Deep beneath the seabed of the Arctic Ocean, researchers have found some very unexpected residents: dozens of new chlamydiae species, cousins of the bacteria that are not so welcome above ground.
It isn’t just the remote location that’s surprised scientists. The sediments here beneath the Arctic Ocean are also devoid of oxygen, crushed by high pressure, and home to no potential hosts for the bacteria. Although certainly unexpected, these unusual conditions could help us understand how other chlamydiae species came to be a prolific pathogen in people and animals alike.
"Finding Chlamydiae in this environment was completely unexpected and, of course, begged the question what on earth were they doing there?" Jennah Dharamshi from Uppsala University in Sweden and lead author of the study said in a statement.
Reporting in the journal Current Biology, a team of Swedish microbiologists found chlamydiae bacteria in sediment core samples dug out from 3 kilometers (1.8 miles) beneath the seabed of a hydrothermal vent field located in the Arctic Ocean between Iceland, Norway, and the Norwegian archipelago, Svalbard. By sequencing the DNA of the microbes found in the samples, they identified a considerable number of new species of chlamydiae, relatives of the bacteria responsible for sexually-transmitted chlamydia infections in humans and koala bears.
But, don't fret: There's no fear of these new seabed-dwelling bacteria ever infecting humans. Chlymidiae usually depend on host organisms to survive, spending their lives in the cells of heir host. As the researchers note, these don't appear to have any host organism at all.
“We found a wide diversity of Chlamydia-related organisms in marine sediments. It is hard to say exactly how many species we found, but perhaps up to several hundred," Thijs Ettema, study author and molecular biologist from Uppsala University, told IFLScience.
“I would like to clearly state that none of these Chlamydiae are pathogens of humans,” Ettema added. “They likely do not even have a host organism. If they do, their hosts will likely be plankton cells."
Curiously, the researchers were not able to grow any of these new species in the lab, which limits what they can currently learn about the bacteria. The researchers believe this is because the bacteria are part of a network that requires compounds from other microbes living in the marine sediments. It does, however, indicate that chlamydiae might play a surprisingly integral role in the microbial communities living in zero-oxygen marine environments. In fact, in some cases, they might even be the dominant bacteria present.
"Chlamydiae have likely been missed in many prior surveys of microbial diversity," adds study author Daniel Tamarit. "This group of bacteria could be playing a much larger role in marine ecology than we previously thought."