Every time a living being dies a stopwatch starts ticking. is used to determine the age of previously living things based on the abundance of an unstable isotope of carbon.
The isotopic distribution of carbon on the Earth is roughly 99% carbon 12 (with 6 protons and 6 neutrons) and 1% carbon 13 (with 6 protons and 7 neutrons).
Bacteria, fungi, and animals eat these plants and each other.
These highly energetic nuclear bullets wreak havoc on the atoms in the upper atmosphere: tearing electrons from their orbitals and setting them free, knocking neutrons and protons from the tight confines of the nucleus and setting them free, generating x-rays and gamma rays as they decelerate, and creating exotic particles like muons and pions directly from their excessive kinetic energy.
These are also highly energetic and will ionize atoms, transmute nuclei, and generate x-rays themselves.