102 



Roosevelt Wild Life Bulletin 



the putrefaction of the algae are frequently apparent along the 

 shore, and may interfere seriously with the utilization of the lake 

 as a recreational center. This has been the experience in the PaH- 

 sades Park, and the blooming in Stahahe Lake during the summer 

 of 1918 marred the camp life both by the odors permeating the 

 region and by its discouragement of bathing. 



The growth of algae in water reservoirs is of even greater eco- 

 nomic importance, since their presence, even in too small quantities 

 to form a noticeable bloom, ma}- seriously affect the taste of the 

 water. This effect of algal growths upon the taste of water is out- 

 side the problem under consideration, although it should be noted 

 that the greatest demand for a study of algal growths and especially 

 of methods for their eradication, has come from the water supply 

 engineers. 



Rate of Growth of Algae. Algae are always present in lakes 

 and it is merely a matter of their multiplication until they occur in 

 sufficient abundance to form a mass of suspended particles dis- 

 cernible to the naked eye. The simplicity- of the al^l structure, 

 which is usually but a single cell, is correlated with the rapidity- of 

 multiplication. In the reproduction of algae there is a division of 

 the original parent-cell into two daughter-cells that soon grow to the 

 size of the original one. As soon as these cells have attained the 

 size of the parent-cell, either two plants are present, or, in the case 

 of forms that do not consist of single cells, the number of component 

 cells has been doubled. This life cycle is of short duration and 

 the division of a cell and the growth of the daughter-cells ma}- not 

 take more than twenty-four hours. Furthermore, increase in the 

 number of cells is not an arithmetic but a geometric progjession, 

 and if, under favorable conditions, each daughter-cell divides once 

 in tvvent}--four hours, it will give rise to an immense number of 

 cells in a few days' time. This theoretical increase in the number 

 of plants is not usuallv found in nature, but at times observ-ations 

 like those of Huff ('16), which are shown in Table I. show a 

 very close approximation to it. The organisms studied (Synedra) 

 are shown on Plate 23, Figures 21-23. These results show. 



Table i . Showing the daily increase in number of cells of Synedra puUhelia presetU 

 in successive days. {After Huff). 



Date 



Aug. 19. 



Date 



IndiTidiials 



•ner c.c. 



Aug. 24 



' 25 

 ' 26 



" 27 



225 



520 



1.080 



3 020 



therefore, that there is nothing in the rate of multipHcation to 

 prevent the accumulation of algae in sufficient quantities to be con- 

 sidered a bloom. In general, limiting factors check the unlimited 



