A Numerical Model for the Estimation of Photosynthetic Production, Integrated Over Time and Depth, in Natural Waters1

A numerical solution of Vollenweider’s photosynthesis model is presented. This model provides for varying types and degrees of inhibition of photosynthesis by light. A digital computer is used to estimate the photosynthetic inhibition parameters and to integrate the model numerically over time and depth. The numerical approach exploits the full generality of the model by allowing the inhibition parameters to assume any values and by using the actual distribution of surface light over a day, thereby removing all the mathematical approximations made by previous authors. The assumptions and limitations of the solution and the data necessary to test it are discussed.