Carbon dating live snail
These carbon 14 atoms then instantaneously react with oxygen present in the atmosphere to form carbon dioxide.
The carbon dioxide formed with carbon 14 is indistinguishable from the carbon dioxide with the other carbon isotopes; hence the pathway of carbon 14 into the ocean, plants, and other living organisms is the same as that of carbon 12 and carbon 13.
Marine organisms and those who consume them take in carbon 14 from the exchange process of carbon 14 (in the form of carbon dioxide) in the atmosphere and the ocean or any body of water.
However, carbon 14 content is not the same at the surface mixing layers and that in the deep ocean; hence, not all marine organisms have the same radiocarbon content.
The atmosphere, oceans, and biosphere are radiocarbon reservoirs of varying concentrations.The mixing of deep waters upward with surface waters—in a phenomenon known as upwelling—is latitude dependent and occurs predominantly in the equatorial region.Coastline shape, local climate and wind, trade winds, and ocean bottom topography also affect upwelling. 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, resulting in very old apparent carbon 14 age.The Delta±R value is only used for marine carbonates.Depending on the age of the marine carbonate, a 200- to 500-year correction (i.e.