Document Type



Virginia Institute of Marine Science

Publication Date



Fluxes between the sediments and overlying water of ammonium, nitrate, total phosphorus, ortho phosphorus, and dissolved oxygen have been measured in the tidal James and Appomattox Rivers, Va. A total of 68 nutrient flux measures, 203 oxygen flux measures, and 18 control measures were collected in the summer months, 1983 and 1984.

Ammonium is predominantly released from the sediments at a mean rate of 9.82 mg/m /hr. Nitrate is predominantly taken up by the sediments at a mean rate of 1.53 mg/m /hr. Total phosphorus is taken up by the sediments at a mean rate of 1.67 mg/m /hr. Ortho phosphorus may be taken up or released. Mean flux is an uptake of 0.75 mg/m /hr. Dissolved oxygen is taken up at a mean rate of 44 mg/m /hr.

The primary implication of this st udy for management is that the occurrence and rate of nitrification in the water column are obscured by the simultaneous sediment release of ammonium and uptake of nitrate. It is recommended that nitrification rates in an existing water-quality model of the James River be recalibrated following inclusion of the benthic nitrogen fluxes.


Water -- Nitrogen content -- Virginia -- James River, Water -- Nitrogen content -- Virginia -- James River Water -- Nitrogen content -- Virginia -- Appomattox River, Water -- Dissolved oxygen -- Virginia -- James River

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