For the first time ever researchers have found a link between "Arctic sea ice dynamics" the variable chemistry of the surrounding air; this phenomenon could lead to an increase of mercury deposits in "fragile" ecosystems on the Earth's far north.
Giant cracks in sea ice that allow warmer water to reach the frigid polar ice cap have been known to create a "pumping effect"; this coupled with ozone destruction could be putting the polar region in danger, a Desert Research Institute news release reported.
"The atmospheric mixing created when thinner, seasonal sea ice opens to form leads is so strong that it actually pulls down mercury from a higher layer of the atmosphere to near the surface," Doctor Chris Moore, of Nevada's Desert Research Institute, said.
Researchers were already aware of a complex chemical process that uses sunlight to remove mercury from the air and deposit it onto the surface, but researchers always thought this process stopped after the ground-level mercury had been removed.
"The newly discovered mixing induced by sea ice leads forces down additional mercury to restart and sustain these reactions," the news release reported.
The researchers worked with a team from NASA's Jet Propulsion Laboratory and to measure ground-level mercury levels in icy Barrow, Alaska. The team also employed NASA's Moderate Resolution Imaging Spectroradiometer to look at the composition of the sea ice and a National Oceanic and Atmospheric Administration model to observe local air transport.
"The 'aha' moment came when we combined satellite data with the air transport model and surface measurements. We considered a variety of chemical processes and sources to explain the increased levels of mercury we observed, until we finally realized it was this pumping process," Doctor Daniel Obrist, also a research professor at DRI and co-leader of the Institute's Environmental Mercury Laboratory, said.
The researchers concluded mercury pumping takes place around a quarter-mile above the Arctic surface. The findings highlight the fact that mercury pollution is a problem across the world.
"Future research will be needed to establish the degree to which changes in sea ice dynamics across the Arctic alter ozone chemistry and impact mercury deposition throughout the sensitive region," the news release reported.
An additional study found "unprecedented" levels of chlorine in the atmosphere in the same region.
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