Antarctic ozone hole modifies iodine geochemistry on the Antarctic Plateau

SPOLAOR, ANDREA; BURGAY, FRANÇOIS; FERNANDEZ, RAFAEL P.; TURETTA, CLARA; CUEVAS, CARLOS A.; KIM, KITAE; KINNISON, DOUGLAS E.; LAMARQUE, JEAN-FRANÇOIS; DE BLASI, FABRIZIO; BARBARO, ELENA; CORELLA, JUAN PABLO; VALLELONGA, PAUL; FREZZOTTI, MASSIMO; BARBANTE, CARLO; SAIZ-LOPEZ, ALFONSO

NATURE COMMUNICATIONS

nature publishing group

Año: 2021 vol. 12

2041-1723

Polar stratospheric ozone has decreased since the 1970s due to anthropogenic emissions ofchlorofluorocarbons and halons, resulting in the formation of an ozone hole over Antarctica.The effects of the ozone hole and the associated increase in incoming UV radiation onterrestrial and marine ecosystems are well established; however, the impact on geochemicalcycles of ice photoactive elements, such as iodine, remains mostly unexplored. Here, wepresent thefirst iodine record from the inner Antarctic Plateau (Dome C) that coversapproximately the last 212 years (1800-2012 CE). Our results show that the iodine con-centration in ice remained constant during the pre-ozone hole period (1800-1974 CE) but hasdeclined twofold since the onset of the ozone hole era (~1975 CE), closely tracking the totalozone evolution over Antarctica. Based on ice core observations, laboratory measurementsand chemistry-climate model simulations, we propose that the iodine decrease since ~1975 iscaused by enhanced iodine re-emission from snowpack due to the ozone hole-driven increasein UV radiation reaching the Antarctic Plateau. Thesefindings suggest the potential for icecore iodine records from the inner Antarctic Plateau to be as an archive for past stratosphericozone trends.