Étude de l’effet des épandages avec des produits résiduaires organiques (PROs) et de la diversité microbienne sur les émissions des composés organiques volatiles (COVs) par les sols

VOCs emissions play a pivotal role on the atmospheric pollution. Biogenic sources of VOCs are between 10 and 11 times higher than VOC emissions from anthropogenic sources. Recently, the importance of the characterization of the VOC fluxes by soils and microorganisms has been highlighted. Instead, VOCs emissions from soil and microorganisms are possible precursors of the particulate matter and the O3 formation. This work is focused on the characterization of the VOCs emissions by soils amended with OWPs over the long and short terms application. The influence of the microbial diversity in soil on VOCs emissions was also analysed. VOC emissions were detected using the PTR-QiTOF-MS technique and all the experiments were performed under controlled laboratory condition using dynamic chambers for the detection of the VOCs emissions from samples. The results showed that different OWPs released different quantity of VOCs emissions and also the chemical and physical properties of the soil were linked to the emissions. Analyses on the influence of microbial biodiversity on VOCs emissions have shown that while the microbial diversity was higher VOC emissions by soils were lower. Furthermore, the diversity of the VOCs decreases when the VOCs emissions by soil are higher. Finally, the study of the dynamics of VOC emissions from microcosms amended with fresh OWPs, showed that the VOC emission flux increased in the first 49 hours after the OWP amendment, due to a disturbance of the microbial community in the soil.Les émissions de COVs jouent un rôle central sur la pollution atmosphérique. Les sources biogéniques des COVs sont entre 10 et 11 fois plus élevées que les émissions des COVs provenant par des sources anthropiques. Récemment, l'importance de la caractérisation des flux de COVs par les sols et les microorganismes a été soulignée. En effet, les émissions des COVs provenant du sol et des microorganismes sont des possibles précurseurs des particules atmosphériques et de la formation d'O3. En particulier, ce travail est centré sur la caractérisation des émissions de COVs par des sols amendés avec des PROs en détectant les émissions toute de suite après l’apport, 1 an et 2 ans après l’apport des PROs. De plus, l'influence de la diversité microbienne du sol sur les émissions de COV a également été analysée. Les émissions de COVs ont été détectées à l'aide de la technique PTR-QiTOF-MS et la totalité des expériences a été réalisées dans des conditions de laboratoire contrôlées en utilisant des chambres dynamiques pour la détection des COVs émis par les échantillons. Les résultats ont montré que les différentes PROs émettent des quantités COVs variables et que les propriétés chimiques et physiques du sol influençaient également les émissions. L’analyse de l'influence de la biodiversité microbienne sur les émissions de COVs a montré que si la diversité microbienne est plus élevée, les émissions de COVs par les sols sont plus faibles. En outre, la diversité des COVs diminue lorsque les émissions de COVs par le sol sont plus élevées. Enfin, l'étude de la dynamique des émissions de COVs par de microcosmes récemment amendés avec du PRO, a montré que le flux des émissions de COV augmentait dans les premières 49 heures après l'apport des PRO en raison d'une perturbation de la communauté microbienne dans le sol

Microbial Volatile Organic Compounds (mVOCs) emission by soil

EABIOMEAGROSUPVolatile organic compounds (VOCs) have a central role in environmental pollution. In particular, biogenic volatile organic compounds (bVOCs) contribute 90% to global VOCs emissions. One of the most important sources of bVOCs are microorganisms. The aim of this bibliography research is to start studying the relationship between microorganisms and VOCs production. To achieve this purpose we begin answering two main questions: firstly, why microorganisms produce VOCs and what can affect their production; secondly, how the PTR-TOF-MS technique can be used for microbial VOC soil analysis. Literature shows that VOC production depends on the sugar degradation pathway, with emissions affected by soil temperature, soil moisture, nutrient and oxygen availability and physiological state of microorganisms. In order to detect VOC emissions a PTR-MS technique will be used. The PTR-TOF-MS is one of the newest and more sensible techniques that allow microbial VOC detection. Also a non-exhaustive summary of VOC production from bacteria and fungi detected by the PTR-MS technique is shown. Finally, future perspectives are discussed

Review : Microbial Volatile Organic Compounds (mVOCs) emissions by soil

EABIOMEINRAAGROSUPReview : Microbial Volatile Organic Compounds (mVOCs) emissions by soil. SOMmi

