Dear Dr. Mandal and Co-Workers,

you received a broad range of reviews (1 minor, 1 major, 1 reject) from the three referees. I see that a majority of the comments ask for clarifications or to be more critical with regard to data interpretations. I consider it most important that you (1) discuss potential alternative interpretations of data, (2) eliminate doubts about data reliability, and (3) highlight the limitations of your methods. I understand from your responses to the referees that you will be able to submit a thorough revision --which will acknowledge the referee's suggestion-- and therefore invite you to upload the revised manuscript. Once received, the manuscript will be returned to 1-2 referees for further consideration.

With kind regards and be safe during this difficult time
Tina Treude

Dear Dr. Mandal and Co-Workers,

the revision of your revised manuscript highlighted a few more (minor) issues that need some attention. It worries me at this point (after two submissions and several rounds of reviews) that the referee still detects incorrect or incomplete information. Please take care of all the issues raised by the referee.

Some additional points to consider:

(1) Please sufficiently highlight (in the abstract, in your discussion/conclusions) that you are trying track the cycle of a compound that is actually not detected in situ (tetrathionate). You should therefore evaluate if your preferred interpretation is the only possibility or if alternative scenarios are imaginable. For example, could the observations be explained by other aspects of S cycling, including abiotic pathways? It is acceptable if you do not have the answer at this point, but you should honestly discuss possible alternatives.

(2) Your Conclusion chapter (4.3) is in major parts a literature review. Literature reviews belong either to the introduction (to set the stage) or to the discussion (to compare with the new data). Please focus the conclusion on the main outcomes and conclusions of YOUR study!

Please provide a point-by-point response to the referee's comment and my comments above, as well as a revised manuscript with tracked changes.

Let me know in case you have any questions.
With kind regards
Tina Treude

Dear Authors,

as we discussed via email, your units for S turnover displayed in the results, Fig. 3 and several supplementary tables need to be corrected, since you can't show rates both per weight AND volume. We agreed on the following unit:

µmol S per L slurry per day

Please make all corrections accordingly before final publication.
Let me know in case you have any questions.

All the best
Tina