Dear dr. Xu,

Thank you for submitting your responses to the comments of the 2 reviewers. As you have seen, both reviewers find the topic of interest and of high scientific significance. However, at the same time, both reviewers are very critical of the presentation and scientific quality. Key issues that need major attention include:
- the English writing
- the presentation of the results, e.g., not all features described are clearly visible in the figures, more quantitative approaches could be used, the statistics need attention.
- the discussion, which could be much more mechanistic, process-based and better grounded in data.
Based on your replies, I conclude that you are willing to address these points. When submitting your revised manuscript, please also include a detailed list of the changes made and a track-changes version of the manuscript.

best regards,
Caroline Slomp

Dear Dr. Peng,

Thank you for submitting a revised manuscript. Two reviewers have now provided comments on this revised version. While both reviewers find the manuscript greatly improved, there are still a number of smaller and larger issues to address prior to publication.

The first larger issue is the English grammar, which should be improved further. While all BG-manuscripts are edited for English in the final stage before publication, a higher initial level is required. Both reviewers provide useful suggestions. If possible, please involve a native English speaker in checking the manuscript. Please note that the title also contains an error: "Enhance" should be replaced by "Enhances". The second larger issue refers to the statistics and presentation of the regression lines in Fig. 5, as pointed out by one the reviewers.

I look forward to seeing a revised manuscript.

best regards,
Caroline Slomp

Dear dr. Peng,

Thank you for submitting your revised manuscript and the detailed response to the comments. The clarity of the manuscript is now much improved.

I have a few minor suggestions for change that you may still consider (as technical corrections):
on page 2:
- line 2: "The explanations" could be changed to "These processes"
- line 2: "the fact that" could be changed to "the observation that"
- line 7: "debatable" could be changed to "debated"
- line 8: "enhanced" could be changed to "enhance"
on page 6:
- line 2: change to "from the "biogenic bloom"
Figure 5: please indicate in the caption what the different symbols in the figure indicate.

I look forward to seeing your manuscript published.

best regards,
Caroline Slomp