The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river.The freshwater reservoir effect

How does salt water affect carbon dating?

Mangerud, global variation in marine radiocarbon reservoir effect evident in shell carbonates are due to the incomplete mixing of upwelling water of “old” inorganic carbonates from the deep ocean where long residence times of more than 1,000 years cause depletion of carbon 14 activity through radioactive decay,