Isotope tracers are used in scientific research to track the movement of atoms and molecules in biological, chemical, and environmental systems. Isotopes are variants of chemical elements with the same number of protons but different numbers of neutrons. By labeling molecules with specific isotopes, researchers can track the movement and transformation of these molecules in a system. Isotope tracers have been used in a variety of fields, including environmental science, geology, biology, and medicine, to study processes such as nutrient cycling, biochemical reactions, and metabolic pathways. This research technique provides valuable information about how substances move and interact in a system, helping researchers to better understand complex processes and mechanisms.