Figure 8. Erosion scarp along edge of smooth cordgrass-needle 

 rush marsh growing on peat. 



percent in shoot growth alone, a figure that compares favorably with 

 upland field crops. The potential for substantial recycling and ex- 

 porting of nutrients to the estuary exists. 



The absorption, conversion, and recycling abilities of marsh plants 

 offer real opportunities for improving water quality^ (Woodhill, 1977). 



d. Sediment Accumulation . Marshes perform a valuable role in 

 trapping sediments, thereby reducing turbidity in bays, sounds, and 

 estuaries. Turbidity reduction is highly beneficial in protecting 

 shellfish beds from excessive siltation and increasing light penetra- 

 tion which promotes phytoplankton production. Chapman (1938) esti- 

 mates accretion rates in New England salt marshes to be 0.1 to 0.4 

 centimeter per year and Ranwell (1964) reported an average value of 

 0.2 to 1.0 centimeter per year for temperate European marshes. Higher 

 rates probably occur in certain marshes growing in sediment-rich 



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