Dear Dr Li:

Thank you for submitting this instructive paper to Biogeoosciences. Your paper has received mixed appreciation by the referees. One referee is rather critical, the other two are in favor of publication pending substantial revision. I have read your rebuttal and believe that a revised version might eventually be publishable in Biogeosciences. I therefore invite you to submit a revised version following the approach of the rebuttal. Your revised version will likely be evaluated again by one or two of the referees.

With best regards, Jack Middelburg, Associate editor

Dear Dr. Li:

Thank you for submitting the revised version. One of the referees evaluated your revision and believes it is ready for publication. I agree with his/her assessment; I enjoyed reading your well-written, instructive paper.
I therefore have to pleasure to inform you that your paper is now accepted for publication pending a few very minor technical corrections.

line 32: meta-analysis (for readability).
line 65, 344: replace on the other hand with however or alike because there is no on the one hand (and they always go together).
line 112: are assumed to be constant/uniform. The logic of calling half-saturation constants well mixed is not clear. Constant is also what matters.

With best regards, Jack Middelburg, Associate editor