Environmental Isotope Studies at the Plitvice Lakes

Abstract

For more than 40 years, isotope research of environmental compartments has been conducted at the Plitvice Lakes. Though it started with initial idea to radiocarbon date tufa, the emerged problems regarding tufa dating eventually led to isotope research of water and carbon cycles, dating of tufa and sediments by other isotopes, using sediment and tufa as natural archives of past climate and environmental conditions. Water from different compartments, precipitation, groundwater, surface and lake water were analyzed by oxygen (stable 18O) and hydrogen isotopes (stable 2H, radioactive 3H). Research have been conducted by carbon (stable 13C, radioactive 14C) isotopes in atmospheric CO2, terrestrial plants and soil, in dissolved inorganic carbon in groundwater and lake water and in aquatic plants, in tufa and in organic and inorganic fraction of lake sediments. Along with carbon isotopes (13C and 14C), 18O and 15 N were also used for analyses of the sediment carbonate and organic fraction, respectively. For dating of recent lake sediments 137Cs and 210Pb were used, while 14C and U/Th were used to date tufa.