Thank you for carefully considering each of the review comments. Would you please go ahead and submit a revised ms, with each of the modifications and data corrections as per your responses here. Please submit this in track changes mode so that we can follow your revisions.
You make a strong case for the use of an enzymatic approach (and will need to include some of this information in the revision). However I did not see an explicit response to the referee criticism:
"I think it is trivial to draw a line at a 45 degree angle and suggest
that anything above the line is P-limited and anything below the line is N-limited. This kind of information just has not been substantiated enough to say whether that line should be 45 degrees, 48 degrees or 10 degrees."
This could be addressed in the Discussion, for example, by noting that the exact position of this boundary will require ongoing attention in future studies, or an additional argument.

Please submit the revised manuscript in track changes Word format so that the revisions can be seen and checked relative to each of the review comments.

Thank you for responding to each of the review and editorial comments, and for inserting the explanations and caveats as suggested (e.g., effects of freezing).
I recommend acceptance with minor editorial revisions:
Table captions: these could be contracted by removing the words Summary of... A table is by definition a summary:
Table 1. Epilimnetic physical...
Table 2. Nutrient limitation and...
Figure captions: The reader will have to search the ms to find what the abbreviations mean. Please consider writing out these enzyme names in full (with abbreviations in parentheses) in the caption for first figure to use these (Fig. 3).
The final concluding section seems to focus on a scenario of decreased C and nutrient input to lakes with a deepeng active layer, but on p. 26, shouldn't 'to change' be replaced by 'to increase':
Conversely, if DOC input into lakes were to change due to increased terrestrial production within catchments, lakes would be predicted to become
universally P-limited.
Also the statement: 'It is likely that as the amount of lake DOM declines, the types of DOM qualities will shift as well' might be better as ''It is likely that as the amount of lake DOM changes, DOM composition and lability will shift as well',
to keep all options open. For example, please see the THAW overview paper, specifically the summary p. 7153 that describes two contrasting scenarios of DOC export as a consequence of active layer deepening:
http://www.biogeosciences.net/12/7129/2015/bg-12-7129-2015.pdf