Permafrost

Scary Amounts of Mercury Have Been Found Lurking in The Permafrost

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If it melts, we could be in trouble.

The northern hemisphere’s permafrost regions have been concealing a really unpleasant surprise: mercury. A lot of mercury. Nearly twice as much mercury as the rest of the planet’s natural mercury combined.

Researchers from the US Geological Survey studied core samples from the Alaskan permafrost, and their estimates show 793 million kilograms of mercury have been trapped in the northern hemisphere’s permafrost since the last Ice Age.

This finding has grave implications if the permafrost melts away.

And the melt has already started happening – in the Arctic, melting permafrost has revealed some giant (thankfully dormant) viruses tens of thousands of years old that could awaken and wreak havoc.

Deforestation has caused permafrost melt in Siberia, which in turn caused the ground to collapse into a giant crater; and in other parts of Siberia, permafrost thaw has been linked to the appearance of mysterious sinkholes and craters.

Now there’s also mercury to worry about. If the permafrost continues to melt, it could release a tremendous amount of mercury, and this could, in turn, impact ecosystems all around the world.

“There would be no environmental problem if everything remained frozen, but we know the Earth is getting warmer,” said lead author Paul Schuster, a hydrologist at the US Geological Survey.

“Although measurement of the rate of permafrost thaw was not part of this study, the thawing permafrost provides a potential for mercury to be released – that’s just physics.”

mercury soil depthThese maps show mercury concentration in micrograms per square metre for four soil depths.

Natural mercury enters the permafrost from the atmosphere. As part of the mercury cycle, atmospheric mercury vapour binds with organic material in the soil, which is then buried by sediment. Over time, it is frozen into the permafrost.

To gauge the mercury levels in the permafrost, Schuster and his team drilled 13 core samples between 2004 and 2012 from different sites around Alaska, selected for their diverse soil characteristics to represent the entire northern hemisphere.

The measurements taken by the team were consistent with published results for other tundra soils, and with 11,000 measurements taken from 4,926 other non-permafrost sites around the world.

According to the team’s calculations, there are 793 gigagrams (793 million kilograms), or more than 15 million gallons, of mercury frozen in the northern hemisphere’s permafrost. That is, the researchers said, roughly 10 times the amount of all human-caused mercury emissions over the last 30 years.

If we include non-permafrost soils in the permafrost regions, there are 1,656 gigagrams of mercury stowed away down there. This is nearly twice as much as is found in non-permafrost regions, the oceans, and the atmosphere combined.

If it were to leach into the waterways, it could have grave implications. Inorganic mercury can be transformed by microbes into methylmercury, a potent neurotoxin. Cases of methylmercury poisoning have occurred in humans after eating fish from methylmercury-contaminated water, and it can cause central nervous system damage and birth defects.

“There’s a significant social and human health aspect to this study,” said Steve Sebestyen, a research hydrologist at the USDA Forest Service in Grand Rapids, Minnesota. Sebestyen was not involved with the study.

“The consequences of this mercury being released into the environment are potentially huge because mercury has health effects on organisms and can travel up the food chain, adversely affecting native and other communities.”

And if the mercury gets into the atmosphere, it could travel around the world.

The next step in Schuster’s research is to model how climate change could cause the permafrost to release mercury, and how it would spread around the world.

“24 percent of all the soil above the equator is permafrost, and it has this huge pool of locked-up mercury,” he said.

“What happens if the permafrost thaws? How far will the mercury travel up the food chain? These are big-picture questions that we need to answer.”

Source: Geophysical Research Letters.

Giant Virus Resurrected from Permafrost After 30,000 Years

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An ultrathin section of a Pithovirus particle in an infected Acanthamoeba castellanii cell observed by transmission electron microscopy with enhancement

pithovirus section
A mysterious giant virus buried for 30,000 years in Siberian permafrost has been resurrected.

The virus only infects single-celled organisms and doesn’t closely resemble any known pathogens that harm humans.

Even so, the new discovery raises the possibility that as the climate warms and exploration expands in long-untouched regions of Siberia, humans could release ancient or eradicated viruses. These could include Neanderthal viruses or even smallpox that have lain dormant in the ice for thousands of years.
“There is now a non-zero probability that the pathogenic microbes that bothered [ancient human populations] could be revived, and most likely infect us as well,” study co-author Jean-Michel Claverie, a bioinformatics researcher at Aix-Marseille University in France, wrote in an email. “Those pathogens could be banal bacteria (curable with antibiotics) or resistant bacteria or nasty viruses. If they have been extinct for a long time, then our immune system is no longer prepared to respond to them.”

