column and, perhaps, be transported 

 into adjacent estuarine and nearshore 

 waters. In general, the high marsh S. 

 patens is not usually thought of as 

 contributing significantly to the 

 export of organic matter from the 

 marsh. There are at least three 

 reasons for this opinion: the high 

 marsh is much less frequently exposed 

 waters, the grasses are 

 tidal creeks, and S^. 

 a dense interwoven mat 

 an open stand of 

 In general, 

 high marsh 



tidal 

 from 

 forms 

 than 



vegetation (Blum 1968). 

 decomposition of the 



to the 

 farther 

 patens 

 rather 



vegetation appears to be relatively 

 slow. This may be true not only 

 because decomposition is usually 

 slower on the ground than in water, 

 but because marsh plants (with the 

 exception of Salicornia , a succulent) 

 are relatively resistant to decay 

 compared with a number of other marine 

 and terrestrial plants (Figure 21). 



Organic Export 



Salt marshes are often valued 

 more for their contribution to other 

 environments than for their intrinsic 

 value. Nowhere is this more evident 



than in the "outwelling" concept 

 developed by E.P. Odum (1968, 1980), 

 in which the export of organic matter 

 and/or nutrients to coastal waters 

 from marshes has often been considered 

 a major part of wetlands valuation 

 (Gosselink et al. 1974). The reality, 

 magnitude, and significance of 

 "outwelling" and its role in 

 valuation have been reviewed by 

 Walker (1973), Haines (1979), W.E. 

 Odum et al. (1979), E.P. Odum (1980), 

 Nixon (1980), and Shabman and Batie 

 (1980), and little will be gained 

 by doing so again here. The high 

 marsh is not usually considered an 

 important source of organic or 

 nutrient exchange with the tidal 

 waters. Upper portions of the 

 intertidal zone with stunted S^. 

 alterni flora may show variable 

 uptake or release of nutrients (Lee 

 1979), and some of the aboveground 

 production of the grass may be carried 

 off the emergent marsh into tidal 

 creeks. It would be difficult, 

 however, to make a convincing argument 

 that the export of organic matter or 

 nutrients from high marshes in general 

 plays an important role in the ecology 

 of New England coastal waters. 



45 



