Isotope fractionation is a process that leads to differences in the relative abundance of isotopes in substances. This can occur through a variety of natural processes such as chemical reactions, physical processes, or biological activity. Isotope fractionation is often used in geology, chemistry, and environmental science to study the movement and transformation of substances through different systems. Researchers can analyze the isotopic composition of substances to gain insights into processes such as nutrient cycling, climate change, and the origin of materials.