Natalia Welzenbach-Marcu | May 21th, 2019
Earthworms are essential to the health of our soil, fertilizing gardens and fields. But their relationship with the earth is complicated–and the link between earthworms and carbon is being continuously investigated by scientists.
North America used to have earthworms; its native species was wiped out thousands of years ago during an ice age. European settlers brought their own variety to their new home, and the continent has been populated ever since.
Earthworms are simple organisms, but they greatly affect the health of our soil. Some feed on topsoil, while others burrow down, coming up to eat dead leaves on the surface. All varieties help fertilize the ground–but sometimes, if the location isn’t right, earthworm activity does more harm than good.
This is especially true for earthworm activity in North American boreal forests, a network of coniferous (evergreen) trees that normally don’t house these small creatures. As the worms dig down through the soil, they release carbon that’s been packed into the forest floor. Boreal forest floors are essentially carbon sponges, and the spread of earthworms to these previously worm-less regions threatens to release all of that stored carbon, further accelerating our current climate change.
Exactly how these earthworms have spread from their more natural habitat to the evergreen forests of North America is a bit of a mystery, with multiple factors–warmer weather, invasive plants, agricultural practices–at play.
Even as these tiny organisms increase in all the wrong places on our side of the pond, in the UK, topsoil feeders are beginning to disappear, threatening the island’s agriculture. Worms, carbon, and our global food supply are all part of a delicate ecosystem that may slowly be unraveling if we don’t step up to figure out why.