Dataset - Limited site-specific blue carbon recovery following tropical seagrass restoration in Thailand.

This dataset accompanies the manuscript “Limited site-specific blue carbon recovery following tropical seagrass restoration in Thailand” and provides field and laboratory measurements used to quantify sedimentary blue carbon dynamics in restored tropical seagrass meadows. Sediment cores were collected from three habitat types: (1) restored seagrass meadows, (2) adjacent natural seagrass meadows, and (3) bare sand reference areas at several sites along the south coast of Thailand (Andaman Sea and Gulf of Thailand), including Bang Phat, Boonkhon Bay, Koh Teab, Modtanoi, and Phang Nga. For each sediment slice, we measured organic matter (OM, %) and organic carbon (OC, %) content along the profile, typically down to ~1 m depth. Whole-core organic carbon stocks were then calculated and expressed as Mg C ha⁻¹. To estimate sediment and carbon accumulation, a subset of cores was analysed for radionuclides, including total and excess 210Pb and 226Ra, from which compaction-corrected depths and depth profiles were derived. The dataset is organised into three main data tables plus supporting metadata: “Sediment properties” – slice-level data (n ≈ 838) including Site, SampleID, Restoration_year, Type (Bare_sand, Restored, Natural), OM(%), OC(%), and Depth(cm). “Organic carbon stock” – core-level data (n ≈ 26) summarising Site, CoreID, Restoration_year, Type, and TotalCarbonCore (Mg/ha). “Sediment and carbon accumulation” – slice-level radionuclide data (n ≈ 547) including Site, Type, CoreID, Compaction_corrected_depth (cm), Total 210Pb_mean, Total 210Pb_sd, Ra-226_mean, Ra-226_sd, Excess 210Pb_mean, and Excess 210Pb_sd. “Metadata” – definitions and units for all variables, including codes used for habitat type and measurement units.