(Table 3) Stable carbon isotope and ...

From the dataset abstract

Soil profile samples are given in meters below surface (m b.s.). Before present (BP), i.e., before 1950. Samples were radiocarbon-dated at the National Ocean Sciences Accelerator Mass...

Source: (Table 3) Stable carbon isotope and radiocarbon composition of Lena Delta first terrace soil profiles and surface water particulate organic matter (2009–2011)