Scientists have discovered massive reserves of mercury hidden in permafrost. Permafrost is a thick subsurface layer of soil that remains below freezing point throughout the year, occurring primarily in the polar regions.



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

Method of Discovery

• Scientists measured mercury concentrations in permafrost cores from Alaska.
• They estimated the amount of mercury that has been trapped in permafrost north of the equator since the last Ice Age.
• Between 2004 and 2012, researchers 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.

The Discovery

• Researchers have discovered permafrost in the northern hemisphere that stores massive amounts of natural mercury.
• The study found approximately 793 gigagrams, or more than 15 million gallons of mercury frozen in northern permafrost soil. 
• The study also found that all frozen and unfrozen soil in northern permafrost regions contain a combined 1656 gigagrams of mercury, making it the largest known reservoir of mercury on the planet. 
• These northern permafrost soils are the largest reservoir of mercury on the planet, storing nearly twice as much mercury as stored in other soils, the ocean and the atmosphere collectively.

Implications of the discovery on human health and ecosystems

• This discovery may have significant implications on human health and ecosystems worldwide as exposure to mercury can cause serious health problems.
• As per the scientists, there would be no environmental problem if everything remains frozen, but that is not certain.
• Warmer air temperatures due to climate change could melt much of the existing permafrost layer in the northern hemisphere. This melting permafrost could release a large amount of mercury that could potentially affect ecosystems around the world. 
• And if this happens, Mercury has a tendency to get accumulated in aquatic and terrestrial food chains, leading to harmful neurological and reproductive effects on animals.
• Moreover, if the mercury is transported across waterways, it could be taken up by microorganisms and transformed into methylmercury, a form of mercury that is a dangerous toxin that causes neurological effects in animals ranging from motor impairment to birth defects.
• Mercury released into the atmosphere can also travel large distances and could affect communities and ecosystems thousands of miles away from the release site.