Today’s Factismal: The “demon worm from Hell” known as Halicephalobus mephisto lives 2.2 miles underground; that makes it the deepest known multicellular organism.
Roundworms are important critters. They creep along the ground or push their way through the top soil, dining on dead leaves and bacteria and creating a soil rich in the organic nutrients that plants need to survive. Without them, forests would be knee-deep in dead leaves and goo, starving for nutrients and air.
But when worms move into the wrong area, they can prove to be almost as deadly as the piles of detritus that they munch on. For example, there are exotic worms in parts of the United States that are killing off orchids by eating their seeds; these invasive worms were probably accidentally introduced by fishermen or gardeners.
But sometimes the invasion happens thanks to nature. That’s the best explanation for how Halicephalobus mephisto ended up living more than two miles underground. Scientists studying the worms, which were discovered thanks to a hunch by one of the researchers, think that the worms were originally washed deep underground many millenia ago by strong rainfalls. The worms couldn’t climb back up, so they made themselves at home by munching on the thick mats of bacteria that thrive in rock fissures. They soon adapted to their new environment, which is as close to hellish as any on Earth: temperatures of 105°F, pressures equal to 1100 atmospheres, little oxygen, and no light. With all of those challenges, it is no surprise that these little worms are only about 0.01 inch long – roughly as long as the period at the end of this sentence.
If you’d like to learn more about invasive worms and maybe even help track their depredations, then why not check out the Great Lakes and Canadian Earth Worm Watches? They are looking for people across North America to hunt worms and report the species and sizes found: