the controversy, it may be said that students of the phytoplankton of 

 inland lakes now generally assume essential uniformity where conditions 

 of the environment are uniform. By essential uniformity is meant such 

 uniformity that samples taken at one point will yield results fairly 

 representative of a large area having similar conditions. In the study 

 of small inland lakes of regular outline and bottom configuration, it 

 is standard practice to take samples at one point in the limnetic region 

 and allow them to represent the lake as a whole. 



Data collected during the present investigation showed 

 clearly that the phytoplankton was not uniformly distributed in the 

 different sections of Western Lake Erie, and this is one of the 

 principal conclusions of the report. Also there was evidence of lack 

 of uniformity in the Island Section, and it was necessary to devise a 

 sampling program adequate to a void inaccuracies from that cause. 

 This was done by taking samples from several stations rather than 

 from one. In the interest of economy of space, the data from the 

 Island Section are not presented here. The question of adequacy of the 

 sanpling program will be considered in a later section. 



Vertical distribution 



The subject of vertical distribution of phytoplankton organisms 

 is given a subordinate position in this report because of the essential 

 uniformity which prevails in Western Lake Erie. Some examples of unequal 

 distribution were noted, but in general, the inequalities were not large 

 and probably existed for short times only. Moreover, the differences in 

 distribution were not consistent; at times the algae were more abundant 

 at the surface, and at other times near the bottom or at intermediate 

 depths. On the whole, it has not been possible to correlate the inequal- 

 ities in distribution with factors in the environment. On some dates 

 the different genera were distributed in such a haphazard way that it 

 would be hopeless to attempt to explain it. Essential uniformity is to 

 be expected from the fact that the water is usually homothermous, per- 

 mitting mixture of the floating vegetation by winds. Periods of thermal 

 stratification are of such short duration that there is little opportun- 

 ity for the biilding up of strata of the passive plankters. That the 

 phytoplankton is usually distributed with essential uniformity is in- 

 dicated by the data in Tables 1x9 and 50, 



Seasonal distribution 



Season of 1929 



Seasonal distribution of phytoplankton groups , Tne season of 

 1929 covered a period from late May to late October, inclusive. Table $1 

 shows the seasonal distribution of the groups of plankton algae during 



1U8 



