Jan., 1921] 
BERGMAN — OXYGEN CONTENT OF WATER 
51 
vegetation and decaying organic matter, the amplitude of variation depend- 
ing on the relative amount of vegetation and of organic matter and on the 
intensity of the light. 
In regard to diurnal variation in the oxygen content of lake water 
Birge and Juday (i, p. 53) state that: 
"Some European observers have noted marked diurnal changes in the amount of 
dissolved oxygen in small, shallow bodies of water, especially fish ponds, and attention has 
been called to such changes in the upper water of Lake Mendota in September, 1908 (p. 43). 
In Mendota, the excess oxygen stratum comprised only the upper two or three meters 
which were readily disturbed by wind and by convection currents. Thus there was a 
pretty thorough mixture of this upper water at night so that the oxygen became uniformly 
disturbed in this stratum. As a consequence, there was an appreciable decrease in the 
quantity of oxygen in the layer having the largest excess, that is at a depth of 1.5 m., and 
on the succeeding day the amount of oxygen would again decrease at this depth, thus 
producing a diurnal variation of i cc. to 1.5 cc. per liter of water. But where the excess 
oxygen has been found in the thermocline region, no appreciable diurnal variations have 
been noted. That is, the difference between day and night observations did not prove 
to be any greater than the differences between two sets of day observations, one of which 
was made immediately after the other." 
Birge and Juday were deahng mostly with large, deep bodies of water 
containing relatively little vegetation and with bottoms free of organic 
deposits. Under such conditions the oxygen content of the water depends 
chiefly upon the temperature of the water. According to Pettersson and 
Sonden (5, p. 1443), a liter of water at 0° C. and 760 mm. pressure is capable 
of absorbing from the atmosphere 10.01 cc. of oxygen. Roscoe and Lunt 
(6) state that under these conditions water requires only 9.7 cc. of oxygen 
for saturation. The oxygen capacity decreases with a rise of temperature. 
Thus Roscoe and Lunt give 6.28 cc. as the amount of oxygen required for 
saturation of water at 20° C. and 5.76 cc. at 25° under 760 mm. pressure. 
The latitude of variation in the carbon dioxide and oxygen content of 
waters in the cranberry region of Massachusetts may be shown by a few 
typical examples presented in table i. 
Spectacle Pond shows the least variation in carbon dioxide and oxygen 
content from day to day and between clear and cloudy weather. The 
carbon dioxide content ranges from o.i to 0.7 cc. per liter and the oxygen 
content from 5.4 to 6.5 cc. per Hter. In Cedar Pond the range is greater, 
the carbon dioxide content varying from 0.4 to 2.8 cc. per liter depending 
on weather conditions and place of sampling. The oxygen content of 
Cedar Pond water varies from 4.8 to 6.0 cc. per liter. The greatest variation 
occurs in the water of the State Bog ditch, the carbon dioxide content 
ranging from 2.0 to 10. i cc. per liter. The oxygen content similarly has a 
wide range, from 1.8 to 5.0 cc. per liter. The same relation obtained in 
1919, as shown in figure i. 
Although there is some variation in temperature on the different days 
and hours at which these readings were made, this variation is not sufficient 
