Atmospheric Transport of North African Dust-Bearing Supermicron Freshwater Diatoms to South America: Implications for Iron Transport to the Equatorial North Atlantic Ocean

Anne E. Barkley, Nicole E. Olson, Joseph M. Prospero, Alexandre Gatineau, Kathy Panechou, Nancy G. Maynard, Patricia Blackwelder, Swarup China, Andrew P. Ault, Cassandra J. Gaston

Research output: Contribution to journalArticlepeer-review

Abstract

The equatorial North Atlantic Ocean (NAO) is a nutrient-limited ecosystem that relies on the deposition of long-range transported iron (Fe)-containing aerosols to stimulate primary productivity. Using microscopy, we characterized supermicron and supercoarse mode African aerosols transported to the western NAO in boreal winter/spring. We detected three particle types including African dust, primary biological aerosol particles, and freshwater diatoms (FDs). FDs contained 4% Fe by weight due to surficial dust inclusions that may be susceptible to chemical processing and dissolution. FDs were typically larger than dust particles and comprised 38% of particles between 10 and 18 μm in diameter. The low density, high surface-area-to-volume ratio, and large aspect ratios of FD particles suggest a mechanism by which they can be carried great distances aloft. These same properties likely increase the residence time of FDs in surface waters thereby increasing the time for Fe dissolution and their potential impact on marine biogeochemical cycles.

Original languageEnglish (US)
Article numbere2020GL090476
JournalGeophysical Research Letters
Volume48
Issue number5
DOIs
StatePublished - Mar 16 2021

Keywords

  • aerosol
  • diatoms
  • dust
  • iron
  • supercoarse mode

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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