Estimated Net Aerial Primary Productivity for Selected Estuarine Angiosperms in Maine, Delaware, and Georgia

Abstract

Annual net aerial primary production (NAPP) was estimated for Distichlis spicata (L.) Greene, Juncus gerardii Loisel., Phragmites communis Trin., Spartina alterniflora Loisel., Spartina cynosuroides (L.) Roth, Spartina patens (Aiton) Muhl. and Sporobolus virginicus (L.) Kunth utilizing the Wiegert and Evans paired plot harvest method in selected east coast salt marshes. Estimates of NAPP ranged from 616 g°m—2°m—2°yr6—1 for highmarsh J. gerardii in Maine to 6.040 g°m—2yr—1 for S. cynosuroides in Georgia. Estimated "turnover" based on maximum living standing crop ranged from 9.6 times/yr (Georgia, D. spicata) to 1.8 times/yr (Delaware, D. spicata). As a result of periodic to erratic tidal inundation and associated removal and/or deposit of detritus, the Wiegert and Evans method could not be adequately evaluated for its accuracy in computing NAPP. The variability of the computed instantaneous rate of detritus flux which ranged from —39 mg°g—1°day—1 (Georgia, Spartina cynosuroides) to 84 mg°g—1°day—1 (Maine, S. patens) was considered to be the weak component. The complexity of the system parameters and the resultant variability of the method indicated that the method may present difficulties when used in salt marsh ecosystems.