The Roots of the Carbon Cycle

Play this interactive to learn how changes to soil may affect the carbon cycle.

“Land, then, is not merely soil; it is a fountain of energy flowing through a circuit of soils, plants and animals. Food chains are the living channels that conduct energy upward; death and decay return it to the soil. The circuit is not closed; some energy is dissipated in decay, some is added by absorption from the air, some is stored in soils, peats and long-lived forests.” Aldo Leopold, 1948

Like all aspects of our environment, soil is part of our planet’s complex and dynamic energy cycles, including the carbon cycle. Carbon is one of the most prevalent and important elements on our planet. Its movement through the environment modifies the temperature of our atmosphere and oceans, provides the structure and fuel for all living organisms, and contributes significantly to the living skin of our earth. As we learn more about how carbon moves through the environment, we discover how changes in one part of the carbon cycle can affect the earth as a whole.

This investigation of soil’s role in the carbon cycle illustrates the importance of soil to our ecosystems, and demonstrates how human interactions with soil may affect the carbon cycle.
“Land, then, is not merely soil; it is a fountain of energy flowing through a circuit of soils, plants and animals. Food chains are the living channels that conduct energy upward; death and decay return it to the soil. The circuit is not closed; some energy is dissipated in decay, some is added by absorption from the air, some is stored in soils, peats and long-lived forests.” Aldo Leopold, 1948

Like all aspects of our environment, soil is part of our planet’s complex and dynamic energy cycles, including the carbon cycle. Carbon is one of the most prevalent and important elements on our planet. Its movement through the environment modifies the temperature of our atmosphere and oceans, provides the structure and fuel for all living organisms, and contributes significantly to the living skin of our earth. As we learn more about how carbon moves through the environment, we discover how changes in one part of the carbon cycle can affect the earth as a whole.

This investigation of soil’s role in the carbon cycle illustrates the importance of soil to our ecosystems, and demonstrates how human interactions with soil may affect the carbon cycle.

This interactive is part of a three-part educational series on soil.

Pre-activity Questions

• What does soil have to do with climate change?
• How do human actions affect the carbon cycle?

Focus Questions during Activity

• How is carbon transferred into and out of soil?
• What is the importance of soil structure and how does it affect the carbon cycle?
• How do changing temperatures in soil affect the carbon cycle?
• How do changing moisture levels in soil affect the carbon cycle?

Post-activity Questions

• What conditions tend to cause soil to accumulate lots of carbon? What conditions tend to cause soil to emit carbon to the atmosphere?
• What might happen if more permafrost starts to thaw?

Extension Activity

Describe how human interactions with soil could affect the carbon cycle. Then describe how your actions as an individual affect soil and the carbon cycle.

Links to Learn More

• Energy Cycles and Ecology, Crash Course Ecology - Learn about the role of the hydrologic and carbon cycles on the ecosystem.
• Federal Carbon Cycle Research, United States Science Carbon Cycle Program - Learn about the role of the hydrologic and carbon cycles on the ecosystem.
• Desertification, Physics of Desertification - Learn about desertification and what is being done to slow it across the planet.
• Biochar, Yale Environment 360 - Biochar removes carbon from the atmosphere and stores it underground, where it does not contribute to global warming. It may play an important role in regulating atmospheric carbon levels.
• Bioreporters, US National Library of Medicine, NIH - Bioreporters are microbial cells that have been genetically modified to recognize chemicals. Scientists are using them to test for pollutants in soil without disrupting the surrounding environment.

NGSS Correlations

• Performance Expectation: Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.HS-LS2-5
• Disciplinary Core Idea: Photosynthesis and cellular respiration are important components of the carbon cycle, in which carbon is exchanged among the biosphere, atmosphere, oceans and geosphere through chemical, physical, geological and biological processes. LS2.B Cycles of Matter and Energy Transfer in Ecosystems
• Crosscutting Concept: Energy and Matter - Energy drives the cycling of matter within and between systems. Systems and System Models - Models (e.g. Physical, mathematical, computer models) can be used to simulate systems and interactions - including energy, matter, and information flows - within and between systems.
• Science and Engineering Practices:Developing and Using Models

Project Partners

Nick Balster is an Associate Professor in the Department of Soil Science and Institute for Environmental Studies at the University of Wisconsin-Madison. His lab, “Collaborations in Ecosystem Science and Environmental Education,” is constantly seeking innovative ways to combine research, teaching, and outreach both in education and the physical sciences. A longtime advocate of teaching and learning, Dr. Balster collaborates with many, including QUEST since 2013.

Craig Kohn teaches Agriscience at Waterford Union High School. Kohn has degrees from UW-Madison in Agriscience and Education and is licensed to teach Biology, Agriculture, and Environmental Science. Kohn has developed a nationally-recognized agricultural education program that seeks to maximize student preparation through rigorous and relevant education and meaningful inquiry-based learning.