Profiles of volatile organic compound emissions from soils amended with organic waste products

Volatile Organic Compounds (VOCs) are reactive compounds essential to atmospheric chemistry. They are mainly emitted by living organisms, and mostly by plants. Soil microbes also contribute to emissions of VOCs. However, these emissions have not yet been characterised in terms of quality and quantity. Furthermore, long-term organic matter amendments are known to affect the microbial content of soils, and hence the quantity and quality of VOC emissions. This study investigates which and how much of these VOCs are emitted from soil amended with organic waste products (OWPs). Four OWPs were investigated: municipal solid waste compost (MSW), green waste and sludge co-compost (GWS), bio-waste compost (BIOW) and farmyard manure (FYM). These OWPs have been amended every two years since 1998 until now at a rate of ~4 tC ha−1. A soil receiving no organic inputs was used as a reference (CN). VOCs emissions were measured under laboratory conditions using a Proton Transfer Reaction-Quadrupole ion guide Time of Flight-Mass Spectrometry (PTR-QiToF-MS). A laboratory system was set up made of two Pyrex chambers, one for samples and the second empty, to be used as a blank. Our results showed that total VOC emissions were higher in BIOW than in MSW. Further findings outlined that the most emitted compounds were acetone, butanone and acetaldehyde in all treatments, suggesting a common production mechanism for these compounds, meaning they were not affected by the OWP amendment. We isolated 21 VOCs that had statistically different emissions between the treatments and could therefore be considered as good markers of soil biological functioning. Our results suggest that organic matter and pH jointly influenced total VOC emissions. In conclusion, OWPs in soil affect the type of VOC emissions and the total flux also depends on the pH of the soil and the quantity of organic matter

Microbial volatiles organics compounds (mvocs) emitted from soils amended with organic wastes

EABIOmEAGROSUPVolatile organic compounds (VOCs) have a central role in environmental pollution. They influence the chemistry and the composition of the atmosphere. In particular, biogenic volatile organic compounds (bVOCs) contribute 90% to global VOCs emissions1. Microorganisms contribute to bVOCs emissions and their emissions could be affected by different type of organic waste in soil2. The aim of this study is focused on determining the effect of organic wastes on VOC emitted by microorganisms in soils. The technique used for mVOC detection is the Proton Transfer Reaction-Time of Flight-Mass Spectrometry*(PTR-TOF-MS). PTR-TOF-MS technique provides on-line detection of VOC with two mains advantages: rapidity and the detection limit as low as 0.1 ppt by volume3. Five sample of the same soil with 4 different organic waste contributions were analyzed: (1) Municipal solid waste, (2) Green waste and sludge, (3) bio-waste, (4) farmyard manure and a control sample without organic waste. We also compared dry and humid conditions for each sample. Results show that VOC emissions are higher in humid samples than dry ones. Different VOCs such as acetone, Methyl Ethyl Ketone, acetaldehyde, toluene, ethanol and monoterpenes contribute between 60% and 80% of total emissions. Furthermore, other compounds emitted in smaller quantities are analyzed in order to identify a VOC profile belonging to each type of organic waste in soil. Finally, perspectives concerning the study of the correlation between mVOC emissions profiles with microorganism diversity and activity in soil will be discussed. Also analysis of soils genetic content and manipulation of genetic diversity of soils will be performed. 1 Roger Atkinson, ‘Atmospheric Chemistry of VOCs and NOx’, Atmospheric Environment, 34.12–14 (2000), 2063–2101 . 2 Mallard P. et al., ‘Impacts environnementaux de la gestion biologique des déchets : bilan des connaissances’ (2005). 3 Christos Soukoulis and others, ‘PTR-ToF-MS, A Novel, Rapid, High Sensitivity and Non-Invasive Tool to Monitor Volatile Compound Release During Fruit Post-Harvest Storage: The Case Study of Apple Ripening’, Food and Bioprocess Technology, 6.10 (2012), 2831–43 . *Financed by ANAeE France <http://www.anaee.com/

Reduced microbial diversity induces larger volatile organic compound emissions from soils

