Researchers at University of York and Leeds discovered a previously unknown marine source of iodine oxide. They detected emissions of hypoiodus acid (HOI) gas, coupled with molecular iodine (I2). The gas was not considered as released from the oceans before.
The study is a continuation of previous work that has established that the ozone above the Atlantic ocean depleted rapidly due to concentrations of reactive iodine and bromine.
Until now, concentrations of reactive iodine in the atmosphere above the oceans have been thought to have occurred as a result of emissions of organic compounds from phytoplankton.
Based on the findings from a number of laboratory experiments, the researchers were able to demonstrate how iodide reacts with ozone to form molecular iodine and hypoiodous acid. The publication co-authored by Professor Lucy Carpenter, of the Department of Chemistry at York, ran several laboratory models, proving that as much as 75% of observed iodine oxide over the Atlantic occurs due to this reaction that takes place on the sea surface at a significant rate.
According to Carpenter, through this research, they were able to identify a self-destructing mechanism for ozone. The findings also show how radionucleides of iodine in seawater are re-emitted into the atmosphere.
Professor John Plane, from the University of Leeds’ School of Chemistry, states that these findings are of a particular importance for oceans in the tropics, because there is much more available iodide in the seawater, and the warmer temperatures increase the rate of the reaction. This newly discovered negative feedback should be taken into serious consideration when regulations about pollution in the outflows from major cities are set.