Monday, November 4, 2013

Episode 186 (11-4-13): Photosynthesis Fun and Fundamentals

Click to listen to episode (3:06)


From the Cumberland Gap to the Atlantic Ocean, this is Virginia Water Radio for the week of November 4, 2013.

This week, we feature another mystery sound...

REPORTER: We break into this show to bring you exclusive audio from the Virginia Tech campus, where a shadowy team of scientists is tinkering with the process underlying all life on earth.  They haven’t yet revealed their possibly nefarious plans, so let’s listen in...

SCIENTIST 1: With this terrarium, we have a model system to test our carbon dioxide-manipulation scheme, and soon we’ll be ready to control earth’s fundamental food-producing process...

SCIENTISTS 1 and 2: Photosynthesis!

SCIENTIST 2.  Are all the components of the system ready?  Green plants with chlorophyll?

SCIENTIST 1.  Check!

SCIENTIST 2.  Soil with proper nutrients?

SCIENTIST 1.  Check!

SCIENTIST 2.  Light?

SCIENTIST 1.  Check!

SCIENTIST 2.  Water?

SCIENTIST 1.  Check!

SCIENTIST 2.  Air with CO2?


SCIENTIST 2.  That’s carbon dioxide!

SCIENTIST 1.  Oh...right...I mean, check!

SCIENTIST 2.  Let the photosynthesis start!  Engage monitoring device!

SCIENTIST 1.  CO2 taken in from the air...water and nutrients being absorbed through roots...light falling on leaves.  All systems go!  Light energy is driving CO2 and water to combine and form glucose, the chemical-energy form, while releasing oxygen.

SCIENTIST 2.  Apply the CO2 inhibitor!

SCIENTIST 1.  Lid applied!  CO2 source blocked...system CO2 levels dropping rapidly...plants responding as expected, using up available CO2.

SCIENTIST 2.  Reverse manipulation!  Apply the CO2 increaser!

SCIENTIST 1.  Lid removed!  CO2 added...plants responding.  Wait, they’re responding too fast!  They’re growing beyond the walls!  One has me...aieeeeeeee!

SCIENTIST 2.  Now it’s got me, too!  Noooooooo.....

REPORTER: Well, this might be a good time for us to return to our regular show.  Back to you....

Unlike this skit, there’s nothing make-believe about earth’s reliance on photosynthesis.  Giant, human-eating plants are a far-fetched fiction, but the role in photosynthesis of light, chlorophyll, nutrients, water, and carbon dioxide is a fact of life.  Thanks to Eli Heilker and John Kidd for participating in this episode.

For other water sounds and music, and for more Virginia water information, visit our Web site at, or call us at (540) 231-5463.  From the Virginia Water Resources Research Center in Blacksburg, I’m Alan Raflo, thanking you for listening, and wishing you health, wisdom, and good water.


[All Internet addresses mentioned were functional as of 11/4/13]

To demonstrate plant uptake of carbon dioxide (CO2) during photosynthesis, the Virginia Tech Department of Forest Resources and Environmental Conservation attaches a terrarium via gas-transporting tubing to the CO2 monitor shown at right.

As this diagram explains, CO2 uptake by trees and other woody plants during photosynthesis results in carbon storage, or “carbon sequestration,” a key concept in the issue of climate change.  Diagram courtesy of John Seiler, Virginia Tech Department of Forest Resources and Environmental Conservation.
In these Red Maple leaves in Blacksburg, Va., on October 30, 2013, the green chlorophyll pigment was breaking down as photosynthesis and chlorophyll production in the leaves were stopping as winter approached.  The breakdown of chlorophyll in the fall allows pigments of other colors in the leaves to be revealed.

Acknowledgments: Virginia Water Radio thanks John Kidd, of the Virginia Tech Department of Forest Resources and Environmental Conservation, and Eli Heilker, a Virginia Tech English major serving an internship in Fall 2013 with the Virginia Water Resources Research Center, for their participation in this episode.

Sources and more information: Information on photosynthesis was taken from Chapter 3, “Gas Exchange,” in Forest Biology and Dendrology Text, by John Seiler, John Groninger, and John Peterson (Blacksburg: Virginia Tech, 2009), online at

An introduction to photosynthesis is available from “NOVA” program Web site, online at  “NOVA” is a production of the Public Broadcasting System (PBS) and WGBH-Boston.

Information on fall leaf-color change is available in “The Miracle of Fall,” University of Illinois Extension, online at

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