Dear authors,

thank you very much for your work, that has been reviewed by three experts in the field. I agree with their overall evaluations and think that your manuscript can be published subject to minor revisions.

I would additionally request that you to specifically address on of the comments of reviewer 2, who wrote: "My only major concern is that they haven’t really succeeded in separating the influence of the architecture of the microhabitat from the myriad of other environmental variables (light, moisture, temperature, chemistry, etc.) that may be influencing the development of the association." I think that this reviewer raised a very important point that you did not follow up in your response. Fact is that your experiments/samplings did not allow to separate the architecture of the microhabitat from the environmental factors in that very microhabitat. Along this line, you obviously define the architecture of the microhabitat in a way that includes the environmental factors (lines 68ff). So I wonder whether architecture is simply a misleading word and what you mean is that the endolithic communities are determined by the microhabitat, not the microhabitat architecture. Please, address this point in your revised version, either changing the wording or clearly defining the term 'microhabitat architecture'.

Thank you very much,
Andreas Richter

Dear authors,

thank you for carefully addressing all comments of the reviewers. I am pleased to inform you that your manuscript can now be accepted for publication.

Thank you for sending your valuable work to Biogeosciences.

Best wishes!
Andreas Richter