The critical zone (CZ) is termed as such because of its essential role in sustaining life on Earth. This thin veneer of vegetation, soil and fractured rock at the earth's surface is constantly infused with the circulation of fresh water and gases, and supports biological activity and weathering processes through persistent cycles of tectonic uplift and erosion. The flux of these fluids through the porous CZ and the distributed biological activity it supports, alter the matrix and landscape over geological time scales. This long-term "evolution" of CZ structure directly affects its ability to function as a "filter" for water and atmospheric gases, and hence to provide essential CZ "services" for the environment and humanity. In the semi-arid southwestern US, mountain regions of the CZ are particularly important because they provide a high proportion of the water that sustains growing urban and sub-urban populations.
The Jemez River Basin - Santa Catalina Mountains Critical Zone Observatory (JRB-SCM CZO), established in 2009, is a "natural laboratory" located in the Jemez (NM) and Santa Catalina (AZ) mountains that focuses on quantifying the effects of climate, lithology, and disturbance on CZ structure, function and long-term evolution. The CZO spans a large gradient in precipitation and temperature representative of the larger, water-limited southwestern US. The JRB-SCM CZO team comprises hydrologists, biologists, soil scientists, geochemists, geomorphologists working together in instrumented watersheds to develop data and models that enable an improved understanding of the coupled surface earth processes that control CZ evolution.
The CZO is training students and postdoctoral scientists to be fluent in an emerging field of CZ science that focuses on the interfaces between the traditional earth science disciplines in order to better resolve these coupled processes. Students are also directly involved in the development of novel approaches to translate their research for the public, including via open science talks, multi-media presentations, museum exhibits and K-12 curricula. Thus, the CZO team includes undergraduate and graduate students working together with postdoctoral scientists, faculty and technical staff to build - not only a functional and dynamic observatory that serves the earth sciences community - but also an integrated, interdisciplinary new field of CZ science that has direct relevance to the increasingly populated, but water-limited southwestern US.
