The foraminifer isotope atlas of Stefan Mulitza and coauthors is much appreciated as a contribution to paleoceanography and paleoclimate, and should be published as soon as possible. In general, the manuscript is well written, and I would suggest only minor changes. I provide an annotated pdf file, which may allow for quick finding of some typos, and explains some suggestions.

To account for the ecology of planktic and benthic foraminifers, I would suggest to define the depths habitats in a bit more explicit way. The terms "shallow" and "deep" dwelling may be misleading. I would suggest to use the term "surface mixed layer" and "sub-thermocline" dwelling. For example, Neogloboquadrina pachyderma may live as deep as 200 m water depth, but which is still in the surface mixed layer of the deep mixed polar ocean. In contrast, Globorotalia truncatulinoides may usually dwell at 200 m water depth in the tropical to temperate ocean, but which is well below the thermocline, at sub-surface water depth. When specifying the habitats more clearly, the isotope ranges of the different taxa may be better explained. This would still not account for the largely latitudinal and seasonal distribution of many taxa.

The benthic foraminifer genera Cibicides and Cibicidoides are not generally epi-faunal. Only two species, Cibicidiodes wuellerstorfi and C. lobatulus are epifaunal, and most of the many species of the genus are shallow infaunal. Some are even deep infaunal. Please refer to the books of Murray (e.g., 2008) and Schiebel and Hemleben (2017), in which the ecology of benthic and planktic foraminifers are explained, respectively.

The term Foraminifera is a systematic term (not foraminifers, foraminiferal), which starts in upper case. By convention, only genus and species names are given in italic style; any addition to the name, such as spp. and sinistral, is not given in italic style, but in normal style.

The genus name of the species sacculifer has changed from Globigerinoides to Trilobatus some time ago, and which may be mentioned at some place in the text, where T. sacculifer is discussed (e.g., on page 5, line 10).

Creseis (spp. and acicula) is a pteropod, i.e., a pelagic snail, and not a foraminifer. This may be discussed in the text. However, given the very different nature (aragonite, not calcite) and ecology (fast swimmer over great water depths, not passive plankton), it may be easier not to present the pteropod in the atlas on Foraminifera.

Mulitza et al., present a global “living” repository of sediment cores with oxygen and carbon isotope data which include new and previously published data. They outline their data sources, organization, coverage, distribution, and potential future applications of this database. The authors explain the merit of the global atlas, how to download and navigate the data, invite others in to contribute data, and recommend uses for the atlas (e.g., education, expedition planning, etc.). I commend their effort to organize for the first time such decentralized and complicated data from many sources. I suggest that the paper be published after some minor revisions which would clarify information flow and provide context for the findings.

Missing data: A database not cited here may have relevant information for the atlas. The authors should compare their atlas to the database at https://doi.org/10.1594/PANGAEA.875998 and accompanying paper (https://doi.org/10.5194/essd-9-739-2017). Borreggine et al., 2017 assessed sediment core collection in the North Pacific, Sea of Japan, Bering Sea, and Sea of Okhotsk. They document meta data and isotope data among other characteristics. It would be beneficial to cross-check your atlas to this database to ensure no cores/records are missing and update numbers (i.e., # of cores, # of records, percentages, distribution data, figures, etc.) if necessary. The accompanying paper may also include analysis that could provide further context to this article.

In Section 3, the authors assess data distribution and offer some brief explanations. Section 3.1 does a good job of explaining core distribution across ocean area and water column depth but does not offer an explanation as to why most cores are found in tropical regions, why isotope records are predominantly found in the Atlantic, or why the Mediterranean has the highest core density. Additionally, Section 3.2 may benefit from a brief analysis on why certain species are the most commonly used.

The authors should provide concrete suggestions on how to apply their database beyond what is mentioned in Section 4. For example, they should expand their discussion in Section 4.3 on the merit of educating students about downcore isotope ratios and Section 5 with information on how to employ PDV.

Since one of the stated goals from the authors is to contribute to the long-term maintainability and consistency of age models through this global atlas, the authors should include more detailed information about how other researchers can contribute new data in Section 6.

The final table belongs in the supplement rather than the main text.

In the attached PDF I have added these comments as well as others to the preprint for the authors to consider. The comments include technical corrections, wording suggestions, typos, and information structuring suggestions. Great work!

This paper describes a new world atlas of foraminifera oxygen and carbon isotopes. This is a very welcome and extremely useful contribution to the paleoceanographic community and will be a very much used tool in the future. The authors have to be commended for the great effort to put this atlas together.

The paper is very well written and to the point. It provides the necessary information to use the database, although at present it was not possible for me to access the database. I assume the link will be activated once the paper is accepted.

The last chapter does not clearly describe if the database is open to additional data and if yes how they can be supplied to the authors, or if the authors plan a updated version in the future, rather than a continuous incorporation of new data as they are provided by other contributors.

Very nice piece of work, that can essentially be published vith only very minor improvements in the last chapter.

Stefano Bernasconi