17:15 〜 18:45
[ACG37-P06] Influence of seasonal warming treatment on CO2 fluxes in a semi-arid grassland ecosystem in Mongolia
キーワード：気候変動、光合成、乾燥地、チャンバー
Global warming is considered to change the timing of snow melting and the thawing of frozen soils in spring. However, little is known about the influence of this kind of seasonal warming on carbon fluxes in semi-arid ecosystems, an important contributor to the interannual variability of global land carbon sink. This study was conducted in a semi-arid grassland ecosystem in Bayan-Unjuul (47°02'32" N, 105°56'58"E) in central Mongolia to examine the influence of seasonal warming on CO2 fluxes. In the study site, we set four treatments (n = 6) using hexagonal open-top chambers (OTCs): continuous warming; summer (May to August) warming; winter (August to next May) warming; and no warming (control). In addition to the passive warming by OTCs in the daytime, we set heat cables inside each OTC for nighttime warming. Those warming treatments were started in August 2022. In mid-August 2023, we measured CO2 fluxes in each plot under a clear sky using a portable automated chamber measurement system consisting of a transparent rectangular chamber and a control box that includes a datalogger (CR1000X, Campbell Scientific Inc., Logan, UT, USA) and a CO2 analyzer (LI-830, LI-COR, Lincoln, NE, USA). As a result, there was no significant difference in CO2 fluxes (gross primary production, ecosystem respiration, and net CO2 exchange) among treatments. However, this result was based on one-time campaign measurement data, and further measurements and analysis are necessary to evaluate the influence of seasonal warming on CO2 fluxes because the condition of vegetation in the study site is considered to change dramatically according to the weather conditions of the year like the frequency, timing, and the amount of rainfall.