43 



This most recent eelgrass decline appears to be to decreased light 

 availability because of increased epiphyte growth and phytoplankton from 

 nutrient loading (Valiela and Costa, in press), and in recent decades, 

 dense layers of drift algae (primarily Cladophora, Gracillaria, and 

 Agarhdiella, up to 70 cm thick) have been accumulating. This dense 

 layer of algae precludes future recolonization of eelgrass because 

 seedlings cannot survive under dense layers of unconsolidated algae. 



From these observations, it appears that the decline of peak C was 

 due to the wasting disease. Peak B documents the recovery of eelgrass 

 in the bay during the 1950's then subsequent decline, and Peak A is 

 present only when eelgrass persisted in recent years as was the case in 

 the vicinity of core WB4. Based on this chronology, the scallop 

 mortalities appear to coincide with the three major hurricanes to impact 

 this region during this century: 1938, 1944, and 1954. Scallop 

 populations have been historically high in Waquoit Bay, accounting for 

 80% of the fishery in all of Falmouth (Alber, 1987). The bay is large 

 and shallow, which may contribute to the burial of spat during storms. 



Within each core, the depositional markers are consistent, but 

 differences exist at each station. The depth of peak B and the most 

 recent Argopectin mortality in this core suggests that the recent 

 depositional rate in the north end of the bay (WB4) is similar to the 

 mid-Bay cores (5.5 mm y~ ) , but slower between 1932 and 1954 (4.8 mm y~ 

 ) than comparable periods in the mid-Bay (5.5 mm y~ ) . During earlier 

 periods at this station the depositional rate here was even lower 

 because peak D is nearer the surface than elsewhere. The more recent 

 increases in sedimentation rate at core WB4 may be due to the 



