Dear Dr. Mariash
Thank you for submitting your work to Biogeosciences. Both reviewers see the significance of your work and are broadly supportive of publication. They do however, note a number of issues, for which you have outlined a satisfactory response. Please revise the manuscript as outlined, clearly noting the changes you have made in response to each point.

Regarding the suggestion for the title given by reviewer 2. I think this is an excellent point, but I would suggest using a more specific term like 'nutrient concentrations' or 'nutrient release' rather than the more generic term 'water chemistry'.

Regards
Perran Cook

Dear Dr. Mariash
Thank you for submitting your work to Biogeosciences. Both reviewers see the significance of your work and are broadly supportive of publication. They do however, note a number of issues, for which you have outlined a satisfactory response. In particular, I agree with your point about retaining the phytoplankton data in response to reviewer 2.

Please revise the manuscript as outlined, clearly noting the changes you have made in response to each point. I will ask one of the reviewers to assess whether you have addressed their comments to their satisfaction.

In addition, I have two minor comments.

pg 9, line 6. Please provide a little more detail on your calculation and loading rate for the comparison with the work of Schindler.

Regarding the suggestion for the title given by reviewer 2. I think this is an excellent point, but I would suggest using a more specific term like 'nutrient concentrations' or 'nutrient release' rather than the more generic term 'water chemistry'.

Regards
Perran Cook

Dear Dr. Mariash
Thank you for your response to the reviewers comments. I note reviewer 2 still has concerns about the presentation of the phytoplankton data, but is supportive of the publication of the nutrient data. The main issue is the lack of replication which means that it is impossible to say whether there was indeed a statistically significant effect on the phytoplankton community. I am, however of the view, that some information (especially hard to collect data) is better than no information, particularly when presented alongside other data and that these results can remain in the manuscript provided that the caveats are clearly outlined and that your statements and title reflect this. My key suggestion for changes include:

1. Title – remove all reference to phytoplankton response
2. Discussion – You need to state clearly upfront that no statistically significant statements can be made about the differences between the treatments (for example you cannot say there was a pronounced response). I think it is ok to then discuss in a short paragraph how the generic differences relate to previous work on eutrophication (ideally in the similar cold waters) and the nutrient concentrations. I note your observations for picoplankton seem to be inconsistent with https://pdfs.semanticscholar.org/ba64/353992834361aa34fc9e8badd9b00bc29ff2.pdf

Figure 4 – a and b are swapped? At the moment the figure shows the opposite of what you state in the text

Also, please refer to 4a and b in alphabetical order in the results.

Dear Dr. Mariash
Thank you for revising the manuscript. I now find it acceptable for publication
Regards
Perran