THE EFFECTS OF pH ON PHOSPHATE ABSORPTION BY ALGAE


Eric P. Brubaker
School of Science and Natural Resources
Lake Superior State University
Sault Ste. Marie, Michigan 49783 USA


	Abstract. The purpose of this experiment was to determine what role, if any, altering
the initial pH of a water sample would have on the algal uptake of phosphate present.
While PO4 is an important component of an algae's photosynthetic abilities, if in short
supply, it can also limit the growth of algae. Therefore, uptake of P04 was used as an
indirect measure of algal growth under various pH regimes. The experiment was
conducted in Lake Huron between Alpena and Rogers City, Michigan. A large water
sample ( 1 L), was split evenly into 3 bottles. The initial pH and phosphate levels of the
three bottles were then measured. The pH of the three subsamples was then adjusted to
acidic basic, and control conditions. Each subsample was then split into replicates and
incubated in situ at a depth of two feet. After seven days, the samples were removed from
the lake and both the final pH and final phosphate levels were measured. A One Factor
ANOVA test (alpha level of 0.05) showed a significant difference in algal phosphate
uptake as a function of initial pH. The final pH of all the samples did not change except
in those samples that were acidified. From this experiment, I concluded that the initial pH
ofthe water sample does play a significant role in the algae's ability to absorb phosphate
present in the water. However, more research needs to be done as to the reasons for the
increase in pH of my acidic samples after incubation.






Selected References


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Riegman, R. and L. R. Mur. 1 986. Phytoplankton growth and phosphate uptake by
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