Articles | Volume 19, issue 22
© Author(s) 2022. This work is distributed underthe Creative Commons Attribution 4.0 License.
Metabolic alkalinity release from large port facilities (Hamburg, Germany) and impact on coastal carbon storage
- Final revised paper (published on 14 Nov 2022)
- Preprint (discussion started on 04 Jul 2022)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
RC1: 'Comment on bg-2022-143', Anonymous Referee #1, 11 Aug 2022
- AC1: 'Reply on RC1', Mona Norbisrath, 08 Sep 2022
RC2: 'Comment on bg-2022-143', Anonymous Referee #2, 16 Aug 2022
- AC2: 'Reply on RC2', Mona Norbisrath, 08 Sep 2022
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Publish subject to minor revisions (review by editor) (12 Sep 2022) by Perran Cook
AR by Mona Norbisrath on behalf of the Authors (26 Sep 2022) Author's response Author's tracked changes Manuscript
ED: Publish subject to minor revisions (review by editor) (06 Oct 2022) by Perran Cook
AR by Mona Norbisrath on behalf of the Authors (11 Oct 2022) Author's response Author's tracked changes Manuscript
ED: Publish subject to minor revisions (review by editor) (14 Oct 2022) by Perran Cook
AR by Mona Norbisrath on behalf of the Authors (18 Oct 2022) Author's response Author's tracked changes Manuscript
ED: Publish as is (19 Oct 2022) by Perran Cook
AR by Mona Norbisrath on behalf of the Authors (24 Oct 2022) Manuscript
This well written and thorough manuscript describes the biogeochemical processes occurring in the Elbe river estuary and links these to anthropogenic influences. The modelled biogeochemical cycles are well considered and describe a large source of TA within the estuary. This TA source is described as being caused by the dissolution of CaCO3 sediments which is assumed to be driven by the increased organic matter and N loading of the estuary. Biogeochemical processes are explored in detail, although much of this is hypothetical discussion.
One weakness of the study is that all biogeochemical processes are estimated from dissolved concentrations rather than from other field observations, for example benthic sediment incubations or water profiles. The estimation of biogeochemical processes within estuaries is complex due to the dynamic interactions occurring over tidal cycles (salt wedge and tidal movements influencing benthic sediment interactions), diel cycles (changes is benthic O2 caused by respiration/photosynthesis), seasonal cycles influencing metabolism rates, and all influenced by different riverine flow rates. While I agree that the processes identified here are likely occurring within the estuary, the accuracy of the predictions (e.g. that 90% of TA is due to CaCO3 dissolution) may have a high level of inaccuracy and may have high temporal variability. It is useful to use modelled results, however it is important to highlight the uncertainties and assumptions associated with them in all sections of the manuscript.
L17 – wording - ‘resulting in maximum’
L60 – I suggest separating the two research questions for clarity. I also note that the 2nd research question doesn’t receive much attention in the abstract or conclusion.
L65 – Provide more detail on ‘surface water samples’.
L139 – What is the source of wind speed measurement DWD? If wind speed was not measured in situ then where was the data source and at what resolution was the data collected as wind speed can greatly influence flux estimates and this uncertainty should be clarified.
L157 – Provide details of box volume measurements and fill time estimates. Errors associated with both volume and fill time should be incorporated into the mass balance calculations. E.g. errors in the generic river width, depth etc. in Table 1.
L176 – Outer boundary conditions measured two months later. Is this an issue? Please justify.
L190 – The sentence is vague and poorly structured. Clarify the term ‘imported’ and clarify the link between PIC and CaCO3 dissolution.
L308 – This section contains the most clear findings of the paper but seems hidden within the manuscript.
Table 3. Errors of species in the first half of the table seem optimistically low. Are all cumulative errors considered? Errors of samples, box volumes, flow rates, fluxes…etc.
L437 – replace ‘vanishing’ with a more appropriate term.
L442-L447 – This speculation reads as discussion not conclusions
END OF COMMENTS