128 



THE METABOLISM OF ALGAE 



mannitol and laminarin contents during the year is more 

 pronounced (Fig. 20). These fluctuations are due to the inter- 

 actions of a number of factors; degree of exposure, temper- 



o 



i 



X 



^ 



3 4 S 6 7 8 9 

 MONTH OF YEAR 



FIG. 20 Seasonal variation in the amounts of laminarin in various 

 littoral algae. The algae occur in the following order upwards 

 from low tide level: Fucus serratus, F. vesiculosus, F. spiralis 

 and Pelvetia canaliculata (data from ref. 35). 



