Can we see differences between the C activities of urban (Zagreb) and rural (Cvetković) sites (central Croatia)?

Radiocarbon (ΔC) was measured for four years (2019-2022) in Zagreb (Croatia) and in Cvetković village near Jastrebarsko (Zagreb County, Croatia) to see whether there are differences between the city site and the rural one because of the fossil fuel combustion. The δC was measured as grab samples once in a month in period December 2020-November 2022. The bomb-produced C has been globally distributed across the planet, but the combustion of fossil fuels that do not contain C causes a local effect of lowering ΔC.

Carbon isotope fractionation in karst aquatic mosses.

Radiocarbon activity (aC) and C composition (C) were measured in hygrophyte and mesophyte (land) mosses collected in the natural habitat of the Plitvice Lakes and along the Zrmanja and Krupa Rivers (typical continental and Mediterranean climates, respectively), Croatia. aC and C values of mosses, of atmospheric CO and dissolved inorganic carbon (DIC) were compared with contemporary data and with data from 30 years ago at the Plitvice Lakes when C activity of atmospheric CO was ∼30% higher. A positive correlation between aC and C was observed for all data reflecting the change of carbon isotopic composition in DIC along the water flows and in atmospheric CO regardless of the climatic regions and historic period.