TOTAL PLANKTON OF LAKE MEN DOT A 



99 



face. The results for the deep water are given in the first part of table 

 26 in which the quantities found for the different months of the year 

 are expressed in kilograms per hectare and in pounds per acre. The 

 average quantity of dry organic matter in the total plankton varies 

 from a minimum of 257.7 kilograms per hectare (230 pounds per acre) 

 in February to a maximum of 521.5 kilograms (465 pounds per acre) 

 in December. "While the largest single catches were obtained in April 



poo 



400 



300 



200 



lOO 



Fig. 36. — Diagram showing the monthly distribution of the total plankton in the 

 deep part of Lake Mendota, 1915 to 1917. This diagram is based on the re- 

 sults given in table 24; it shows the average number of kilograms of dry 

 organic matter per hectare of surface for the area bounded by the twenty 

 meter contour line. 



in 1915 and in 1916 and in May, 1917, the averages for these two 

 months fall below that of December; this is especially true of the 

 month of May. 



The averages for the different months of the year are shown graph- 

 ically in figure 36 in which the various columns indicate the average 



