Effect of Leaf Litter on Phosphorus Retention and Hydrological Properties at a First Order Stream in Northeast Oklahoma, USA

Abstract

ABSTRACT We examined the relationship between phosphorus (P) uptake length (Sw) measured by stable PO4 additions and the level of PO4 enrichment from the additions during summer and fall in a first order stream in the southwestern portion of the Ozark Plateaus in northeast Oklahoma, USA. The y-intercept of this relation was used to more closely approximate ambient Sw and other metrics of P retention efficiency during summer and fall and determine the effect of leaf litter input on P retention efficiency and hydrological properties. Under similar discharge, the presence of the leaf litter during fall decreased water velocity and the dispersion coefficient, while the transient storage area increased compared to summer. An increase in Sw was generally observed with an increase in the level of P enrichment, and the linear relation (y-intercept) estimated Sw at 117 and 86 m during summer and fall. The slope of the linear relation was variable because a 5 μg L−1 increase in P enrichment resulted in a 27 and 5 m increase in Sw estimation during summer and fall. Overall, the input of leaf litter into the stream had a relatively small effect on Sw, but our results suggest P retention was slightly greater during fall compared to summer.