EFFECTS OF REDUCED TEMPERATURES 443 



TABLE 2 



STANDING CROP* OF Ascophyllum nodosum DURING 



SURFACE DISCHARGE (1973-1974) AND AFTER 2 YEARS 



OF DIFFUSER DISCHARGE AT FOXBIRD ISLAND (1977) 



*Values given are mean (X) and standard deviation (SD), and those having a 

 common letter (a,b) are not significantly different (P ^ 0.05 Student's t-test). N 

 is the number of quadrats. 



Biomass 



Standing-crop estimates for Foxbird Island are given in Table 2. 

 Means and standard deviations for zones 1 and 2 are given for two 

 stressed years (1973 and 1974) and a poststress year (1977). Biomass 

 estimates in 1977 for zones 1 and 2 were 83 and 82% higher, 

 respectively, than in 1974, the year of maximum stress. Both 

 estimates are significantly higher (P < 0.05) than values for 1974 but 

 are not different from 1973 nor from earlier predischarge periods 

 (Vadas, Keser, and Rusanowski, 1976). 



Growth 



Apical tips in August and November at Hodgson Island, the 

 regional control, were significantly shorter in poststress than in 

 stressed years because of extremely high growth rates (20% above 

 normal) in the spring of 1973 and 1974 (Vadas, Keser, and Larson, 

 1977). Increased growth was anticipated at Hodgson Island during 

 1976 because of the presence of warmer waters regionally, but it 

 never materialized. 



Growth patterns in Montsweag Bay during poststress periods 

 closely reflect local differences in water temperature. During stressed 

 years at Foxbird Island, growth, when present at all, was significantly 

 lower than it is today. Growth at Young Point during 1973—1974 

 was marginally stressed because of the proximity of the dis- 

 charge, and, although apical tips were longer in spring, they were 



