Forms of Sediment Phosphorus Under Varying Redox Potentials.

The purpose of study was to evaluate the effects of varying redox potential on phosphorus (P) transformation in four stream bank sediments (Camp Creek, Roberts Creek, Gunder, and Pre-Illinoian Till) of Walnut Creek, Iowa. Before P fractionation, each sediment was treated by anaerobic incubation, anaerobic incubation with addition of glucose, or without anaerobic incubation. P in the four sediments was differentially distributed among P forms, and those forms varied by incubation treatment.  Anaerobic incubation resulted in lower redox potential (Eh) and higher pH, which might have led to the change on the distribution of organic and inorganic P fraction of the sediments.  Water-extractable P increased with anaerobic incubation, but then decreased when glucose was added in the anaerobic incubation process. Anaerobic incubation increased bicarbonate extractable inorganic P (exchangeable P), but it decreased 0.1 M NaOH extractable inorganic P (slowly cycling Fe-P). Varying redox potential did not change the stable inorganic P fractions.