Environmental influences on dietary carbon and C-14 ages in modern rats and other species

Diet can play a significant role in anomalous radiocarbon ages derived from bone and other tissues when the food web incorporates depleted C-14 reserv oirs, such as the marine environment. Dietary effects from a post-bomb carb on variation have also been found in modern invertebrates and populations o f Rattus exulans (Beavan and Sparks 1998). We now present the effect on abs olute percent modern (pMC) and the conventional radiocarbon age (CRA) of a modern aquatic/terrestrial food web in a volcanic zone of the North Island, New Zealand. At Lake Taupo, geothermal venting transfers C-14 depleted car bon to lake waters, which aquatic plants fix into the food chains depleted C-14 is shown to then pass on to shellfish, waterfowl, and Norway rat (Ratt us norvegicus). The geothermally induced C-14 variations from modern atmosp heric pMC and CRA can increase apparent C-14 ages by >2000 years.