ABSTRACT PROPOSAL # : DEB-9725611 INVESTIGATOR(S) : WALLBRIDGE INSTITUTION: GEORGE MASON UNIVERSITY The aims of this research are to develop and test a new method for determination of soil P mineralization, based on natural isotopic fractionation of the associated O that occurs as part of enzyme-catalyzed phosphate ester hydrolysis in soils. Initial experiments are to be done in the laboratory, followed by field tests in a well-studied chronosequence of sites in Hawaii, where soil P chemistry is known to vary with soil age. The research is high-risk but potentially very useful. Lack of an appropriate method for estimation of P mineralization in the field is widely recognised as limiting to progress in understanding of nutrient limitation and nutrient interactions in ecosystems. If successful, this method is certain to be widely used and to lead to important new insights on the cycling of P in terrestrial ecosystems.
