THE EFFECT OF CLOUDINESS ON THE OXYGEN CONTENT 
OF WATER AND ITS SIGNIFICANCE IN CRAN- 
BERRY CULTURE 
H. F. Bergman 
(Received for publication July 22, 1920) 
In the culture of cranberries it is often necessary to flood the bogs as a 
protection against frost and certain insects. The length of the flooding 
period may vary from a few hours to several days. To ascertain the relation 
between the oxygen content of waters and injuries which had occurred to 
the vines as a result of flooding, an investigation was begun in 1918. This 
work was carried on during the seasons of 191 8 and 191 9 in the cranberry 
regions of Massachusetts and Wisconsin. 
One of the first things that became apparent as a result of the study of 
flooding water of cranberry bogs was the extent of variation of the oxygen 
and carbon dioxide content of water from different sources and the correla- 
tion of these variations with weather dnd other conditions. The oxygen and 
carbon dioxide content of exposed waters under certain conditions varies 
considerably as between day and night. The extent of this variation is 
affected by the amount of sunlight during the day as determined by the 
presence or absence of clouds. The velocity and direction of the wind 
and the temperature of the water also affect the gas content of flooding 
waters but are less important than Hght intensity. 
The effect of cloudiness on the oxygen and carbon dioxide content of 
water is indirect, resulting from the action of light on submerged vegetation. 
When plants are submerged, oxygen and carbon dioxide during respiration 
or photosynthesis are absorbed from the water or given off into it in solution. 
Accordingly, the oxygen content of the water is increased during the day in 
proportion to the amount of vegetation present and to the light intensity, 
while the carbon dioxide content decreases under the same conditions. 
The presence of oxidizable organic matter in the water or in the sub- 
stratum tends to reduce the oxygen and to increase the carbon dioxide 
content of the water. This effect has been observed in the marshes, 
used by many Wisconsin cranberry growers for reservoirs, and in the water 
of cedar swamp reservoirs in Massachusetts. On a clear day the amount 
of oxygen produced by photosynthesis is much in excess of that used up in 
respiration or by the oxidation of organic matter. For this reason, when 
vegetation is present, an accumulation of oxygen occurs. In cloudy weather 
the accumulation is less. The oxygen content may even decline in densely 
cloudy weather. A diurnal variation is thus to be expected in ponds with 
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