Geochemical and microbiological fingerprinting of airborne dust that fell in Canberra, Australia, in October 2002

Patrick De Deckker*, Raeid M M Abed, Dirk De Beer, Kai Uwe Hinrichs, Tadhg O'Loingsigh, Enno Schefuß, Jan Berend W Stuut, Nigel J. Tapper, Sander Van Der Kaars

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

During the night of 22-23 October 2002, a large amount of airborne dust fell with rain over Canberra, located some 200 km from Australia's east coast, and at an average altitude of 650 m. It is estimated that during that night about 6 g m-2 of aeolian dust fell. We have conducted a vast number of analyses to "fingerprint" some of the dust and used the following techniques: grain size analysis; scanning electron microscope imagery; major, trace, and rare earth elemental, plus Sr and Nd isotopic analyses; organic compound analyses with respective compound-specific isotope analyses; pollen extraction to identify the vegetation sources; and molecular cloning of 16S rRNA genes in order to identify dust bacterial composition. DNA analyses show that most obtained 16S rRNA sequences belong mainly to three groups: Proteobacteria (25%), Bacteriodetes (23%), and gram-positive bacteria (23%). In addition, we investigated the meteorological conditions that led to the dust mobilization and transport using model and satellite data. Grain sizes of the mineral dust show a bimodal distribution typical of proximal dust, rather than what is found over oceans, and the bimodal aspect of size distribution confirms wet deposition by rain droplets. The inorganic geochemistry points to a source along/near the Darling River in NW New South Wales, a region that is characteristically semiarid, and both the organic chemistry and palynoflora of the dust confirm the location of this source area. Meteorological reconstructions of the event again clearly identify the area near Bourke-Cobar as being the source of the dust. This study paves the way for determining the export of Australian airborne dust both in the oceans and other continents.

Original languageEnglish
Article numberQ12Q10
JournalGeochemistry, Geophysics, Geosystems
Volume9
Issue number12
DOIs
Publication statusPublished - Dec 2008

Keywords

  • 16SrRNA cloning
  • Aeolian dust
  • Biogeochemistry
  • Polymerase chain reaction
  • Trace element geochemistry

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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    De Deckker, P., Abed, R. M. M., De Beer, D., Hinrichs, K. U., O'Loingsigh, T., Schefuß, E., Stuut, J. B. W., Tapper, N. J., & Van Der Kaars, S. (2008). Geochemical and microbiological fingerprinting of airborne dust that fell in Canberra, Australia, in October 2002. Geochemistry, Geophysics, Geosystems, 9(12), [Q12Q10]. https://doi.org/10.1029/2008GC002091