Guest Blog Post by Ben Koch, Senior Research Associate, NAU
Researchers at NAU’s Center for Ecosystem Science and Society (ECOSS) have partnered for the second year with one of Kathryn Wertz's 6th grade science classes at Sinagua Middle School in Flagstaff as part of the ‘Scientists in the Classroom’ program founded by Jillian Worssam, and assisted by STEM City. In November, ECOSS scientists worked with students to begin a 5-month-long decomposition experiment in the forest near the school. The students learned that decomposition is the process by which living things are broken down into simpler and simpler pieces, and that decomposers like invertebrates, bacteria, and fungi accomplish this feat by consuming dead organisms in order to get the energy they need to survive, grow, and reproduce. The students considered which kinds of dead organisms decompose quickly, and which kinds decompose more slowly, depending on their chemical composition (i.e., a deer skeleton will take longer to decompose than an earthworm because it is made of bone, not soft tissue).
The students are investigating these ideas with a field experiment in which they are comparing the decomposition rates of leaves from two different species of trees: Oak and Ponderosa Pine. The students deployed set amounts of each of these leaf species in mesh bags on the forest floor near their school, and they used bags with two different sizes of mesh: coarse (the black bags in the photos) and fine (the white bags in the photos). When placing the leaf-bags in the forest, the students made observations and predictions about which leaf type and which bag type will yield the fastest decomposition. In April, ECOSS scientists and the students will retrieve their leaf-litter experiment to measure the mass loss of the leaves in each bag. The students will then take a field trip to the ECOSS laboratories on the NAU campus, where, among other activities, they will be able to weigh their leaf-bags and create a graph of their experimental results.