Department Surface Waters - Research and Management

Calcite precipitation in Swiss lakes


Calcite precipitation is the formation of inorganic calcium carbonate particles on the lake surface. Such precipitation can be triggered by algal blooms, as photosynthesis raises the pH of the lake water. The precipitation of calcite from the surface layer is an important component of the carbon cycle of lakes.
As early as 1978, an Earth observation satellite was used to map calcite precipitation in a lake, whose colour can be strikingly different from surrounding water. The improved measurement accuracy and revisit time of the latest generation of European Earth observation satellites allow a correspondingly more detailed description of precipitation processes.

Between 2019 and 2021, we observe daily satellite data during typical precipitation periods and measure on-site various water quality parameters during precipitation events. We use these novel measurements to improve the interpretation of optical satellite data on one hand, and to investigate the biotic and abiotic causes of precipitation processes on the other hand.