Silica in sapropel sediments of small lakes across different landscape zones in the south of Western Siberia

Using IR-spectroscopy, the ratio of biogenic to silicate (terrigenous) silica was determined in small lakes of the Baraba Lowland, located in different landscape zones of the south of Western Siberia. These lakes exhibit substantially differing hydrochemical water parameters and sapropel composition. It was established that in sapropel deposits across all landscape zones, regardless of sapropel type, class, or genetic kind, the content of biogenic SiO₂ (SiO₂bio) ranges from 12% to 29% of the total silica content (siliceous sapropel: 12–29%; calcareous sapropel: 13–25%; mixed sapropel: 12–29%).