Thank you for your submission to Biogeosciences. Potential reviewers were highly interested in your MS, and we received a total five reviews, all from highly qualified researchers in this field. All agree that this MS is well-written and addresses a topic of interest to Biogeosciences readers, but numerous corrections, edits, and suggestions for improvement were offered. In particular, multiple reviewers indicated that it will be necessary to better distinguish this paper from the earlier associated Nature paper and to clarify the differences between them. Furthermore, multiple reviewers requested some of the information in the Obrist et al. 2017 Nature paper reiterated here, which would help this paper stand alone without requiring readers to go to that paper (which might not be accessible to them), as well. Thus, you are encouraged to find ways to concisely provide these details to the maximum extent you are able. Beyond that, several other helpful and specific suggestions were offered. Thus, I will be happy to consider a revised submission that substantively addresses these reviewer comments. From reading your responses to the reviewers in the Interactive Discussion, it appears that you are well on your way to addressing the reviewer comments.

Please pay careful attention to clearly address or rebut all of the reviewers' comments, and please be sure that the rebuttals are thoroughly justified in your responses, and importantly, that the clarifications provided in your responses to reviewers are clearly incorporated into the manuscript text. Furthermore, please consider providing clarifications in areas of the text that drew questions from reviewers; in some cases the clarifications are currently only in your responses to reviewers with no changes made to the manuscript, but these clarifications might also be helpful to other readers.

Finally, please detail how the text was revised according to the reviewer comments when submitting your revised manuscript. Thank you for these edits, and for your support of Biogeosciences.

Sincerely,

Michael N. Weintraub
Associate Editor
Biogeosciences

Thank you for your revised submission to Biogeosciences. You will be pleased to hear that, based on your responses to the reviews and my own assessment, I have concluded that this manuscript is now ready for publication. Nice work on this! Thank you for your efforts, and for your support of Biogeosciences.

Sincerely,
Mike Weintraub
Associate Editor
Biogeosciences