CONTRIBUTION OF A BURNED FIELD TO THE AEOLIAN DUST IN PATAGONIA

AUGUSTO C. CRESPI-ABRIL; ANTONELLA DE CIAN; GASPAR SORIA; RODRIGO J. GONÇALVES; ELENA S. BARBIERI; FLAVIO E. PAPARAZZO; CLAUDIO LÓPPEZ-MORENO

Conferencia; III International Conference on Atmospheric Dust; 2018

Fire activity in the Patagonian region of Argentina (39ºS-45ºS) is frequent in summer due to the high temperatures and dry weather. In the northern region of Patagonia (742º20?S ? 65ºW) a fire took place on December 22nd 2015 and continued for four days. In this period, at least 40 thousand hectares were burned. The diminution of vegetation coverage after this fire exposed the soil to aeolian erosion and particles removed were transported long distances to the Argentinean shelf. The aim of this research is to estimate the dust deposition in a burned region in Patagonia, to study its temporal evolution, and to analyze the elemental composition of dust particles. Four passive collectors were installed in the burned region and four on a control (unburned) region in January 8th 2016 and were monitored during a complete year. Collected dust wascarefully removed from the collector monthly and was weighted on the laboratory using an analytical scale (precision 0.001 mg). A sample of dust was collected and analyzed using Energy-dispersive X-ray spectroscopy mounted on a Scanning Electron Microscope to determine the elemental composition. The deposition rate in the burned region decreased from February to May (from 73 to 12 mg /day, respectively), afterward the values remained constant around 10 mg/day. The deposition rate in the control region was significantly lower (0.19 mg/day) and remained constant throughout the year. The elemental composition of thecollected dust was mainly Si and O both in burned and control region. However, a peak of C was detected in the burned region but not in the control region. These results show that the burned region in Patagonia represents a source that emits a significant amount dust due to the reduced vegetation coverage. Also, thisregion represents an input of carbon to the sea that would affect the marine productivity.