Dear Dr. Pennino:

Thank you for submitting this paper to Biogeosciences. Based on the reviews and your rebuttal, your revised version will very likely be acceptable for publication. I therefore invite you to submit a revision incorporating the changes as you indicate in your reply.
While preparing your revision, please change the use of ppt for salinity. Use either no unit (as oceanographers do), or use practical salinity unit (psu). ppt is part per trillion, part per thousands is permille.

I am looking forward receiving your revision,

With best regards, Jack Middelburg, Associate Editor

Dear Dr Pennino:

Thank you for submitting this paper to Biogeosciences. I have read the revised version and I am happy to inform you that your paper is now accepted for publication.
However, while reading I identified a few minor issues that require correction.
- L. 113: replace below with either downstream or south
- L. 118: model with small cap
- L 130: give not only million gallons per day, but also, or only, SI units.
- L. 141/143: used to look twice. Please modify.
- L. 282: delete water (not needed).
- L. 374: TMDL (explain to reader)
- L. 479: eutrophication and model not starting with cap
- L. 530-532: Recent work.... (Kaushal et al., 2014a). It has been shown in the 70/80-ies that estuaries are nitrogen transformers (e.g. papers by Billen).
- L. 559: present also SI units
- L. 736: delete floating .

I am looking forward seeing your paper published.

With best regards,

Jack Middelburg, Associate Editor