They have established that the majority of ozone-depleting iodine oxide observed over the remote ocean comes from a previously unknown marine source. The research team found that the principal source of iodine oxide can be explained by emissions of hypoiodous acid (HOI) – a gas not yet considered as being released from the ocean – along with a contribution from molecular iodine (I2).
Since the 1970s when methyl iodide (CH3I) was discovered as ubiquitous in the ocean, the presence of iodine in the atmosphere has been understood to arise mainly from emissions of organic compounds from phytoplankton -- microscopic marine plants.
This new research, which is published in Nature Geoscience, builds on an earlier study which showed that reactive iodine, along with bromine, in the atmosphere is responsible for the destruction of vast amounts of ozone – around 50 per cent more than predicted by the world's most advanced climate models – in the lower atmosphere over the tropical Atlantic Ocean.
The scientists quantified gaseous emissions of inorganic iodine following the reaction of iodide with ozone in a series of laboratory experiments. They showed that the reaction of iodide with ozone leads to the formation of both molecular iodine and hypoiodous acid. Using laboratory models, they show that the reaction of ozone with iodide on the sea surface could account for around 75 per cent of observed iodine oxide levels over the tropical Atlantic Ocean.
Professor Lucy Carpenter, of the Department of Chemistry at York, said: "Our laboratory and modelling studies show that these gases are produced from the reaction of atmospheric ozone with iodide on the sea surface interfacial layer, at a rate which is highly significant for the chemistry of the marine atmosphere.
"Our research reveals an important negative feedback for ozone – a sort of self-destruct mechanism. The more ozone there is, the more gaseous halogens are created which destroy it. The research also has implications for the way that radionucleides of iodine in seawater, released into the ocean mainly from nuclear reprocessing facilities, can be re-emitted into the atmosphere."
Professor John Plane, from the University of Leeds' School of Chemistry, said: "This mechanism of iodine release into the atmosphere appears to be particularly important over tropical oceans, where measurements show that there is more iodide in seawater available to react with ozone. The rate of the process also appears to be faster in warmer water. The negative feedback for ozone should therefore be particularly important for removing ozone in the outflows of pollution from major cities in the coastal tropics."
The research was funded by the UK Natural Environment Research Council SOLAS (Surface Ocean Lower Atmosphere) programme.
David Garner | Source: EurekAlert!
Further information: www.york.ac.uk
More articles from Earth Sciences:
Tracking the Earth’s Mantle
24.05.2013 | Syracuse University
Strong earthquake at exceptional depth
24.05.2013 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
This morning at 05:45 CEST, the earth trembled beneath the Okhotsk Sea in the Pacific Northwest. The quake, with a magnitude of 8.2, took place at an exceptional depth of 605 kilometers.
Because of the great depth of the earthquake a tsunami is not expected and there should also be no major damage due to shaking.
Professor Frederik Tilmann of the GFZ German Research Centre for Geosciences: "The epicenter is exceptionally deep, far below the earth's crust in the mantle. Such strong ...
The Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn.
He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of ...
New indicator molecules visualise the activation of auto-aggressive T cells in the body as never before
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to examine individual cells and their activity directly in the tissue.
The development of new microscopes and fluorescent dyes in ...
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
24.05.2013 | Life Sciences
24.05.2013 | Ecology, The Environment and Conservation
24.05.2013 | Physics and Astronomy
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News