Ruttenberg, K. C., University of Hawaii/Dept of Oceanography, Honolulu, USA, kcr@soest.hawaii.edu
Tamburini, F. ., ETH-Zentrum/Plant Nutrition Institute, Zurich, Switzerland, federica.tamburini@ipw.agrl.ethz.ch

PHOTOREDUCTION OF AEOLIAN FE-OXYHYDROXIDES IN OLIGOTROPHIC SURFACE SEAWATER: IMPLICATIONS FOR BIOAVAILABLE PHOSPHORUS

Sequestration of carbon in organic matter through photosynthesis constitutes the biological pump that regulates atmospheric carbon dioxide concentration with consequent effects on climate over time. The availability of macro (i.e., phosphorus and nitrogen) and micro (i.e., iron) nutrients in ocean surface waters controls this process. While nitrogen is present in the atmosphere (as di-nitrogen gas) and can be converted into a bioavailable form by the process of nitrogen fixation, phosphorus (P) and iron (Fe) can only be supplied to the ocean surface upon (1) upwelling of deep, nutrient-rich waters, and (2) transport of dissolved and particulate material from the continent. Eolian transport is the only vector providing particulate iron to open oligotrophic regions of the ocean. Fe-oxyhydroxides in aeolian dust are also carriers of P, with which they became associated in the soil formation and weathering environment. We present results of photoreduction experiments evaluating the potential release of P to oligotrophic seawater as a consequence of photoreduction of the carrier Fe-oxyhydroxide phases.

Oral presentation

Presentation is given by student: No
Session #:SS01
Date: Friday, June 13, 2008
Time: 11:45 AM

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