Nutrient Use and Remineralization - Freshwater Ecology: Concepts and Environmental Applications - page 312

16 Nutrient Use and
Remineralization
Use of Nutrients
Nutrient Limitation and Relative Availability
Relative Availability of Nutrients
Nutrient Limitation
The Paradox of the Plankton and Nutrient Limitation
Resource Ratios and Stoichiometry of Primary Producers
Nutrient Remineralization
What Short-Term Processes Control the Levels of Dissolved
Inorganic Nutrients Such as Ammonium and Phosphtate?
Processes Leading to Remineralization
Remineralization as a Source of Nutrient Pulses in Lentic Systems
Stoichiometry of Heterotrophy, Their Food, and Nutrient
Remineralization
Summary
Questions for Thought
Nutrients serve as the base of food webs in aquatic systems because
they often limit primary production or heterotrophic activity. Understand-
ing ecosystem production, nutrient pollution, and interactions among het-
erotrophs, autotrophs, and their environment requires an elucidation of
nutrient dynamics. In this chapter, I discuss how nutrients are acquired and
assimilated, the relative amounts needed in different systems, and the cru-
cial concept of nutrient limitation. How nutrients are made available (re-
cycled) by heterotrophs as they cycle through the food web of aquatic sys-
tems is also discussed.
USE OF NUTRIENTS
In the broadest sense, a nutrient is any element required by organisms for
growth. Even though organisms are composed of large amounts of oxygen
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