IV-F-5 



Thayer, G.W., and S.M. Adams. 1975. Structural and functional aspects 

 of a recently established Zostera marina community. Pages 518-540 

 jjlL.E. Cronin, ed., Estuarine research, Vol. 1. Academic Press, New York. 



Although the value of eel-grass productivity to an ecosystem has 

 been recognized for over 50 years, little quantitative information 

 is available on any major portion of the eel -grass community in North 

 America, save for on the grass itself. The epifaunal and infaunal 

 invertebrates and the fishes inhabiting a grass bed in the Newport 

 River estuary are dominated by only a few species. The density and 

 biomass of these groups are considerably greater than in the adjacent 

 unvegetated portions of the estuary. Fishes using the grass bed appeared 

 to exact some control over the density of the epifaunal community. 



The macrofauna in the bed consume an amount of energy equivalent 

 to 55 percent of the net production of eel -grass, phytoplankton, and 

 benthic algae in the bed. There is sufficient available energy to 

 support the estimated bacteria-microfauna-meiofauna compartment. 

 The data further suggest that there is an excess of plant production 

 in the bed, a portion of which is increasing the organic content of 

 the sediments. The remainder is probably exported to the adjoining 

 estuary. This export may be highly significant to the trophic function 

 of the shallow estuarine system near Beaufort, since eel -grass is 

 estimated to supply as much as 64 percent of the total production of 

 phytoplankton, cord grass and eel -grass in this system. (A. A.) 



Keywords: eelgrass, productivity, biomass, invertebrates, estuarine 

 system 



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