These values are similar to those for New York marshes, but substantially 

 lower than the southern marsh types. The efficiency of production 

 of marsh grasses in the New England marsh was lower than reported 

 for southern areas. 



A simulation model based on the laboratory and field metabolism 

 and biomass measurements of parts of the embayment system was developed 

 to predict diurnal patterns of dissolved oxygen in the marsh. The 

 model was verified with field measurements of diurnal oxygen curves. 

 The model indicated the importance of the timing of high tides in 

 determining oxygen levels and was used to explore simulated additions 

 of sewage BOD and increases in temperature. 



Energy flow diagrams for the marsh system on representative days in 

 summer and winter are presented. Effort is directed toward expanding 

 details of the energy flow in the marsh creeks and embayments that 

 are coupled with the tall stands of grass and serve as tidal pathways 

 linking the emergent marsh with larger estuaries and offshore waters. 

 Emphasis is placed on the great importance of detrital food chains 

 and large sedimentary organic storage in the embayment. The diagrams 

 also indicate that large standing crops of plants and animals may be 

 supported in the marsh-embayment complex, and that high levels of 

 primary production occur over short periods from submerged vascular 

 plants, attached algae, and phytoplankton in the embayment. however, 

 the marsh embayment appears to be a consumer system that depends on the 

 import of organic matter fixed on the emergent marsh by grasses and 

 sediment algae. 



A table is given providing the annual energy budget for a marsh 

 embayment. The value used for total organic input to the embayment 

 is largely a function of the estimate of detritus entering from the 

 emergent marsh. 



The results of this study indicate that even in the less extensive 

 marshes of New England, the development of large populations of fish 

 and shrimp in the marsh area can be documented, and that the maintenance 

 of the system necessary for the culture of these large populations 

 depends on inputs of organic matter from the productive meadows of 

 Spartina . (A. A. and H.D.) 



Keywords: salt marshes, energy flow, primary productivity. New England, 

 Rhode Island 



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