Navel Gazing: You Might Be Surprised By What’s Living In There

If eyes are the window to the soul, belly buttons are the portal to a tropical rainforest. Bear with us. Newscripts wrote about the Belly Button Biodiversity team last year, complete with photos of petri dishes growing all sorts of bacterial strains straight from participants' navels. Now the Belly Button Biodiversity researchers are back with a PLoS One paper in which they compare the richness of rare bacterial life they found in human navels to that of the biodiversity found in rainforests. "The vast majority of these species are rare. Right away something struck an ecological chord. The belly buttons reminded me of rain forests," team leader and ecologist-turned-microbiogist Dr. Rob Dunn writes of their research.

Petri dishes merely give that belly button bacteria more room to grow. Credit: Belly Button Biodiversity

Dunn explains that some tropical rainforests, despite having many species of trees, have oligarchs--species that are both present in most forests and common when present. And people's belly buttons also seem to have oligarchs. Although there were no species that were found in all samples, the most frequently found species across samples were the also most abundantly found within samples. For example, a common genus of skin bacterium, Staphylococcus, was found widely across the samples. And the inverse is true as well: infrequently found species tended to make infrequent appearances. For instance, the researchers found three phylotypes of Archaebacteria--often found in extreme environments--that have not been previously reported to live on human skin. Perhaps not entirely surprising, two of these three phylotypes were found in the belly button of a participant who acknowledged not having showered or bathed for several years. In a way, the Newscripts gang muses, that might qualify as an extreme environment after all. While the team can predict which species are more or less likely to be found in an individual's belly button, they haven't yet figured out how to explain why certain people have certain sets of bacterial strains. That's next on their agenda, the researchers say. So they'll soon be poking around to see whether lifestyles--including frequency of washing that oft-forgotten crevice--can help determine which bacteria will set up camp in your belly button.

Author: Sophia Cai

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