A new saltmarsh soil dataset comprising of geochemical and physical property
data from 752 soil samples collected through a sampling program supported by
citizen scientists has been brought together with existing data to make the first
national estimates of the surficial (top 10 cm) soil OC stock for Great British (GB)
saltmarshes. To allow the inclusion of secondary data in the soil stock estimate
a new bespoke organic matter to organic carbon conversion for GB saltmarsh
soil was developed allowing organic matter data measured using loss-onignition to be convert to organic carbon content. The total GB surficial soil OC
stock is 2.320 ± 0.470 Mt; English saltmarshes hold 1.601 ± 0.426 Mt OC,
Scottish saltmarshes hold 0.368 ± 0.091 Mt OC, and Welsh saltmarshes hold
0.351 ± 0.082 Mt OC. The stocks were calculated within a Markov Chain Monte
Carlo framework allowing robust uncertainty estimates to be derived for the
first time. Spatial mapping tools are available to accompany these stock
estimates at individual saltmarsh habitats throughout GB. This data will aid in
the protection and management of saltmarshes and represents the first steps
towards the inclusion of saltmarsh OC in the national inventory accounting of
blue carbon ecosystems.