Increase of 14C Activity of Dissolved Inorganic Carbon Along a River Course

From the 12th International Radiocarbon Conference held in Trondheim, June 24-28, 1985.Results of measurements for 3 years (1981-1983) of 14C activity of dissolved inorganic carbon (DIC) in water samples from the Korana River, as well as that of recent tufa and aquatic plants, showed that 14C concentration increases from karst spring to the estuary. A model describing the increase of 14C activity was developed assuming that the increase is due to the exchange of the dissolved CO2 in stream water with atmospheric CO2 and to dissolution of CO2 from the decay of organic material and root respiration. It is possible to distinguish these two contributions by measuring the delta-13C values of DIC in water. As expected, our data show that the exchange process between atmospheric CO2 and DIC dominates at rapids and waterfalls, while biologic contribution is much higher in lakes and along the lowland flow of the Korana River. Agreement between the calculated and the measured activities supports the proposed mechanisms of chemical and isotopic exchanges in stream waters.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information.Migrated from OJS platform February 202