Scientists have learned that a massive amount of mercury is currently encased within the Arctic permafrost — which could have significant ramifications for ecological and human health beyond the far North. “This discovery is a game-changer,” Paul Schuster, study lead author and hydrologist at the U.S. Geological Survey in Boulder told AGU. “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.” Of particular concern is the permafrost-enclosed mercury’s relationship to a warming climate. Schuster said, “There would be no environmental problem if everything remained frozen, but we know the Earth is getting warmer.”
In a study published in Geophysical Research Letters, a journal of the American Geophysical Union, scientists recorded mercury concentrations within permafrost cores in Alaska and extrapolated how much of it is estimated to have been trapped in northern permafrost since the last Ice Age. The researchers found that permafrost soils of the north contain the largest store of mercury on the planet, nearly twice as much as all other soils, the ocean, and the atmosphere combined. The mercury originally became trapped within the permafrost when atmospheric mercury bonded to organic material in the soil, then became frozen, stuck until melting.
The release of large quantities of the element, which can negatively impact the reproductive and neurological health of animals, becomes more likely as the permafrost thaws. One concern is that it could contaminate waterways, where it could be absorbed by microorganisms and converted into methylmercury, a dangerously toxic form. While such a massive surge of mercury could affect ecosystems far south of the Arctic, its effects would be felt acutely by local communities. “Rural communities in Alaska and other northern areas have a subsistence lifestyle, making them vulnerable to methylmercury contaminating their food supply,” Edda Mutter, science director for the Yukon River Inter-Tribal Watershed Council, told AGU. “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.” To better understand the risks, the research team plans to produce another study that models the potential impact of the mercury’s release on the global mercury cycle and ecological health.