Science Journey: How Soil Microbes Help Us Fight Climate Change
Hannah Dion-Kirschner
Geobiology graduate student
About the Presentation
Climate Change • Microbiology • Music • Scientific Method
Increasing levels of greenhouse gases in the atmosphere are causing changes to Earth's climate. These changes put plants, animals, and humans at risk. Some organisms do the planet a favor by removing greenhouse gases from the atmosphere. The lab that I am a part of studies microbes—tiny organisms that can typically only be seen under a microscope—in soil that eat methane, a powerful greenhouse gas. We want to understand how these methane-eating microbes will respond to ongoing changes in the environment. I will discuss my research and share my personal story, including what designing science experiments has in common with practicing a musical instrument.
About the Speaker
Hannah Dion-Kirschner is from Milwaukee, Wisconsin. She grew up playing piano and French horn, climbing trees, and reading every book she could get her hands on. During her first year of college, where she went originally to study music performance, Hannah learned that it was possible to have a career working outdoors and learning about our planet. She began working in a lab studying samples from Greenland that could tell us about Earth's past climate, and she was immediately hooked.
Hannah now investigates biological processes that remove greenhouse gases from the atmosphere. She hopes to help people better understand the two-way relationship between climate change and biology. In her spare time, she volunteers for Caltech's GO-Outdoors, which provides geoscience educational materials, lessons, and field trips to Pasadena classrooms. Hannah still loves to read, hike, and play music.
Vocabulary
Enrich your knowledge around the lecture topic by reviewing relevant terms, provided by Hannah.
The change over time in Earth's processes and cycles, including shifts in temperature, sea level, and the intensity of storms. While Earth's climate has changed throughout history due to its position in space relative to the sun and natural occurrences like volcanic eruptions, the planet's current warming trend is extremely likely to be the result of human activity since the mid-19th century.
A gas that traps thermal radiation from the earth, heating the planet (a process known as the greenhouse effect). Greenhouse gases include carbon dioxide, methane, and nitrous oxide. While greenhouse gases are naturally occurring, human activities, including burning fossil fuels, produce them in large and harmful quantities.
A color-less, odor-less greenhouse gas. (If you have a gas stove at home, it likely uses methane to cook.) This gas is more potent but less abundant and shorter lived in the atmosphere than carbon dioxide. Methane is emitted naturally (e.g., from cow burps) and by humans (e.g., from landfills, coal mines, agriculture, and oil and natural gas operations).
Beneficial bacteria that live in almost all the soil on the earth and eat methane as food. The name literally means "methane eaters."
Tiny organisms that can typically only be seen under a microscope.
Also known as the scientific process. A set of steps used to perform research. Researchers following the scientific method typically develop and then test a hypothesis (which is an idea that can be supported or rejected by evidence), then test the hypothesis by observing the cause and effect of different experiments or natural processes.
Activity for the Classroom
Soil microbes are too small to see without special instruments. However, we can observe evidence of their activity as they decompose—or eat and break down—material, in this case, plants. For this demonstration, you'll need a scale that can measure grams with two or three decimal points, and bags of pure green or rooibos tea.
Weigh an unused tea bag and record the measurement. Then, bury the bag—or several—about three inches deep in soil. Be sure to mark where you've placed the tea and note any observations about the environment. Is the soil shaded? Are there many plants nearby? Is there much human activity?
After 90 days, dig up the teabags, clean them off (but not with water!), and dry them. Once dry, weigh again. What do you notice? You can examine differences in microbial activity by burying the bags in more than one location.
—Adapted from the Teabag Index, www.teatime4science.org
Recommended Resources
Videos, books, and classroom activities recommended by Hannah
Videos
- A video exploring the scientific method
- A visualization of methane in the atmosphere
- More about the value of soils and the effects of human action on soils
Books
- A book about women who are leading the fight against climate change
- A book summarizing some of the most important data about Earth's climate
Activities
- A bank of classroom activities focused on the environment, from Caltech's GO-Outdoors group
- A website with tons of climate science educational materials from UCAR Center for Science Education
Interested in learning more about sustainability? Check out the Caltech Science Exchange for explainers about greenhouse gases, batteries, wind and solar, water resources, and more.
About the Series
In Science Journeys, Caltech graduate students and postdoctoral scholars share their research to inspire scientific curiosity. Programs are designed for middle and high schoolers, but all are welcome.
These programs are made possible through the generosity of the Friends of Beckman Auditorium.
If you have questions, please email Mary Herrera at mhh@caltech.edu.
