High-resolution monitoring of water temperature and oxygen concentration in Lake Murten (Switzerland)
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Lake Murten is located in the Lake District in western Switzerland and so far, it has been poorly investigated. The Environmental Service of Fribourg (SEn) has monitored this lake once a month for several years by water profiles (water temperature, pH, dissolved oxygen, conductivity) at its deepest part. The SEn identified the stratification of water masses as one of the main causes for oxygen consumption in the hypolimnion. In the present study, a Lander System was deployed in Lake Murten from April to September 2015 at 20 m depth at the northwestern part of the lake to monitor water temperature and dissolved oxygen at higher resolution (30 s interval). These records were compared with time series of atmospheric parameters like atmospheric temperature, wind speed and precipitation. A clear correlation of lake temperatures with wind speed was observed during the Spring and Autumn. The water mass stratification evolved through the season and reached its peak during Summer, preventing surface turbulences to reach the deeper part (20 m) of the water column and to partially oxygenate the metalimnion.
KeywordsWater parameters Stratification Monitoring High-resolution Lake Murten
We gratefully acknowledge the Environmental Service of Fribourg (SEn) for their valuable studies during the years contributing to a better understanding of Lake Murten. We thank Pierre Schaer for his valuable help and for giving access to his boat for deployment, recovery and maintenance of the Lander System. We thank the Swiss National Science Foundation (SNSF) project 200021_149589 and the Department of Geosciences for providing financial and technical support. We acknowledge the editor Prof. Wilfried Winkler for his assistance and two anonymous reviewers for their valuable comments that helped to considerably improve this manuscript.
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