Critical zone processes refer to the complex interactions between the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere that shape and sustain Earth's critical zone - the near-surface layer of the planet that extends from the top of the vegetation to the base of weathered bedrock. These processes include weathering, erosion, soil formation, nutrient cycling, water movement, and biogeochemical cycling. Understanding critical zone processes is important for predicting how ecosystems will respond to environmental changes, such as land use changes, climate change, and pollution. Researchers in this area use a combination of field observations, laboratory experiments, and modeling techniques to study these processes and their impacts on the environment.