From the beginning of the dung beetle’s existence this species of insect has had a bad rap until recently. Seriously, how can a beetle that sifts through cow feces all day really be a beneficial member to our world? Well, a recent study by Atte Penttila and colleagues discovered that the activity produced by dung beetles might actually be beneficial in reducing the effects of climate change. In their study, dung beetles were linked to a decrease in the amount of methane (CH4), carbon dioxide (CO2) and nitrous oxides (N2O) released into the atmosphere from cow feces.
Figure 1: Dung Beetle
Greenhouse gases (GHGs) are gases in the air that enhance the greenhouse effect trapping incoming solar radiation within our atmosphere, leading to eventual warming of the Earth (Figure 2). The atmosphere has always contained greenhouse gases but with more and more human interaction, the levels of these harmful greenhouse gases have increased dramatically. (Further information about the greenhouse effect can be found here).
Figure 2: Greenhouse effect in Earth’s Atmosphere
In their study they measured the levels of the three harmful greenhouse gases within cow dung patties. They analyzed both dung patties with and without intervention and had a control group of grass without feces. In doing so, they were able to see that methane, carbon dioxide, and nitrous oxide emissions were decreased in patties with dung beetle intervention (Figure 3).
Figure 3: Shows the levels of methane released over the three experiment groups.
The scientists lead to believe that the reason behind the decreased levels of GHGs was due to the aerating effect produced by the dung beetle tunnels. By digging these holes, the dung beetles allowed for faster drying and more availability to oxygen which increased the aerobic decomposition. Overall, there was a decrease by about one-third in the levels of harmful GHGs being released by cow feces.
Although this study is a first of its kind, it is a breakthrough in the further analysis of the impacts animals and insects have on climate change. In the grand scheme of things, cow feces are not a major contributing factor to the greenhouse effect but is just one of many human influenced processes at play.
References
Penttila, A., Slade, E., Simojoki, A., Riutta, T., Minkkinen, K., & Roslin, T. (2013). Quantifying Beetle- Mediated Effects on Gas Fluxes from Dung Pats. PLoS ONE, 8(8), E71454-E71454. Retrieved November 25, 2014, from 10.1371/journal.pone.0071454
Figures:
Figure 1: Jochen Smolka, Lund University
Figure 2: http://climatecommission.gov.au/causes/greenhouse-effect//
Figure 3: Penttila et al, 2013.
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