The whole idea is that worms’ fecal matter (yeah… yuks!) transforms carbon into its more decay resistant form, gets deeper in the soil, and it’s nutritious to plants which are the ones helping transform CO2 into O2. These excrements also add physical structure to the soil that holds the carbon, reducing erosion and making it crumbly which helps plants grow. On top of that, earthworms also burrow in the soil creating passages that aerate and help water circulate, which is what plants need to be healthy.
But is it all good? Why are
we finding this now? There are some other investigations that actually show the
contrary, that earthworms just contribute adding to the greenhouse gas
emissions. How is that? As they go through their soil-transforming business, eating
from the soil and digesting it, they are actually releasing the already trapped
carbon in such soil. These investigations indicated these worms could be
causing one third of the increase in carbon dioxide emissions.
Even if such researches do
seem to collide and pull in different directions, they both agree the
earthworms have unmistakable benefits. This is why more studies are being
conducted to determine if the earthworms’ fertilization of the soil can truly
boost plant growth and outweigh their own carbon footprint, which we know, we
all do by just existing.
Source
Kerling, Kat. "'Global Worming': Earthworms Contribute to Climate Change: UC
Davis News & Information." UC
Davis News & Information. UCDAVIS, 4 Feb. 2013. Web. 25 Feb. 2015. http://goo.gl/3SgUUi