Ozone Hole Impacts Antarctic Chemical Processes

Not just human health and terrestrial and marine ecosystems. The ozone hole also affects the environmental chemical processes of the South Pole. This is demonstrated by an international research team coordinated by the Institute of Polar Sciences of the National Research Council (Cnr-Isp) and the Ca 'Foscari University of Venice which studied for the first time the consequences of ozone depletion on iodine trapped in Antarctic ice .

The results of the study, in which researchers from the Paul Scherrer Institut (PSI, Switzerland), Institute for Interdisciplinary Science (Icb-Conicet, Argentina), Institute of Physical Chemistry Rocasolano (Csic, Spain), Korea Polar Research Institut ( South Korea), National Center for Atmospheric Research (United States) and University of Rome 3, are published in the journal Nature Communications .

In Antarctica , where ice holds precious information about the past of our planet's atmosphere, researchers have extracted an ice core about 12 meters long near the Concordia international research station with the aim of chemically analyzing the evolution time of iodine over a period of about 200 years (from 1800 to 2012).

“For the first time it was possible to observe and evaluate the effects of ultraviolet radiation on the concentration of this element in the snow,” explains Andrea Spolaor , CNR-Isp researcher and first author of the work. "Iodine plays a fundamental role in polar atmospheric chemistry and in the planet's radiation balance, therefore studying how it is exchanged between snow and the atmosphere is also crucial in order to refine future climate and environmental projections."

To evaluate and interpret the trend of the iodine concentration in the ice core, the researchers employed a multidisciplinary approach which, in addition to chemical analyzes, included atmospheric and chemical-physical models.

"We found almost constant concentrations of iodine from 1800 to 1974, and then found a clear and significant reduction from 1975 to 2012. Our research shows that the reduction in the concentration of iodine and its consequent emission into the atmosphere in this last period of time , is attributable to the reduction in the concentration of stratospheric ozone, and therefore to the increase in UV radiation that reaches the surface of Antarctica ”, continues Spolaor.

“The implications of this discovery”, adds Carlo Barbante , director of Cnr-Isp and professor at Ca 'Foscari “are manifold and have the potential to open new research horizons. In particular, we could apply the study of iodine in Antarctic ice cores to evaluate the presence of other stratospheric ozone depletion phenomena that occurred in the past , potentially up to 1.5 million years ago, thanks to the imminent start of the project. international Beyond Epic , coordinated by the CNR-Isp and which participates in Ca 'Foscari ".

"More than 40 years after the identification of the depletion of the stratospheric ozone layer, these results are also relevant in light of present and future environmental and climatic challenges", concludes François Burgay , co-author of the research and post-doc at the Paul Scherrer Institut. “With this work we show how the effects of man on the environment, even if suitably mitigated through the adoption of international protocols, continue for many decades and with consequences that are still largely unknown. For this reason, also in view of the upcoming COP26 in Glasgow , we need to act quickly to limit the long-term effects of ongoing climate change. The time factor is decisive ”.

Reference
Spolaor A, Burgay F, Fernandez RP et al. Antarctic ozone hole modifies iodine geochemistry on the Antarctic Plateau. Nat Commun 12, 5836 (2021). doi:10.1038/s41467-021-26109-x

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