Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Cryospheric and Polar Processes Seminar

Why is there so much mercury in permafrost? by Dr. Kevin Schaefer, NSIDC



We estimated the total amount of mercury (Hg) in permafrost soils based on in situ measurements of sediment total mercury (STHg), Soil Organic Carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon.  We measured a median STHg of 43±30 ng Hg g soil-1 and a median RHgC of 1.6±0.9 µg Hg g C-1, consistent with published results of STHg for tundra soils and 11,000 measurements from 4926 temperate, non-permafrost sites in North America and Eurasia. We estimate the northern hemisphere permafrost regions contain 1656±962 Gg Hg, of which 793±461 Gg Hg are frozen in permafrost.  Permafrost soils store nearly twice as much Hg as all other soils, the ocean, and the atmosphere combined, yet global budgets assume little or no Hg in permafrost.  This is ten times the total anthropogenic Hg emissions over the past 30 years and this Hg is vulnerable to release as permafrost thaws over the next century.  Here we explain how we made the estimate, how the Hg got in the permafrost, and what may happen to the Hg in the future.


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Wednesday, February 7, 2018
11:00 am to 12:00 pm




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East Campus, RL-2, Room 155