The Baule-Mitscherlich limiting factor equation evaluated in freshwater habitats

Summary

The Baule-Mitscherlich limiting factor equation, slightly modified (base 2 instead of e) has been evaluated for freshwater lakes sampled in the USEPA National Eutrophication Survey (1972–76). The four factors used were N, P, C, and light. N and P were expressed in mg · l⁻¹, C was expressed as titratable base (meq · 1⁻¹) and light supply as the ratio of euphotic zone thickness to mean depth. In the equation:

M = M_o (1–2^−knN) (1–2-^−kpp) (1–2^−kpC (1–2^−KeEE)

When M was expressed as chlorophyll (mg · m⁻³) the values of the four k's were: k_n = 1, k_p = 8, k_c = 2, k_e = 4, and M_o = 400. The departures of the observed chlorophyll values from those predicted by the equation can be indicated by using the operators x/ ÷ 2.

The equation can also be used to predict:

(1)	Phytoplankton volume (Mo = 200 ml · m−3)
(2)	Photosynthetic yield (Mo = 160 mmol C fixed · m−3 · hr −1)
(3)	Areal photosynthesis (Mo = 1.6 mol C fixed · m−2 · day −1) and
(4)	Community metabolism (Mo = 2 mol C processed · m −2 · day −1).