Information Concept in Ecology 



157 



MEAN 

 PHOTOSYNTHESIS 



(gcal cm"2day"') 



5-1 



(10,2,257) 



(2,10,1.06) 



COLLECTION DEPTH (ft) 



Fig. 8. Photosynthesis as a function of sample collection and_suspension depths 

 (means for ten experiments). 



18.5), (6,6,19.5), and (10,10,44.7) in Figure 9 indicate a 2.4-fold 

 efficiency increase at 10 ft. compared to 2 ft. 



Two phenomena may be involved in this increased efficiency 

 of the deeper populations: 1) the purely numerical "swamping" 

 effect of more photons in the upper layers of the water column 

 than can possibly be absorbed by the plant pigments (34), and 

 2) actual increase in the thermodynamic efficiency of chlorophyll 

 with depth. The latter is illustrated in Figure 10 in which mean 

 photosynthesis per unit mean illumination per unit mean initial 

 concentration of total chlorophyll in the ten experiments is graphed. 



