Dear Authors,

Thank you for your revised manuscript and replies to referees.

I have reviewed these, and judge that a further round of review is required. However, before I return the manuscript to your referees, I noted a number of points that it would be helpful if you could address. Some of these are minor and may just require a short clarifying statement, while others may require a little more investigation. Please address these and then return your manuscript.

If you have any questions, please feel free to get in contact.

With best regards,

Andrew Yool

- Table 5: is there a reason why "deep ocean" is mentioned in the “total ocean O2” row?; is it not more straightforward to just use total ocean O2?
- Table 5: regarding “production (prod)”, I think that the upper span of the range here may have been miscalculated; the Carr et al. (2006) reference confusingly refers to estimates based on 6 months of data, but the units used suggest a maximum PP of ~60 Pg C / y (5000 Tmol C / y in your units); Figure 5a of the paper has a single GCM with a PP close to ~80 Pg C / y (6667 Tmol C / y in your units); also, why are you using Tmol C / y when Pg C / y is the more common unit, and its non-SI equivalent, Gt C / y is used in Carr et al., 2006?
- Figure 3b: you could dispense with this blow-up by plotting both a and c here on a log(time) scale; this would expand the most interesting period of the model's evolution; however, you may have already tried this and decided against it
- Figure 3b caption: "in the *first* two hundred thousand years"
- Page 6 of your response: you say “Anaerobic remineralization releases its product to the atmosphere” but this is unclear to me; releases its product to the atmosphere?; this is the sediments we’re talking about, no?; one would assume they were quite isolated from the atmosphere
- Page 7 of your response: has any of this made it into the manuscript or its supplementary material; this would be a reasonable addition to the latter if it's not already there; and it’s would be of interest / value to readers in any case
- Table 3 in the revised manuscript: this O2:P ratio was mentioned by referee 2 but the point was not addressed in the authors' response, and does not appear to have been changed either
- More generally, it’s not completely clear whether you have addressed the specific comments from referee 2; the preceding point would rather suggest not

Dear authors,

Following your last revisions, your manuscript has undergone a further round of review, and two referee reports have been submitted.

As you will be able to see, these are both generally positive. However, both also raise a number of relatively minor issues that require addressing before publication.

Referee #1 notes that your model description lacks some clarity on its sinking particles, and makes assumptions about anaerobic remineralisation that are contrary to observations. Referee #2 notes some issues in the equations that describe your model, which may be simple typos but could indicate problems that would need to be properly addressed if so.

I would appreciate it if you could attend to these final comments with a revised draft and a response that addresses the points raised and fully describes the resulting revisions to the manuscript.

If you have any questions, please do not hesitate to get in contact with me.

With best regards,

Andrew Yool.

Dear Authors,

Thank you for your earlier revisions to your manuscript and referee responses.

Your referees have reviewed these and both have responded positively to the revised manuscript draft. Both are happy for the manuscript to be accepted provided that some final comments and suggestions laid out in their reports are addressed.

I would be grateful if you could respond fully to these reports and resolve the remaining issues raised by your referees. Please ensure that your response makes clear the resulting edits to your manuscript. And if you have any questions about the referee comments, please do get in contact.

With best regards,

Andrew Yool.

Dear Authors,

Thank you for your revised manuscript. I have reviewed this, and your responses to your referees, and am pleased to be able to accept your paper for publication in Geoscientific Model Development.

Your manuscript will now be being passed to our production team in preparation for publication, and they will be in contact to ensure that the final published version of it is fully satisfactory to you.

However, if you require any additional assistance, please feel free to contact me.

Thank you again for choosing to publish your best work with GMD. And apologies for the delays along the way.

With best regards,

Andrew Yool.