Dear Dr. Kelley and co-authors,

Your manuscript is now accepted for publication in Ocean Science. The response to the reviewers is satisfactory. Below is a list with some technical issues, that I hope you will account for while preparing your revised manuscript for final submission.

Title: I suggest using the term pH in it. For example: … autonomous pH sensor SEAFET …

I encourage the authors to reduce the use of the word “SEAFET”, which occurs maybe 100 times or more. In some cases it will certainly be possible to speak of “the sensor” or similarly. This would increase the readability.

L26 … and one in British …
L31 A non-U.S. reader may have difficulties understanding what AK stands for. Please write out full.

L40 SEAFET (without –s)
L45 seawater hydrogen ion [H+] …

L47 … the carbonate concentration [CO32-] …

L51 … as continued release of anthropogenic CO2 ensues … (“burning of fossil fuels” is not the only source of CO2 increase in the atmopshere)

L118 delete: the commercially available (has been mentioned before twice)
L141 … the Steinhart and Hart (1968) equation …

L178 VFET does not occur in equations (1) and (2)
L180 ST is different from St in equation (2). This should be consistent.
Please check the equations and definitions again for consistency.

L229 … by Uppström (1974) and Lueker et al. (2000) …

L352-360 Same as written at L180. Please check the equations and definitions again for consistency.

L608-609 I think the following construction reads better: …for electrodes non-conditioned and electrodes conditioned to the environment.

L638-639 Suggestion: … although this is likely not a realistic change as this was the maximum difference within a 3 h period.

L668 Define pHest or write estimated pH

L825 45% should be 45 permille (‰)
L850 Part-II
L877-879 Any update?
L885, L896 Deep-Sea Research

Figure 1: define APSH in caption

With best wishes
Mario Hoppema