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Soil respiration (SR) is one of the largest fluxes in the global carbon cycle, exceeding anthropogenic CO2 emission by more than an order of magnitude. Estimation of the heterotrophic component of SR is necessary to assess the carbon balance on the ecosystem and on the regional, national, and global scales. Within the framework of the most important national innovation project "Development of a System of Ground-based and Remote Monitoring of Carbon Pools and Greenhouse Gas Fluxes on the Territory of the Russian Federation," the first Russian national network is organized to monitor CO2 emission from soils and other linked parameters. The SR values and the relationship with the temperature of the upper 5- to 10-cm layer of soil (TS) are analyzed for the first time on the territory of Russia based on methodologically identical field measurements conducted simultaneously in the summer period (June–August 2023) at 75 monitoring sites in the different ecosystems in the main Russian bioclimatic zones from the tundra to the semidesert. The positive effect of soil temperature on the mean summer SR rate and the maximum monthly SR values is observed in the interval of mean TS from 10 to 20°C. Among the ecosystems studied, the lowest SR values are recorded in tundra and bog ecosystems, while the highest values are in the forest–steppe. Amongst the forest ecosystems, the lowest SR rates are characteristic of larch forests, while the highest SR values are observed in broadleaved forests of the forest–steppe zone. To clarify the regularities obtained, it is necessary to expand studies in all bioclimatic zones, but mainly in agrocenoses, tundra, and steppe ecosystems. [ABSTRACT FROM AUTHOR]

Sequential (S) and equal-time (ET) methods were applied to assess the temperature sensitivity of respiration of peat soils in different terrestrial ecosystems: southern tundra, northern taiga, and mixed coniferous–broadleaved forests. The Q10 values varied widely (1.3–4.8) and in case of the ET method decreased from northern to temperate latitudes. In the cold range (5–15°С), Q10 increased from the southern tundra (3.5) to the northern taiga (4.8) and then sharply decreased in the zone of mixed forests (2.5). Meanwhile, warm range (15–25°С) showed a clear decline of Q10 from northern to temperate latitudes: southern tundra (2.6) > northern taiga (1.6) > coniferous–broadleaved forests (1.3). Application of the S method resulted in low variability of Q10 values. Our results demonstrate a higher temperature sensitivity of the respiration of peat soils in northern latitudes as compared to that in the temperate zone. The Q10 values obtained in this study can be useful for calibration of regional carbon cycle datasets that consider the contribution of peat soils. [ABSTRACT FROM AUTHOR]

Dissolved inorganic carbon is an essential component of the carbon cycle, especially in the northern regions; however, its loss through water bodies is still rarely included in regional carbon models. The tasks of the work comprise a detailed coverage of the methodological approach of "headspace equilibration" for assessing the concentration of dissolved CO2 in soil and surface waters and estimation of the CO2 concentration range in waters of different geneses in the landscapes of northern Western Siberia. The performed methodological work has allowed a headspace equilibration protocol for measuring the CO2 concentration in waters to be elaborated and described with detailed calculations. The CO2 concentration in soil (suprapermafrost) and surface waters (river, bog, lake, etc.) ranges from 13 to 2983 µmol/L (274 to 57 000 µatm), and the vast majority of objects are supersaturated with CO2 relative to the atmosphere. The maximum concentrations are characteristic of suprapermafrost soil and bog waters, and the minimum concentrations are in the waters of aquatic ecosystems (thermokarst and forest lakes). A high variability of CO2 concentrations in waters necessitates a large number of measurements to provide adequate estimates. [ABSTRACT FROM AUTHOR]

Peatland soils in permafrost area are among the major components of global carbon cycle. In the case of predicted climate change, they may act as a significant source of greenhouse gases efflux. A four-year transplantation experiment (transplantation of soil cores of 20 cm in height and 10 cm in diameter to other natural positions) with the peat horizon was arranged to assess the temperature sensitivity of CO2 efflux from palsa peatlands in the north of Western Siberia. The rise in temperature by 7°С caused a positive feedback (30–70%) of CO2 efflux (measured by the closed chamber method) from transplanted soils as compared with the control. Temperature dependence of CO2 efflux from transplanted soils had the highest value (R2 = 0.8) in the first two years as a result of maximum contrast of temperature conditions between sites and decreased in the next two years. On the contrary, the temperature sensitivity of CO2 efflux from transplanted soils showed a high value during most of observations (Q10 = 3–6) thus indicating the increased rate of organic matter mineralization in peat soils of permafrost area for a long (four years) period. Our results might be useful for calibration of regional carbon cycle data sets that consider the contribution of organic permafrost-affected soils. [ABSTRACT FROM AUTHOR]

In the course of studies in typical forest ecosystems of the northern, middle, and southern taiga of Western Siberia performed at the peak of the growing season, the spatial variation of soil CO2 emissions and their relationships with the content of extractable and microbial soil carbon and soil hydrothermic parameters were estimated. The studied parameters of the soil carbon cycle are characterized by the high spatial variability in all the studied ecosystems. This fact indicates the need for a detailed investigation of the greenhouse gas soil emission in all ecosystems typical of a given natural zone. There is a statistically significant difference between the soils of the green-moss pine forests and the soils of the lichen pine forest of the northern taiga. In the green-moss pine forest, the carbon content of microbial biomass is 1.5 times higher (195 ± 24 and 127 ± 16 mg C/kg soil, respectively), the content of extractable carbon is 4 times higher (157 ± 25 and 41 ± 5 mg C/kg of soil, respectively), and the CO2 emission is 1.7 times higher (324 ± 20 and 190 ± 10 mg CO2/(m2 h), respectively) than those in the lichen pine forest. In the northern taiga zone, carbon dioxide emissions from soils in the green-moss pine forests are largely determined by the soil temperature; the role of soil moisture is less significant. In the soils of lichen pine forests, the CO2 emission is mainly controlled by the content of extractable carbon. Significant factors influencing the soil СО2 emission in forest ecosystems of the taiga zone are the content of extractable and microbial carbon and hydrothermic parameters of the soils. [ABSTRACT FROM AUTHOR]