Dear Johannes Hepp,

Let me start by thanking both reviewers for their thorough review. Reading the comments and the replies I have to say I find the replies very dismissive of the reviewers comments and in some places even a bit aggressive. The peer review system is quite delicate and replies like these make it harder and harder to find good reviewers willing to put in the time to review manuscripts. Therefore I would like to ask the authors to rewrite their replies, seriously, carefully and thoroughly addressing the reviewers comments without things like bold font statements, for instance. If the authors are not willing or able to write such a reply to the reviewers comments, perhaps Biogeosciences is not the outlet for them.

Best regards,

Marcel

BG-2019-197

Dear Johannes Hepp,

First of all I would like to thank you for this reply to the reviewers comments, much better than the original reply. I also want to thank the reviewers again for their reviews. I totally agree with you that the limited amount people doing this combined approach should not affect your development and application of the proxy in anyway. That being said, I do see the point of the reviewers as well. I guess the measurements are quite tricky and you have to make quite a few assumptions, like a fixed bio, to make this work. All and all maybe not so convincing yet for other users to get involved in, with the emphasis on yet. I do see the advantage of this combined approach. Of course hydrogen and oxygen behave very similarly with respect to humidity, temperature, evaporation etc. and I can’t really judge if that is good or bad. There are benefits to independent proxies, say hydrogen isotopes from organic molecules and oxygen isotopes from inorganic carbonates for instance. Of course you did measure completely independent proxies for temperature and pH, but these are not linked to the isotope results in anyway? Is there anything you say based on the isotope data that can be back-up by the GDGT data? Something about the local (micro) climate being different from that of the weather stations, for instance? The GDGTs were measured on the same samples as the isotopes, they should reflect the same “micro” climate. Or the underestimation of the RH, can that be linked/supported by some of the other results? Just to link the two independent methods a bit more together? The other thing I was thinking about is that, since the water isotopes behave so similarly you could use the combined measurements to examine , for instance, bio. Flip your proxy around so to say. Plenty of options for future work, I think.
I have a few minor comments; You mention in your response and in the discussion that you cannot see the difference between damping or differences in bio, this has been left out of the abstract? In the introduction you mention quite a few variables on which the hydrogen isotopic composition of n-alkanes depend, some of these are what you would like to reconstruct, so that is not a bad thing right? In the figure 1 legend you mention that the map is sourced by the US National Park Service (just checking)? In line 351 after the, it says “precipitation drops …. “ I don’t see how this is linked to the rest of this sentence?
I think that after you address these minor issues you manuscript is suitable for publication in Biogeosciences.

Best regards,

Marcel

Thank you for your reply Johannes Hepp. I am happy to accept you manuscript for publication.

Best regards,

Marcel