The cracks in the Arctic sea ice may be doing more than just helping in global warming and raising sea levels, as a new research published January 15 says tiny tempests above the cracks in Arctic sea ice help pull down toxic mercury and ozone from the sky, becoming an unexpected new source of mercury pollution in the polar environment.
Vigorous mixing in the air above large cracks in the sea ice that expose seawater to cold polar air pumps atmospheric mercury down to the surface, according to a NASA field campaign published in the journal Nature. This process can lead to more of the toxic pollutant entering the food chain, where it can negatively affect the health of fish and animals who eat them, including humans.
An Unpleasant Surprise
Scientists measured increased concentrations of mercury near ground level after sea ice off the coast of Barrow, Alaska, cracked, creating open seawater channels called leads. The researchers were in the Arctic for the NASA-led Bromine, Ozone, and Mercury Experiment (BROMEX) in 2012.
“None of us had suspected that we would find this kind of process associated with leads,” said Son Nghiem, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. Nghiem is the BROMEX principal investigator and a coauthor of a paper reporting the discovery.
“This came as a surprise,” Daniel Obrist, an atmospheric scientist at the Desert Research Institute in Nevada and a co-author of the study, told Live Science.”We would not have thought that this physical mixing would lead to a resupply of mercury.”