Iodine from the sea influences the global climate. It enters the atmosphere from the oceans, destroys ozone and contributes to cloud formation. Iodic acid plays a central role in these processes. With the international CLOUD experiment at the European Laboratory for Particle Physics CERN in Geneva (Switzerland), a research team with Austrian scientists has now been able to clarify how iodine acid is formed.
The researchers reported on this in the journal “Nature Chemistry”. Thus, so-called condensation nuclei are needed so that water vapor in the atmosphere can become droplets and then clouds. They can come from leftovers from human activities, such as soot particles, or from natural processes, such as small grains of sand or aerosols.
Iodine emissions have tripled since 1950
Last year, the CLOUD team demonstrated the important role of iodine and iodine acid in this process. This is important because iodine emissions in the Northern Hemisphere have tripled since 1950.
Ice in the Arctic is getting thinner
Iodine is formed when ozone (O3) reacts with iodide dissolved in sea water. When released into the air through the oceans, it acts as a catalyst in the depletion of ozone, but is not consumed in the process. The problem with this is that human activities are causing an increase in ground-level ozone and rising temperatures. As a result, the ice in the Arctic is thinning and more iodide dissolved in water can come into contact with ozone and release iodine. Both effects increase iodine emissions.
Armin Hansel and colleagues from the University of Vienna are part of the research team using the CLOUD (Cosmics Leaving Outdoor Droplets) large-scale experiment at CERN for their work. There, in a stainless steel tank of 26 cubic meters, the formation of aerosol particles and clouds can be investigated under extremely precisely controllable conditions.
A central intermediate step in the cycle in which iodine enters the atmosphere from the oceans, forms aerosols and ultimately destroys ozone, is the formation of gaseous iodic acid (HIO3) in the atmosphere. In the current work, the researchers were able to decode the individual steps of this response pathway not only in the CLOUD experiment, but also through field measurements at the Maido Observatory in the French overseas department of Réunion.
They showed that gaseous iodine in the atmosphere forms reactive radicals that actually only intervene under the influence of light in chemical reactions near the coast or above the oceans and destroy ozone. However, because iodine can be transported in aerosol particles over long distances and is released far from the source, the iodine cycle has global effects.
Source: Krone
I’m Wayne Wickman, a professional journalist and author for Today Times Live. My specialty is covering global news and current events, offering readers a unique perspective on the world’s most pressing issues. I’m passionate about storytelling and helping people stay informed on the goings-on of our planet.
