Bone-eating worms discovered in the Antarctic by Spanish researchers

The new species, together with Osedax antarcticus, found parallel by a 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. Results have been recently published on the journal Proceedings of the Royal Society B and spread by other publications, such as Nature, Science and National Geographic. 

Conxita Àvila, researcher from the University of Barcelona, 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 metres, whereas O. deceptionensis, found at a depth of 20 metres, is the first one discovered at such a low depth”.

This bone-eating worm, which dines on decaying whale skeletons, was found within 2010 campaign of Actiquim-II project in an experiment carried out on Deception Island, at the Spanish Antarctic base Gabriel de Castilla.

Besides Conxita Àvila, professor from the Department of Animal Biology of the UB and member of the Research Institute in Biodiversity (IRBio) of the University, researchers Sergio Taboada, from the former department, and Javier Cristobo, from the Spanish Institute of Oceanography, participated in the research.

“In 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 Taboada.

“Obviously, Antarctic difficult conditions to collect samples stress the importance of the discovery”, highlights Javier Cristobo. “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.

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 femalesʼ 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 femalesʼ 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 boneʼs inner part.

At the Antarctic base Gabriel de Castilla, the team carries out an extensive research activity, which includes laboratory experiment protocols as well as seafloor sampling done by means of aqualung dives into Antarctic waters.

Globally, the project Actiquim-II contributes to integrate the knowledge about marine ecosystemsʼ functional nature and structure, the environmental management and conservation, as well as the ecological basis to develop new bioactive substances with potential uses in pharmaceutical and biotechnological sectors.