14 DAY TRIAL // A type of bacteria can remain in hibernation for as much as 100 million years, and this makes them the organisms with the longest known life cycle on the planet. Experts say that the microorganisms live on the Arctic sea floor, and that they make the best use possible of the conditions in their environment.
The organisms were discovered by accident, as investigators were carrying out a scientific study of the sea floor off the Norwegian island of Svalbard. They were looking for patterns of biological activity in sediment samples collected from this location.
What they discovered were bacteria that could apparently live for more than 100 million years, by reducing their metabolism to nearly-undetectable levels. The study was carried out by experts at the Newcastle University, in the United Kingdom.
NU Geosciences Group expert Casey Hubert led the investigators, and he believes that the long hibernation is just a part of a massive biological cycle. His theory is that these organisms in fact develop in hot niches on the ocean floor.
Sweeping currents then remove them from these locations, and moves them into the freezing Arctic seawaters. As sediments accumulate on the ocean floor, the bacteria are buried and frozen.
They remain in this state until sufficient sediments accumulate on top of them to allow for higher temperatures. When this happens, the microorganisms germinate, returning to life. This cycle can last in excess of 100 million years, Daily Galaxy reports.
“It's like there's a seed bank in the sediment of diverse thermophiles. This could explain how thermophiles colonize these subsurface niches and populate the deep biosphere,” the team leader adds.
But not everyone is convinced that the newly-found organisms are part of such a large cycle. Cardiff University geomicrobioloigst John Parkes, for example, says that oceanic circulation needs to be taken into account too.
“The entire ocean is circulated through deep oceanic crust about every million years, so buried sediments could be inoculated as this fluid flows through them on its return to the ocean,” he says.
Regardless of which of the explanations is correct, the fact that microorganisms in general can endure for millions of years has been demonstrated in other studies. Some species were found in submerged Antarctic lakes that were separated from the world outside when the continent was covered in ice.