Dear Dr Goldman

Thank you for your response to reviewer comments. I would like to invite you to submit a revised manuscript including the changes that you detail in your response. I addition, I would like to request that you pay attention to two particular points raised by reviewers. Firstly, in your response to reviews you include a justification for working in a dam-controlled system. Please add this to your introduction as it helps to justify your study. Secondly, please revise your introduction as requested by reviewer 1 to include further detail from previous studies. I take your point that fully quantitative detail may not be applicable, however process knowledge certainly is relevant. At present you only list what types of studies have been performed in the parafluvial zone, and not what those studies actually found. It is usual in an introduction to set out what is currently known about the subject of a study, in this case parafluvial biogeochemistry.

If you have any questions please let me know.

Best regards,

Clare Woulds

Dear Dr Goldman

Thank you for your revised manuscript. I am happy with the way that you have addressed most of the reviewer comments. I would however like to request further changes to figure 6, as I feel it is slightly inconsistent. Firstly, the two hyporheic zone block drawings should be the same size, and side by side (rather than one set back, and therefore smaller). Secondly, I feel that an arrow with width indicating CO2 emissions should be added to the circle representing submerged sediment in both scenarios. To be fully clear, I'd actually suggest having two versions of the circle for submerged sediment, one for each block. Perhaps most importantly, I'm not really sure how the figure represents the different response to re-wetting in recently and less recently submerged sediment. Should you actually have four blocks in the diagram, rather than just two? Is this what the '+ time' dotted line is supposed to represent?

If you have any questions please let me know.

Regards,

Clare Woulds

Dear Dr Goldman

Many thanks for your revised manuscript, I am now happy to recommend publication in Biogeosciences.

Best regards,

Clare Woulds