A new international study which was compiled with the participation of the Universities of Bremen and Hamburg has arrived at some startling conclusions. The drastic retreat of sea ice in the Arctic over the past decade has led to large quantities of bromine being released into the atmosphere – possibly with catastrophic consequences. On the one hand, it results in a breakdown of ozone. On the other, it leads to contamination of the Arctic habitat by large deposits of toxic mercury. What is happening? The shrinkage of the Arctic ice cap causes increased interaction with the salt contained in sea ice, the frosty temperatures found in the region, and sunlight. The resulting release of bromine triggers a chain of chemical reactions known as “bromine explosions” that release bromine molecules into the atmosphere. The bromine subsequently reacts with a gaseous form of mercury, which is then deposited on the Earth’s surface.
Under the leadership of Son Nghiem from the Jet Propulsion Laboratory of NASA, scientists from Canada, Germany, Great Britain, and the USA combined satellite data, a model that depicts the movement of air currents in the atmosphere, and a number of other observations. Their objective was to determine whether there were any linkages between the changes affecting the Arctic sea ice and the bromine explosions occurring from over the Beaufort Sea up to Amundsen Gulf in the Canadian Arctic.
Moreover, they also wanted to find out precisely where in the atmosphere these bromine explosions take place – in the troposphere, the lowest layer and thus in the air we breathe, or in the overlying stratosphere. The environmental physicists assume that in future, when the sea ice becomes increasingly dominated by young ice with higher salinity, the occurrence of bromine explosions will increase. Climate change could also bring about more frequent periods of extreme cold in the Arctic, and thus accelerate the process further. However, scientists are far from being in accord on this score, as illustrated by Prof.Lars Kaleschke from the University of Hamburg and Prof. John Burrows from the University of Bremen when they say: “On the other hand, climate warming might lead to a decrease in bromine explosions, and subsequently to a rise in ozone concentrations at ground level”.
There is therefore a pressing need for more research to determine the amount of mercury released into the environment by bromine explosions. This is the aim of recently started new efforts in the Arctic within the context of the so-called bromine, ozone, and mercury experiment run by NASA (BROMEX). It involves the participation of more than 20 institutions, and once again includes the Universities of Bremen and Hamburg.
For further information contact:
Prof.Dr. John Burrows
Universität Bremen
Phone: +49 421-218-62100
Prof.Dr. Lars Kaleschke
Universität Hamburg
KlimaCampus
Phone: +49 40-42838-6518.
