The Pulses of Soil CO 2 Emission in Response to Rainfall Events in Central Siberia: Revisiting the Overall Frost-Free Season CO 2 Flux
Boreal forests nowadays act as a sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to weather conditions and, specifically to ongoing climate warming. Extreme weather events such as heavy rainfalls or, conversely, heat waves during the growing season migh...
| Published in: | Forests |
|---|---|
| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
MDPI AG
2024
|
| Subjects: | |
| Online Access: | https://doi.org/10.3390/f15020355 https://doaj.org/article/00e25267a6b3432bbbc1e7112f8d68a2 |
| Summary: | Boreal forests nowadays act as a sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to weather conditions and, specifically to ongoing climate warming. Extreme weather events such as heavy rainfalls or, conversely, heat waves during the growing season might perturb the ecosystem carbon balance and convert them to an additional CO 2 source. Thus, there is an urgent need to revise ecosystem carbon fluxes in vast Siberian taiga ecosystems as influenced by extreme weather events. In this study, we focused on the soil CO 2 pulses appearing after the rainfall events and quantification of their input to the seasonal cumulative CO 2 efflux in the boreal forests in Central Siberia. Seasonal measurements of soil CO 2 fluxes (both soil respiration and net soil exchange) were conducted during three consecutive frost-free seasons using the dynamic chamber method. Seasonal dynamics of net soil exchange fluxes demonstrated positive values, reflecting that soil respiration rates exceeded CO 2 uptake in the forest floor vegetation layer. Moreover, the heavy rains caused a rapid pulse of soil emissions and, as a consequence, the release of additional amounts of CO 2 from the soil into the atmosphere. A single rain event may cause a 5–11-fold increase of the NSE flux compared to the pre-rainfall values. The input of CO 2 pulses to the seasonal cumulative efflux varied from near zero to 39% depending on precipitation patterns of a particular season. These findings emphasize the critical need for more frequent measurements of soil CO 2 fluxes throughout the growing season which capture the CO 2 pulses induced by rain events. This approach has inevitable importance for the accurate assessment of seasonal CO 2 soil emissions and adequate predictions of response of boreal pine forests to climatic changes. |
|---|