Co-nutrient limitation of diatom growth under nitrogen or silicon limitation. A reply to the paper of Flynn & Martin-Jézéquel.

Flynn and Martin-Jezequel (J. Plankton Res., 22, 447-472, 2000) derived a mechanistic model for nitrogen and silicon physiology of diatoms. During their analysis, they compared the output of this model with that of the co-nutrient model of Davidson and Gurney (J. Plankton Res., 21, 839-858, 1999). They highlighted some discrepancies between the predictions of the two models, which occurred subsequent to exhaustion of the yield-limiting nutrient, and suggested that the co-nutrient model contained technical inaccuracies in its output. Here it is shown that by simply modifying the numerical values of two of the parameters of the co-nutrient model, while retaining exactly the same model structure, it is possible to produce similar dynamics to those exhibited by the model of Flynn and Martin-Jezequel.