The Critical Zone Exploration Network (CZEN) is a community of people and a network of field sites investigating processes within the Critical Zone, defined as the Earth’s outer layer from vegetation canopy to the soil and groundwater that sustains human life. CZEN members are a diverse group of researchers and educators who study the physical, chemical and biological processes shaping and transforming Earth’s Critical Zone. This research spans a wide range of disciplines including geosciences, hydrology, microbiology, ecology, soil science, and engineering. CZEN encourages all researchers working in the Critical Zone to join the effort by registering on this site and contributing content. CZEN’s primary goal is to create a network of observatories for investigating Critical Zone processes such as weathering and soil formation. Through this network, researchers can access and integrate data in a way that allows isolation of environmental variables and comparison of environmental effects across gradients of time, lithology, human disturbance, biological activity and topography.