Sensitivity analysis of PROTECH, a new approach in phytoplankton modelling

The lake phytoplankton community model, PROTECH includes nested regression equations for the effect of surface:volume ratio, temperature and irradianc e on growth rate. A sensitivity analysis was carried out of the effect of c hanging the regression slope coefficients on three aspects of the simulated output for Blelham Tarn, English Lake District, with fixed environmental v ariables. The assessed variables were K, the maximum biomass; K, time taken in days to reach K and the exponential growth rate, r'. It was found that the light adjustment equation was the most sensitive to changes in the slop e parameters. Changes in the base growth rate and temperature adjustment fu nctions had less effect. Because PROTECH uses the light adjustment equation the least, it was argued that any error caused by it was tolerable.