Interactive comment on “From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost

L. 25: "We demonstrate that" It would be helpful in this sentence to operationally identify the fraction being discussed (that is, how was it isolated physically?) to better understand how it is being interpreted as "bioaccessible." Can you define the term bioaccessible? Is it synonymous with the more common "bioavailable" or does it specifically refer to physical accessibility? Methods: The methods indicate soil drill cores are taken but do not highlight what depths are analyzed and presented. The text states in L. 102 : "Our analyses focused on selected layers only, as shown in Table 1" but Table 1 does not include this information. One would expect that the contribution of POM vs MAOM and the state of decomposition may vary with soil depth (perhaps not in the traditional predictions) yet the paper does not describe what depths are being analyzed. Discussion: The discussion is quite long with extensive paragraphs that have multiple ideas, which makes it sometimes a little difficult to follow all the ideas. Consider where the discussion can be streamlined and how paragraphs could be split into smaller blocks of text. Section 4.1The section heading is perhaps not the most informative of the text, as permafrost processes (other than one mention to cryoturbation) are not discussed in depth here. Consider renaming the section or including more information on processes. It may also be helpful to separate the text into a paragraph on C and N stocks and another one on composition of SOM, mainly C:N ratios. Section 4.2: It is very interesting that the POM and MAOM fractions play such different roles in C and N storage in these soils.