Document Type

Report

Department/Program

Virginia Institute of Marine Science

Publication Date

1976

Series

Contribution (Virginia Institute of Marine Science) no. 767

Abstract

Annual nitrogen, phosphorus and carbon budgets for two Virginia salt marshes were determined .by monthly measurements of water discharge and constituent concentrations over tidal cycles.

Considering all three forms of phosphorus measured (total, dissolved organic and orthophosphate) there was a net loss from the estuary to the marches. The data reveal a loss of particulate phosphorus of estuarine origin to marsh sediments and mineralization of this phosphorus in the marshes with subsequent export of dissolved inorganic and organic phosphorus back to the estuary.

Nitrogen flux data show a loss of nitrate and nitrite to the marshes. Particulate nitrogen is imported to the marshes where it is mineralized and returned to the estuary as ammonia and dissolved organic nitrogen. The magnitude of nitrogen export suggests significant fixation of atmospheric nitrogen by marsh flora with subsequent export as dissolved species.

Carbon flux data show significant contributions of both particulate and dissolved organic carbon to the estuary from the marshes. Estimates of export, based on marsh grass productivity, suggest a loss of 36 and 49 percent of a year's primary production on the marshes as detritus for Ware and Carter Creeks respectively.

Publication Statement

Published as: Virginia Water Resources Research Center Bulletin No. 79.

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