While it was previously thought that just large concentrations of carbon dioxide and methane were trapped within the permafrost of the Northern Hemisphere, researchers with the American Geophysical Union have recently discovered that this permafrost also contains the largest reservoir of mercury on the planet. Published on February 5th, 2018 in the journal Geophysical Research Letters, the study details their discovery that permafrost in the Northern Hemisphere contains an enormous amount of mercury; a finding that has extremely negative implications for the health of not only humans but ecosystems all over the world.
Permafrost, the permanently frozen soil that occurs in locations with high latitudes, makes up 24% of the land in the Northern Hemisphere and supports various ecosystems. As a result of climate change, permafrost in the Northern Hemisphere is at risk of melting. Model projections that assume anthropogenic greenhouse gas emissions continue at their current rate estimate a 30-99% reduction of the Northern Hemisphere’s permafrost by 2100.
If this occurs, not only will the structural integrity and ecosystems of permafrost regions be at risk, but massive amounts of carbon dioxide, methane, and mercury will be released, harming ecosystems all over the world. Mercury specifically can accumulate in the food chains of both aquatic and terrestrial networks, harming the reproductive and neurological systems of animals.
This study, which took place between 2004 and 2012, had 13 sampling sites across Alaska that represented a variety of characteristics and ages typical of permafrost soils. After analysis in the U.S. Geological Survey (USGS) Research Laboratory in Boulder, Colorado, researchers found that their measurements were consistent with published data on mercury in both samples of permafrost and non-permafrost soils from thousands of other sites worldwide. With these observations they calculated the total amount of mercury stored in permafrost in the Northern Hemisphere and created a map of mercury concentrations in the region.
Based on these observations and calculations, the researchers deduced that the Northern Hemisphere permafrost region contains nearly twice as much mercury as all other soils, the ocean, and the atmosphere combined. They concluded that there is a need to reevaluate the role of the Arctic region in the global mercury cycle.
Paul F. Schuster, Kevin M. Schaefer, George R. Aiken, Ronald C. Antweiler, John F. Dewild, Joshua D. Gryziec, Alessio Gusmeroli, Gustaf Hugelius, Elchin Jafarov, David P. Krabbenhoft, Lin Liu, Nicole Herman-Mercer, Cuicui Mu, David A. Roth, Tim Schaefer, Robert G. Striegl, Kimberly P. Wickland, Tingjun Zhang. Permafrost Stores a Globally Significant Amount of Mercury. Geophysical Research Letters, 2018; DOI: 10.1002/2017GL075571