Wildfire-Related Changes of Bog Water Chemistry in Forest-Tundra and Taiga Zones of Western Siberia

The relevance of the study is due to the need to assess changes in waters chemical composition of bogs under the influence of the pyrogenic factor. The aim of the work to study bog water chemistry of postfire areas in the forest-tundra and taiga zones of Western Siberia, to analyze the conditions for its formation and patterns of spatial variation depending on the degree of surface burnout. The objects of study were the Great Vasyugan bog, Ust-Bakchar bog, and palsa bog near the village of Pangody. Laboratory analysis of the water chemical composition was carried out by titrimetry, spectrophotometry, and flame photometry at the Laboratory and Analytical Center of the Siberian Research Institute of Agriculture and Peat. Analysis of the content of Cu, Pb, Cd, Zn, P, and Mn in water samples was carried out by inductively coupled plasma mass spectrometry at the Plasma Chemical Analytical Center. Statistical analysis of the data was carried out using the nonparametric Wilcoxon test, cluster analysis, and principal component analysis. Studies have shown that an indicator of the influence of the pyrogenic factor on the water chemistry is an increase in pH, total dissolved solids and concentrations of K⁺ and \({\text{SO}}_{4}^{{2-}}\) , as well as Са²⁺, Mg²⁺, \({\text{HCO}}_{3}^{-}\) , Fe_total, \({\text{NO}}_{3}^{-}\) , P, Mn, Zn, Cd, Cu, and Pb. During the self-restоratiоn of bogs after a fire, a gradual increase in the concentrations of \({\text{NH}}_{4}^{ + }\) , DOC and COD is noted in the waters. Analysis of data showed 4- to 16-times higher concentrations of Са²⁺, Mg²⁺, K⁺, Na⁺, \({\text{NH}}_{4}^{ + }\) , \({\text{NO}}_{3}^{-}\) , Fe_total, \({\text{HCO}}_{3}^{-}\) , DOC and COD, P, Mn, Cu, Zn, Cd, and Pb in the waters of the palsa bog in the forest-tundra zone in comparison with water samples taken in the burnt areas in the taiga zone of Western Siberia. Factor analysis showed that the leading factor in the formation of water chemistry is the degree of surface burnout, water temperature, and water table levels. Thus, studies have shown that the water chemistry of postfire bogs largely depends on the degree of surface burnout, the initial genetic characteristics of the bog, and the time elapsed after the fire.