98 



unchanged from the 1950's {Fig. 15 top) because of losses due to 

 dredging and new declines in poorly flushed coves. For example, 

 eelgrass was present in Hideaway Village Cove during the 1950's, but 

 largely disappeared by 1966. Today no eelgrass grows along the inner 

 shore of this cove. Eelgrass continued to decline in the deepest parts 

 of the Bay during the 1970 's and 1980 's (Fig 15, bottom) but greatly 

 expanded in Little Buttermilk Bay and other shallow areas. 



The losses of eelgrass in the deep portions of the Bay and in some 

 poorly flushed coves appear related to nutrient loading or increased 

 turbidity. Today, eelgrass is absent from areas with the highest 

 nutrients concentrations, depth of growth in Buttermilk Bay correlates 

 with dissolved inorganic nitrogen content of seawater (Costa, 1988) . 



Overall, Buttermilk Bay has not experienced the large declines 

 observed in other highly developed bays. This is probably due to the 

 high flushing rate, and because the Bay is so shallow, most beds are not 

 at the lower depth limit of growth. The loss of some vegetation since 

 the 1960's, however, suggests that Buttermilk Bay may be affected by 

 future increases in nutrient loading and sediment resuspension. 



South of Buttermilk Bay, a 1 km wide tidal delta has been formed 

 at the entrance of the Cape Cod Canal. This delta has been migrating 

 southward at rates as high as 9 to 18 m y~^. This feature is 

 interesting because a large eelgrass bed grows on the south edge of the 



