Observations of a hydrothermal plume in a karstic lake

Abstract

A hydrothermal plume with vertical and horizontal length scales of ∼ 18 and ∼ 300 m, respectively, develops in a karstic lake. The plume is generated at the bottom of a basin that contains sediment in suspension, which is at a higher temperature than the water immediately above (the hypolimnion of the lake). The rising convective plume entrains colder hypolimnetic water and develops upward, until it reaches the base of the seasonal thermocline, carrying an important amount of sediment particles from the bottom, which are used as tracers to describe the spatial distribution of the plume. At the level of neutral buoyancy, the plume spreads laterally, as a horizontal baroclinic intrusion.