Study guide: How to interrogate a soil

Want to be ready for Dr. Tony Hartshorn's Rough Cut Science talk on Feb. 18? We worked with Tony to create the first-ever online study guide to complement his Rough Cut Talk! If you're giving a Rough Cut Talk and want to make a study guide, we can help you! -OR, if you're a member of the public and you wish more scientists would communicate like this, send us an email:  -

"How to Interrogate a Soil"

(Join us live at noon MST in Room EPS 126, MSU campus or via Webcast at Be sure to list your hometown or organization when you log in so we know who's in the online audience)

Check out this study guide and you'll be set! 

Below you'll find:

  • A glossary (three terms to know before the talk)
  • What's going on in Tony's Lab
  • Two short videos to preview, and
  • One question to be thinking about before the talk


You can view Tony's recorded talk here:


Respiration = the conversion of carbohydrates into gaseous waste products... by macrobes (that's you!) & microbes

... can be aerobic if the carbohydrates are respired with the help of oxygen or

... can be anaerobic if the carbohydrates are respired in the absence of oxygen (nitrate, ferric iron, sulfate, carbon dioxide)

... ever since Santorio Santorio 400 years ago, we've known that most of the mass we eat  or drink ends up being respired, not pooped or pee'd

Need a bigger version of this graphic?

Mass balance = notion that you are not allowed to snap your fingers at a soil and have some or all mass disappear (or heavens-to-Betsy be converted into energy via that nasty equation E=mc^2); because some elements are more mobile/leachable/slurpable than others, the loss of mobile elements, from a mass balance perspective, means that this leads to a "residual enrichment" in less mobile elements such as--of course--zirconium (Zr). 

Quick example.  A rock is exposed with 100 parts per million (ppm) Zr.  As that rock begins to "rot" (see glossary item below), more mobile constituents (say, sodium) are lost from the rock, such that even if the volume were to stay the same, the concentration of Zr might rise to 150 ppm.  As more mass is lost as a soil is "rotted", the "immobile" Zr concentration could increase to 500 ppm.  So what, you ask?  Well, things that are lost from a soil (all that sodium that washes out of our soils to the Gulf of Mexico), leads to residual enrichment of the Zr.  And things that are lost are hard to measure... all we might know would be that whatever the concentration of sodium, the original sodium concentration must have been greater in the rock.  Ah... but if we measure the Zr of soil, and compare that to the Zr of unweathered/unrotted rock, we can quantify the extent of chemical weathering or rot.

Chemical weathering = one of two ways that landscapes lower, the other being physical erosion.  Chemical weathering is a fancy term for "rot," which happens to be--analogously--why your dental hygienist wishes you'd floss your teeth more regularly.  In fact, the hydroxyapatite (a mineral) in our teeth is susceptible to rot, the same way the minerals that make up the Gallatins, the Crazies, or the Bridgers are susceptible to rot.

What Tony's Soil Interrogation Lab aims for:


Check out these videos ahead of time:

What You Should Know About the Carbon Cycle


Earth system science is just like human system science... just a little bit bigger


One question to be thinking about ahead of time:

If soils are born from rock, how then does a plant root or mycorrhizal hypha obtain the "slurpable" nutrients it needs, in the right proportion, at the right time?


MSU IoE Office

Montana State University
605 Leon Johnson Hall
Bozeman, MT 59717
(406) 994-2374
MSU Director: Bruce Maxwell

UM IoE Office

The Universityi of Montana

The University of Montana
Davidson Honors College
Missoula, MT 59812
(406) 243-6058
UM Director: Maury Valett


Montana University System

Montana University System

Office of the Commissioner of Higher Education
2500 Broadway Street
Helena, MT 59620