Sea spiders ‘farm’ methane-eating bacteria on their bodies

Creatures in the shape of a spider living near methane ooys on the seabed seem to cultivate and consume microbial species on their bodies that feed on energy rich in energy. This widens all the organizations known to rely on symbiotic relationships with microbes to live in these environments of another world.

Shana Goffredi to Western College of California and his colleagues collected sea spiders – marine arthropods appointed for their resemblance to arachnids – living nearly three different methane ooys in the Pacific Ocean. They found three species before unknown of the genus Sea Spider Séricosura which seem abundant only close to these gas oozes.

Other types of sea spiders that do not live near the oozes largely eat other invertebrates. But researchers have discovered that new sea spiders seem to obtain most of their nutrition by eating a distinctive whole of bacterial species that live on their bodies. These bacteria harvest energy by metabolizing methane and methanol from the oozing, the energy which would be otherwise inaccessible to sea spiders.

The researchers discovered that bacteria were confined to the exoskeletons of spiders as a “microbial fur coat”, pushing in what Goffredi describes as “volcano” clusters. Bacterial growth layers also had marks like lawn tracks where spiders can have scratched on them using their hard “lips” and three tiny teeth.

To confirm that sea spiders really ate bacteria, the researchers also used a radioactive labeling technique to follow how carbon in methane was consumed by laboratory spiders. “We have seen that methane enter the microbes that are on the surface of the spiders, then we saw that the carbon molecule move into the spider tissues,” explains Goffredi.

Researchers do not think that sea spiders eat only what happens to grow on their exoskeletons. Because the species that live on exoskeletons are distinct from what is generally in the environment, it suggests that a kind of selection process is at stake, explains Goffredi. “Spiders cultivate and definitively cultivate a very special type of community.”

Sea spiders would not be the first organisms to cultivate microbes to access chemical energy. “Whenever we look [at ecosystems around methane seeps]We find it more and more, ”explains Erik Cordes at Temple University in Pennsylvania. He worked with Goffredi on a previous project that found a similar symbiosis in the Tube worms. The abundance of life found near the sun “is fueled by methane and other chemicals and not by the energy of the sun. It’s quite incredible, ”he says.

Cordes stresses that bacteria also want to win by driving on the bodies of sea spiders. Unlike cows on a ranch, they obtain protection and access to better pastures. For example, if an oozing of methane moves to another part of the seabed, sea spiders could move bacteria to the new source. “Sea spiders keep them in the perfect habitat,” he says.