International audienceMicroorganisms in soil are known to be a source and a sink of volatile organic compounds (VOCs). The role of the microbial VOCs on soil ecosystem regulation has been increasingly demonstrated in the recent years. Nevertheless, little is known about the influence of the microbial soil community structure and diversity on VOC emissions. This novel study analyzed the effect of reduced microbial diversity in soil on VOC emissions. We found that reduced levels of microbial diversity in soil increased VOC emissions from soils, while the number of different VOCs emitted decreased. Furthermore, we found that Proteobacteria, Bacteroidetes and fungi phyla were positively correlated to VOC emissions, and other prokaryotic phyla were either negatively correlated or very slightly positively correlated to VOCs emissions. Our interpretation is that Proteobacteria, Bacteroidetes and fungi were VOC producers while the other prokaryotic phyla were consumers. Finally, we discussed the possible role of VOCs as mediators of microbial interactions in soil

Short-Term Effect of Green Waste and Sludge Amendment on Soil Microbial Diversity and Volatile Organic Compound Emissions

International audienceSoil amendments with organic waste products (OWPs) have been widely supported in Europe to improve soil fertility, causing wide changes in the microbial community structure and diversity, especially in the short-term period. Those changes are known to affect the volatile organic compound (VOC) emissions by soil. This work aimed to characterize, in terms of quantity and composition, the effect of green waste and sludge (GWS) application on soil VOC emissions and microbial community 49 h after the last GWS application. Two different soil samples were compared to test the effect of the soil history on VOC emissions and microbial communities. For this reason, we chose a soil that received GWS input for 20 years (GWS sample) and one that did not receive any organic input during the same period (CN sample). Furthermore, samples were manipulated to generate three microbial dilution diversity gradients (low, medium, and high). Results showed that Bacteroidetes phyla took advantage of the GWS application in all samples, increasing their relative abundance by 22% after 49 h, while the Proteobacteria phylum was penalized by the GWS amendment, passing from 58% to 49% relative abundance 49 h after the GWS application. Microbial structure differences between microbial diversity dilution levels remained even after the GWS application. GWS amendment induced a change in the emitted VOC profiles, especially in samples used to receiving GWS. GWS amendment doubled the VOC emissions from samples used to receiving GWS after 49 h. Finally, the microbial community was strongly correlated to the VOC emissions. Firmicutes, Proteobacteria, Actinobacteria, and Crenarchaeota were positively correlated (Pearson coefficient > 0.6), while other phyla, such as Bacteroidetes and Verrucomicrobia, were found to be negatively correlated (Pearson coefficient < −0.6) to the VOC emissions. After the addition of GWS, these correlations shifted from positive to negative and from negative to positive

Volatile organic compound fluxes over a winter wheat field by PTR-Qi-TOF-MS and eddy covariance

International audienceVolatile organic compounds (VOCs) contribute to air pollution through the formation of secondary aerosols and ozone and extend the lifetime of methane in the atmosphere. Tropospheric VOCs originate to 90 % from biogenic sources on a global scale, mainly from forests. Crops are also a potentially large yet poorly characterized source of VOCs (30 % of the VOC emissions in Europe, mostly oxygenated). In this study, we investigated VOC fluxes over a winter wheat field by eddy covariance using a PTR-Qi-TOF-MS with high sensitivity and mass resolution. The study took place near Paris over a 5-week period and included flowering, crop maturity and senescence. We found a total of 123 VOCs with fluxes 3 times above the detection limit. Methanol was the most emitted compound with an average flux of 63 µg m −2 h −1 , representing about 52 % of summed VOC emissions on a molar basis (36 % on a mass basis). We also identified ethanol, acetone, acetaldehyde and dimethyl sulfide among the six most emitted compounds. The third most emitted VOC corresponded to the ion m/z 93.033. It was tentatively identified as furan (C 6 H 4 O), a compound not previously reported to be strongly emitted by crops. The average summed VOC emissions were about 173 ± 6 µg m 2 h −1 , while the average VOC depositions were about 109 ± 2 µg m −2 h −1 and hence 63 % of the VOC emissions on a mass basis. The net ecosystem flux of VOCs was an emission of 64 ± 6 µg m −2 h −1 (0.5 ± 0.05 nmol m −2 s −1). The most deposited VOCs were identified as hydroxyacetone, acetic acid and fragments of oxidized VOCs. Overall, our results reveal that wheat fields represent a non-negligible source and sink of VOCs to be considered in regional VOC budgets and underline the usefulness and limitations of eddy covariance measurements with a PTR-Qi-TOF-MS