Dear Dr Pracht and co-authors,

I think you handled the reviews well and think your manuscript is fit for publication in Biogeosciences.

Sincerely,

Lennart

Dear Ms Pracht,

I have carefully read your replies to the two reviewers and your new manuscript. Although your manuscript has improved due to the reviewers’ comments, I have some additional ones, which I hope will further help you to improve your manuscript. After those corrections, your manuscript is likely fit for publication in Biogeosciences.

Sincerely,

Lennart

page 7, line 17: Please avoid references to non-peer reviewed work (Peeters, unpublished data).
The significance of the trends in 5c and 5d is now explained at the end of section 3.2 (next time please indicate this explicitly in your reply to the reviewers). Following the second reviewer’s comment, however, I agree that it would be informative to add the 95% CI’s of the trendlines in 5c and 5d.
Considering the second reviewer’s comment on the vagueness of using “above and below 100 m” (again: in your reply please indicate where we can find the changes you made), I fail to see how your added text (end of 4.2) answers the question. Please respond more precisely by either narrowing down the depths or by explaining why you decided to refrain from it.
It is very thoughtful of reviewer 2 to direct the authors to some unpublished results. I have no doubt that the Dr Wychech is correct in her statements on the contribution of GAM calcite to the overall oxygen isotopes, but it is (unfortunately) not ok to refer to unpublished results (and btw: the references are currently not in the revised version of the manuscript). Therefore, I suggest to remove the references and only add them if the relevant work has been published/ accepted in the meantime. The authors will therefore also need to rephrase the newly added text at the end of 4.2. I have no objection in keeping the general idea of the added text intact.
Technical comments:
Abstract, lines 11-14. This sentence is difficult to understand. Please simplify or divide into several sentences.
Abstract, line 16: please add “single” before “chamber”.
Abstract, line 18: there is a verb missing here. Consider: “The formation of the final chamber happens at temperatures that are approximately ..., suggesting... ”.
Abstract, lines 20-21: please remove “..., based upon measured size as opposed to sieve size, ...”.
Introduction, page 2, line 5: replace “The knowledge of how” by “Understanding how”.
Introduction, page 2, line 6: replace “in order” by “to”.
Introduction, page 2, lines 6-7: replace “...reduce associated error. ” by “...reduce the uncertainty in reconstructed parameters.“
Introduction, page 2, line 15: should be “individuals’ depth distribution”.
I am not a big fan of the subdivision into ‘Questions’. Consider renaming them by e.g. “depth migration by T. sacculifer” for Q1. Then the different methods sections can also be combined rather than be kept separate for every ‘question’ (these sections are often a bit short in the current version of the manuscript).
Introduction, page 3, lines 6-7: replace “by those same species... and closing nets.” by “...by presences or absence of species in stratified net tows.” or something similar.
Introduction, page 3, line 18: replace ‘situation’ by ‘conditions’
Introduction, page 4, line 9: “shell” should be subscript. Also noted at other places: please check the complete text for this typo.
Introduction, page 4, line 19: “reduced temperature variation”? I suspect that this refers to a relatively small seasonal temperature variability. Please rephrase.
Introduction, page 4, line 30: distribution of what? del18O?
Methods, page 5, line 8: is there a reference for this protocol? Otherwise, remove “the methodological protocol of the VUA”
Methods, page 6, line 21: ‘vital effect’ is not (necessarily) the same as ‘size effect’: please replace the former by the latter.
Methods, page 7, line 11-12: I don’t understand this sentence, please rephrase.
Methods, page 7, line 17: insert a comma after ‘results’
Results, page 7, line 23: ‘To aid the reader’ is awkward phrasing. To aid (the reader) with what?
Results, page 7, line 25: ‘errors’.
Results, page 7, line 27-28: it is obvious that measuring size and weighing generates data about size and weight. Remove “..., generating data about size and weight”.
Results, page 8, line 2: replace ‘greater’ by ‘larger’.
Results, page 8, line 3: should be: “...or non-linear growth of the foraminiferal shell.”
Results, page 8, lines 4-5: this is only true for Rotaliid foraminifera, not foraminifera in general.
Results, page 8, line 9: ‘larger’ instead of ‘bigger’.
Results, page 8, line 9: what does ‘wilder’ mean?
Results, page 8, line 11: ‘F’ should be ‘F chamber’ I guess.
Results, page 8, line 11: ‘the shell’ likely refers to the shell of large specimens. Please add.
Results, page 8, line 14: ‘the area of the final chamber’.
Results, page 8, line 15: please remove ‘; values become more scattered”.
Results, page 8, line 15: As shell ‘sizes’ increase?
Results, page 8, line 16: replace ‘body’ by ‘shell’.
Results, page 8, line 16-17: this sentence is unclear. Please rephrase. Suggestion: ”Large specimens often have disproportionally large or small final chambers.”
Results, page 8, line 24: try to avoid using ‘we’.
Results, page 9, line 1: insert another comma before ‘respectively’.
Results, page 9, lines 8-9: insert another comma before ‘respectively’.

Dear Dr Pracht and co-workers,

I think your manuscript is fit for publication in Biogeosciences. Congratulations and looking forward to see the final version!

Sincerely,

Lennart de Nooijer