Photosynthesis is the primary process by which carbon moves from the atmosphere into living things. Radiocarbon Dating Groundwater The application of radiocarbon dating to groundwater analysis can offer a technique to predict the over-pumping of the aquifer before it becomes contaminated or overexploited. Researchers have studied other radioactive isotopes created by cosmic rays to determine if they could also be used to assist in dating objects of archaeological interest; such isotopes include 3 He10 Be21 Ne26 Aland 36 Cl. InLibby moved to the University of Chicago where he began his work on radiocarbon dating. The releases of carbon dioxide into the biosphere as a consequence of industrialization have also depressed the proportion of carbon by a few percent; conversely, the amount of carbon was increased by above-ground nuclear bomb tests that were conducted into the early s.
The improvements to these curves are based on new data gathered from tree rings, varvescoralplant macrofossilsspeleothemsand foraminifera.
Carbon is distributed throughout the atmosphere, the biosphere, and the oceans; these are referred to collectively as the carbon exchange reservoir,  and each component is also referred to individually as a carbon exchange reservoir. Libby's method was soon superseded by gas proportional counterswhich were less affected by bomb carbon the additional 14 C created by nuclear weapons testing. Scientists measure the ratio of carbon isotopes to be able to estimate how far back in time a biological sample was active or alive. It frequently happens that a sample for radiocarbon dating can be taken directly from the object of interest, but there are also many cases where this is not possible.