The Mystery of 'Venus's Hair' After a Volcanic Eruption
How do long, white filaments grow out of barren rock?
In the summer of 2011, earthquake swarms started hitting the Canary Islands off the African coast. The ocean belched up sulfur, staining the water yellow and green. Fish died. Seawater bubbled over like a jacuzzi. Smoking lava balloons leapt from the roiling surface.
These violent events were all hallmarks of an erupting underwater volcano, which over 138 days blanketed the seafloor with newly formed volcanic rock.
By the time a group of Italian and Spanish scientists sailed to the Tagoro Volcano in 2014, things had quieted down—geologically, at least. Biologically, something extraordinary was happening. The once barren rock was now covered in a lush carpet of long, white hair, the size of eight tennis courts. “It was an impressive and surreal landscape, like discovering life on Mars,” one of the researchers, Cinzia Corinaldesi, a marine biologist at Polytechnic University of Marche, told me in an email.
What was this “life” they had discovered? The team sent a remote-operated vehicle to pluck several strands of the white hair, which was likely a new microbe. In the water, the undulating hair had a divine serenity. So they called it Venus’s hair, after the Roman goddess of love who was born of sea foam and wed to Vulcan, the god of fire and volcanos. “However, when Venus’s hair was pulled out of the seawater,” Corinaldesi wrote, “the aspect of the hair changed, losing as if by magic beauty and fullness.” And like most microbes, the Venus’s hair refused to grow in a lab.
That might have been the end of the Venus’s hair investigation in a previous era, but today’s microbiologist have powerful genetic tools at their disposal. The “hair” went limp and lost its magic out of the water, but it was no less full of DNA. Corinaldesi and her co-authors report the DNA sequencing results in a Nature Ecology & Evolution paper, where they lay out the evidence that Venus's hair is indeed a new species of bacteria.
The hairs themselves turn out to be bacterial cells, strung together and covered in a protective sheath. The DNA sequencing, though only 82 percent complete, shows some clues about the life of Venus’s hair. The bacteria likely fed on sulfur, which was plentiful in the aftermath of the volcanic eruption. And it had a gene that could allow it to pump out heavy metals, which tend to leach out of newly formed volcanic rock.
Volcanic eruptions are ecological reset buttons. They allow scientists to see how a complex ecosystem eventually emerges from barren rock. After an eruption on land, lichens are the first pioneers. In the water, Venus’s hair appears to play that role. It attaches—very firmly—to rock, gaining a foothold for other microorganisms and marine animal larvae. “It’s really acting like a foundation species,” says Craig Moyer, a marine microbiologist at Western Washington University, who was not involved in the study.
Most volcanic vents tend to be either deep underwater, far from land, or both. The Tagoro volcano is neither. “This is the beauty of the system,” says Isabel Ferrara, a microbiologist at the Marine Sciences Institute in Barcelona, Spain, “It’s very close to land and shallow.” Ferrara has also studied the aftermath of Tagoro’s eruption, though she focused on free-floating bacteria in the water. Her collaborators, who are still doing regular surveys of the area, were there as recently as last month. According to them, the Venus’s hair mats have expanded since the 2014 survey, and it now covers even the top of the volcano.
The team that sequenced Venus’s hair is still working on culturing it in a lab and puzzling out the bacteria’s lifestyle. (Where, for example, did it come from? How exactly was it surviving before the volcano released all that sulfur that it likely uses for energy?) One hitch is that they were initially not able to sequence the entire genome, and a crucial gene they missed was for 16S rRNA, a gene classically used to identify and sort microbes.
Moyer notes that the sequencing method the team used, which he himself has used, is sometimes controversial. It involves chopping up all the DNA in a sample, sequencing it all, and sorting the partial sequences into groups by algorithm. Each group is supposed to be roughly equivalent to a different species. But sometimes, the sorting can go wrong. Still, says Moyer, this is a fascinating first go. He’s seen Venus’s hair or similar microbes growing near volcanic vents before, but nobody had systematically studied them. “I’m tickled to see somebody actually take the time to answer these questions,” he says.
How can something so visually arresting never have been studied? Perhaps that tells you just how much is still unknown about the ocean.