Marine & Environmental Sciences Faculty Articles

Title

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

Document Type

Article

Publication Date

3-16-2021

Publication Title

Geophysical Research Letters

Keywords

aerosol, diatoms, dust, iron, supercoarse mode

ISSN

00948276

Volume

48

Issue/No.

5

First Page

e2020GL090476

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.

Comments

Research Funding:

  • National Science Foundation (NSF). Grant Number: AGS‐1944958
  • University of Miami (Miami University). Grant Number: Provost Award

DOI

10.1029/2020GL090476

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Peer Reviewed

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