Tracer research focuses on tracking the movement and behavior of substances or materials within a system or environment. Tracers are typically introduced into the system or environment and their concentration or presence is monitored over time. This allows researchers to understand processes such as dispersion, diffusion, mixing, and transport within the system. Tracer research is used in various fields such as environmental science, hydrology, geology, and atmospheric science to study the movement of pollutants, nutrients, contaminants, and other substances.