Abiotic and biotic drivers of microbial respiration in peat and its sensitivity to temperature change

Qian Li (1, 2) , Fabien Leroy (1, 2) , Renata Zocatelli (1, 2) , Sébastien Gogo (1, 2) , Adrien Jacotot (1, 2) , Christophe Guimbaud (3) , Fatima Laggoun-Défarge (1, 2)

1 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
2 Biogéosystèmes Continentaux - UMR7327
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

The effect of climate change on peatlands is of great importance due to their large carbon stocks. In this study, we examined microbial biomass and effect of temperature and O2 availability on soil respiration of surface and subsurface Sphagnum peat. The interactive effect of biotic and abiotic factors significantly affects soil respiration. Increasing temperature enhanced the microbial respiratory activity and thus the soil respiration, while there is a temperature threshold. The more decomposed subsurface peat showed a lower CO2 production due to less labile carbon and lower microbial biomass, but a higher temperature sensitivity. Q10 of aerobic respiration increased from 1.93 ± 0.26 in surface to 2.20 ± 0.01 in subsurface peat. The linear relationship between Q10 and depth in the uppermost 50 cm peat section can be used to improve the estimation of CO2 production in peat profiles.

Keywords: soil respiration; temperature sensitivity; microbial biomass; peatland

Domains: Sciences of the Universe [physics]; Sciences of the Universe [physics]; Continental interfaces, environment

Qian Li, Fabien Leroy, Renata Zocatelli, Sébastien Gogo, Adrien Jacotot, et al.. Abiotic and biotic drivers of microbial respiration in peat and its sensitivity to temperature change. Soil Biology and Biochemistry, 2021, 153, pp.108077. ⟨10.1016/j.soilbio.2020.108077⟩. ⟨insu-03013568⟩