Phosphorus cycling at mineral-water interface: role of mineral dissolution and transformation
EMSL Project ID
35596
Abstract
Phosphorous (P) is an essential but limiting nutrient for all live forms. Mineral bound PO4 is conditionally available to (micro)organisms depending on the mineral properties, type of bonding environment and degree of PO4 saturation of surface sites as well as organisms' specific ability to access mineral bound PO4. The chemical environment in which microbial iron reduction occurs determines the rate and extent of iron reduction and the nature of reduced solids. Dissolution, transformation and precipitation of minerals control kinetic fractionation and may change the equilibrium oxygen isotopic composition of PO4. Factors dictating the specific mineralization pathway may include pH, redox potential, and supply of respiration-driven Fe(II). Proposed research, therefore, attempts to identify mineral transformation associated specific mineralization pathway using Mössbauer spectroscopy, X-Ray diffraction and electron microprobe. Findings from the proposed research will help understand the isotopic fractionation associated with specific mineral transformation pathway and in the presence of specific mineral and mineral assemblages, and the mechanism PO4 uptake/release both by minerals and bacteria and kinetic/equilibrium oxygen isotope fractionation of PO4 during mineral transformation. Use of delta-18Op helps to understand detail reaction mechanism of PO4 uptake/release as well as to test hypotheses whether (and under what condition) oxygen isotopes of mineral bound PO4 can be taken as a paleo-temperature proxy and a signature of life. This finding will also have an important implication to understand the origin of life on earth, life extreme environments and presence of biomarkers in other planets including Mars.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2009-10-05
End Date
2012-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Jaisi DP, and RE Blake. 2010. "Tracing sources and cycling of phosphorus in Peru Margin sediments using oxygen isotopes in phosphates." Presented by Jaisi, Deb and Blake, Ruth (Invited Speaker) at Goldschmidt Conference, Knoxville, TX on June 14, 2010.
Jaisi DP, RK Kukkadapu, LM Stout, T Varga, and RE Blake. 2011. "Biotic and abiotic pathways of phosphorus cycling in minerals and sediments: insights from oxygen isotopes in phosphate." Critical Reviews in Environmental Science and Technology.
Jaisi, D.P. Stout, L.M., Blake, R.E. Bioavailability of mineral-bound
phosphates: Insights from O isotopes in PO4. "Frontiers in Geomicrobiology and Palaeontology Symposium (poster)" Yale Univ., May, 2010.