Measured and modelled effects of temperature, dissolved oxygen and nutrient concentration on sediment-water nutrient exchange

Abstract

Empirical models of sediment-water fluxes of NH4 +, NO3 − were and PO4 3− were formed based on published reports. The models were revised and parameters evaluated based on laboratory incubations of sediments collected from Gunston Cove, VA. Observed fluxes ranged from — 18 (sediments uptake) to 276 (sediment release) mg NH4 + m−2 day−1, −17 to −509 mg NO3 − m−2 day−1, and −16.4 to 8.9 mg PO4 3− m−2 day−1. The model and observations indicated release of NH4 + was enhanced by high temperature and by low DO. Uptake of NO3 − was enhanced primarily by high NO3 − concentration and to a lesser extent by high temperature and by low DO. Direction of PO4 3− flux depended on concentration in the water. Release was enhanced by low DO. No effect of temperature on PO4 3− flux was observed.