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.

Наблюдаемый рост температуры, вызванный увеличением концентраций климатически активных (парниковых) газов в атмосфере, в первую очередь диоксида углерода (CO2) и метана (CH4), может быть причиной прогнозируемого высвобождения углерода, аккумулированного за тысячелетия на обширных территориях северных широт. Масштабы и длительность ожидаемого эффекта остаются открытым вопросом, что обусловлено спорадичностью количественных оценок потоков углерода. В работе отражены текущий статус, направления и основные результаты многолетних инструментальных исследований потоков углерода в экосистемах подзоны средней тайги Центральной Сибири, на базе Средне-Енисейского стационара Института леса им. В. Н. Сукачева СО РАН (обсерватории ZOTTO). Представлена динамика концентрации СО2и CH4в атмосфере с 2009 по 2020 г. Приведены данные чистого экосистемного обмена СО2для лесоболотных комп­лексов, свидетельствующие, что они выступают поглотителем (стоком) СО2атмосферы. Для репрезентативных экосистем дана оценка почвенных эмиссионных потоков СО2и сезонный ход фотосинтетической ассимиляции углерода доминантами подчиненного яруса растительности. Выявлены закономерности поведения растворенных форм углерода в водах ручьев, дренирующих олиготрофный и эвтрофный болотные массивы в районе исследований, представлены показатели эмиссии СО2с водной поверхности. The observed increase in temperature, caused by increasing concentrations of climate-active (greenhouse) gases in the atmosphere, primarily carbon dioxide (CO2) and methane (CH4), may be responsible for the projected release of carbon accumulated over millennia in large areas of northern latitudes. The scale and duration of the expected effect remains an open question, due to the sporadic nature of quantitative estimates of carbon flows. The work reflects the current status, directions and main results of long-term instrumental studies of carbon flows in the ecosystems of the middle taiga subzone of Central Siberia, on the basis of the Middle Yenisei experimental station of V. N. Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences (ZOTTO observatory). The dynamics of CO2and CH4concentrations in the atmosphere from 2009 to 2020 are presented. The values of net ecosystem exchange of CO2for forest-swamp complexes are given, indicating that they act as a sink (sink) of atmospheric CO2. For representative ecosystems, an assessment of soil CO2emission fluxes and the seasonal variation in the values of photosynthetic carbon assimilation by dominants of the subordinate vegetation layer are presented. The patterns of behavior of dissolved forms of carbon in the waters of streams draining oligotrophic and eutrophic swamps in the study area were revealed, and the values of CO2emission from the water surface were presented.

Lichens and other terrestrial photosynthetic unicellular organisms of the planet consume nearly 14.3 billion tons of atmospheric CO2. Due to climate change, such important components of the forest ground cover as lichens are very vulnerable. This study evaluates the photosynthetic activity in widespread lichens by measuring the indices of net photosynthesis, dark respiration, and prompt fluorescence. Hence, cryptogams of pine forests in Central Siberia near the Zotino tall tower observatory (ZOTTO) are characterized as highly active. Cladonia stellaris (Opiz.) Brodo and Cladonia rangiferina (L.) are the main representatives of ground cover species. The purpose of this study was to determine the photosynthetic activity in dominant species of ground cover lichens during a growing season. We found the seasonal dynamics of photosynthesis with the lowest values being observed in June, and the highest ones in August. Dark respiration peaks in June and is the lowest in September. Fluorescence values are within the range of 6.7 ± 0.3. The species under study that grow on podzol soils in pine forests show fast kinetic activation.

The peatlands in the northern hemisphere cover just 3% of the global landmass but their impact to the carbon emission is huge. The current climate changes exert influence on these ecosystems by changing water supply, temperature regime, plant growing activity and others. Nowadays studies predicted the important role of the northern bogs and peatlands as an additional source of atmospheric CO 2 . In our study we estimated how microrelief and microclimatic conditions can control the CO 2 emission from the bog area. We compared also the waterlogged bog conditions and forest ecosystem to find out the main drivers of soil emission dynamics during the summer season. The rate of CO 2 emission varies widely within bog area depending on the microrelief of the area: hollow – 0.74±0.03, ridge – 1.69±0.08 kg CO 2 m –2 . The comparative analysis versus the forest area showed that the upland parts of the bog area are not inferior to the forest area in terms of the emission rate. Moisture conditions determined the CO 2 efflux for the hollow site ( r =0.49, p<0.05 ) and forested area ( r =0.39, p<0.05 ). The temperature impact is observed for all sites and it is significant throughout the season.

