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What is the Calhoun Critical Zone Observatory?

Justin Richardson in Adventures in the Critical Zone

Jul 14, 2016

An illlustrated introduction to the Calhoun Critical Zone Observatory!

By Justin Richardson and Dan Richter.

Illustrated by Alana McGillis










Panel 1. A stream flows through a forested landscape as seen at the Calhoun Critical Zone Observatory (CCZO) in South Carolina.

Panel 2. Dr. Dan Richter waves and says, “Hi, I am Dr. Dan Richter and I lead the research conducted at the Calhoun CZO!”

Panel 3. Dr. Richter shows a soil profile and explains that CCZO researchers want to know how the bedrock, soil, water, plants, and people work together.

Panel 4. The Calhoun Experimental Forest was once a cotton plantation where life was difficult for most farmers but even tougher for slaves.  People pick cotton in a cotton field.

Panel 5. An eroded hillside shows that farming was also hard on the land causing massive erosion.

Panel 6. A forest scientist plants tree seedlings across a landscape in effort to learn how forests and soil regenerate after farming.

Panel 7. Since planting the trees, researchers have been watching the regeneration of the forest and soil. Dr. Richter cores a tree for data collection.

Panel 8. Scientists from the 1950s, 1970s and today stand in the same soil pit. Soils and trees have been sampled continuously at the Calhoun Experimental Forest for 70 years.

Panel 9. A flux tower and soil probes in the CCZO study the atmosphere and deeper weathered rock and ground water below.

Panel 10. Dr. Richter explains the goal is to understand our impact on the CZ so Earth can support a healthy and productive environment.


What is the Calhoun Critical Zone Observatory?
(2 MB pdf)
Printable 2-page version of this comic.

Justin B. Richardson

CZO INVESTIGATOR, STAFF. National Office outreach officer, Former CZO Post-Doctoral Fellow. Specialty: Soil biogeochemistry of plant-essential and toxic metals.

CZO Profile | Personal Website

Outreach / Education Research   EDUCATION/OUTREACH   General Public   K-12 Education  

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Justin Richardson and his guests answer questions about the Critical Zone, synthesize CZ research, and meet folks working at the CZ observatories

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General Disclaimer: Any opinions, findings, conclusions or recommendations presented in the above blog post are only those of the blog author and do not necessarily reflect the views of the U.S. CZO National Program or the National Science Foundation. For official information about NSF, visit

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