Production of Oxygen- and Sulfur-Containing Volatile Organic Compounds by Marine Bacteria From Coastal Seawater

Abstract

Previous studies primarily examined volatile organic compound (VOC) production and consumption in isolated cultures or bulk seawater. In contrast, this study focused on natural bacterial assemblages, excluding phytoplankton, to elucidate bacterial contributions to VOC cycling in marine ecosystems. Marine bacteria have traditionally been viewed as contributors to the degradation of oxygenated volatile organic compounds (OVOCs), with their role as producers being less understood. By incubating marine bacterial assemblages with ¹³C-glucose as a carbon source, we identified VOC production derived exclusively from bacterial metabolic processes with distinct VOC profiles generated during different phases. During glucose drawdown, marine bacteria contributed to acetaldehyde production at a net production rate of 6.5 nM d⁻¹ despite functioning as rapid decomposers with a turnover time of 1.0 days. After glucose drawdown, acetone was produced at a rate of 84.0 nM d⁻¹ with a much lower degradation rate at 2.1 nM d⁻¹ and a turnover time of 68 days, suggesting that bacteria play a greater role in acetone production than degradation. Sulfur-containing VOCs (VOSCs), including dimethyl sulfide (DMS) and methanethiol, were also produced after glucose drawdown. These findings suggest that natural bacterial assemblages can generate acetone and VOSCs from their metabolic byproducts. By revealing the dual role of marine bacteria as both producers and degraders of VOCs, this study advances our understanding of their broader ecological and biogeochemical significance.