Dear authors,
Thank you for your letter of response to the reviewers. In view of their recommendations, I would like to invite you to submit a revised version of your manuscript, which will be sent for additional review to one of the original reviewers. In preparing your new manuscript, please bear in mind the need, highlighted in particular by reviewer 2, for more detail and more clarity regarding analytical procedures, method assumptions, and interpretation of results. Making the text more accesible to a wide range of readers will help to ensure that your approach is incorporated into the set of tools that microbial ecologists use to assess nutrient limitation in aquatic ecosystems.
Thank you for submitting your work to Biogeosciences.
Best regards,
Emilio Marañón

Dear authors,
The revised version of your manuscript has now been examined by one of the original reviewers. This reviewer considers that you have adequately addressed the required changes. After revising the manuscript myself, I have decided that your article can now be accepted for publication. However, publication is subject to a minor revision of Fig. 1. I concur with the reviewer that it would be helpful if this Fig. illustrates also the case of P-limitation and even the case of a balanced system. I suggest that you include those situations by showing two additional lines, perhaps using a different colour or shade, on the same panel, and referring to those lines in the figure legend.
Note also the reviewer has spotted a minor grammatical error on page 10 line 9.
Thank you for submitting your work to Biogeosciences.
Best regards,
Emilio Marañón