LARRANCE: PRIMARY PRODUCTION IN MID-SUBARCTIC REGION 



Table 2.— Chlorophyll a in the euphotic zone, measured and estimated primary productivity values, and ratios of 

 productivity to chlorophyll a in the mid-Subarctic Pacific Region (averaged within upper zone oceanographic do- 

 mains) 1966-68. 



1 Mean values for each cruise. 



lation were undoubtedly real. From these re- 

 sults, productivity and photosynthetic capacity 

 south of lat 46° N appear to be neither char- 

 acteristically high nor low, except in spring 

 during bloom conditions, but fluctuate over a 

 wide range. 



Because relatively few measurements were 

 made south of lat 46° N and the Pr/Ch ratios 

 varied rather widely, only the data between lat 



46° N and the Aleutian Islands were compared 

 to determine seasonal patterns of production. 

 If all the data are treated as if taken in the 

 same calendar year, a seasonal pattern of pro- 

 ductivity can be approximated (Figure 5) . Pro- 

 ductivity in winter was uniformly low through- 

 out the area (Pr =96 and Pk = 74 mg C/m^ 

 per day). The mean chlorophyll o concentra- 

 tion (11.2 mg/m-), however, was similar to 



603 



