The trace element composition of suspended particulate matter in the upper 1000m of the eastern North Atlantic Ocean: A16N

Samples of total suspended matter were collected from the upper 1000m of the eastern North Atlantic between 62°N and 5°S during the CLIVAR/CO2 Repeat Hydrography section A16N from June to August 2003. Particulate matter samples were analyzed by energy-dispersive X-ray fluorescence for Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb. Intense seasonal deposition of Saharan dust produces maxima in particulate Fe (>3.3nM) and Al (>10nM) in surface waters between 10 and 20°N. A broad mid-depth enrichment of particulate Fe (>5.4nM) and Al (>19nM) between the equator and 20°N is sustained by vertical transport of lithogenic particles and scavenging of dissolved Fe released by remineralization. Surface distributions of particulate Fe and Al show maxima over a narrower, northerly shifted latitude range and are consistent with the seasonal location of atmospheric deposition associated with the Intertropical Convergence Zone, while the location of the mid-depth maximum reflects the full annual latitude range of surface inputs and suggests similar winter and summer atmospheric fluxes. Spatial offsets between surface maxima in particulate and dissolved Al distributions indicate relatively short residence times (8days and