Dear Yifei Dai, Long Cao, and Bin Wang,

Thank you for the extensive revisions to your manuscript 'Marine biogeochemical cycling and oceanic CO2 uptake simulated by the NUIST Earth System Model version 3'. These have improved the manuscript substantially. The improved motivation and framing of the manuscript was particularly useful.

I am recommending a further round of minor revisions to allow you to more fully address a few of the reviewers' comments.

1) Please can you revise your discussions section, to ensure that ALL of the statements you make are backed up with evidence (i.e. at present there are lots of statements which are probably underpinning by your results section, but there is no reference back to the figure etc. which presents that evidence).

2) Please can you also significantly expand the paragraph your have added P25 L9-18. The reviewer sensibly asks for this comparison, but your response is much too light.

3) Finally, please undertake a (hopefully) final proof-read and edit to ensure that throughout the manuscript the subject of each sentence is completely clear. For example, you have revised the final paragraph of the manuscript to:

'Overall, compared with both observations and CMIP5 models, the NESM v3 does a good job in simulating ocean biogeochemical fields and oceanic carbon uptake. Despite these model-observation discrepancies, it is expected that NESM v3 can be used as a useful modeling tool to study interactive feedbacks between the ocean carbon cycle and climate change and the underlying mechanisms.'

The second sentence says 'Despite these model-observation discrepancies...' but the preceding sentence (and consequently nowhere in the paragraph it) makes no reference to model-observation discrepancies.

Thank you in advance for your revisions. Kind regards,
Paul Halloran

Dear Yifei Dai and co-authors.

Thank you for taking the time to address my final points. I'm pleased to accept this manuscrupt for publication.

Kind regards,
Paul Halloran,