marine reservoir effect

The marine reservoir effect occurs because oceans contain "older" carbon—carbon that has been part of the ocean's carbon cycle for centuries. When scientists date marine organisms (like shells or fish bones) using radiocarbon dating, they often find these samples appear older than they truly are. This is because the carbon in the ocean is sometimes less "fresh" than atmospheric carbon. As a result, the marine reservoir effect can cause dates to be off by several hundred years, affecting the accuracy of archaeological or geological dating of marine materials.