Soil VOC emissions of a Mediterranean woodland are sensitive to shrub invasion

Abstract

Many belowground processes, such as soil respiration and soil-atmosphere VOC (volatile organic compounds) exchange, are closely linked to soil microbiological processes. However, little is known about how changes in plant species cover, i.e. after plant invasion, alter these soil processes. In particular, the response of soil VOC emissions to plant invasion is not well understood.• We analysed soil VOC emissions and soil respiration of a Mediterranean cork oak (Quercus suber) ecosystem, comparing soil VOC emissions from a non-invaded Q. suber woodland to one invaded by the shrub Cistus ladanifer. Soil VOC emissions were determined under controlled conditions using online proton-transfer time-offlight mass spectrometry. Net soil VOC emissions were measured by exposing soils with or without litter to different temperature and soil moisture conditions.• Soil VOC emissions were sensitive to C. ladanifer invasion. Highest net emission rates were determined for oxygenated VOC (acetaldehyde, acetone, methanol, acetic acid), and high temperatures enhanced total VOC emissions. Invasion affected the relative contribution of various VOC. Methanol and acetaldehyde were emitted exclusively from litter and were associated with the non-invaded sites. In contrast, acetone emissions increased in response to shrub presence. Interestingly, low soil moisture enhanced the effect of shrub invasion on VOC emissions.• Our results indicate that shrub invasion substantially influences important belowground processes in cork oak ecosystems, in particular soil VOC emissions. High soil moisture is suggested to diminish the invasion effect through a moisture-induced increase in microbial decomposition rates of soil VOC.

Effects of drought and recovery on soil volatile organic compound fluxes in an experimental rainforest

“…After the second rain event C 3 H 8 OS soil fluxes recovered to pre-drought levels. Soil emissions of C 4 H 10 S, tentatively identified as isopropyl methyl sulfide, have been previously reported but its origin is not well understood 38 , 39 . Mancuso et al, 38 suggested C 4 H 10 S as a potential intermediate product of the dimethyl sulfide metabolic pathway.…”

Correlation between microbial communities and volatile organic compounds in an urban soil provides clues on soil quality towards sustainability of city flowerbeds

“…The plethora of detected VOCs from soil collected from the selected flowerbeds suggested the presence of a complex substrate, i.e. , urban soils, where belowground processes, such as microbial respiration and exchange of VOCs, occurred [ 51 ]. However, and unexpectedly, it has been recently demonstrated that the amounts of various VOCs released from soils rose while the amount of microbial diversity in the soil decreased [ 52 ].…”