ECOLOGY OF BUZZARDS BAY: An Estuarine Profile 



113 



Table 6.3. Projected losses of upland acreage in Buzzards 

 upon low and high estimates of sea-level rise (SLR). Adapted 

 and Aubrey 1987. 



Bay coastal towns Based 

 from Giese 1990, and Giese 



frequency and duration. Along the eastern coast of 

 North America, low marsh areas tend to be colo- 

 nized by S. alterniflora. as is the case for the Buz- 

 zards Bay estuary. In fact, the region of the tidal 

 range (mean high - mean low water) where S. 

 alterniflora will persist appears to be constrained 

 to a zone of about two-thirds of the tide range (al- 

 though subject to local variation), which is also true 

 for Cape Cod marshes (Fig. 6.9). The difficulty in 

 maintaining low and high marsh within the appro- 

 priate flooding range stems from the need to bal- 

 ance the accretion of the marsh surface with the 

 rate of sea-level rise. In the southeastern Massa- 

 chusetts marshes, accretion is predominately from 

 the accumulation of decomposed roots and rhizomes 



of the wetland plants with little inorganic accumula- 

 tion (Redfield 1 972; Howes et al. 1 985; Orson and 

 Howes 1 992). This contrasts with wetlands in ar- 

 eas receiving significant sediment loading from riv- 

 ers (e.g., Mississippi Delta) where inorganic accu- 

 mulation predominates (Baumann et al. 1 984; Sali- 

 nas etal. 1986). 



While accretion rates vary within each marsh, 

 the marsh flats colonized by S. alterniflora appear 

 to be accreting at the same rate as relative sea level 

 is rising. This is the case for two marsh systems 

 proximate to Buzzards Bay, Barnstable (Redfield 

 1 972) and Waquoit (Orson and Howes 1 992). The 

 continual rise in relative sea level accommodates 

 wetland elevation increase without significantly 



