The Antartic Worm that Eats Bones

By Bibiana Bonmatí, University of Barcelona Press

Image: Tube of Osedax deceptionensis. Pals can be seen against the light. January 2013 campaign. (Photo: Sergi Taboada, UB)

A group of researchers from the University of Barcelona and the Spanish Institute of Oceanography (IEO) has discovered a new species of Osedax, a marine invertebrate who eats bones, named Osedax deceptionensis. This bone-eating worm, which dines on decaying whale skeletons, was found within the 2010 campaign of the Actiquim-II project, in an experiment carried out on Deception Island, at the Spanish Antarctic base Gabriel de Castilla.

The new species, together with Osedax antarcticus, found by a parallel research group led by the Natural History Museum in London, are the first two species of worms found on the icy-cold seafloor of the Southern Ocean.

To date, only five species have been described within the genus Osedax; all of them come from warmer latitudes. These polyphyletic annelid worms, first described ten years ago, share some characteristics. Males are much smaller than females (about 100–150 microns) and are attached to females’ bodies, acting as sperm banks.

Females live in symbiosis with bacteria; that enables them to degrade the organic material trapped in whale bones. They have no stomach, so they use bacteria to eat. Therefore, these organisms contribute to recycle the organic material trapped in bones.

Broadly speaking, a part of females’ body is out of the bone; it is composed by a trunk and a cephalic area from which palps emerge. Palps are reddish as a result of blood vessels and they work as gills as they are responsible for respiration. Roots containing bacteria are located at bone’s inner part.

Conxita Àvila, researcher from the University of Barcelona and the Research Institute in Biodiversity (IRBio), explains that “the most interesting fact is that both species were found at really close locations, but at different depths. Therefore, they are two species adapted to different depths due to bathymetry differences, as it can be observed on the genetic studies developed . . . To date”, adds the researcher, “most species were found at a depth of hundreds or even thousands of metres, whereas O. deceptionensis, found at a depth of 20 metres, is the first one discovered at such a low depth”.

“In the 2010 campaign, even if we only found a 2 mm specimen, we had enough information to describe the species. We were able to develop a morphological and genetic analysis from that female specimen. In later campaigns, we have been able to collect more specimens, so a better description of the species and group relationship has been done”, explains Sergio Taboada (University of Barcelona).

“Obviously, Antarctic difficult conditions to collect samples stress the importance of the discovery”, highlights Javier Cristobo (IEO). “To dive in cloudy waters which are at -1.5 ºC and carry out experiments during one year implies a really careful logistics preparation”. Moreover, researches have been able to describe three new species of annelid worms, two Dorvilleidae and one Cirratulidae.

 

Further information:
http://www.ub.edu/web/ub/en/menu_eines/noticies/2013/09/013.html

Comments

[Publicado por: RPor]

Interesting discover and strnage too of course.