Surface soil characteristics for six thermokarst chronosequences near Toolik Field Station and Noatak National Preserve, Alaska

Surface organic and mineral soil layers were sampled in retrogressive thaw slump disturbance scars and nearby undisturbed tundra to estmate the influence of this thermo-erosional--thermokarst--disturbance type on soil carbon (C) and nitrogen (N) pools. Within six independent sites, we identified multiple thaw slump scars and determined time after disturbance for each scar by (1) aging the population of tall deciduous shrubs rooted in the mineral soil and (2) by dating the basal layer of the re-accumulating soil organic matter. Within each scar or paired undisturbed tundra site, we sampled replicate soil profiles volumetrically and analyzed samples for horizon depth, coarse, fine and rock fractional contribution, pH, bulk density, moisture content, and C and N concentration.