So biology does molecular nuclear fusion: Turning CO2 water into 14C, 3He and 18O.
The half life of 14C is 5,700 years
That of 3He only 7.6 × 10–22 seconds
But 15O is 122.2 seconds. But 17O and 18O are very stable. So 17O and 18O could be used to correct Carbon dates for high levels of radioactivity.