on July 16, 1945, and the subsequent above ground testing between 19, caused a rise in neutrons which in turn increased Carbon-14 concentrations around the world.
In a similar way, solar cosmic radiation fluctuates and would cause a fluctuation in the amount Carbon-14 being produced at any one an ongoing process.
The process would continue, halving the amount left every 5,730 years until, theoretically, nothing remained of the original pound.
If one were to believe the Bible, the earth was surrounded by a layer of water vapor between Creation and the Flood.This bombardment causes a nuclear reaction to take place.The Carbon-14 produced by this process is then converted into carbon dioxide, just as normal Carbon-12 becomes carbon dioxide.In high school biology courses they often teach about the inevitable failures of closed systems by taking an aquarium and placing snails, plants and a bowl of water inside; then sealing the aquarium so that no air may get in or out.The idea is that snails produce carbon dioxide which is utilized by the plants, the plants produce oxygen which utilized by the snails. Of course, it doesnt take long before the experiment fails in death for all those in the aquarium.