662 



Marine Microbiology 



higher 



aquatic 



plants 



zooplankton 



..y" 



y 



0.2 



IN- 

 ORGANIC 

 PO. 



soluble or- 

 ganic P via 

 biosynthesis 



cells of 

 phytoplankton 

 a bacteria 



sed. 



4% /day 



WATER 



t 



/ 



MUD 



bacteria 



inorganic reaction 

 of Einsele a Ohie 



Fig. 5. Transformations of phosphonis in a lake with turnover times for 

 different equilibria. Very heavy lines indicate the first action with floating 

 cells, for which the time is given in minutes. Other times in days. Lighter 

 solid lines are reactions at intermediate speeds— two or three orders of 

 magnitude slower than the initial one. Dashed line is the rettu-n from mud 

 by inorganic release, a still slower turnover. Dotted lines at top indicate 

 reactions too slow to measure, called infinitely slow by comparison with the 



rest. 



inorganic P the mechanism has the same turnover as the bac- 

 terial action just described, namely three days. The return to 

 water however is much slower, at fifteen days. 



REFERENCES 



1. Coffin, C. C, Hayes, F. R., Jodrey, L. H. and Whiteway, S. G.: Ex- 



change of materials in a lake as studied by the addition of radioactive 

 phosphorus. Can. J. Res., D, 27:207-222, 1949. 



2. Harris, E.: Radiophosphonis metabolism in zooplankton and microor- 



ganisms. Can. J. Zool, 35:769-782, 1957. 



3. Hayes, F. R.: The effect of bacteria on the exchange of radiophosphorus 



at the mud-water interface. Verh. Int. Ver. Limnol., 12:111-116, 1955. 



