Carbon uptake in aquatic plants deduced from their natural 13C and 14C content

Abstract

δ13C and 14C activity measurements were made on terrestrial, marsh and aquatic plants growing in the Plitvice Lakes, NW Yugoslavia. δ13C values were c-47‰ for aquatic mosses, which indicate that the carbon source was dissolved inorganic carbon (DIC) from alkaline karst waters, following a C3 pathway, and c-25‰ for marsh plants, indicating the carbon source was atmospheric CO2. 14C activity of true aquatic plants and submerged parts of helophytes was close to 14C activity of DIC, whereas that of emergent parts of helophytes and terrestrial plants was similar to atmospheric CO2 activity. Aquatic plants which use DIC in freshwater for their photosynthesis are not suitable for 14C dating, unless the initial activity of incorporated carbon is known. -from Authors