Dear authors

Having now read your answers to the reviewer’s comments and projected changes to the manuscript, I am happy to encourage you to proceed with the full revision of your manuscript. In addition to all the minor adjustments you have mentioned, I recommend you carefully address in your revised MS the following important points raised by both referees:
1. Shorten the “review” section, at least don’t call it a review, just an extensive introdution
2. Provide all additional data required to satisfy the referee’s criticisms
I am happy with the term “inland waters”, although I suggest you add the term “flowing” (flowing inland waters) because most of your conclusions apply to lotic systems (Rivers / tidal rivers), but not to lentic environments. Alternatively use simply the term “river” in the title.
In addition, I suggest you remove Figure 9, which I found useless, and take benefit of the spare space to include more quantitative info (additional tests/data in text figures Tables) and qualitative info (discussion in text)
Looking forward to reading this soon.

Best regards, Gwenaël Abril

Dear authors

Having now read the revised version of your technical note, I conclude it should be accept for publication in BG, after some minor revision. I made my own review of your MS and I suggested some changes on several points that need clarification before publication. Looking forward reading a revised version of your paper.
With best regards,
Gwenaël Abril


L55 eddy covariance measurements also include the paper by Polsenaere et al (2013)
Polsenaere P., Deborde J., Detandt G., Vidal L.O., Pérez M.A.P. and Abril G. (2013) Thermal enhancement of gas transfer velocity of CO2 in an Amazon floodplain lake revealed by Eddy Covariance. Geophysical Research Letters 40, 1734–1740, doi:10.1002/grl.50291.
L191 what was the motivation for choosing a different water flow in each equilibrator type? Later in the discussion, water flow must be considered as an important parameter that affects response time.
L217 please specify which CO2 concentration was selected to span the LICOR, and which ones were used for linearity check
L328 change “good agreement” to “excellent agreement” (R>0.99)
L335-336 please consider that faster equilibration in the spray-type compared to the marble-type can be due to differences in water flow (2.5 L min-1 versus 1.5 L min-1)
L345 to L353, avoid repetition on the fact that passive equilibration is slower
L378 Frankignoulle et al. have compared equilibrator data with pCO2 calculated from pH and alkalinity, and not headspace equilibration.
L381 what does “(approximately 12:00) refer to ? please clarify
L382 provide the value of upper detection limits of the sensors.
L420 change “could have amplified” by “apparently amplified”
L437 and throughout the MS: change “spot” to “discrete”
L446 simplify: “Other mechanical antifouling techniques (e.g., brushing and wiping) could be applied to the membrane-enclosed sensor system; nevertheless, the copper-mesh screen could be superior for long-term pCO2 monitoring programs that require easy deployment, minimal maintenance, and low energy demand. “ to something like “Other mechanical antifouling techniques (e.g., brushing and wiping) could be applied to the membrane-enclosed sensor system, but would consume more energy”
L468 & L492 “spot measurements/sampling” > “discrete measurements/sampling”
L498 remove the last sentence “Our technical recommendations and caveats can form a solid empirical basis for further studies that is required to improve the performance and maintenance of gas equilibration systems during continuous pCO2 monitoring in a wide range of inland waters.” Let’s let the scientific community involved in pCO2 measurements decide for that in the future.

Dear authors,
thanks for these corrections and the extensive revision of the initial MS. I think your paper is now a significant contribution to BG.
In the reference list, please insert a line break between reference #1 and ref #2 and between ref #3 and ref #4
Thank you for submitting your work to Biogeosciences
G Abril