California's Eel River Critical Zone Observatory (CZO) is part of the National Science Foundation CZO network. Bill Dietrich of the Earth and Planetary Science Department serves as the lead Principal Investigator for the observatory. Research at the Eel River CZO is rooted in intensive field monitoring in the critical zone, which follows watershed currencies (water, solutes, gasses, biota, sediment, energy, and momentum) through a subsurface physical environment and microbial ecosystem of the critical zone into the terrestrial ecosystem, up into the atmosphere, and out through drainage networks to the coastal ocean. The core team spans four of UC Berkeley's departments and has expertise in geomicrobiology and biogeochemistry (Banfield), low temperature geochemistry (Bishop), microbial ecology (Firestone), salmonid ecology (Carlson), food web ecology (Power), geomorphology and hydrology (Dietrich), tree physiology (Dawson), ecohydrology theory and observation (Thompson), and climate modeling (Fung). The CZO's diversity gives it the ability to pursue deeply many fundamental questions that lie at the interface of many disciplines.