Scientists find massive reserves of mercury hidden in permafrost

Scientists find massive reserves of mercury hidden in permafrost
Maps of mercury concentrations (micrograms of mercury per square meter) in Northern hemisphere permafrost zones for four soil layers: 0-30 centimeters, 0-100 centimeters, 0-300 centimeters, and permafrost. The permafrost map represents the mercury bound to frozen organic matter below the Active Layer Depth (ALD) and above 300 cm depth. Credit: Schuster et al./GRL/AGU.

Researchers have discovered permafrost in the northern hemisphere stores massive amounts of natural mercury, a finding with significant implications for human health and ecosystems worldwide.

In a new study, scientists measured mercury concentrations in permafrost cores from Alaska and estimated how much mercury has been trapped in permafrost north of the equator since the last Ice Age.

The study reveals northern permafrost soils are the largest reservoir of mercury on the planet, storing nearly twice as much mercury as all other soils, the ocean and the atmosphere combined.

The new study was published today in Geophysical Research Letters, a journal of the American Geophysical Union.

"This discovery is a game-changer," said Paul Schuster, a hydrologist at the U.S. Geological Survey in Boulder, Colorado and lead author of the new study. "We've quantified a pool of mercury that had not been done previously, and the results have profound implications for better understanding the global mercury cycle."

Warmer air temperatures due to climate change could thaw much of the existing permafrost layer in the . This thawing permafrost could release a large amount of mercury that could potentially affect ecosystems around the world. Mercury accumulates in aquatic and terrestrial food chains, and has harmful neurological and reproductive effects on animals.

"There would be no environmental problem if everything remained frozen, but we know the Earth is getting warmer," Schuster said. "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."

The new findings have major implications for understanding how Earth stores mercury and for human and environmental health, according to James Shanley, a research hydrologist at the U.S. Geological Survey in Montpelier, Vermont, who was not involved with the new research.

"This study is very novel and makes a big discovery in an area that was previously somewhat ignored," Shanley said. "It shows permafrost represents a huge source of mercury, and if it thaws due to climate change the mercury could be released and could significantly add to the global mercury burden."

Tackling an unknown question

Natural mercury found in the atmosphere binds with organic material in the soil, gets buried by sediment, and becomes frozen into permafrost, where it remains trapped for thousands of years unless liberated by changes such as .

Schuster's team determined the total amount of mercury locked up in permafrost using field data. Between 2004 and 2012, the study authors drilled 13 permafrost soil cores from various sites in Alaska, and measured the total amounts of mercury and carbon in each core. They selected sites with a diverse array of soil characteristics to best represent permafrost found around the entire northern hemisphere.

Schuster and his colleagues found their measurements were consistent with published data on mercury in non-permafrost and permafrost soils from thousands of other sites worldwide. They then used their observed values to calculate the total amount of mercury stored in permafrost in the northern hemisphere and create a map of mercury concentrations in the region.

The study found approximately 793 gigagrams, or more than 15 million gallons, of mercury is frozen in northern permafrost soil. That is roughly 10 times the amount of all human-caused mercury emissions over the last 30 years, based on emissions estimates from 2016.

The study also found all frozen and unfrozen soil in northern permafrost regions contains a combined 1,656 gigagrams of mercury, making it the largest known reservoir of mercury on the planet. This pool houses nearly twice as much mercury as soils outside of the northern permafrost region, the ocean and the atmosphere combined.

The effects of the released mercury

Scientists are still unsure how much of the stored mercury would affect ecosystems if the permafrost were to thaw. One major question revolves around how much of the mercury would leach out of the soil into surrounding waterways, according to Steve Sebestyen, a research hydrologist at the USDA Forest Service in Grand Rapids, Minnesota, who was not involved with the new research.

If the mercury is transported across waterways, it could be taken up by microorganisms and transformed into methylmercury, he said. This form of mercury is a dangerous toxin that causes neurological effects in animals ranging from motor impairment to birth defects.

"There's a significant social and human health aspect to this study," Sebestyen said. "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."

Edda Mutter, science director for the Yukon River Inter-Tribal Watershed Council, said the new study demonstrates thawing permafrost could have grave consequences for local ecosystems and indigenous communities in the northern hemisphere.

"Rural communities in Alaska and other northern areas have a subsistence lifestyle, making them vulnerable to methylmercury contaminating their food supply," Mutter said. "Food sources are important to the spiritual and cultural health of the natives, so this study has major health and economic implications for this region of the world."

The release of mercury could also have far-reaching global consequences, according to Shanley. Mercury released into the atmosphere can travel large distances and could affect communities and ecosystems thousands of miles away from the release site, he said.

Schuster believes his team's research gives policymakers and scientists new numbers to work with and calibrate their models as they begin to study this new phenomenon in more detail. He intends to release another study modeling the release of mercury from permafrost due to climate change, and said this work changes scientists' perspective of the global mercury cycle.

"24 percent of all the above the equator is permafrost, and it has this huge pool of locked-up mercury," he said. "What happens if the thaws? How far will the travel up the food chain? These are big-picture questions that we need to answer."

Explore further

Mercury from industrialized nations is polluting the Arctic – here's how it gets there

More information: Paul F. Schuster et al, Permafrost Stores a Globally Significant Amount of Mercury, Geophysical Research Letters (2018). DOI: 10.1002/2017GL075571
Journal information: Geophysical Research Letters

Citation: Scientists find massive reserves of mercury hidden in permafrost (2018, February 5) retrieved 19 October 2019 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

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User comments

Feb 05, 2018
Wow, they just keep on finding new and different ways GW is gonna kill us.

Feb 05, 2018
wow ! stake a claim , start mining !

Feb 06, 2018
Wow, they just keep on finding new and different ways GW is gonna kill us.

Wow no sh%& monkey goracle and FIY the list is growing by the day if you care to stop swing those branches and at least try to think you will realize we actually live in reality. A place where your echos from the bubble you live in from your own sockpuppets don't exist.

Feb 06, 2018
wow ! stake a claim , start mining !

Wow ! Total Moron, no respect for the earth nor a care in the world ! Stop swinginging those trees and stop chest thumping ! start thinking !

Feb 06, 2018
Another "game-changer"! Since the Arctic was supposed to be ice-free in two years, I wonder which game is changing? And how?

Can one of the True Believers point me to a chart that shows this is the hottest it's ever been? Because a temperature reconstruction of the past 2000 years shows it was hotter about 1000 years ago. (http://www.drroys...atures/) Why wasn't the mercury liberated then?

Feb 06, 2018
How many oz /ton ? $$$$$$ !

Feb 06, 2018
Mercury in the arctic is measured in nano grams / li thats 1 x10 minus 9 grams , [or in micrograms ,thats a millionith of a gram per CUBIC METER , too make the number bigger] i found a random paper with higher background levels in WA state. In other words if they are measuring in nanograms one would expect to ask what is the normal background in the rest of the world . i think they are using the tolal mass of the permafrost to create more climate alarmism . & yes i can post the ref [ i'm too lazy now]

Feb 25, 2018
The https://en.wikipe..._in_fish in marine fish is currently well above 1 mg/kg and they're still recommended as an nutrient product.

And yet your link shows only 1 fish above 1 mg/kg, and it's one in the list of fish where consumption should be limited to only a few times a month. Not above torturing the data to "prove" your point, eh?

Feb 25, 2018
The more I think about it, the more uncertain I am as to what mackita/Zephir's point is. That we shouldn't eat soil?

Mar 21, 2018
So there goes the fall back plan to turn the northern wastelands to new breadbaskets.

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