Carbon isotopes demonstrate multiple sources of dissolved inorganic carbon in shallow carbonate and marlstone aquifer assemblages

In groundwater, isotopes of dissolved inorganic carbon (DIC) are used to indicate both transit times and biogeochemical evolution of groundwaters. We applied a novel graphical method for tracking changes in δ13C and 14C of DIC in three distinct aquifer complexes identified in the Hainich Critical Zone Exploratory (CZE), a platform to study how water transport links surface and shallow groundwaters in carbonate and marlstone rocks in central Germany.