Title

Bioavailable Iron in Equatorial Pacific Ocean Aerosol Samples

Presenter Information

Hsiang Teng
Hoi Ting
Dan Hinz
Lindsey Shank

Document Type

Oral Presentation

Location

SURC Ballroom C/D

Start Date

15-5-2014

End Date

15-5-2014

Keywords

Oceanic iron, Aerosol, Photochemistry

Abstract

Oceanic iron fertilization experiments performed in remote regions have established that iron additions draw carbon into the ocean at least over the months-long time frame of the experiments. However, the mechanisms that control iron speciation in atmospheric aerosol particles before and after deposition into the surface ocean remain largely unknown. This is in part due to the analytical challenge of quantifying iron at environmentally significant sub-nano molar levels. Here, we explore the near-real time determination of pico-molar levels of both Fe(II) and H2O2 produced from real marine aerosol particles collected over the Equatorial Pacific Ocean, as a function of both sunlight and electron donors such as dimethyl sulfide and organic acids. Results indicate that Fe(III) is reduced in the presence of light with electron donors that are already present in the collected aerosols, and that external additions of electron donors have an enhancing effect in some of the samples. These results contribute to resolving current inconsistencies in chemical models on the speciation of iron, formation of H2O2 and sulfur cycle in the marine atmosphere.

Poster Number

14

Faculty Mentor(s)

Johansen, Anne

Additional Mentoring Department

Chemistry

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May 15th, 8:30 AM May 15th, 11:00 AM

Bioavailable Iron in Equatorial Pacific Ocean Aerosol Samples

SURC Ballroom C/D

Oceanic iron fertilization experiments performed in remote regions have established that iron additions draw carbon into the ocean at least over the months-long time frame of the experiments. However, the mechanisms that control iron speciation in atmospheric aerosol particles before and after deposition into the surface ocean remain largely unknown. This is in part due to the analytical challenge of quantifying iron at environmentally significant sub-nano molar levels. Here, we explore the near-real time determination of pico-molar levels of both Fe(II) and H2O2 produced from real marine aerosol particles collected over the Equatorial Pacific Ocean, as a function of both sunlight and electron donors such as dimethyl sulfide and organic acids. Results indicate that Fe(III) is reduced in the presence of light with electron donors that are already present in the collected aerosols, and that external additions of electron donors have an enhancing effect in some of the samples. These results contribute to resolving current inconsistencies in chemical models on the speciation of iron, formation of H2O2 and sulfur cycle in the marine atmosphere.