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Alfred Johny Wüest

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Publications associées (118)

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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

Stratification, mixing and transport processes in Lake Kivu

Alfred Johny Wüest

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top â ¼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ...

Springer2012

Tributaries affect the thermal response of lakes to climate change

Alfred Johny Wüest, Damien Bouffard

Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine trib ...

European Geosciences Union2018

Effects of upstream hydropower operation and oligotrophication on the light regime of a turbid peri-alpine lake

Alfred Johny Wüest

Anthropogenic activities in catchments can alter the light regimes in downstream natural waters, affecting light attenuation and the perceived optical properties of the waters. We analyzed the effects of upstream hydropower operation and oligotrophication ...

Birkhauser Verlag Ag2007

Nutrient cycling in Lake Kivu

Alfred Johny Wüest, Natacha Pasche

This chapter summarizes the knowledge on mixing and transport processes in Lake Kivu. Seasonal mixing, which varies in intensity from year to year, influences the top ∼65 m. Below, the lake is permanently stratified, with density increasing stepwise from ∼ ...

Springer2012

Ice-covered Lake Onega: effects of radiation on convection and internal waves

Alfred Johny Wüest, Damien Bouffard, Natacha Pasche

Early-spring under-ice convection in the Petrozavodsk Bay of Lake Onega (Russia) was investigated as part of an interdisciplinary research project conducted during March 2015. Measurements performed using a thermistor chain and vertical profiling sensors w ...

Springer Verlag2016

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

Alfred Johny Wüest, Damien Bouffard, 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

Seasonality of density currents induced by differential cooling

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

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

Evaluating oxygen fluxes using microprofiles from both sides of the sediment-water interface

Alfred Johny Wüest

Sediment-water fluxes are influenced by both hydrodynamics and sediment biogeochemical processes. However, fluxes at the sediment-water interface (SWI) are almost always analyzed from either a water-or sediment-side perspective. This study expands on previ ...

Association for the Sciences of Limnology and Oceanography (ASLO)2010

Penetrative Convection Modifies the Dynamics of Downslope Gravity Currents

Alfred Johny Wüest, Hugo Nicolás Ulloa Sánchez, Tomy Doda

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

Stability of a Double-Diffusive Interface in the Diffusive Convection Regime

Alfred Johny Wüest

In this paper, the authors explore the conditions under which a double-diffusive interface may become unstable. Focus is placed on the case of a cold, freshwater layer above a warm, salty layer [i.e., the diffusive convection (DC) regime]. The "diffusive i ...

Amer Meteorological Soc2012

Mechanical energy budget and mixing efficiency for a radiatively heated ice-covered waterbody

Alfred Johny Wüest, Damien Bouffard, Hugo Nicolás Ulloa Sánchez

Ice-covered waterbodies are far from being quiescent systems. In this paper, we investigate ice-covered freshwater basins heated by solar radiation that penetrates across waters with temperatures below or near the temperature of maximum density. In this sc ...

Cambridge University Press2018

Model-based data analysis of the effect of winter mixing on primary production in a lake under reoligotrophication

Alfred Johny Wüest, Camille Roland Marie Minaudo, Hugo Nicolás Ulloa Sánchez, Shubham Krishna

Nutrient loading, in combination with climate change are important drivers of primary productivity in lakes. Understanding and forecasting future changes in primary production (PP) in response to local and global forcing are major challenges for developing ...

ELSEVIER2020

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

Development of overturning circulation in sloping waterbodies due to surface cooling

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

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

Hypolimnetic oxygen depletion rates in deep lakes: Effects of trophic state and organic matter accumulation

Alfred Johny Wüest, Robert Vincent Schwefel, Beat Mueller

This study investigated the consumption of oxygen (O-2) in 11 European lakes ranging from 48 m to 372 m deep. In lakes less than similar to 100 m deep, the main pathways for O-2 consumption were organic matter (OM) mineralization at the sediment surface an ...

American Society of Limnology and Oceanography2020

Effects of impoundment on nutrient availability and productivity in lakes

Alfred Johny Wüest

We investigate the hydraulic alteration and the effect on primary productivity of the Hugh Keenleyside Dam built at the outlet of the Arrow Lakes (British Columbia, Canada) in 1967. Three dam-induced hydraulic changes have been identified as relevant: (1) ...

American Society of Limnology and Oceanography2007

Modeling of temperature and turbidity in a natural lake and a reservoir connected by pumped-storage operations

Alfred Johny Wüest

Pumped-storage (PS) systems are used to store electric energy as potential energy for release during peak demand. We investigate the impacts of a planned 1000 MW PS scheme connecting Lago Bianco with Lago di Poschiavo (Switzerland) on temperature and parti ...

Amer Geophysical Union2012

Large lakes as sources and sinks of anthropogenic heat: Capacities and limits

Alfred Johny Wüest

The goal of reducing carbon fuel and thereby saving energy will increase the use of lake water for heating and cooling of riparian infrastructures. This raises the question of which heat use designs meet the ecological and technical requirements for lakes, ...

2014

Spatial Heterogeneity of Methane Ebullition in a Large Tropical Reservoir

Alfred Johny Wüest

Tropical reservoirs have been identified as important methane (CH4) sources to the atmosphere, primarily through turbine and downstream degassing. However, the importance of ebullition (gas bubbling) remains unclear. We hypothesized that ebullition is a di ...

Amer Chemical Soc2011