Lake Geneva is the largest lake in Western Europe. An important question affecting the biodiversity of the lake is whether it is warming due to climate change. The lake’s surface area is about 580 km2, and heat exchange at the surface is the dominant mechanism for adding heat to the lake. Even if a warmer climate increases the temperature of surface waters, this water is buoyant and does not sink. Consequently, it does not affect the majority of the lake, which is 300 m deep.
Bois Chamblard’s location on the shores of Lake Geneva, with its gently sloping nearshore bathymetry, offers an excellent opportunity for investigation of near-shore hydrodynamic phenomena. ECOL is investigating cold-water density currents, which are generated in shallow shore regions particularly during winter months when rapid nearshore cooling occurs. The increased density generates negatively buoyant water masses near the shoreline that can propagate into deep areas of the lake and so can affect the lake’s overall energy balance. To investigate their formation and propagation, ECOL has set up a long-term in situ data gathering system, using fibre-optic cables and other equipment for temperature and current profile measurements.