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Peterson, Walter F. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume LX (1972)

Bartell, Steven; Richman, Sumner
Kinetics of orthophosphate uptake by phytoplankton populations in Lake Winnebago,   pp. 147-178 PDF (8.7 MB)

Page 148

 148 Wisconsin Academy of Sciences, Arts and Letters [Vol. 60 
biological implications of nutrient enrichment. When these effects are undesirable
the process is a form of pollution. One of the effects of increasing importance
in aquatic biological research is the role of nutrients in relation to the
productivity of the system. Because of the accompanying degradation of water
quality for recreational and industrial use, much concern has been given
to the increase in biological productivity that results from the addition
of nutrients to the aquatic system. While the process is natural and a function
of the age of the particular system, man's industrial, agricultural, and
domestic activities may effectively increase the natural rate of eutrophication.
In order to determine how to best minimize the effects of man's activities
on the rate of eutrophication, the role of nutrients in relation to productivity
must be determined. This not only necessitates the elaboration of effects
of individual nutrients upon the system, but also includes the determination
of the synergistic relationships among the various plant nutrients. For example,
iron has been found necessary in some systems to enhance the availability
of other major nutrients, such as nitrate and phosphate (Schelske, 1962).
The particular nutrient (s) that determines the trophic nature of a system
varies greatly from lake to lake and from fresh water to marine environments.
 Ryther found nitrate to be the limiting factor in primary productivity in
Great South Bay off Long Island, New York (1971). Schelske determined that
iron was the limiting nutrient in several Michigan marl lakes (1962). Micronutrients
such as sulfur, potassium, magnesium, calcium, boron, zinc, copper, cobalt,
sodium, and chloride are also essential nutrients for growth (Lee, 1970).
Molybdenum and manganese have been shown to limit productivity in Castle
Lake, California (Goldman, 1965). Provasoli (1969) has shown that certain
organic compounds, such as vitamin B,2, thiamine, and biotin are necessary
requirements for several marine phytoplankters. However, the nutrient most
often implicated as the limiting factor in biological production is phosphorous
(Wentz and Lee, 1969). 
 Considering its importance as a vital structural component of DNA, RNA,
and protein, as well as its functional significance in intermediary metabolism;
the common occurrence of phosphate as a limiting factor of productivity is
logical from a theoretical viewpoint. In addition phosphate usually occurs
in minute concentrations compared to other nutrients in lakes (Tucker, 1957).
 The purpose of this study was to investigate the influence of phosphorous
on the realization of productivity potential in Lake Winnebago by comparing
the uptake of phosphate enrichments by natural phytoplankton assemblages
as the natural available 

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