geneva

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel

Lake Geneva is recovering from its eutrophic past but no significant trend in the areal hypolimnetic oxygen depletion rate has been observed over the last 30 years. Due to the large depth of 309 m, the lake is not mixed completely every winter which can le ...

2015

Lake surface cooling drives littoral-pelagic exchange of dissolved gases

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

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

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

Alfred Johny Wüest, Damien Bouffard, Hugo Nicolás Ulloa Sánchez, Oscar Rodrigo Sepúlveda Steiner

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

Resolving biogeochemical processes in lakes using remote sensing

Alfred Johny Wüest, Damien Bouffard, Theo Baracchini, Vincent Maurice Nouchi

Remote sensing helps foster our understanding of inland water processes allowing a synoptic view of water quality parameters. In the context of global monitoring of inland waters, we demonstrate the benefit of combining in-situ water analysis, hydrodynamic ...

2019

Gyre formation in open and deep lacustrine embayments: The example of Lake Geneva, Switzerland

David Andrew Barry, Alfred Johny Wüest, Ulrich Lemmin, Damien Bouffard, Amir Mehdi Razmi

Numerical simulations were carried out to investigate gyres within open lacustrine embayments subjected to parallel-to-shore currents. In such embayments, gyre formation occurs due to flow separation at the embayment’s upstream edge. High momentum fluid fr ...

Springer Verlag2017

Measurement and simulation of viscous dissipation in the wave affected surface layer

Alfred Johny Wüest

In this study we compare turbulence parameters from field observations and model simulations specifically under the influence of weak to moderate wind forcing and breaking short waves. The experiment was performed during 12 days under very weak stratificat ...

2005