When cosmic rays reach Earth’s upper atmosphere, physical and chemical interactions form the radioactive isotope carbon-14. Living organisms absorb ... requires samples of 10 to 100 grams (0.35 to 3.5 ...

This reveals the composition of carbon isotopes in the molecule and gives the chemical its fingerprint, a feat that had not previously been achieved with forever chemicals. The work is important ...

Stable isotopes have helped uncover migratory routes, trophic levels, and the geographic origin of migratory animals. They can be used on land as well as in the ocean and have revolutionized how ...