Global Worming: A Quantitative Study about Greenhouse Gas Flux in Surface Soils Facilitated by the Anecic Earthworm, Lumbricus terrestris, Under Rising Global Temperature

Author(s)

Rachel Briden Frei, University of Rhode IslandFollow
Jose A. Amador, Univeristy of Rhode IslandFollow

Major

Environmental Science and Management

Advisor

Amador, Jose, A.

Advisor Department

Natural Resources Science

Date

5-2016

Keywords

Global Warming; Climate Change; Greenhouse Gases; Earthworms; Environmental Science, Microcosms

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

Abstract

Climate change is the long-term alteration in the Earth’s average weather conditions believed to be driven by greenhouse gases (GHG): carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). These alterations are expected to cause more extreme weather events, gradually warmer global temperatures and greater amounts of precipitation. Roughly 20% of the Earth’s CO₂, one-third of CH₄ and two-thirds of N₂O emissions, originate from soils, and earthworms are known to accelerate GHG. As climate change proceeds, there is expected to be an increase in global temperature of 2-6ºC. Temperature is a key factor in determining the rate of soil biological processes that produce and consume GHG. To test how temperature could impact the effects of earthworms on GHG production in soils, we placed earthworms in microcosms with agricultural or forest soil with plant detritus, and incubated the microcosms at 15ºC and 20ºC for six weeks. We found that CH₄ soil consumption decreased at higher temperature and in the presence of earthworms, while CH₄ consumption fluctuated negatively and positively in soils without earthworms at both lower and higher temperature. Production of CO₂ decreased at higher temperature in the absence of earthworms, but production increased in the presence of earthworms at higher temperature. N₂O production increased, lowering the soils ability to absorb N₂O, with higher temperature and the presence of earthworms. CH₄ production was increased in agriculture soil with some minor decrease in absorption in forest soil. CO₂ production fluctuated greatly in agriculture soil. Forest soil CO₂ production was mostly stable with little variability. Both soils experienced the same trend in N₂O flux where there was a sudden production of gas followed by a slowed leveling out with minor fluctuation between production and consumption. Our results show strong evidence that changes in temperature, due to climate change, can impact the effect of earthworms on GHG production and consumption.