Global Worming: A Quantitative Study about Greenhouse Gas Flux in Surface Soils Facilitated by the Anecic Earthworm, \u3ci\u3eLumbricus terrestris\u3c/i\u3e, Under Rising Global Temperature
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
