Post-fire ecological consequences within the drained site of the Great Vasyugan Mire: retrospective water-thermal regime and pyrogenic disturbance estimation

Abstract

The aim of this research is to carry out an assessment of pyrogenic load after the fire event in 2016 within the drained site of Great Vasyugan mire (Bakchar bog, North-East part of The Great Vasyugan mire). Specifically, the objectives of this study were to: 1) perform a retrospective analysis of the water-thermal regime of the area under study according to monitoring data on the nearby site for estimation of development emergence of a fire-dangerous situation conditions; 2) determine the quantitative characteristics of vegetation and microtopography fire transformation based on field data; 3) estimate zone of contamination by combustion products and 4) estimate the hydrocarbons composition of mire and river water, peat and typical plants of the pyrogenic disturbed bog. The water-thermal retrospective analysis confirmed that in August 2016, the most favourable conditions for the emergence of a fire-dangerous situation were developed. The area of fire spread was 5.54 km2, including within the mire of 4.44 km2. The area of Zn and Pb pollution covers an area of 8 km, which is consistent with the prevailing wind direction and atmospheric deposition data for 2016. The zone of extreme pollution of heavy metal peat deposits is limited mainly by the zone of intensive burning of the surface, however, and beyond it, there was also a significant (2 times) Zn, Cd and Pb concentration (except Cu) increase, mainly due to the migration of elements with water flow. Carbon losses for the burned area of 1 square metre to a depth of 30 cm were about 3,800 gC/m2. Against the background of a decrease in the content of n-alkanes, their share in the composition of peat lipids of the burnt area increases slightly, and among them the content of homologues C23–C25 increases, C29–C33 decreases and the CPI value decreases.

Assessment of Present-Day Heavy Metals Pollution and Factors Controlling Surface Water Chemistry of Three Western Siberian Sphagnum-Dominated Raised Bogs

“…Studies have shown a significant increase in Zn and Pb in GVM river waters in the year following a fire event that occurred 8 km south of the sampling point in 2016. This is because 2016 was characterized by dry conditions and low water levels, which contributed to the prolonged duration of the fire event from August to October 2016 [30]. A periodic increase in the Cu content of up to 17.5 µg/L in the studied streams was also noted in January of 2017, which was also due to the fire event in 2016 and the regional transfer of pollutants from industrial enterprises in the region.…”

“…The most intense burning of the site occurred from August to October 2016, when 80% of the area was exposed to fire. The extent of the fire was 5.54 km 2 [30]. In addition, a fire also occurred in the eastern part of the GVM and the adjacent forest in October 2019, 20-27 km from the monitoring sites [31].…”

“…According to our data, the increased Zn, Pb and Cd in atmospheric depositions are also associated with their release into the atmosphere as a result of the 2016 and 2019 wildfires. In August-October 2016, there was a fire in the GVM, located 8-9 km south of the monitoring sites, and this caused increased Zn in dust deposits [30]. In 2017, bulk deposition of Zn halved in comparison with 2016.…”

Seasonal Stream Water Chemistry Response To Long-Term Forestry Drainage And Wildfire: A Case Study In A Part Of The Great Vasyugan Mire

“…Currently, due to ditch overgrowth, self-restoration has been observed (Sinyutkina 2021). In 2016, a fire burned an area of 3.10 km 2 in the Gavrilovka River basin, with a burnt layer thickness of 5-15 cm (Sinyutkina et al 2020). A similar pristine area of the GVM, located 3 km to the north within the 76 km 2 catchment area of the Klyuch River, a right-bank tributary of the Bakchar River, was selected as a background area.…”