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 = Mo (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: kn = 1, kp = 8, kc = 2, ke = 4, and Mo = 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). |