Maintaining meromixis in Lake Pavin (Auvergne, France): The key role of a sublacustrine spring

作者:Bonhomme Celine*; Poulin Michel; Vincon Leite Brigitte; Saad Mohamed; Groleau Alexis; Jezequel Didier; Tassin Bruno
来源:Comptes Rendus Geoscience, 2011, 343(11-12): 749-759.
DOI:10.1016/j.crte.2011.09.006

摘要

Lake Pavin is a deep meromictic lake. Its water column is divided into two parts: the mixolimnion, which is subjected to mixing during seasonal overturns; and the monimolimnion which remains unmixed. Using high precision and high frequency temperature and conductivity profiles along with continuous temperature measurements, this study reveals the presence of a sublacustrine, intermittent cold spring at the bottom of the mixolimnion at a depth between 50 and 55 m. This cold-water input rises in the water column by saline convection. The use of a simple conceptual model, representing turbulent diapycnal diffusivity and convection correlated with the presence of the spring within the water column indicates its role in maintaining the meromixis characteristic of the lake on the intra-annual time scale. The spring also influences seasonal overturns and thus contributes to establish the depth of the mixolimnion-monimolimnion interface on the inter-annual time scale.

  • 出版日期2011-12