Biology subjects

Roslund, K.

Publications and source records attributed to Roslund, K..

3 recordsLinked to original sources

bioRxiv2026

Exploring Volatile Sulfur Production by Arctic Soil Bacteria and Emissions from Thawing Permafrost

Warming of the Arctic enhances microbial activity and the decomposition of large stocks of organic matter retained in permafrost soil. Resulting changes in the availability of sulfur may lead to increased emissions of volatile sulfur compounds (VSCs), which impact atmospheric particle and cloud formation, terrestrial and aquatic acidification, and malodor. Marine microbial production of dimethyl sulfide (DMS) has been studied for decades but other VSCs have been largely ignored, while VSC emissions from terrestrial ecosystems are even less studied. Currently, we lack fundamental understanding of the metabolic processes behind VSC production in permafrost soil bacteria, essential for estimating how emissions may change due to thawing. To fill this knowledge gap, we measured VSC emissions from thawing permafrost and three bacterial strains isolated from Greenlandic permafrost and biological soil crust. We show that the bacterial strains produced high levels of VSCs in vitro - including hydrogen sulfide, methanethiol, DMS, dimethyl disulfide, and dimethyl trisulfide. We further show that the same VSCs were also emitted from permafrost upon thaw. Metabolic pathway mapping of the bacterial strains revealed both inorganic sulfate reduction pathways and amino acid metabolism behind bacterial VSC production. High production of VSCs in the late-active and stationary phase suggests connection to secondary metabolism, except for DMS which was linked to early growth, and possibly, primary energy metabolism. Our findings suggest that thawing increases VSC emissions from permafrost soil, possibly leading to higher input of sulfur into the atmosphere from the warming Arctic in the future.

microbiology↗

bioRxiv2026

Volatile emissions from diverse estuarine bacteria share core compounds with a subset of strain-specific, low abundance compounds

Biogenic volatile organic compounds (BVOCs) are gases that influence atmospheric chemistry, nutrient cycling, and species interactions, yet the contribution of heterotrophic marine bacteria to marine BVOC emissions remains poorly constrained. In addition, the extent to which the volatilome is linked to bacterial phylogeny is unknown. Here, we characterize the volatilome of 16 heterotrophic bacterial strains isolated from Baltic Sea surface water, spanning Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Bacteroidota, and Actinomycetes. Headspace BVOCs were quantified under standardized growth conditions using Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). A broadly overlapping bacterial volatilome was identified, with compound composition and proportional abundance similar across many strains, irrespective of phylogeny. Namely, most strains shared a core set of abundant compounds with a subset of strain-specific, low abundance compounds. Acetone accounted for more than 50% of the emissions in most volatilomes. The remaining fraction of emissions were primarily comprised of other low-molecular-weight oxygenated compounds. Interestingly, two strains demonstrated strain-specific emission patterns, significantly diverging from the group in their emission rate and compound composition. Together, these findings suggest that marine heterotrophic bacteria may contribute a broadly conserved collection of BVOCs to the ocean-atmosphere interface, highlighting their role as a widespread source of trace gases in marine ecosystems.

microbiology↗

bioRxiv2025

Volatilomic complexity of three Northern Greenland bacterial isolates across a salt gradient

The High Arctic deserts of remote northern Greenland are expected to become warmer and wetter due to climate change. Precipitation changes will increase fluctuations in surface soil salinity, and the same happens for thawed permafrost soil where stable salt concentrations are replaced with fluctuating salinity during annual freeze-thaw cycles. Both have unknown effects on the microbial communities and their emissions of microbial volatile organic compounds (MVOCs). These compounds are produced from various pathways mainly as secondary metabolites and have ecological and climatic implications when released into the environment and the atmosphere. Thus, it is important to explore the effects of environmental changes, such as changes in salinity, on soil microbial communities and their MVOC emissions. Here, we characterize the MVOC production of three novel bacterial isolates from northern Greenland throughout their growth period under low, moderate, and high salt concentrations. We demonstrate that salinity significantly alters both the quantity and composition of MVOCs emitted by all three strains, including changes in the emissions of sulphur- and nitrogen-containing compounds, potentially leading to ecosystem nutrient loss. The observed changes in MVOC profiles suggest that changes in soil salinity due to climate change could alter microbial metabolism and MVOC emissions, with potential implications for Arctic nutrient cycling and atmospheric chemistry.

microbiology↗