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Oxygen isotope fractionation in phosphate during iron oxide-phosphate interaction


EMSL Project ID
29411

Abstract

Measurements of 18O/16O ratio of organic and inorganic PO4 in laboratory experiments have found that microbial metabolism of PO4 is accompanied by specific oxygen isotope fractionations. More importantly, phosphate resists isotopic exchange and fractionation with water at low, near surface temperatures in non-biological, abiotic processes (<80oC). Until now, all reaction networks that involve P cycling in natural environments have been fully understood except important remaining puzzle: phosphate-iron oxides interactions. The primary goal of this project, therefore, is to complete this puzzle to develop a new application of PO4 oxygen isotope (18O/16O ratio i.e. &#948;18Op) with &#948;18O as biomarker and indicator of microbial activity in specific reaction pathway. The proposed research, therefore, will investigate the mineral transformation (ferrihydrite &#8594; goethite &#8594; hematite) at environmentally relevant conditions using Mössbauer spectroscopy. This information will be vital to understand the kinetic and equilibrium oxygen isotope fractionation of phosphate during its sorption/desorption on iron oxide

Project Details

Project type
Exploratory Research
Start Date
2008-06-09
End Date
2009-06-14
Status
Closed

Team

Principal Investigator

Deb Jaisi
Institution
University of Delaware

Team Members

Ruth Blake
Institution
Yale University

Related Publications

Jaisi, D.P. Blake, R.E., Kukkadapu, R. Fractionation of oxygen isotopes in phosphate during its sorption/desorption to iron oxides (Submitted: Geochimica et Cosmochima Acta).
Jaisi, D.P., Blake, R.E., Kukkadapu, R.K. Fractionation of oxygen isotopes in phosphate during its interactions with iron oxides. Geochimica et Cosmochimica Acta 74 (2010) 1309?1319