Origin and radiogenic isotope fingerprinting of aerosols over the Southwestern Atlantic and corresponding Southern Ocean Sector

Abstract

Abstract Tracing potential source regions of aerosols/dust is a key factor in understanding the atmospheric circulation regimes. In this context, Nd and Sr isotopes in continental fine sediments have been used as tracers (or fingerprints) of dust found in deep cores retrieved from the Antarctic ice sheets. In order to demonstrate the utility of radiogenic isotopes as dust fingerprint we have conducted atmospheric samplings from latitude 30°S to 64°S, over the Southwestern Atlantic Ocean, the Southern Ocean/Drake passage and coastal waters of the northern Antarctic Peninsula. We aimed at comparing the radiogenic isotope signature of the collected aerosols and their most likely sources as described in the literature. Aerosol samples were collected during oceanographic cruises carried out in 2010, 2011 and 2012 by the Brazilian Antarctic Program. Measured isotope ratios 87Sr/86Sr and 143Nd/144Nd were compared with inventories for Patagonia, Australia and Antarctica. In our study, origins of aerosols over sea were attributed to: (1) the Patagonian influence over the Argentine continental shelf; and (2) in the Southern Ocean where prevails a mix of dust sources from Patagonia, Australia and rock outcrops existing in the Antarctic continent.