(A “non-zero” probability just means the chances of the event happening are not “impossible.”)

Giant viruses

In recent years, Claverie and his colleagues have discovered a host of giant viruses, which are as big as bacteria but lack characteristic cellular machinery and metabolism of those microorganisms. At least one family of these viruses likely evolved from single-celled parasites after losing essential genes, although the origins of other giant viruses remain a mystery, Claverie said. [Tiny Grandeur: Stunning Images of the Very Small]

In the researchers’ hunt for more unknown pathogens, they took a second look at permafrost samples collected from Kolyma in the Russian Far East in 2000. Because the permafrost was layered along steep cliffs, drillers could extract samples from 30,000 years ago by drilling horizontally into the ice, thereby avoiding contamination from newer samples.

The team then took samples of this permafrost and put them in contact with amoebas (blob-like single-celled organisms) in Petri dishes. The researchers then waited to see what happened.

Some of the amoebas burst open and died. When the scientists investigated further, they found a virus had killed the amoebas.

The ancient virus infects only amoebas, not humans or other animals. This pathogen belongs to a previously unknown family of viruses, now dubbed Pithovirus, which shares only a third of its genes with any known organisms and only 11 percent of its genes with other viruses. Though the new virus resembles the largest viruses ever found, Pandoraviruses, in shape, it is more closely related to classical viruses, which have an isocahedral shape (with 20 triangular-shaped faces), Claverie said.

Pathogens reawakened?

The findings raise the possibility that other long-dormant or eradicated viruses could be resurrected from the Arctic. As the climate warms and sea ice and permafrost melt, oil and mining companies are drilling many formerly off-limit areas in Russia, raising the possibility that ancient human viruses could be released.

For instance, Neanderthals and humans both lived in Siberia as recently as 28,000 years ago, and some of the diseases that plagued both species may still be around.

“If viable virions are still there, this is a good recipe for disaster,” Claverie said. “Virions” is the term used for the virus particles when they are in their inert or dormant form.

But not everyone thinks these viruses spell potential doom.

“We are inundated by millions of viruses as we move through our everyday life,” said Curtis Suttle, a marine virologist at the University of British Columbia in Canada, who was not involved in the study. “Every time we swim in the sea, we swallow about a billion viruses and inhale many thousands every day. It is true that viruses will be archived in permafrost and glacial ice, but the probability that viral pathogens of humans are abundant enough, and would circulate extensively enough to affect human health, stretches scientific rationality to the breaking point.”

“I would be much more concerned about the hundreds of millions of people that will be displaced by rising sea levels than the risk of being exposed to pathogens from melting permafrost.”

Mammoth carcass found in Siberia.

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A well-preserved mammoth carcass has been found by an 11-year-old boy in the permafrost of northern Siberia.

The remains were discovered at the end of August in Sopochnaya Karga, 3,500km (2,200 miles) northeast of Moscow.

A team of experts from St Petersburg then spent five days in September extracting the body from frozen mud.

The mammoth is estimated to have been around 16 years old when it died; it stood 2m tall and weighed 500kg.

It has been named Zhenya, after Zhenya Salinder, the 11-year-old who found the carcass while walking his dogs in the area.

Alexei Tikhonov, from the St Petersburg Zoology Institute, who led the team excavating the mammoth, said this specimen could either have been killed by Ice Age humans, or by a rival mammoth.

He added that it was well preserved for an adult specimen.

His colleague Sergei Gorbunov, from the International Mammoth Committee, which works to recover and safeguard such remains, said: “We had to use both traditional instruments such as axes, picks, shovels as well as such devices as this “steamer” which allowed us to thaw a thin layer of permafrost.

“Then we cleaned it off, and then we melted more of it. It took us a week to complete this task.”

But several juvenile examples have come to light that are more complete.

Earlier this year, a very well preserved juvenile mammoth nicknamed Yuka was unveiled by scientists.

Found in the Yakutia region of Russia, it preserves much of its soft tissue and strawberry-blonde coat of hair. There were also signs from its remains that humans may have stolen the carcass from lions and perhaps even stashed it for eating at a later date.

Source:BBC