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Chapter 17

Nutrient Use and Remineralization

Dodds & Whiles

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FIGURE 17.1

Carboys used for an in situ bioassay of nutrient limitation at Milford Reservoir, Kansas. The first four experimental additions (from right to left) are control, N, P, and N 1 P. One week after addition, the nitrogen 1 phosphorus treatment had the most chlorophyll.

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FIGURE 17.2

Graphical representation of equations used to describe nutrient uptake and assimilation: (A) Michaelis–Menten, (B) Droop, and (C) Monod relationships.

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FIGURE 17.3

Graphical representations of the equations used in Example 17.1 for uptake and growth as a function of nutrients for two algae: (A) Michaelis–Menten uptake, problem 1; (B) Monod growth, problem 2; and (C) Droop growth, problem 3.

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FIGURE 17.4

Uptakes of nitrate (A) and ammonium (B) as a function of light (reproduced with permission from Dodds and Priscu, 1989) and nitrate (C) as a function of ammonium (reproduced from Dodds et al., 1991, by permission of Oxford University Press) for epilimnetic plankton in Flathead Lake Montana, July 1987.

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FIGURE 17.5

Reference and current median concentrations of (A) total phosphorus and (B) total nitrogen for rivers in the major ecoregions of the United States. (Data from Dodds et al., 2009).

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FIGURE 17.6

Summary of nutrient bioassays reported in the literature indicating stimulation of biomass of phytoplankton (A), wetland plants (B), and stream periphyton (C). (Data in A from Elser et al., 1990a; data in B from Verhoeven et al., 1996; and data in C compiled from various sources).

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FIGURE 17.7

Charles Goldman showing President Clinton and Vice President Gore a plankton sample from Lake Tahoe in 1998. (Photograph courtesy of the Sacramento Bee).

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FIGURE 17.8

Graphical representation of the concept that gross nutrient uptake and regeneration can stabilize dissolved nutrient concentrations. This occurs when net uptake 5 0 and gross uptake 5 regeneration. The graph illustrates a net increase in nutrients (excess regeneration) when nutrient concentrations are low and a net decrease (excess uptake) when nutrient concentrations are high. (Redrawn from Dodds, 1993).

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FIGURE 17.9

Uptake and remineralization from a variety of surface waters. Note the approximate 1:1 correspondence between therates. (Reproduced with permission from Dodds, 1993).

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FIGURE 17.10

Nitrogen retention efficiency as a function of C:N ratio of food source for bacteria. Note that when food is relatively nitrogen rich (i.e., C:N is low), a low percentage of the nitrogen is used and most of the nitrogen ingested is remineralized. (Redrawn from Goldman et al., 1987).

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FIGURE 17.11

Data showing N:P ratio of Daphnia is lower than that of copepods, indicating different nutrient requirements for both types of grazers. (Reproduced with permission from Elser et al., 1996. © American Institute of Biological Science).

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FIGURE 17.12

Variation in carbon to phosphorus ratios of aquatic consumers by taxonomic group (A) and functional group (B). Fishes have significantly lower C:P than all other taxonomic groups, and detritivores have significantly greater C:P than predators or grazers. (Data replotted from Frost et al., 2006).

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FIGURE 17.13

Variation in diversity of stream invertebrate primary consumers (A) and predators (B) from rivers and streams in Kansas, Missouri, and Nebraska in spring and autumn samples as a function of water phosphorus concentration. There were significant breaks in the relationships as denoted by the two lines, with the predator break occurring at greater total phosphorus than the consumers. (Data from Evans-White et al., 2009).