This apparent age of oceanic water is caused both by the delay in exchange rates between atmospheric CO2 and ocean bicarbonate, and the dilution effect caused by the mixing of surface waters with upwelled deep waters which are very old (Mangerud 1972).A reservoir correction must therefore be made to any conventional shell dates to account for this difference.In the northern hemisphere the amount of artificial carbon in the atmosphere reached a peak in 1963 (in the southern hemisphere around 1965) at about 100% above normal levels.Since that time the amount has declined owing to exchange and dispersal of C14 into the Earth's carbon cycle system.In this page, we consider natural reservoir variations and variations brought about by human interaction].
A number of researchers found that the activity they expected from material growing since 1890 AD was lower.
The effect of this has been to almost double the amount of C14 activity in terrestrial carbon bearing materials (Taylor, 1987).
De Vries (1958) was the first person to identify this 'Atom Bomb' effect.
The volcanic effect has a limited distance however. (1980) found that at 200 m away from the source, plants yielded an age in agreement with that expected.
They suggested that the influence of depleted CO2 declined rapidly with increasing distance from the source.
One of the most commonly referenced reservoir effects concerns the ocean.