HR: 10:40h
AN: B11F-02    [PDF]
TI: Temporal Variability of Iron in the Upper Ocean at Hawaii Ocean Time-series Station ALOHA
AU: * Boyle, E A
EM: eaboyle@mit.edu
AF: Earth, Atm., Planetary Sciences, Massachusetts Institute of Technology, E34-158, 77 Mass. Ave., Cambridge, MA 02139 United States
AU: Bergquist, B A
EM: bardot@mit.edu
AF: Earth, Atm., Planetary Sciences, Massachusetts Institute of Technology, E34-158, 77 Mass. Ave., Cambridge, MA 02139 United States
AU: Wu, J
EM: jwu@iarc.uaf.edu
AF: Earth, Atm., Planetary Sciences, Massachusetts Institute of Technology, E34-158, 77 Mass. Ave., Cambridge, MA 02139 United States
AB: Trace metal clean techniques were used to sample Hawaii Ocean Time-series (HOT) station ALOHA on seven occasions between Nov. 1998 and Oct. 2002. On three occasions, full water column profile samples were obtained; on the other four occasions, surface and near-surface euphotic zone profiles were obtained. Together with three published samplings (Rue and Bruland, 1995; Johnson et al., 2003), this site may have been monitored for "dissolved" ($<$0.4 or $<$0.2 æm) Fe more frequently than any other deep-sea site in the world. Low Fe concentrations are seen in the lower euphotic zone ($<$0.1 nmol/kg). Significant temporal variability is seen in near surface Fe concentrations (ranging from 0.2 - 0.7 nmol/kg); we attribute these surface Fe fluctuations to variable dust deposition and biological uptake. This variability can only occur if the surface layer Fe residence time is less than a few years. Given that residence time and typical values of Fe at HOT (~0.4 nmol/kg from June through November), a higher percentage of the total aerosol Fe must be released typically from North Pacific aerosols compared to North Atlantic aerosols (as was also surmised by Johnson et al., 2003 for a single dust storm in April 2001).
DE: 1615 Biogeochemical processes (4805)
DE: 4875 Trace elements
DE: 9355 Pacific Ocean
SC: Biogeosciences [B]
MN: 2003 Fall Meeting