Chemistry 131 



Phytoplankton 

 0.027 



0.015 



0.033 



0.0075 



Sestonic 

 Bacteria 

 0.14 



0.13 



0.074 



Zooplankton 

 1.4 



0.084 



r 



0.42 

 0.42 



0.07 



0.11 



Sestonic 



Detritus 



0.17 



1.0 



o a. 



0.42 



0.42 



LiL 



Water 



0.11 



0.72 



1.1 



1.2 



0.73 



1.2 



Benthic 



Algae 



17 



3.8 



0.0075 



0.43 



Benthic 



Bacteria 



56 



7.2 



0.0026 

 1_ 



Benthic 



An i ma 1 s 



22 



"f 



0.26 





c ™ 



M 0) 



1.2 



0.39 



Sediment 



0.47 



—i 



0.22 



Sediment and Detritus 

 10000 



10cm 



5 cm 



FIGURE 4-19. Phosphorus flow diagram for Pond B, 12 July 1971. 

 Rates are in mg P m~^ day^ and concentrations are in mg P m'^; a 10-cm- 

 deep water column is assumed. 



suggestion of Lean (1973a) that colloidal P is formed by combination of 

 XP and colloids appears more likely in the Barrow ponds. 



The XP and colloidal P occur in significant quantities throughout the 

 season; their sum was never observed to be less than that of DRP (Table 4- 

 16, Figure 4-19). Since phosphorus in these two labile organic pools 

 rapidly cycles through DRP, this means that phosphorus available for 

 plankton growth is usually 2 to 4 times the observed DRP concentration. 

 This alone could account for the lack of correlation between DRP and 

 plankton productivity. 



Other information on labile organic P comes from the experiment 

 described by Figure 4-17 and 4-18. The highest amounts of colloidal P 

 (and also XP) are formed during the periods of highest photosynthesis. 



