Dear David,

Many thanks for your response to referees’ comments, and apologies for the delay of my own response. Your file arrived at the very beginning of my holidays from which I have only just returned.

The reviews of the manuscript were positive throughout, despite some detailed queries by referee 2 in particular. I am also very supportive of this manuscript which I think presents a fantastic data set and opens up some challenging questions with regards to temporal variability in d13C (or absence thereof), and very important implications of how we use such variations in attempts to partition soil derived respiratory fluxes. What appear to be main criticisms by referee 2 are in my view manifestations of the very interesting absence of variability. I am more than happy to accept the presentation of these results in the present form and the honest ‘admission of mystery’! I am sure that this will attract considerable interest, and doesn’t require any attempt of tenuous explanations or guesswork.

There are a number of useful comments amongst the notes from referees 2 and 3. I would like to ask you to revise the manuscript along the lines indicated in your response. I hope that we will then be able to proceed to publication with fewer delays than we had up to now. (I have no holidays planned in the near future!)

With best wishes,
Jens

Dear Dave,

Many thanks for revising the manuscript and incorporating comments by referees. I'm happy for this paper to now be published. I'm sure that it will be an important point of reference for researchers using continuous isotopic measurements.

Many thanks again for submitting it to Biogeosciences, and for your patience with the prolonged review process!

All the best,
Jens