Dust Deposition to the Sargasso Sea: A Comparison of Estimates Using Aluminum in the Surface Ocean Versus Aerosols and Rainwater
Abstract As a major component of mineral aerosol that partially dissolves in seawater, aluminum (Al) has been used to estimate time‐averaged dust fluxes to the ocean, based on dissolved aluminum (DAl) concentrations and an assumed replacement time of DAl ( τ DAl ) in the surface mixed layer, along with the fractional solubility (Al s ) and mass abundance of Al in dust. We apply this method in the Bermuda region using seasonal water‐column DAl concentrations, and compare our results with fluxes estimated from Al measured in Bermuda aerosols and rain. Inventories of DAl over the maximum mixed‐layer depth of 200 m and empirically derived Al s values yield mean dust fluxes of 5.3–11.2 g m −2 yr −1 , around 4‐ to 9‐fold higher than fluxes estimated from aerosols and rain, which average 1.2 g m −2 yr −1 over a 318‐day sampling period. This discrepancy likely reflects an underestimate in τ DAl and lateral transport of DAl in the surface ocean.
Authors
- B. M. Sohst (ORCID: https://orcid.org/0000-0002-4983-5223)
- Peter N. Sedwick (ORCID: https://orcid.org/0000-0003-0663-8323)
- Salvatore Caprara
- Rodney J. Johnson (ORCID: https://orcid.org/0000-0002-3645-4851)
- Joseph A. Resing (ORCID: https://orcid.org/0000-0002-7334-4176)
- Alessandro Tagliabue (ORCID: https://orcid.org/0000-0002-3572-3634)
- Kristen N. Buck (ORCID: https://orcid.org/0000-0002-3871-870X)
- Daniel C. Ohnemus (ORCID: https://orcid.org/0000-0001-6362-4134)
- Laura E. Sofen (ORCID: https://orcid.org/0000-0003-0311-4743)
- T. E. Williams (ORCID: https://orcid.org/0000-0001-6694-7334)
- Benjamin S. Twining (ORCID: https://orcid.org/0000-0002-1365-9192)
Institutions
- Skidaway Institute of Oceanography (US)
- Bermuda Institute of Ocean Sciences (BM)
- Oregon State University (US)
- University of Liverpool (GB)
- Cooperative Institute for Research in Environmental Sciences (US)
- University of Georgia (US)
- University of Washington (US)
- NOAA Pacific Marine Environmental Laboratory (US)
- Bigelow Laboratory for Ocean Sciences (US)
- University of South Florida St. Petersburg (US)
- Old Dominion University (US)
- College of Marin (US)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2025-04-28
- DOI
- https://doi.org/10.1029/2024gl113217
- Primary Topic
- Atmospheric chemistry and aerosols
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- National Oceanic and Atmospheric Administration