The three major issues raised by the referees have been carefully answered by the authors. The paper emphasizes very interesting results, and is extremely useful for the OUTPACE program.
In agreement with reviewer#2, one can nevertheless regret that a quantitative impact of diazotrophy on the carbon and nutrient cycles is not presented, even shortly. As an example, one of the main objective of OUTPACE is to quantify the impact of diazotrophy on the export of carbon flux, and the biological carbon pump. This information is easily available from model outputs. Although it does not depend only on PP, but also on grazing and particle dynamics, it could have been interesting to get an estimate of the potential increase of export due to diazotrophy in the present model configuration. One can assume that the carbon and nutrient budgets will be presented in an additional short paper.

Obvioulsy, the authors have answered to all the major comments of the reviewers, which makes the paper more clear and precise (exept presenting some budget on the carbon cycle and export).
Nevertheless, one can regret that the simulations and analyses are still not entirely convincing. There is no explanation why the same model is not used for both stations. If the model with diazotrophy were correct, diazotrophs would not grow in WGY, if it is really the shift of the depths of the two main nutriclines which explain the difference at the two stations. In fact, as iron limitation is not considered, one might guess that the model with diazotrophy could not work in WGY, but we do not know. Nothing is said about that issue, which weakens the demonstration. The model without diazotrophy, used in WGY, could also have been run at WMA, in order to show that it is necessary to consider EXPLICITELY the diazotrophs to get correct fluxes and seasonal cycle (point on which the authors insist).
Nevertheless, the main point (P regeneration vs. N regeneration) is now correctly presented. If one or two sentences are added in order to explain the point raised above, the paper can be published.