Dear Dr. Paetsch and Thomas:

Thank you for submitting your paper to Biogeosciences, for your detailed responses to the comments received and for the intention to incorporate the color scheme corrections suggested by Fabian Grosse. Both referees believe that your paper is interesting and worthwhile to be eventually published, but they also identified a long list of shortcomings. Most of these concern the presentation and the logic, some relate to small calculation errors or better incorporation of existing knowledge.
On the basis of these reviews, and your rebuttal, I invite you to submit a revised version that will be evaluated again by (a subset of) the referees. Based on the quality of your revision and the feedback of the referee(s) I will then decide whether we need another round of review or not.

With best regards, Jack Middelburg, Associate Editor

Dear Dr. Schwichtenberg and co-workers:

Thank your for submitting your revised version to Biogeosciences. The very same two referees have evaluated it again and agree that your paper has very much improved. However, they identified some remaining small issues that require attention. I therefore invite you submit another revision that, after inspection by me, will likely be acceptable for publication.

With best regards, Jack Middelburg, Associate editor

Dear Dr. Schwichtenberg and co-authors:

Thank you for submitting your second revision to Biogeosciences. I have read it, and although some alternative processes might be involved, I am happy to inform you that your paper is now accepted for publication.

While reading I identified the need for a few minor corrections:

All through, please only use “on the other hand” when it is following a ‘on the one hand’.

Please check your units again: sometimes you use micromole per liter sometimes per kg (e.g. see Table 1 vs. Table 2-4). Try to avoid use of TA concentrations if writing TA or TA level will do. See comment of one of the referees about TA equivalent vs. concentration (but this is discipline dependent).

Line 507: Logic. Nitrate uptake by phytoplankton only produces alkalinity if the organic matter is preserved. It was unclear from your text whether this is the case.

Line 528: specify aerobic oxidation here. Anaerobic oxidation may generate TA and thus enhance buffering.

With best regards

Jack Middelburg, Associate Editor