Dear Authors
Thank you for the responses to the important comments by the two reviewers. Please acknowledge my apologies for the long delay in taking my decision. Note that these two reviews were very consistent and converge to the conclusion that your MS need profound revisions before it reaches the standards of Biogeosciences. Although they are both experts in the field of your study, their comments clearly demonstrated that the submitted MS was not adequately written, a that a lot of fundamental information was missing. Please submit a revised MS together with a version that indicates the changes made.
Thank you for submitting your interesting work to BG
With best regards
Gwenaël Abril, associate editor

Decision#2

Dear authors
Thank you for the revision of your MS. From your responses to the reviewers’ comments and my own reading of your revised MS, I believe this research has the potential to be published in BG. However, this new version is still not satisfactory for publication in its present form and needs an extensive revision of language, an improvement of phraseology avoiding unclear statements. Revision by a native English speaker that includes the meaning of sentences and a clearer formulation of ideas as well as a detailed reading by co-authors would be very welcome

I also made few suggestions on how to improve figures. See below my line-by-line comments which are far from being exhaustive, as I am also non-native English speaker.

Please submit a revised MS together with a file that shows all the changes made in the MS.

Looking forward reading this soon

With best regards

Gwenaël Abril


Define DOC and SRP in the abstract
L30 “while the others more or less resembled the bulk DOC uptake” > Others what?
L46 “alter the toxicity” increase or decrease or both?
Section 2.1 Site description: it would informative to localize (as an additional zoomed panel in figure 1, maybe some photographs?) the “several inflows, two natural springs, six drainage pipes”, the “site with groundwater infiltration” the “small wetland”. The ‘(dense) grass growth on the banks”, the “deciduous forest at the beginning and end of the study reach” as well as the location of stream discharge and water quality continuous monitoring, the “two lateral inflows”, even if this information is resumed in Fig 2.

Fig. 2 “downstream from 1 in m” do you mean downstream distance from point/station 1 in meters?
L192 you use the term “terrain model” only once a time here in the mat and meth section. Dou you mean “digital terrain model”? Is this term necessary?

You jump from section 2.5 to 2.7 without section 2.6
L219 what do you mean by “while vf should compensate this problem”, what problem? Why is it a problem? Please rephrase/explain
L220 “U incorporates the concentration of the solvent”, not clear, please better explain
L222“because the compensation of hydrologic conditions makes general uptake patterns better visible” not sure what you mean here do you mean that Vf is compensating the changes in discharge, making the changes in other parameters and particularly the biological ones, better reflected by Vf than U or Sw?
L228 > “by doing that”
L252 “these models” What models? why plural?
L254&256 concentrations of what?
L260 thus “we” did not; “restrict the sign” do you mit “fix” or “impose” the sign?
L262 “this is significant” what is significant?
L281&289 not “by that” > “by doing that” (I doubt the paper has been edited by a native speaker)
L299&300 not sure “resemblance” & “resembled” are appropriate words. Similarity? Similar…
L300: “composition” if fluorescence is the criteria, not sure “composition” the appropriate word
L331: “these three” what? Revise phrasing
L333-334 where can we see the lower DOC peaks?
L335 “This demonstrates how a low number of observations or erroneous data influences results in Bayesian statistics” how do they influence? Please be more explicit
L336 “However, although we cannot make reliable statements in all relation to other leachates, we get the probable range of uptake velocities” what statement? What relation? Please explain/rephrase
L345 taken up slower, WHEREAS SRP,… language editing is needed
L373 “Although the model improved decisively in comparison to the one without interactions” improve language
L376 delete “no additional information could be gained from the available data.” Write “For Hum- micter (C3) and N-NO3, we found no effects of variable collinearity within the models”
L380 delete “we found substantial evidence that”
L381 Not sure what is the meaning of “concurred” here
L392 “to get the effect, their uncertainty would have on the model” > to get the effect of their uncertainty on the model results?
L396 “Hence, we do not expect a more sophisticated model to reveal any more details” not sure what you mean here
L398 “The higher error of the model compared to the assumed effect of the measurements on the accuracy shows that” please improve phraseology.
L404 “as also observed”
L411 “Interestingly, the same sequence of increasing uptake velocities from cow dung leachate to leaf leachate and corn leachate was observed in a laboratory flume experiment using the same organic matter sources as this field study, but different sediments (Weigelhofer et al., 2020)”
L414 “There, however...” improve language
L418-L419 So what? Do you mean that “in addition, leaf leachate uptake also varies with P fertilization of trees”?
L420 I would say it lies in the upper range
L427 “was taken up slowest” > most slowly. It looks like this MS has NOT been edited by a native speaker as the authors say
L430 remove “about”
L438 “was only intermediate in our study” not sure what you mean here
L437 “The uptake of N-NO3 was the lowest of all components due to its high background concentrations in the water column” not clear why high background NO3 induce lower NO3 uptake, looks like counterintuitive
L443 “huge number of different bacterial strains” not sure what you mean here
L445 “we do not believe that... Rather, we assume that”. Based on what facts? Looks speculative
L458 “However, as the molar ratios of C:P were low in our stream, showing no P limitation, and we also did not raise the SRP concentrations in our stream additionally to the P content of the leachates, SRP-related effects on DOC retention might have stayed uncovered” Almost impossible to understand. Please improve phraseology.
Same for the next sentence “performed much better” performed what? You mean have better performance?
L466 and on several other occasions “This efficiency loss can be explained by the processing capacity of the stream ecosystem, which is influenced by adaptions of the microbial community to usually occurring concentrations” this is a very vague explanation. Usually, biological uptake increases with the concentration of the substrate (first order or Michaelis – Menten kinetics) what is happening here? L467: how can transport become limiting if availability of the substrate increases? This looks strange. I can see that some detailed explanations are given later, I think the discussion should be better worded and structured in order to avoid such crude counter-intuitive statements at the beginning of a paragraph.
Page 23 and 24 and at many places in the MS: no need to separate the text in so many small paragraphs
L488: please explicit what are the “substantial evidences”. Or write later “these evidences are:… good degradation conditions, ideal stoichiometric ratios”, etc… you writing style is too imprecise
L496: sorption on what? Sediments? Again, be precise. We often have to read 2-3 sentences before understanding the first one
L508: “The INSBIRE approach was developed after the data from the experiment was acquired due to limitations in other data analysis methods developed for inorganic nutrient uptake (Stream Solute Workshop, 1990), such as the lack of a strategy to handle interactions among DOM components.” I did not understand
I guess a detailed review by co-authors can improve the MS particularly section 4.4