EGU22-429
https://doi.org/10.5194/egusphere-egu22-429
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Permafrost thawing and changes on peat biological activity of palsa mire in Western Siberia 

Stanislav Chuvanov1, George Matyshak2, Victoria Trifonova2, and Maria Timofeeva1
Stanislav Chuvanov et al.
  • 1Dokuchaev Soil Science Institute, Moscow, Russian Federation (stas.chuvanov@gmail.com)
  • 2Lomonosov Moscow State University, Moscow, Russian Federation

Peatlands comprise 19% of the permafrost area in the subarctic zone, they store 277 Pg of organic carbon. Peatlands in that area are represented by palsa mire. The palsa mire consists of frozen peat mounds (palsa), thermokarst depression and the wet bog without permafrost.

Climate change and thawing of permafrost leads to a change in soil moisture, both drying and wetting. This can lead to a change in the carbon balance of the ecosystem and increase or decrease the emission of greenhouse gases (CO2 and CH4).

The aim of the work was to study the effect of changes in soil moisture on the biological activity of palsa mire peat soils in the north of Western Siberia (65°18'52"N, 72°52'32"E). The studies were conducted in 2018-2021 in the northern taiga in the discontinuous permafrost zone.

The two palsas (Cryic Histosol) and the surrounding bog (Fibric Histosol) were examined. Palsa soils were characterized by high variability of the studied parameters; active layer thickness was 0.66±0.07 m, soil moisture - 30.98±2.49%, soil temperature - 8.31±0.45°C. The soils of the bog were characterized by the absence of permafrost, a higher soil temperature - 13.58±0.26°C and soil moisture - 74.59±0.26%. Despite the difference in the studied parameters of these ecosystems, no significant differences in biological activity were found (185.97±30.51 mgCO2/m2/h).

Based on field measurements, 3 plots were identified with the same type of vegetation and soil temperature, but significantly differ in soil moisture. Depending on soil moisture, the plots were named “Dry” (25.73±1.89%), “Wet” (38.44±0.70%) and “Moist” (53.09±1.06%). Biological activity did not vary significantly between the studied sites but had a multidirectional dynamic in different years. This shows the complexity of palsa, their multifactorial nature and an ambiguous response to changes in moisture.

An added experiment was set up to change soil moisture - transplantation. Measured of CO2 emissions from undisturbed peat soil of a large volume transferred from dry palsa to a wetting bog. And vice versa. The biological activity of the soils did not differ considerable both during wetting and draining. In different years, there was a vary dynamics in CO2 emissions.

According to the results of the study, with climate change, thawing of permafrost and palsa degradation, there will be no significant CO2 flux. This may be due to the multifactorial nature of ecosystems, a wide optimum of soil moisture for peat soils. The influence of additional factors is also significant: the size of the methanotrophic barrier, the transport of CO2 with solutions over the surface of the palsa permafrost.

How to cite: Chuvanov, S., Matyshak, G., Trifonova, V., and Timofeeva, M.: Permafrost thawing and changes on peat biological activity of palsa mire in Western Siberia , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-429, https://doi.org/10.5194/egusphere-egu22-429, 2022.

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