Mercury is a neurotoxic element found naturally in the environment, but human activities such as fossil fuel combustion, mining, smelting and waste combustion have increased global atmospheric mercury pollution by a factor of three to five over the last 150 years. That increased pollution can then be transported thousands of miles through the atmosphere to fragile ecosystems in the Arctic.
"Mercury is one of the most fascinating elements, because it has very complex cycling between the atmosphere, soil, snow, and plants," said Obrist. "The reason for this is that mercury is semi-volatile so that atmospheric deposition is subject to re-emission back to the atmosphere. So the degree of this re-emission can ultimately determine the exposure of ecosystems to atmospheric mercury pollution."
Funded by the NSF Arctic Natural Sciences Program, Obrist and his colleague Detlev Helmig, from the Institute for Alpine and Arctic Research (INSTAAR) at the University of Colorado, Boulder, will assess the theory that, in the Arctic, extended periods exist when mercury deposition to tundra ecosystems is enhanced.
This enhancement may be due to a chemical conversion of gaseous mercury, which can be easily re-emitted to the atmosphere, to forms that like to remain in the snow. Then when the snow melts this additional mercury retained by the snow gets transferred into aquatic ecosystems, where it may more easily accumulate in fish and wildlife. In this four-year study, Obrist and Helmig will measure mercury in the atmosphere, in snowpack, and in underlying tundra soil, to track how mercury moves in the tundra.
"An important aspect of our study," Obrist said, "is that we also study the role of soils. This is highly relevant since Tundra soils are undergoing fast changes, experiencing longer thawing periods and loss of permafrost."
While laboratory work and project planning will take place both in Reno, Nev. and in Boulder, Colo., intensive field campaigns will be done at Toolik Field Station in Alaska, which is operated and managed by the University of Alaska Fairbanks with support from the Office of Polar Programs Division of Arctic Sciences at NSF.
Obrist said the project will directly involve high school, undergraduate, and graduate students from both Nevada and Colorado.
"We're hoping to also expand an existing partnership with local high school chemistry classes through research presentations in classrooms, laboratory tours, and data analysis," he added, "and hopefully bringing up students and teachers with us to the research station in Alaska."
Provided by Desert Research Institute
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