Laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (LDI-FT-ICR MS) data, chemistry, and radiocarbon data of sequentially extracted sediment samples from the Rappbode predam reservoir.

Supporting information and processed and quality checked FT-ICR MS data for sequentially extracted sediment samples measured by LDI-FT-ICR MS (data underlying Figure 3 and figures in the SI file).

The processed (blank-corrected, base-peak-corrected, normalized) FT-ICR-MS data, including difference mass spectra used to study predicted sequential extract compositions, is provided as a separate table ("ds01.xlsx"). For explanations of variables and abbreviations used in this table, see the first sheet of the file.

Also provided are raw FT-ICR-MS data including the complete initial molecular formula assignments ("ds02_formulas.csv") and related aggregated values ("ds02_eval_summary.csv") as well as a definition file ("ds02_repository_file_definition.csv").

Sampling and measurement conditions are described in the companion paper (Tittel, J.; Rosenlöcher, Y.; Dadi, T.; Lechtenfeld, O. J.; Simon, C., THE AGE OF BURIED CARBON CHANGES THE GREENHOUSE GAS BUDGET OF A DAM. JGR Biogeosciences, 2024, submitted) or in the supporting information file ("SI_Revision_3.pdf"). The supporting information file includes the following content:

Text S1: LDI-FT-ICR-MS measurements and data processing.
Figure S1: Average molecular formula distributions of sediment samples.
Figure S2: Average molecular formula distributions of predicted extract compositions.
Figure S3: Average compositional data of Suwannee River Fulvic Acid.
Figure S4: Average molecular properties of sediment samples and predicted extract compositions.
Figure S5: Molecular insight into sedimentary organic matter after sequential extraction.
Figure S6: Correlations between molecular formula ion abundances and percent modern carbon.
Figure S7: H/O distribution of 14C-correlated molecules over mass.
Table S1: Location of sampled dams.
Table S2: OC burial in Rappbode predam.
Table S3: Data underlying Figure 1. Chemical and isotope measurements in depth–integrating sediment samples.
Table S4: Methane fluxes from the dam to the atmosphere.
Table S5: Radiocarbon in sediment OC in three preliminary studied dams.