How accurate are marine Δ14CDIC modelling approaches?

It has been estimated that Δ¹⁴C values of marine dissolved inorganic radiocarbon (Δ¹⁴C_DIC) are primarily governed by transport and radioactive decay. This implies that Δ¹⁴C_DIC can be considered as a radioconservative tracer which can be implemented into Earth system models without a full marine carbon cycle model. Here we evaluate the accuracies of the radioconservative modelling approach and of a further modelling approach which considers a different simplified representation of the marine radiocarbon cycle, presenting simulation results obtained with the ocean general circulation model FESOM and the marine biogeochemistry model REcoM. The relative uncertainties between the two simplified and the comprehensive treatments of the marine radiocarbon cycle are less than 5%. Therefore, the simplified Δ¹⁴C_DIC modelling approaches should be sufficiently accurate for many marine radiocarbon studies.