Dear Johan,
I have read the comments of the three reviewers on your manuscript as well as your answers to them. Based on that I encourage you to submit a revised version of your work. On some points reviewers agree which strengthen their criticisms. In particular, I would appreciate you consider the remarks raised by two of the reviewers on the organization of the manuscript. In particular, I also agree that the last lines (16-21) of section 1.1 page 3 are as you say very important and certainly worth to be mentioned. I find however, that this part would be even more understandable if it was placed after having analyzed the results. I guess that the point of the reviewers is not that you remove this part but rather than it would be better fit in a discussion section. Same remark for the limitation of the low resolution, this is already a conclusion and recommendation gained based of the analysis of model results and that will be more easily interpreted when having read the results.
Another point on which reviewers agree is that the description of the model structure needs to be enhanced. You can for instance write the model equations for the concerned state variables. Even if it is described somewhere else, it would be helpful for a reader to find the information in the manuscript and to be able to reproduce the modeling exercise. I support your idea to add a table with parameters and variables associated to the modeling of the macroalgae.
One of the reviewers strongly recommend that you enhance the discussion on how the limitations of the modelling approach may impact the conclusions of this study
Please note that the revised version will be sent to the reviewers for a second round.
I thank you very much for your efforts in revising the manuscript.

Kind regards
Marilaure

Dear Johan,
Two reviewers have evaluated the revised version of your manuscript. They both agree that the manuscript is significantly improved and they underline the efforts you made. One of the reviewers still has minor comments that need to be considered before acceptance of your manuscript for publication in Biogeosciences. These comments concern the description of model equations and in particular the definition of the units used in some terms. He/she provides a detailed description of his/her concerns.
I would like that you consider these minor revisions.
Thank you for your efforts,
Kind regards
Marilaure

Dear Johan,
I have read the last version of your manuscript as well as your answers to the last comments provided by one of the reviewers. Based on that I am pleased to accept your paper for publication in Biogeosciences. I have a last comment that concerns Figures 14 and 15 which do not seem to be in logarithmic scale but rather on a linear scale. Please clarify.
Thank you for your efforts and for having chosen Biogeosciences for publishing your work.

Kind regards,

Marilaure