“Frozen virus comes back to life 30,000 years later” sounds like a producer’s pitch for a really bad science fiction monster film, but one frozen virus did just that in a French laboratory recently. The organism, called Pithovirus sibericum, belongs to a new class of giant viruses that were first discovered 10 years ago.
This particular frozen virus was found in a core sample taken from the Siberian permafrost layer as part of a study to monitor conditions in the permafrost layer. No one goes looking for giant viruses under the Siberian permafrost. Scientists were evaluating the condition of the permafrost by taking core samples and the virus was discovered in one of the core samples.
Permafrost is soil – dirt – that has remained frozen for two years or more. It consists of two layers, relatively thin “active” layer that thaws out during the summer months for a certain length of time each year and the densely frozen “under-layer” – the true permafrost – which has remained frozen, we know now, for more than 30,000 years.
The active layer can be anywhere from a fraction of an inch to more than four meters of dirt that freezes and thaws on a yearly cycle. This thawed top layer hosts a wide array of vegetation during the summer months, providing grazing for animals and farming sites for humans in the region.
Twenty-four percent of the ice-free areas of the Northern Hemisphere are affected by permafrost, an area covering more than 19 million square kilometers or 49 million square miles. The permafrost layer can be up to 1,494 meters (4,898 feet) thick. More carbon is stored in the permafrost layer as methane or peat than exists in all living things. There is twice as much carbon stored in the permafrost than exists in Earth’s atmosphere.
Monitoring the condition of the permafrost is important because of the devastating impact on the planet’s ecology that would result if a substantial percentage of the carbon locked in the permafrost were to be released by continued climate change. That probably won’t happen overnight, because scientists estimate that it took over half a million years to solidify three-quarters of a mile of direct.
There is not much that anyone can do to stop the melting of the permafrost layer, except to worry about it. Now, with the discovery of this “Ichabod Crane” virus, scientists have something else to worry about.
As giant viruses go, this one is a real behemoth, measuring 1.5 micro microns in length which is equal to one trillionth of a meter. Unlike smaller viruses, this one is actually big enough to be seen under a standard microscope. Anyone thinking this is the oldest living thing on Earth would be wrong.
This particular virus would make a poor science fiction movie monster because it only attacks and kills amoebas so, unless you keep amoebas around the house as pets, you are safe from this particular virus. Amoebas are really, really tiny single cell organisms that don’t do much of anything other than eating and reproducing asexually. It does not appear to infect humans or animals, other than the amoeba.
The Pithovirus sibericum virus kills amoebas by invading the organism and multiplying until it strangles the amoeba from the inside out. The virus in question was found buried 100 feet under the surface of the permafrost layer, and it is the oldest surviving organism to come back to life when thawed out, hence the Ichabod Crane nickname.
Scientists are concerned about the possibility that there might be other, far more dangerous viruses hidden in the permafrost that may come out to bite us. The scientists that revived the giant virus believe that there may be other, far more dangerous things lurking in the permafrost.
The concerns about the dangerous things that might lay under the permafrost are related to increasing industrial activity in the permafrost regions. As mining and drilling operations increase, they weaken the permafrost. Climate change that warm and cool the transpolar regions will call a freeze and thaw cycle that could release more viruses from captivity.
Now that scientists know that one frozen virus can come back to life after 30,0000 years in hibernation, scientists are deeply concerned about other viruses might crawl out of the deep cold dark to attack the human with old, familiar viruses as well strange new ones for which we have no prevention or cures.
Environmental scientists are becoming alarmed at the rate with which the Siberian permafrost is melting and releasing methane into the atmosphere. One symptom of the big thaw is that the Siberian people are hunting mammoths again for the first time in 4,500 hundred years. The mammoths are dead, of course, but they are coming back into the light of day as the permafrost around them melts to reveal sometimes perfectly preserved specimens…. and the Siberians are still hunting for the preserved remains of ancient long-death mammoths, which can still be sold to museums and collectors. No one is very happy about seeing them, not even the mammoth hunters, because of the implications of the big thaw.
The implications, when a frozen virus comes back to life 30,000 years after it went into the deep freeze, has chilling implications for both climate change and public health concerns about unknown viral agents. The Siberian people are selling artifacts retrieved from the melting permafrost online right now. They are appearing all over the world, and no one knows whether or not old – or new – deadly viruses are being shipped with them.
By Alan M. Milner