EPPLEY: PHYTOPLANKTON AND TEMPERATURE 



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TEMPERATURE °C 



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Figure 1. — Variation in the specific growth rate (m) of photoautotrophic unicellular algae 

 with temperature. Data are all for laboratory cultures. Growth rate is expressed in dou- 

 blings/day. Approximately 80 of the points are from the compilation of Hoogenhout and 

 Amesz (1965). That listing is restricted to maximum growth rates observed, largely in con- 

 tinuous light. The figure also includes additional data, mostly for cultures of marine phy- 

 toplankton, from the following sources : Lanskaya (1961), Eppley (1963) , Castenholz (1964, 

 1969), Eppley and Sloan (1966), Swift and Taylor (1966), Thomas (1966), Paasche (1967, 

 1968), Hulburt and Guillard (1968), Jergensen (1968), Smayda (1969), Bunt and Lee (1970), 

 Guillard and Myklestad (1970), Ignatiades and Smayda (1970), Polikarpov and Tokareva 

 (1970). The latter papers include about 50 strains of marine phytoplankton. The line is 

 the growth rate predicted by Equation (1), i.e., the line of maximum expected /i. Small 

 numbers by points indicate the number of values which fell on the point. 



I will avoid speculation on possible reasons 

 why such a curve would include algae from a 

 wide variety of taxonomic groups, including both 

 eucaryotic and procaryotic cell types, cells with 

 different complements of photosynthetic pig- 

 ments, and diverse morphologies. Nevertheless, 



the curve and Equation (1) appear to be useful 

 as a generalization of maximum /x to be expected 

 for photosynthetic unicellular algae. 



Equation (1) is essentially a van't Hoff for- 

 mula and can be expressed in the more typical 

 form 



1065 



