Dissolved iron measured along surface transects of the CARUSO-EISENEX experiment

Measurements of Fe(II) and H2O2 were carried out in the Atlantic sector of the Southern Ocean during EisenEx, an iron enrichment experiment. Iron was added on three separate occasions, approximately every 8 days, as a ferrous sulfate (FeSO4) solution. Vertical profiles of Fe(II) showed maxima consistent with the plume of the iron infusion. While H2O2 profiles revealed a corresponding minima showing the effect of oxidation of Fe(II) by H2O2, observations showed detectable Fe(II) concentrations existed for up to 8 days after an iron infusion. H2O2 concentrations increased at the depth of the chlorophyll maximum when iron concentrations returned to pre-infusion concentrations (<80 pM) possibly due to biological production related to iron reductase activity. In this work, Fe(II) and dissolved iron were used as tracers themselves for subsequent iron infusions when no further SF6 was added. EisenEx was subject to periods of weak and strong mixing. Slow mixing after the second infusion allowed significant concentrations of Fe(II) and Fe to exist for several days. During this time, dissolved and total iron in the infusion plume behaved almost conservatively as it was trapped between a relict mixed layer and a new rain-induced mixed layer. Using dissolved iron, a value for the vertical diffusion coefficient Kz=6.7±0.7 cm**2/s was obtained for this 2-day period. During a subsequent surface survey of the iron-enriched patch, elevated levels of Fe(II) were found in surface waters presumably from Fe(II) dissolved in the rainwater that was falling at this time. Model results suggest that the reaction between uncomplexed Fe(III) and O2? was a significant source of Fe(II) during EisenEx and helped to maintain high levels of Fe(II) in the water column. This phenomenon may occur in iron enrichment experiments when two conditions are met: (i) When Fe is added to a system already saturated with regard to organic complexation and (ii) when mixing processes are slow, thereby reducing the dispersion of iron into under-saturated waters.

UM Men's Swimming Team, 1987

Front Row: swimming coach Jon Urbanchek, Stephen Hamerski, William T. Hayes, Michael G. Bayerl, David A. Kerska, co-captain Joseph E. Parker, Lee C. Michaud, Mats O. Nygren, diving coach Dick Kimball.

2nd Row: manager Jeff Gordon, Martin T. Moran, Richard K. Wilkening, Richard R. Fabian, Matthew R. Smith, Caldwell B. Esselstyn, Matthew D. Curry, Daniel J. Dewhirst, Guy R. Williams.

3rd Row: Timothy S. Petsche, Jon A. Teppo, Jim A. O'Donnell, Alejandro Alvizuri, Ronald M. Melnyk, Alec Campbell, Mike Creaser, David R. McNear, Gregory B. Varner, grad assistant Marc C. Parrish.

4th Row: assistant coach Fernando Canales, Bjoern Warland, Christopher J. Martin, Jan-Erick Olsen, David Goch, William J. Kopas, Robert M. Ceresa, Brent D. Lang, grad assistant Alex Wallingford.

A compilation of the messages and papers of the presidents, 1789-1902 /

v. 1. 1789-1817 -- v. 2. 1817-1833 -- v. 3. 1833-1841 -- v. 4. 1841-1849 -- v. 5. 1849-1861 -- v. 6. 1861-1869 -- v. 7. 1869-1881 -- v. 8. 1881-1889 -- v. 9. 1889-1897 -- v. 10. 1897-1902 -- Index / revised and enlarged by George Raywood Devitt.

Morgan horses /

Reprint of chapters V to VII of D.C. Linsley's Morgan horses.

The price of freedom; Greece in world affairs, 1939-1953.

Mode of access: Internet.

The defeat of home rule in Salt Lake City.

Mode of access: Internet.

A compilation of the messages and papers of the presidents, 1789-1897.

Vols. 1-10 issued also as House misc. doc. no. 210, 53d Cong., 2d sess.

Research in crashworthiness of vehicle structures. Volume I of V.

National Highway Safety Bureau, Washington, D.C.

Corn movements in the United States : interregional flow patterns and transportation requirements in 1985 /

"September, 1990."

A compilation of the messages and papers of the presidents, 1789-1905 /

Mode of access: Internet.

The essentials of modern carpet installation.

At head of title: Carpet and Rug Institute.

The 1960 definition of farm residence and its marked effects on farm population data,

Mode of access: Internet.