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Concept

Lac Nyos

Publications associées (15)

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

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

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

Controlling factors of phytoplankton distribution in the river–lake transition zone of a large lake

David Andrew Barry, Frédéric Charles Soulignac

River–lake transition zones have been identified as major drivers of phytoplankton growth. With climate change reducing the frequency of complete lake overturns, it is expected that the Rhône River, the main tributary to Lake Geneva (France/Switzerland), w ...

2023

Chimney‐Like Intense Pelagic Upwelling in the Center of Basin‐Scale Cyclonic Gyres in Large Lake Geneva

David Andrew Barry, Ulrich Lemmin, Rafael Sebastian Reiss, Seyed Mahmood Hamze Ziabari, Mehrshad Foroughan

Basin-scale quasi-geostrophic gyres are common features of large lakes subject to Coriolis force. Cyclonic gyres are often characterized by dome-shaped thermoclines that form due to pelagic upwelling that takes place in their center. At present, the dynami ...

2023

Density currents driven by differential cooling in lakes: occurrence, dynamics and implications for littoral-pelagic exchange

Tomy Doda

Cross-shore flows exchange water laterally in lakes, with ecological implications for the ecosystem. One example is the convective circulation induced by differential cooling, also known as the thermal siphon. This lateral flow forms when the sloping sides ...

EPFL2022

Oxygen depletion in Lake Geneva

Robert Vincent Schwefel

Low oxygen concentrations remain a global concern for the ecological health of lakes. High nutrient inputs and climate-induced changes in stratification and mixing are anthropogenic threats which largely impact aquatic oxygen budgets and overall ecosystem ...

EPFL2017

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

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

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

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

Methane formation and future extraction in Lake Kivu

Alfred Johny Wüest, Natacha Pasche

This chapter summarises the current knowledge on the vertical distribution of methane (CH4) and its formation in Lake Kivu. Additionally, we review the objectives and restrictions under consideration for sustainable extraction (safe, environmentally accept ...

Springer2012

Methane sources and sinks in Lake Kivu

Alfred Johny Wüest, Natacha Pasche

Unique worldwide, Lake Kivu stores enormous amounts of CH4 and CO2. A recent study reported that CH4 concentrations in the lake have increased by up to 15% in the last 30 years and that accumulation at this rate could lead to catastrophic outgassing by sim ...

Amer Geophysical Union2011

Double-diffusive convection in Lake Kivu

Alfred Johny Wüest

Double-diffusive staircases with a total of 230-350 mixed layers and sharp interfaces were observed in nine microstructure temperature profiles measured during February 2004 in Lake Kivu. The presence of these staircases at depths. 120 m indicates that dia ...

American Society of Limnology and Oceanography2010

Physical and biogeochemical limits to internal nutrient loading of meromictic Lake Kivu

Alfred Johny Wüest, Natacha Pasche, Beat Mueller

Lake Kivu is one of the large African Rift lakes situated between the Democratic Republic of the Congo and Rwanda. In its permanently stratified hypolimnion, unusually high methane concentrations have increased further in recent decades. Because methanogen ...

American Society of Limnology and Oceanography2009

Balancing nutrient inputs to Lake Kivu

Alfred Johny Wüest, Natacha Pasche, Beat Mueller

The primary production in meromictic Lake Kivu is sustained by external nutrient inputs and by internal loading due to upwelling caused by sub-aquatic sources. We present here the results of external loading of phosphorus (P), nitrogen (N) and silica (Si) ...

Elsevier Sci Ltd2009

Simulation of CO2 concentrations, temperature, and stratification in Lake Nyos for different degassing scenarios

Alfred Johny Wüest

[ 1] A large gas cloud erupted unexpectedly in 1986 from Lake Nyos, the larger of the two Cameroonian "Killer Lakes,'' with devastating consequences. Regular monitoring subsequently revealed that the deep water of the lake was gradually recharged with CO2. ...

Amer Geophysical Union2006