Title

Water Discharge, Nitrate Concentration and Nitrate Flux in the Lower Mississippi River

Document Type

Article

Publication Date

10-1-1993

Department

Marine Science

Abstract

Thirty-five years of monthly lower Mississippi River water discharge, nitrate concentration and nitrate flux have been analyzed. The potential predictability of these quantities has been evaluated. Results indicate a large amplitude, long-term cycle in the nitrate concentration that is not observed in the water discharge. A decrease in average nitrate concentration from a peak in 1983 to the present confirms that this variability is more cyclic than trend-like. River-water discharge variation was greatest in association with the annual cycle. The annual water discharge and nitrate concentration cycles were similar; high nitrate concentrations usually occurred near the vernal freshet, and low concentrations usually occurred along with autumnal low-flow conditions. Nitrate flux variations exhibited a low amplitude, long-term modulation of a dominant, annual cycle. A predictor-hindcast analysis indicates that truly skilled forecasts of all three fields are feasible.

Publication Title

Journal of Marine Systems

Volume

4

Issue

4

First Page

315

Last Page

326