Is litter biomass a driver of soil volatile organic compound fluxes in Mediterranean forest?
Résumé
Soil biogenic volatile organic compound (BVOC) emissions have been studied in different biomes, showing that their emissions are considerable. However, so far, previous studies have neglected the role of litter accumulation (considered here to be the amount of litter) in soil BVOC fluxes, and most of them refer to coniferous and evergreen forests, while litter emissions from Mediterranean deciduous forests remain poorly explored. To fill these gaps, the present work aimed to study BVOC fluxes in a Mediterranean deciduous forest, with particular attention being paid to the relationships between litter biomass accumulation in soil, microbial abundance, and soil BVOC fluxes. Measurements were performed in southern France in the downy oak (Quercus pubescens Willd.) forest of the Observatoire de Haute Provence (O3HP) during the late spring of 2023 using dynamic chambers coupled to an online proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). We investigated in situ daily BVOC fluxes from bare soil and different litter biomasses mimicking current, lower, or higher litter production as both decreases and increases in litter accumulation are expected in the Mediterranean region under the current context of climate change and greening management policies. The results showed a high BVOC diversity, with more than 135 emitted compounds. For a large majority of the measured compounds, fluxes were negative, suggesting that soil (bare soil covered by litter) takes up compounds through biochemical and/or physical processes. Some compounds, such as acetone, methanol, or sesquiterpenes, increased with increasing litter biomass, suggesting the importance of considering litter accumulation when assessing soil BVOC emissions from Mediterranean deciduous forests. Microbial abundance was highlighted as a potential driver of this relation between litter biomass and VOC fluxes.
Auteurs, date et publication :
Auteurs Manon Rocco , Julien Kammer , Mathieu Santonja , Brice Temime-Roussel , Cassandra Saignol , Caroline Lecareux , Etienne Quivet , Henri Wortham , Elena Ormeño
Publication : Biogeosciences
Date : 2025
Volume : 22
Issue : 14
Pages : 3661-3680