Metabolomics analysis of unresolved molecular variability in stoichiometry dynamics of a stream dissolved organic matter

•Metabolomics-based analysis affords high-resolution molecular fingerprinting of DOM.•Stoichiometric ratio analysis provides low-resolution molecular classification.•Metabolomics analysis resolves variability in the molecular features of stream DOM.•Spatiotemporal changes in DOM stoichiometry are due to specific molecular subgroups.