Very good response and changes / upgrades.

Small remaining issues (including a few typographical changes that proofreading will probably NOT pick up).

1) Wherever you use the DOI to point to these data, please use this form instead: https://www.doi.org/10.25921/2swk-9w56. Most journals now adopt this slightly-revised format because - for most users - the new format allows one-click access whereas the prior format required cut and paste or search through DataCite.

2) Thank you for mention of FAIR principles (e.g. line 63). But, FAIR deals primarily with access, while this paper - to its credit (!) - deals almost entirely with quality. Perhaps, to follow the mention of FAIR, add some short reference to your own substantial work on quality? E.g. FAIR principles supplemented by substantial quality control efforts by this/our group. We do not want to allow an impression that meeting FAIR principles somehow substitutes for or replaces expert efforts on any data, but especially not on ocean CO2 data.

Line 74 - calculate air-sea CO2 fluxes, rather than calculated (correct in the second use in that sentence)?

Line. 113 - instruments 'have performed'. Do the authors mean performed under these conditions for these data, or have performed to specs in other oceanographic applications?

Line 418 - "For Flux calculations" should be 'For flux calculations'?


Thank you again for using ESSD!