SUMMARY: There are two types of microbes that are involved in methane cycling: ones that produce methane (methanogens) and ones that use methane as a source of energy and convert it to carbon dioxide (methanotrophs). This article review looked at all the different factors that can cause changes to methanogens and methanotrophs. Past studies have looked at the effect of soil type, water availability, temperature, pH, atmospheric methane concentrations, methane sources and sinks, microbial biodiversity, and plant biodiversity, on the methane cycle. Each section of this article review gives both the overall trend as well as contradictory studies. It is clear that methane cycling interacts with other biogeochemical cycles and results vary across ecosystems. Attempts to reproduce what is observed in nature proved to be difficult and often did not produce expected results. In the conclusion section, the authors note the uncertainties about methane cycling and suggests that further research should include the role microbial communities play in methane sinks and sources.
LESSON COMMENTS: Topics that can be covered include: chemical reactions, energy, ecosystem relationships, decomposition, carbon cycle, and the difficulties of studying/observing an ecosystem as a whole versus the individual parts in a controlled lab setting. I would start with teaching students the basics of methane production and methane to carbon dioxide conversion. From there, students should use what they know from chemistry and/or biology to explain the factors that affect methane and carbon dioxide production/conversion.
Aronson, E. L., Allison, S. D., & Helliker, B. R. (2013). Environmental impacts on the diversity of methane-cycling microbes and their resultant function. Frontiers in microbiology, 4, 225. doi:10.3389/fmicb.2013.00225