1915] 



SETCHELL DISTRIBUTION OP MARINE ALGAE 



303 



doubling point, but not beyond it. 



plained the fact that from 0°C. (or — 2°C.) to 10 °C. of 



In this way may be 



mean su mm er temperatur 

 Boreal and Uriner Austral 



marks the limits of the Upp 



at 



The marine algae inhabit 

 these zones are subjected to a range of not over 10° C 

 nv. or all. times. The snecies 



enduring a mean summ 



species of the Temperate zones, 

 temperature of 10° 0. to 15° C. 

 have a range of 10 to 12 °C, probably not over, at any or all 

 times. Similarly those of the Subtropical and Tropical zones 

 endure a range of not over 10° C. If, therefore, tentatively, 

 a temperature efficiency coefficient be estimated according to 

 the formula of Livingston and Johnson ( '13, p. 365) but modi- 

 fied by leaving out the assumption of an initial temperature 



higher than 0°C, viz 



2 



t 



10 



the efficiency coefficient in the 



case of the Upper Boreal and the Upper Austral zones (0 to 

 10° C.) will be unity to 2, in case of the Lower Boreal and also 

 the Lower Austral (10 to 15°C), will be 2 to 3, for the Temper- 

 ate zones (15 to 20°C), the coefficients will be 3 to 4; for the 

 Subtropical zones (20 to 25°C), the coefficients will be 4 to 5, 

 and for the Tropical zones (25 to 30°C), the coefficients will be 

 5 to 6. Incidentally to carry out this idea of temperature 

 efficiency coefficients, it may be said that the application to the 

 case of thermal algae, where I find the 10° C. amplitude rule 

 also to apply, would carry the coefficient index up as high as 

 16, i.e., in the case of those species enduring highest temper- 

 atures (80°C), and even to 18 in the case of thermal bacteria 



(90°C). 

 In conclusion, I may say that while much detail remains 



be considered and brought into order before the final data and 

 conclusions may be published, I have reason to believe that 

 the statements and conclusions I have either made or brought 

 forward in this preliminary account, will probably not need 

 be changed, at least to any great extent. 



List of Works Referred To 



Borgesen, F. ('02). Marine algae. Botany of the Faeroes 339-532. f. 51-110. 

 1902. 



, ('05). The algae-vegetation of the Faeroese coasts with remarks on 



the phyto-geography. Ibid. 683-834. pi. 13-24. f. 151-16^. 1905. 



