25 



Chapter 2 

 Eelgrass iZostera marina L.) production in Buzzards Bay 



Introduction 



The contribution of Zostera marina L. (eelgrass) to primary 

 production in Buzzards Bay has not been estimated. Elsewhere, Zostera 

 beds contribute sizably to coastal primary production, especially in 

 shallow embayments, where they may account for 50% of all primary 

 production including benthic algae and phytoplankton (Sand-Jensen and 

 Borum, 1983; Nienhuis and Van Ireland, 1978). 



In Chapter 1, I showed that there are 2930 ha of eelgrass bed 

 cover in Buzzards Bay. This estimate was calculated from photographs of 

 si: 25, 000 scale photographs, and adjusted for percent cover as perceived 

 on that scale imagery. This process ignores bare patches within 

 eelgrass beds that are too small to be seen on those photographs, and 

 which are only visible underwater or with small scale imagery. It is 

 impossible to quantify small scale patchiness in every bed in this 

 region, so this bed cover area was multiplied by a correction factor 

 (0.8) based on field experience and microscopic study of photographs 

 (Costa, 1988). Therefore, the "production area" of eelgrass in Buzzards 

 Bay is 2482 ha 



In southeastern Massachusetts, annual above- and belowground 

 eelgrass production is approximately 393 g C m~^, and aboveground 

 production alone is 350 g C m"^ (Costa, 1988). Hence, the 2500 ha 



