Isotope tracing is a scientific technique used to track the movement and behavior of substances in various systems. It involves using isotopes, which are variants of elements with different atomic masses, to label specific molecules. By analyzing the distribution of these isotopes, researchers can gain insights into processes like metabolism, environmental changes, and even geological formations. This method is widely applied in fields such as biology, environmental science, and geology. For example, scientists can use isotope tracing to study how nutrients move through ecosystems or to investigate the origins of water sources. This helps in understanding complex interactions within natural systems.