HR: 0830h
AN: B21F-0772    [PDF]
TI: The Speciation and Solubility of Aerosol Iron and Aluminum in the North Atlantic Ocean: Results from the 2003 CLIVAR A16N Expedition
AU: Buck, C S
EM: buck@ocean.fsu.edu
AF: Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 United States
AU: * Landing, W M
EM: landing@ocean.fsu.edu
AF: Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320 United States
AU: Resing, J
EM: resing@pmel.noaa.gov
AF: Joint Institute for Study of the Atmosphere and Ocean, NOAA/PMEL 7600 Sandpoint Way NE, Seattle, WA 98115 United States
AU: Lebon, G T
EM: lebon@pmel.noaa.gov
AF: Joint Institute for Study of the Atmosphere and Ocean, NOAA/PMEL 7600 Sandpoint Way NE, Seattle, WA 98115 United States
AB: As part of the 2003 CLIVAR cruise in the north Atlantic, we collected 24-hour aerosol samples aboard the R/V Ronald H. Brown leaving Reykjavik, Iceland on June 19, 2003 and arriving in Natal, Brazil on August 8, 2003. The goal of this research was to measure the solubility and speciation of Fe and Al in continental dust, especially as a result of the Saharan dust plume. The cruise track passed directly through the plume as clearly shown by the deposition of red dust on the ship that persisted for several days. Four replicate samples were collected using an automatic sector-controlled aerosol sampling system that collected only when the wind was $\pm$ 90$^{o}$ off the bow of the ship and exceeded 0.5 m/sec. The aerosols were collected on 47 mm PCTE and polypropylene filters for roughly 24-hour periods, filtering as much as 70 m$^{3}$ of air through each filter. In addition, we deployed a Multiple Orifice Uniform Deposition Impactor (MOUDI) to collect size fractionated aerosol samples. Surface seawater samples, collected every 60 naut. miles, were processed using cross-flow ultrafiltration to quantify the impacts of soluble Fe and Al deposition on the formation of colloidal species. The polypropylene filters were quickly leached with 100 mL of either freshly collected 0.2 $\mu$m filtered surface seawater at natural pH or 100 mL of unacidified ultrapure water that had equilibrated with the atmosphere. Seawater filtrates were analyzed for soluble Fe(II) using the Ferrozine colorimetric method. These samples were also analyzed for total soluble Fe using the ICP-MS isotope dilution method upon returning to FSU. The ultrapure water filtrate samples were frozen until they could be analyzed at FSU for major anions using ion chromotography. The PCTE filters were analyzed for total Fe (and other elements) using energy-dispersive X-ray fluorescence at the NOAA/PMEL laboratory.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 4801 Aerosols (0305)
DE: 4808 Chemical tracers
DE: 4875 Trace elements
SC: Biogeosciences [B]
MN: 2003 Fall Meeting