Whole-soil warming drives depth-dependent molecular reorganization of dissolved organic matter in alpine grassland

This dataset supports the manuscript entitled “Whole-soil warming drives depth-dependent molecular reorganization of dissolved organic matter in alpine grassland”. The data include processed Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) results for soil dissolved organic matter (DOM) collected from an eight-year in situ whole-soil warming experiment in an alpine meadow on the northeastern Tibetan Plateau. Soil samples were collected from control and warmed plots across four depth intervals spanning the 0–100 cm soil profile: 0–10 cm, 10–30 cm, 30–60 cm and 60–100 cm.

The dataset contains sample metadata, assigned molecular formulae, peak mass-to-charge ratios, signal intensities or relative intensities, elemental groups, operational compound classes, and molecular traits used in the manuscript, including H/C, O/C, N/C, modified aromaticity index, double bond equivalents, Kendrick mass defect for CH2, nominal oxidation state of carbon, and carbon efficiency. The dataset also includes information needed to identify treatment-specific molecular assemblages and to reproduce the molecular composition, molecular trait, and depth-dependent response analyses reported in the study.

DOM was extracted from soil using Milli-Q water, purified by PPL solid-phase extraction, and analysed using negative electrospray ionization FT-ICR-MS. Molecular formulae were assigned after peak filtering and quality control according to the procedures described in the associated manuscript. These data are intended to support reproducibility and reuse in studies of soil DOM chemistry, alpine soil carbon cycling, climate warming experiments, and molecular-level biogeochemical responses to global change.