60 Conservation Department 



These analyses taken all tog-ether show that the lake contains 

 only a normal amonnt of nitrogenous substances which are very 

 essential to the successful production of micro-organisms and fish 

 in the lake. 



As regards industrial i)ollution, whether acid or alkali, the reac- 

 tion of the water to phenolphthalein and methyl-orange and the 

 pH showed no indication of any such pollution. The limits of 

 variability found may all be interpreted as normal phenomena. 



It is well known that wastes are being emptied into the lake 

 from various sources. Why, then, does the lake not show indications 

 of this pollution? In answer it may be stated that the process 

 of dilution is operative in vast measure in a body of water 

 the size of Lake Erie. Any concentrated source of pollution is 

 made very dilute by mixing with an enormous quantity of water. 

 In the open water normal oxidation processes change the suspended 

 organic stuffs into soluble form. In the Buffalo region these wastes 

 are being poured down the Niagara river in tremendous quantities. 



In conclusion, let it be stated that the analyses made and the 

 conclusions drawn from the assembled data do not apply to con- 

 ditions that may exist in shallow water near shore. As regards 

 the open lake water the analyses warrant the conclusion that the 

 lake proper is normal and free from objectionable pollution. 



4. — MicropJanl-ton Sfiulies of Lal'e Erie 

 By Paul R. Burkiiolder 



Studies of the microplankton life of Lake Erie were undertaken 

 as part of the general biological survey during the summer of 

 1928. The objects of this particular phase of the work were the 

 folloAving : 1. To study the kinds and quantity of micro-organisms 

 existent in tlie lake, and 2. To determine something of their 

 significance in the economy of the lake, more particularh^ as 

 regards their bearing on the problem of fish production. 



In order to secure representative samples it was necessary to 

 establish a number of stations at various points on the eastern 

 ])ortion of the lake included in this survey. Those stations were 

 chosen which were deemed eitlier biologically significant, i.e., near 

 .sources of ])ollution, outwash from streams, etc., or were signifi- 

 cant on account of the depth of the water or their geographical 

 location. 



Field Methods. — Quantitative samples of microplankton were 

 secured by the following method: Water was drawn from the vari- 

 ous stations and depths by using a double action haiul pum]:) and 

 rubber* hose. This method of securing water samples is deemed 

 adequate for the microj)lankton. though not for the rajiid swim- 

 ming macroplankton forms which manage to evade the puiu]) suc- 

 tion stream. The hose, attached to a cable running from a hand 

 winch, was let (h)wn to the |)roi)ei- depth as (h'terniined by reading 

 the meter wheel. After the hose had been tlioroughly j)umped 

 out so as to remove the organisms that might be foreign to the 



