Dynamics and Characterization of Aeolian Dust Deposition from a Burned Shrubland at Chubut Coastal Patagonia in Argentina

Abstract

The aim of this work is to evaluate the dynamics of dust deposition and characterize its elemental composition in case study at Chubut coastal Patagonia in Argentina after a shrubland fire. On 22 December 2016, a fire took place (42°20′ S?65° W) covering ~ 30 thousand hectares (300 km2) of shrublands. Immediately after the fire (2 January 2017), monthly deposition of dust was recorded using passive collectors in burned and control regions until December 2017. The dust plume of the burned region, visible from MODIS imagery, reached more than 150 km from the coast toward the marine area. In the burned region, dust deposition rates peaked in February (84.75 mg/day m−2), decreased until May (mean value = 12 mg/day m−2), and afterward remained constant (mean value = 10 mg/day m−2) above background level during the studied period. In the control region, dust deposition was constant and significantly lower (mean value = 0.19 mg/day m−2). Overall, the dust elemental composition was mainly Si and O corresponding to silicate minerals. Material from the burned region presented peaks of C. On the other hand, C signals were not present in the dust from the control region. The presence of C, suggests a direct consequence of the burned vegetation. The burned region may become a significant source of dust due to the reduced vegetation coverage, and may constitute an additional input of C into the marine ecosystem. The present study is the first report that provides insights that a burned region in Patagonia may act as a dust source.