Dear Dr. Groeneveld,
thank you for your response to the Reviewers' comments.

The reviewers concluded that the submitted manuscript discusses new results that contribute to our understanding of the temporal variability in DIC photoproduction and contribution to CO2 fluxes in humic boreal lakes. The work presented would be of considerable interest to the Biogeosciences community and relevant to the scope of the Biogeosciences Journal. At the same time, the reviewers had a number of comments and suggestions to improve the manuscript, including assessing the statistical significance of temporal AQY variability in terms of the uncertainty in measurements, providing a better description of the methodology and specifically the impact of Supor Polyethersulfone filters on CDOM absorbance measurements, re-evaluation of the argument of the lag between irradiance and DIC photoproduction, and revising the title and discussion to highlight the novelty and major contributions of this study. These comments have been addressed in the Authors’ responses to referees’ comments, and need to be incorporated in a revised version of the manuscript before publication. Please refer to the reviewers’ comments and your answers for the revisions.

Sincerely,
Maria Tzortziou
Associate Editor, Biogeosciences

Dear authors,
I am please to accept your article based on the detailed replies to reviewers' comments and your revised manuscript.
Sincerely,
Maria Tzortziou