Where Only Robots Dare to Tread
As Warming Planet Grows Hostile to Humanity
Will Humanity Be Forced to Merge
with Humanoid Robots to Escape a Hostile Planet?
Dangers lying in wait
Science fiction is rife with fanciful tales of deadly organisms emerging from the ice and wreaking havoc on unsuspecting human victims.
From shape-shifting aliens in Antarctica, to super-parasites emerging from a thawing woolly mammoth in Siberia, to exposed permafrost in Greenland causing a viral pandemic – the concept is marvelous plot fodder.
But just how far-fetched is it? Could pathogens that were once common on Earth – but frozen for millennia in glaciers, ice caps and permafrost – emerge from the melting ice to lay waste to modern ecosystems? The potential is, in fact, quite real.
In 2003, bacteria were revived from samples taken from the bottom of an ice core drilled into an ice cap on the Qinghai-Tibetan plateau. The ice at that depth was more than 750,000 years old.
In 2014, a giant “zombie” Pithovirus sibericum virus was revived from 30,000-year-old Siberian permafrost.
And in 2016, an outbreak of anthrax (a disease caused by the bacterium Bacillus anthracis) in western Siberia was attributed to the rapid thawing of B. anthracis spores in permafrost. It killed thousands of reindeer and affected dozens of people.
More recently, scientists found remarkable genetic compatibility between viruses isolated from lake sediments in the high Arctic and potential living hosts.
Earth’s climate is warming at a spectacular rate, and up to four times faster in colder regions such as the Arctic. Estimates suggest we can expect four sextillion (4,000,000,000,000,000,000,000) microorganisms to be released from ice melt each year. This is about the same as the estimated number of stars in the Universe.
However, despite the unfathomably large number of microorganisms being released from melting ice (including pathogens that can potentially infect modern species), no one has been able to estimate the risk this poses to modern ecosystems.
Giant viruses in the forest soil
Scientists have discovered an “astounding diversity” of giant viruses taking on “previously unimaginable” shapes and forms in just a few handfuls of forest soil.
These giant viruses have alien-looking appendages and internal structures that have never been seen before.
The soil sample was collected in 2019 from Harvard Forest, a short drive from Boston in the US.
It was flown to the Max Planck Institute in Germany, where it was examined using transmission electron microscopy, a process that magnifies objects using a beam of electrons.
This revealed that the soil was packed with giant viruses up to 635 nanometers in width.
These giants are smaller than the largest virus ever discovered (which is 1,500 nm wide) but much larger than the viruses that humans usually encounter (COVID-19, for instance, is 50–140 nm).
The researchers could be “quite confident” that they were looking at viruses (rather than structures discarded from cells) because the shells, called capsids, have distinctive shapes, including the unmistakable icosahedral shape of a 20-sided polygon.
“Transmission electron microscopy … revealed an astounding diversity of virus-like particles,” write the researchers.
“Amazingly, we found that a few hundred grams of forest soil contained a greater diversity… than… all hitherto isolated giant viruses combined.”
Giant viruses that parasitize algae have been studied for decades. But the field really took off in 2003 when the first giant (400-nm-wide) virus growing in amoebae was found in a cooling tower in England. It was named ‘mimivirus’ as it mimicked the appearance of bacteria.
A world record was set in 2010 with the discovery of the whopping 700-nm-wide Megavirus chilensis off the coast of Chile.
In 2013, a 1,000-nm pandoravirus was found in a pond in Melbourne. It was named after the mythical Pandora’s Box.
The current record-holder is the 1,500-nm-wide Pithovirus sibericum, a giant virus buried in the Siberian permafrost for 30,000 years but discovered when the ice thawed in 2014.