Reflections on post-OECD eutrophication models

In recent years a contrast has become apparent between oversimplified models (regression lines) relating primary production in lakes to phosphate loadings, and complicated conceptual models, depending on the rate constants of the most important processes. In the latter, rate constants from the literature are used. Most modellers assume that such constants are valid everywhere and always, but very little research concerning their validity has been carried out.It is generally believed that Smith's equation for photosynthesis and Monod's for bacterial growth under nutrient limited conditions are proven conceptual models — and that Monod's equation may be used for algal growth as well.