National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2016

Changes in the distribution of Al and particulate Fe along A16N in the eastern North Atlantic Ocean between 2003 and 2013: Implications for changes in aerosol dust deposition

Barrett, P.M., J.A. Resing, N.J. Buck, W.M. Landing, P.L. Morton, and R.U. Shelley

Mar. Chem., 177(1), 57–68, doi: 10.1016/j.marchem.2015.02.009 (2015)

Particulate Al and Fe and dissolved Al concentrations were analyzed in seawater samples from the upper 1000 m of the eastern North Atlantic Ocean along the CLIVAR/CO2 Repeat Hydrography Program section A16N in summer 2013, repeating trace metal observations made along the A16N transect a decade earlier. Upper-ocean trace metal distributions in the equatorial and subtropical regions of the North Atlantic are heavily influenced by atmospheric aerosol sources. Using changes in the concentrations of subsurface particulate Al and Fe and mixed-layer dissolved Al in the equatorial North Atlantic, we estimate dust deposition to surface waters in the eastern North Atlantic increased by approximately 15% between 2003 and 2013. Increased concentrations of dissolved Al in subtropical mode waters suggest that dust deposition may have also increased in the western basin. Our observations are consistent with recent reports linking increasing sea surface temperatures in the tropical North Atlantic to increased removal of atmospheric dust via precipitation over the past several decades and highlight the importance of accurate representation of dust deposition processes for modeling Fe biogeochemistry.

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