Question Prompt:
What does decomposition look like in the garden?
Figure 1. Hyphae growing in the garden soil viewed under a Foldscope at 50X magnification
(Photo Credit: Holly A. Stuart)
Whether you choose to address the question prompt above or create your own questions, you and your students can take a deep dive into the microscopic world of decomposition with a classroom set of Foldscopes.
Figure 2. Healthy and moldy tomatillo skin from the garden
(Photo Credit: Holly A. Stuart)
Background:
Decomposition is an important step in recycling nutrients within an ecosystem. When dead organic matter is present, detritivores get to work breaking it down and returning the nutrients back to the soil. This process provides nutrients to future generations of plants. Detritivores can include fungi, bacteria, earthworms, millipedes, and beetles. Having a variety of these organisms in your garden helps to keep your soil healthy.
Figure 3. A variety of mushrooms found in the garden area
(Photo Credit: Holly A. Stuart)
This month you will look for evidence of decomposition and observe detritivores in action. This blog includes sample ideas, slide techniques, and student research suggestions to guide you and your class’s longitudinal study in the garden!
Materials:
-
Dissecting Kit or Set of Tweezers
-
Petri Dishes (these are in the Foldscope 2.0 Accessory Pouches)
-
Ring Stickers (a variety of thicknesses)
-
Moldy plant parts
Figure 4. Rotten tomatoes found in my garden
(Photo Credit: Holly A. Stuart)
Detritivores
Decomposition requires many different detritivores working together. The process starts with larger macroscopic detritivores like millipedes, beetles, and worms. They physically break down dead organic matter into smaller pieces. The increase in surface area on the organic material provides a greater number of access points for microbial life to proceed with the chemical decomposition process. Microscopic detritivores like bacteria and fungi take care of the final steps of returning the nutrients from organic matter back to the soil. Tiny fungal spores will develop into colonies large enough to be seen with the naked eye, but the individual structures of the fungi require a microscope to observe them.
Figure 5. Fungal spores (left) and hyphae (right) viewed under a Foldscope 2.0 at 140X magnification plus 5X digital zoom on phone using reflective lighting
(Photo Credit: Holly A. Stuart)
To collect microscopic detritivore samples, use a pair of tweezers to pick up a small piece of the mold. You can either pick up only the mold or peel off a thin piece of the decomposing plant material. The sample can be mounted on a slide using a clear sticker or coverslip for a very thin sample or a ring sticker for a thicker mass of mold.
When studying the fungal structures, students can investigate where on the plant they see more hyphae, branching, and spores. They can also investigate the connection between weather conditions and decomposition.
Decomposition Process
How do plants break down and release their nutrients back to the soil? With the help of bacteria and fungi. These microbes chemically break down the cell walls of the plants, converting the cellulose, hemicellulose, and pectin into simple sugars.
Figure 6. Healthy tomato skin (left) and moldy tomato skin (right) viewed under Foldscope 2.0 at 140X magnification plus 5X digital zoom on phone
(Photo Credit: Holly A. Stuart)
To see decomposition in action, make a comparison of healthy fruit skin and moldy fruit skin. Take a pair of tweezers and use them to peel off a thin layer of fruit skin. Place the skin on the slide and secure it with a cover slip or clear sticker. You should see clearly defined cell walls on the healthy fruit and thinner, less defined walls on the decomposing fruit skin. You may even see holes in the skin where hyphae are growing.
Figure 7. Moldy tomatillo skin viewed under Foldscope 2.0 at 50X magnification (left) and 50X magnification plus 5X digital zoom on phone (right)
(Photo Credit: Holly A. Stuart)
Students can look at different plant parts to study the rate of decay of stems or leaves, or fruits. Do they all decay at the same rate? Why or why not?
Fungal Biodiversity
By studying decomposition in the garden, students can see that all molds are not the same. They have different colored and shaped mushroom fruits, different shaped and sized spores, hyphae of varying thicknesses and branching patterns. Scientists can use these physical features to identify or classify the mold.
Figure 8. Different fungal spore shapes viewed under a Foldscope 2.0 at 340X magnification plus 5X digital zoom on phone
(Photo Credit: Holly A. Stuart)
Collecting mold samples can be done in a number of different ways. You can touch a clear sticker to a mushroom cap or fuzzy mold patch and then place it on a slide to view the thickness and branching of the hyphae and the shapes, colors, and sizes of the spores. The mushroom gills, which contain the spores, can be plucked off with a pair of tweezers and placed on a slide. The fluffy bits of mold on plant matter can be placed on a slide with a ring sticker using a pair of tweezers. This allows you to see both hyphae and spores with more depth because you are providing space to maintain the three dimensional structure.
Figure 9. Different hyphae shapes viewed under a Foldscope 2.0 at 140X magnification plus 5X digital zoom on phone
(Photo Credit: Holly A. Stuart)
Students can investigate the relationship between fungal type and plant or plant parts by looking at a variety of moldy plants and plant parts under their Foldscope.
Connect:
Remember, these are only suggestions to guide you along your garden study. What questions do your students want to answer? How many different types of mold did you find hard at work recycling the nutrients of the dying plant material? Did you observe other detritivores with your Foldscope? Let us know! Share your observations, discoveries, and pictures with the Foldscope community on the Microcosmos. Your contributions will build up a strong scientific database that can help support new and innovative scientific research. Tag us on social media, too. We love to see how Foldscopers around the world are using their Foldscopes in new and innovative ways!
For the month of October, we will turn our attention to the world of leaves. Their changing colors are beautiful on the trees and under the Foldscope! Until then, happy gardening and happy Foldscoping!
Figure 10. Colorful leaves in the garden
(Photo Credit: Holly A. Stuart)
Facebook: @Foldscope
Instagram: @teamfoldscope
Blue Sky: @teamfoldscope.bsky.social
TikTok: @foldscope
Threads: @teamfoldscope
Twitter: @TeamFoldscope
Sources:
https://baynature.org/article/when-a-plant-dies/
https://artsci.usu.edu/herbarium/activities_fun-stuff/fun-facts-about-fungi/decomposition
