26 



(production area) of eelgrass in Buzzards Bay fix (above and 

 belowground) 0.9 x 10^" g C each year. 



Comparison of eelgrass and other primary producers in Buzzards Bay 

 Phytoplankton 



Carbon fixation in Buzzards Bay is approximately 10 g C m~^ y~^ 

 (Roman and Tenore, 1978). Because the area of Buzzards Bay and its 

 adjoining bays and estuaries is 5.5 x 10° m"^ (Signell, 1987), 

 phytoplankton annual production in Buzzards Bay is = 5.9 x 10 g C. 



Macroalgae 



Many macroalgae grow deeper than eelgrass, and drift algae often 

 accumulate on the bottoms of quiescent bays. Nonetheless, macroalgal 

 cover, like eelgrass, is not appreciable in Buzzards Bay because most of 

 the Bay is greater than 10 m deep, and light penetration is insufficient 

 at that depth to support a large biomass of benthic algae. Furthermore, 

 in the open bay, most algae are restricted to solid substrate, and rocky 

 areas are only extensive around the Elizabeth Islands, offshore of 

 Westport and Dartmouth, and in shallow areas, especially within 100 m of 

 shore. The vast majority of the shallow margins of the Bay bottom is 

 mud and sand, and is suitable only for eelgrass colonization. Based on 

 aerial photographs, it appears that algae cover less than 10% of the 

 habitat area of eelgrass, or about 400 ha. 



Production estimates for attached algae in temperate waters are 

 quite variable and generally range from 100 - 1000 g C m ^ y (Ferguson 

 et al., 1980; Josselyn and Mathieson, 1978; Mann, 1972; Wassman and 



