Assessment of Greenhouse Gas Emissions into the Atmosphere from the Northern Peatlands Using the Wetland-DNDC Simulation Model: A Case Study of the Great Vasyugan Mire, Western Siberia

Abstract

The peatlands of Western Siberia occupy an area of about 1 million km2 and act as important regulator of carbon exchange between the earth and the atmosphere. Extrapolation of the results of discrete field measurements of CO2 fluxes in bog ecosystems to such a territory is a difficult task, and one of the ways to overcome it is to use a simulation model such as DNDC. However, using this model with a specific territory requires ground verification to confirm its effectiveness. Here, we tested the DNDC model on the largest pristine bog ecosystem of the world, the Great Vasyugan Mire (GVM). The GVM of western Siberia is virtually undisturbed by anthropogenic activity and is the largest bog of Northern Eurasia (53,000 km2). Based on various ground-based observations, the performance of the Wetland-DNDC model was demonstrated (Thale coefficient 0.085 and R2 = 0.675 for CO2). Model input parameters specific to the GVM were constrained and model sensitivity to a wide range of input parameters was analyzed. The estimated annual terrestrial carbon fluxes in 2019 from the GVM test site are mainly controlled by plant respiration (61%) and forest floor degradation (38%). The net CO2 emission flux was 8600 kg C ha−1 year−1, which is in line with estimates from other independent studies.

Soil Water Regime, Air Temperature, and Precipitation as the Main Drivers of the Future Greenhouse Gas Emissions from West Siberian Peatlands

“…Statistical processing of the results from the Wetland-DNDC simulation model showed that the modeled hydrothermal factors (T, P, and WT) are not correlated with each other, and the model efficiency is high (R 2 = 0.675)-as shown in the earlier publication [16]-therefore, our next target was a computer simulation of different hydrothermal scenarios and estimation of greenhouse gas fluxes under the change of these hydrothermal parameters (T, P, and WT).…”

“…At the land surface, the Sphagnum mosses cover 95 to 100%, of which 80% is contributed by Sphagnum fuscum, with little presence of Sphagnum divinum and Sphagnum angustifolium. Some more details on the study site are presented in our earlier publication [16].…”

“…At the land surface, the Sphagnum mosses cover 95 to 100%, of which 80% is contributed by Sphagnum fuscum, with little presence of Sphagnum divinum and Sphagnum angustifolium. Some more details on the study site are presented in our earlier publication [16]. In situ measurements of CO2 fluxes were made by a chemical absorption method based on capturing CO2 emitted from a land surface with NaOH [23] once a month dur- In situ measurements of CO 2 fluxes were made by a chemical absorption method based on capturing CO 2 emitted from a land surface with NaOH [23] once a month during the growing season (from 25 May to 17 October) in 2019.…”

“…Wetland-DNDC has shown high performance in a recent study of the Great Vasyugan Mire [16]. In this study, the most significant model input parameters were identified to estimate carbon fluxes and net ecosystem exchange (NEE), and it opens perspectives for use as a prognostic model with the set-up of different scenarios of climate change.…”

“…There are a few simulation (ecosystem) models that have shown good performance in simulating natural processes in wetland ecosystems, which work with a range of climate change scenarios [11,12]. Wetland-DNDC [13][14][15][16] has the capability to predict CO 2 and CH 4 emissions under conditions of climate change, change hydrological conditions, and has various biogeochemical features of soils and for different vegetation (land cover types) [17].…”