Soil CO2 emission is one of the most important components of the global carbon cycle. This study analyzes the seasonal dynamics of soil emission for various land cover types in the middle taiga subzone of central Siberia during five growing seasons. It is shown that, throughout a vast area covered by pine forests and their derivatives formed on sandy soils, seasonal CO2 emission values are determined primarily by the moisture conditions and only secondarily by the temperature regime and ecosystem type. The effect of the forest type is manifested only under the most favorable moisture conditions. A new approach is proposed: divide the growing season into dry and moist periods depending on the threshold soil moisture for areas with different vegetation types.

Количество осадков или условия увлажнения территории являются основным лимитирующим фактором для всех биологических процессов в бореальных лесах [IPCC, 2001]. Почвенная эмиссия СО2 (Rs), как один из основных потоков углерода в экосистеме, существенно влияет на функциональную роль территории, меняя ее качественные характеристики из стока в дополнительный источник углерода [Davidson et al., 1998]. На сегодняшний день, большое число исследований указывают на то, что почвенная эмиссия СО2 в экосистемах, лимитированных поступлением воды, имеет импульсный ответ на поступление осадков [Yuste et al., 2003; Jarvis et al., 2007]. Влажность почвы может влиять на Rs нелинейно (параболически), ограничивая корневую и микробную активность в почве при низких уровнях влажности почвы и ограничивая коэффициент диффузии CO2 при высоких уровнях влажности почвы [Orchard and Cook, 1983; Maier et al., 2010]. Основное влияние условий увлажнения отмечается в течение вегетационного сезона, когда в наиболее активной фазе находятся все биогеохимические реакции [Yuste et al., 2003]. Сезонная динамика содержания воды в почве может варьироваться от года к году и влиять на значение Q10 [Davidson et al., 1998]. Было высказано предположение о том, что небольшое отклонение в Q10 может вызвать значительное смещение в оценке Rs [Xu и Qi, 2001]. Таким образом, применение Q10 в прогнозировании будущих потерь CO2 из почвы без учета годовых и сезонных колебаний определенных факторов (включая влажность почвы) может привести к значительным ошибкам. Кроме того, сезонная зависимость Rs от содержания воды в почве до сих пор плохо изучена, поскольку изменения температуры почвы и содержания воды часто коррелируют, а независимое влияние каждой переменной трудно обнаружить или интерпретировать [Davidson et al., 1998].

Boreal forests in Siberia cover more than 70% of the area of this region. Due to climate change these ecosystems represent a very sensitive and significant source of carbon. In the forests, the total ecosystem respiration tends to be dominated by the soil respiration, which accounts for approximately 70% of this large flux. Global models predict that the soil respiration will increase more than the total net primary productivity in response to climate warming and increasing precipitation. In consequence, the terrestrial carbon sink is expected to decline. However, for the Siberian boreal forest there is still a gap in understanding of the future response of soil emission to drought or overprecipitation conditions. In our study we estimate how various moisture conditions could change soil emission in the boreal zone. From field observation data we find optimal soil moisture conditions. The highest dependence between the soil temperature and soil emission rates has been obtained under the optimal soil moisture conditions.

Аннотация.Изучение почвенной эмиссии лесов бореальной зоны на сегодняшний день остается предметом научных дискуссий.Изменения температуры, увеличение резких перепадов в количестве осадков и интенсификация антропогенной активности -факторы, которые меняют биологическое равновесие в таежных экосистемах Сибири

The results of study of regeneration periods in pine forests after natural and anthropogenic disturbanses have been presented. It has been found that the rate of recovery depends on the type of disturbing factor. The differentiated effect of climatic factors (air temperature, amount of precipitation) on the growth rate of forests with different types of disturbances has been investigated.