MELIMEX, AN EXPERIMENTAL HEAVY-METAL POLLUTION STUDY - VERTICAL MIXING IN A LARGE LIMNO-CORRAL

In a limno-corral (diameter 12 m, depth to sediments 10 m), located in Baldeggersee (Switzerland), vertical mixing has been measured during more than one year and compared to the conditions in the open lake (maximum depth 65 m, surface area 5.3 km2). The temperature method by McEwen and Hutchinson yields Kz values between 5×10-2 cm2s-1 at the upper boundary of the thermocline and 2×10-3 cm2s-1 at the bottom, a value near the molecular diffusion of heat at 4°C (1.36×10-3 cm2s-1). Kz calculated from profiles of excess radon-222 generally agree with those from the temperature data. Compared to the open lake, the corral has a more shallow epilimnion. However, during calm meteorological conditions, vertical mixing in the upper 10 m is similar outside and inside the corral. © 1979 Birkhäuser Verlag.