Study of the distribution of anionic bromine and iodine compounds in polar snow samples (Svalbard islands): seasonal variability and climate change

Abstract

The present thesis project focuses on the study of the distribution of anionic species of bromine (Br) and iodine (I) in polar snow and ice samples, obtained from the Svalbard islands Archipelago, in order to understand the seasonal variations of the two elements, associating them to the current climate changes. The main source of bromine is the oceanic surface, but first year sea ice was found to be enriched in bromine as well. On the other hand, iodine emissions are largely linked to biogenic production in the ocean, especially in ice-free regions. Bromine and iodine are significant species for polar regions, since their interactions with the snowpack and the atmosphere above, as well as the influence that the surrounding ocean plays on them, allow the occurrence of a chain of reactions that are crucial for the polar atmosphere, with effects on the atmospheric concentrations of ozone, and on the formation of cloud condensation nuclei. In order to assess the concentration profiles of bromine and iodine, to understand their seasonal variations, the snow samples were analyzed through inductively coupled sector field mass spectrometry, coupled with ion chromatography (IC-ICP-SFMS) not only to exploit the high instrumental sensitivity of the ICP-SFMS, but also for the quantification of bromine and iodine species.