RELATION OF ALGAE TO DISSOLVED GASES. 177 
cline, the only place where an abundance of carbonic oxide 
occurred, while oxygen was to be found at all depths. At 
this time it was observed that above the thermocline the water 
was alkaline to phenolphthalein, indicating the presence of a 
certain amount of normal carbonates in solution. This alka- 
linity has been more frequently observed in connection with 
a vigorous growth of blue-green alge. It is possible that cer- 
tain organisms under certain conditions have the power of 
taking carbonic oxide from the hypothetical! bicarbonates of 
alkaline earths. This would accord with the facts noted long 
ago by one of the authors, that in Massachusetts water — 
supplies, heavy growths of organisms were somewhat more 
likely to occur in hard waters than in soft waters. This 
fact has been observed since by a number of others, notably 
Wesenburg-Lund (’08) and Birge and Juday, to whom 
reference is made more fully later. 
The cause of the sudden appearance of “water-bloom” is 
but little understood. Whether it is the cause of the changes 
noted in the alkalinity and gas content of the water, or 
whether it is the result of these conditions is still a ques- 
tion. Studies have been made to determine its danger to 
fish, ete., but scarcely anything is known as to the physio- 
logical relations to its environment. Steuer (’11) and others 
have claimed that by the rapid respiration at night of the 
plants comprising the ‘“water-bloom,” the water is robbed 
of so much dissolved oxygen that fish have been suffocated. 
Baldwin and Whipple (’06) more recently report a case 
in Weequahic Lake, Newark, N. J., of a rapid growth of 
“water-bloom” followed by the sudden death of large 
quantities of fish, and attributed by them to the exhaustion 
of oxygen from the water. They remark that while green 
alge are “powerful oxygenators” there is some reason to 
believe that the blue-green algz are not so vigorous in this 
respect. It had been noted for a number of years that 
1Some of the alkaline earth bicarbonates have recently been pre- 
pared by Keiser and McMaster, Jour. Am. Chem. Soc. 30: 1713-17. 
1908, and Keiser and Leavitt, Jour. Am. Chem. Soc. 30:1717. 1908. 
