Publication

Sediment oxygen uptake in Lake Geneva

Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel
2014
Conference Papers

Abstract

Between 1960 and 1980, the trophic state of Lake Geneva (situated between France and Switzerland) has changed from oligotrophic to eutrophic. Since then, the areal hypolimnetic oxygen demand of 1.31 gm-2 d-1 is now the highest measured in Switzerland and low oxygen contents of less than 4 mg l-1 regularly occur in the deepest parts (300m deep). Oxygen depletion is to a large amount driven by sediment oxygen uptake (SOU). In a large and complex lake like Lake Geneva, SOU can vary significantly temporally and spatially and is strongly dependent on the diffusive boundary layer (DBL) thickness which in turn varies with bottom boundary layer (BBL) currents.

Official source

https://infoscience.epfl.ch/entities/publication/70b36346-10da-4c12-96b4-7a3f88c65ece

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Alfred Johny Wüest, Damien Bouffard, Robert Vincent Schwefel
2014
Conference Papers

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/70b36346-10da-4c12-96b4-7a3f88c65ece

About this result

Related concepts (16)

Boundary layer

In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condition (zero velocity at the wall). The flow velocity then monotonically increases above the surface until it returns to the bulk flow velocity. The thin layer consisting of fluid whose velocity has not yet returned to the bulk flow velocity is called the velocity boundary layer.

Trophic level

The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it is from the start of the chain. A food web starts at trophic level 1 with primary producers such as plants, can move to herbivores at level 2, carnivores at level 3 or higher, and typically finish with apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a food "web".

Trophic cascade

Trophic cascades are powerful indirect interactions that can control entire ecosystems, occurring when a trophic level in a food web is suppressed. For example, a top-down cascade will occur if predators are effective enough in predation to reduce the abundance, or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore). The trophic cascade is an ecological concept which has stimulated new research in many areas of ecology.

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