Influence of Moisture on the CO.sub.2 Flux from Palsa Mire Soils in the North of Western Siberia

• Published in: Eurasian soil science 2023-04, Vol.56 (4), p.434
• Main Authors: Matyshak, G. V, Chuvanov, S. V, Goncharova, O. Yu, Trifonova, V. A, Timofeeva, M. V, Isaeva, A. V, Tarkhov, M. O
• Format: Article
• Language: English
• Subjects: Ecosystems; Peat; Peat-bogs; Soil microbiology; Soil moisture; Soils
• ISSN: 1064-2293
• DOI: 10.1134/S1064229322602530

The influence of the moisture content on the CO.sub.2 emission from peat soils of palsa mires in the discontinuous permafrost area was studied in the north of Western Siberia (Nadym region). The СÐ.sub.2 flux was measured in Histic Cryosols of permafrost peatlands (palsas) and Fibric Histosols of surrounding bog using the closed chamber method for four years at the peak of the growing season (August). Despite a significant difference in the soil moisture (34.8 ± 13.2 and 56.2 ± 2.1% on average), no significant difference in the CO.sub.2 emission from these ecosystems was found in any of the observation years; the rates of emission averaged 199.1 ± 90.1 and 182.1 ± 85.1 mg CO.sub.2 m.sup.-2 x h.sup.-1, respectively. Experimental wetting or drying (with a twofold difference in the moisture content) of peat soils at the two sites via their transplantation to a different position showed no significant effect on the CO.sub.2 emission even three years after the beginning of the experiment. The absence of significant differences in the CO.sub.2 flux between the two different ecosystems was explained by the presence of permafrost and the influence of many multidirectional factors mitigating changes in the CO.sub.2 production by soils. An increased CO.sub.2 emission from the peat soils of bogs was possible due to the additional contribution of the methanotrophic barrier and the lateral runoff of dissolved CO.sub.2 over the permafrost table from the palsa toward the surrounding bog. The absence of response of the CO.sub.2 emission to a significant change in the soil moisture content may be indicative of a wide optimum of this characteristic for the microbiological activity of peat soils in the studied region. The obtained data suggest that, while studying CO.sub.2 fluxes in cryogenic soils of hydromorphic landscapes, it is necessary to take into account not only biogenic sources, but also other factors, often of a physical nature, affecting the balance of CO.sub.2 fluxes and CO.sub.2 emission from soils.