March 21, 2016

The following is part nine in a series on the National Science Foundation's Critical Zone Observatories (CZO) Network. Parts one, two, three, four, five, six, seven and eight are posted on the NSF website.

Each year on the United Nations-designated World Water Day, March 22, people around the world consider the importance of freshwater to ecosystems -- and to us.

On World Water Day 2016, the National Science Foundation (NSF) looks at Earth's critical zone -- the realm on our planet's surface between the forest canopy and bedrock -- and the role water plays in sustaining that zone.

NSF spoke with scientists at California's Eel River Critical Zone Observatory (CZO). The site is one of 10 NSF CZOs located across the country. Eel River CZO geologist William Dietrich and biologist Mary Power, both of the University of California, Berkeley, and NSF CZO program director Richard Yuretich offer insights into the role of water in the future of the critical zone -- and our planet.

1. What is the critical zone, and why are we concerned about it?

Yuretich: Many of processes supporting life on Earth are hidden from our view because they take place between the top of the vegetation, or tree canopy, through soil and weathered rock, to bedrock. This is the critical zone, where water is stored, transformed and released to support life on Earth's surface. Water circulation among the critical zone, the surface, and the atmosphere regulates local climate and influences the evolution and dynamics of landforms and ecosystems. This thin skin where life meets rock is the part of our planet that's critical to maintaining a hospitable environment for all living things, from microbes to humans.

2. Are people part of this critical zone?

Yuretich: Absolutely -- and it is a two-way street. Our actions alter the balance of the storage, transformation, and transport processes that take place in the critical zone, and these changes affect things we depend upon, including our food and water supply. Results of research at the Eel River Critical Zone Observatory show that human interventions and environmental change affect the water flow, toxic cyanobacteria, and salmon populations in northern California rivers.

Continue reading NSF's interview with Eel River CZO PI William Dietrich and investigator Mary Power.