ture on the several dates for which data are available. The differences of 

 temperature between Stations 2h9 and 250 in Table 29 may be considered as 

 resulting from mixing of water from the two sources. I^at considerable mix- 

 ing occurs is shgwn by the fact that the methyl orange alkalinity at Station 

 2h9 was uniformly much higher than at Station 250. 



The true explanation for the high oxygen of 1930 is probably 'to be found 

 in the great abundance of plankton algae in that year. Reference to Table 56 

 will show that the counts were much higher in 1930 than in 1929 for corres- 

 ponding times of the season. It is believed that the photosynthetic activi- 

 ties of such tremendous numbers of chlorophyll-bearing organisms would be 

 anple to accoxint for the unusually high oxygen values of 1930, as compared 

 with those of 1929- 



It will not be necessary to dwell at length on the results from the sta- 

 tions farther from the river. It will be noted that samples from Station 2$1 

 showed an improvement over those at Station 250 for each date for which data 

 are available, and that on three of the four dates the improvement v;as marked. 

 In some cases the oxygen content was higher at Station 2^1 than at S"^ations 

 252 and 25[t. Such differences may be accounted for by the greater abundace of 

 algae at the inner station, assuming that the abundace at Station 25l was 

 intermediate between that of Stations 250 and 252 (Tables 56 and 57). At Sta- 

 tion 25l, each sample showed a decided deficiency of free carbon dioxide, and 

 high pH. At the two outer stations the pH never fell below 8.0. It is worthy 

 of note that, with minor exceptions, there was a progressive decrease in 

 methyl orange alkalinity from the river outward. The most pronounced change 

 was found between samples from Station 2U9 and Station 250, indicating that 

 considerable mixing occurs directly at the mouth of the river. In spite of 

 the high oxygen values at all stations out from the mouth of the river, it 

 is certain that much of the polluting material is still present in an 

 uncompletely decomposed form. (Table 32). Apparently it becomes so diluted 

 that the chlorophyll-bearing organisms are able to con-ipensate for loss of 

 oxygen in the process of decay. Agitation of the water by the wind also 

 must help in replenishing the supply of oxygen and in liberating the excess 

 carbon dioxide. 



In view of the lack of evidence of pollution in Maumee Bay , except at 

 the mouth of Maumee River, one would not expect to find such evidence along 

 the shores outside of the bay. Table 30 shows the data obtained at two 

 points near the south shore, east of Maumee Bay in 19?8 and 1930. Stations 

 106 and 105 are one mile apart and lie in an area about two miles from the 

 shore and four miles east of Little Cedar Point. Both surface and bottom 

 samples were taken on several occasions but the results were so uniform 

 that only bottom samples are recorded. Obviously the data offer no evidence 

 of pollution. 



Somewhat similar results, were obtained at Station 116 in 1928 and 1930 

 (Table 31). This station is located 1-1/8 miles off the shore at Toledo 

 Beach, Michigan, and 5 miles in a generally northwest direction from Toldeo 



100 



