Our bodies are prolific artists, creating new cells throughout the body.
Some cells, like those found in skin, hair, and the lining of the gut, are produced and discarded on a regular basis, like doodles on scrap paper. Kirsty Spalding was one of the scientists who doubted that assessment.
Or more precisely, how old are your cells..cells in your liver, or your spleen, or your brain?
It's a question that's harder to answer than you think.
These techniques are made possible by sensitive electronic instruments developed in the late twentieth century. A computer program for radiocarbon age calibration.
Both methods rely on the ongoing production of radiocarbon in the upper atmosphere.
Thus, it dilutes the activity of the lake meaning that the radioactivity is depleted in comparison to 14C activity elsewhere.
The lake, in this case, has a different radiocarbon reservoir than that of the majority of the radiocarbon in the biosphere and therefore an accurate radiocarbon age requires that a correction be made to account for it.
I have been a faithful fan of Radiolab for past 5 years.The ratios are consistent among species, and the slight (1-3%) differences can also be calculated from the ratio of C) decreases as the radiocarbon decays. Libby determined, one gram of pure carbon should produce about 14 (13.56) radioactive decays per minute. The Beta-counting method detects the rate at which purified carbon decays. A rate of 7 decays/gram/minute would indicate an age of one half-life, or 5730 years old. A shellfish alive today in a lake within a limestone catchment, for instance, will yield a radiocarbon date which is excessively old.The reason for this anomaly is that the limestone, which is weathered and dissolved into bicarbonate, has no radioactive carbon.