Bone-eating ‘zombie’ worms drill with acid
Posted by Xeno on June 30, 2012
Deep sea worms use acid to eat the bones of seabed skeletons, according to US scientists.
The so-called “zombie worms” of the Osedax family are known to bore into bones and remove nutrients.
Fresh analysis of the root-like tissues the worms use to attach to bones has identified acid-secreting enzymes.
Until now scientists did not understand how the tiny creatures fed on bone, as they lack the body parts needed to “drill” physically.
Dr Sigrid Katz from the Scripps Institution of Oceanography, University of California, San Diego will present the team’s research at the Society for Experimental Biology’s annual conference.
Found at the bottom of the sea living on the fallen skeletons of whales and fish, the unusual group of worms have caused fascination since their “accidental” discovery in 2002 by the Monterey Bay Aquarium Research Institute (MBARI).
The MBARI team provided the whale bones and specimens used by Dr Katz and her colleagues.
Scientists were perplexed when they only discovered females but further investigation revealed that the males remained in their microscopic larval stage, living inside the female worms.
The unusual group’s name Osedax is Latin for “bone devourer”, and the worms have no mouth, gut or anus yet are still able to remove nutrients from bones.
Previous studies have revealed that symbiotic bacteria inside the worms digest the fats and oils extracted, but the question of how the worms physically bore into the bones had been a mystery.
Close analysis of the worms failed to find any abrasive structures the worms could use to mechanically “drill” into bone.
This prompted Dr Katz and colleagues to investigate whether the worms had a chemical strategy for penetrating the bones.
By analysing the worms’ tissues, the team found that acid-secreting enzymes were abundant in the root-like parts that attach to bones.
“The acid is secreted through the skin of the roots region,” said Dr Katz….
I don’t think the BBC is using the word ‘zombie’ correctly in this story… but it does make the story a bit more attention grabbing.