Dramatic reductions in Arctic sea ice in the last decades may be intensifying bromine release, which results in ozone depletion and toxic mercury deposition in the Arctic environment, a new study reports.
Appearing in an upcoming edition of the Journal of Geophysical Research – Atmosphere, the NASA-led study involved five members from the University of Manitoba’s Centre for Earth Observation Science (CEOS): David Barber, Feiyue Wang, Gary Stern, Jeffery Latonas, and Matthew Asplin.
The team of scientists found that when the salt in sea ice, frigid temperatures, and sunlight interact with each other, the salty ice releases bromine atoms into the air. This starts a cascade of chemical reactions called a “bromine explosion”, which creates more and more molecules of bromine in the atmosphere. Bromine then reacts with a gaseous form of mercury, turning it into a pollutant that falls to Earth’s surface.
Changing conditions in the Arctic might increase bromine explosions in the future.
Over the past 30 years we have lost a significant proportion of multiyear sea ice (ice that survives the summer melt and grows again the next year). This multiyear sea ice is replaced by much thinner and more salty first year sea ice, which now appears – besides altering the Arctic marine system — to drive contaminant and chemical processes in the atmosphere, said U of M professor and study co-author David Barber. He is a Canada Research Chair in Arctic-System Science and he led the International Polar Year program, which collected the field data used in this study.
“Since the reaction between bromine and mercury greatly enhances the deposition of atmospheric mercury to the surface environment, increased bromine explosions due to sea ice change have the potential to increase mercury input to the Arctic Ocean, though its contribution to the mercury contamination in the Arctic marine ecosystems is an area for further investigation,” said University of Manitoba professor and co-author Feiyue Wang, who led the mercury measurement of the study.
As the world-leaders in sea ice research, the U of M researchers are further investigating the role of frost flowers in this cascade of chemical reactions. Grown on the surface of newly formed sea ice, frost flowers can be several times saltier than seawater and may have played a key role in bromine explosion. Wang and his team have recently recreated frost flowers in the Sea Ice Environmental Research Facility (or SERF) at the University of Manitoba, which is the first experimental sea ice facility in Canada.
“Shrinking summer sea ice has drawn much attention to exploiting Arctic resources and improving maritime trading routes. But the change in sea ice composition also has impacts on the environment,” the study’s lead author, Son Nghiem of NASA’s Jet Propulsion Laboratory, said.
Bromine explosions were first discovered in the Canadian Arctic two decades ago and they have since puzzled scientists. Using an unprecedented combination of European and US satellite observations together with field measurements from the University of Manitoba-led International Polar Year (IPY) program, this study established that the Arctic bromine explosion occurs in the troposphere (the lowest layer of the atmosphere, the air we breathe) and is tied to recent changes in the Arctic’s sea ice.
The study, which has been accepted for publication in the prestigious Journal of Geophysical Research – Atmospheres, was undertaken by an international team from Canada, Germany, United Kingdom, and United States, led by Nghiem
Organizations participating with the University of Manitoba in this study include the NASA Jet Propulsion Laboratory, University of Washington (US), University of Bremen (Germany), NERC Center for Ecology and Hydrology (UK), Purdue University (US), Environment Canada, National Ice Center (US), Department of Fishery and Oceans (Canada), NASA Goddard Space Flight Center (US), and University of Hamburg (Germany).
The study was funded by the Canadian International Polar Year Program, the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs program, Environment Canada, NASA, NOAA, NSF, and several European science agencies.
For more information please contact Dr. Feiyue Wang, Centre for Earth Observation Science, University of Manitoba, at 204-474-6250 (email@example.com),
or Dr. David Barber, Centre for Earth Observation Science, University of Manitoba, at 204-510-6981 (firstname.lastname@example.org),
or Sean Moore, Marketing Communications Office, University of Manitoba, 204-474-7963 (email@example.com).
For video of Frost Flowers and the SERF facility please visit: http://www.youtube.com/watch?v=z_APhab0Tdc
For video of Dr. Barber explaining his previous work on disappearing multiyear Arctic Sea Ice, please visit: http://youtu.be/LjaVp6AS5XU
For media interested in using footage taken from the Arctic right click and save the following: