The import and export of organic nitrogen species at a Scottish ombrotrophic  peatland

McKenzie, Rebecca M.; Özel, Mustafa Z.; Cape, J. Neil; Drewer, Julia; Dinsmore, Kerry J.; Nemitz, Eiko; Tang, Y. Sim; van Dijk, Netty; Anderson, Margaret; Hamilton, Jacqueline F.; Sutton, Mark A.; Gallagher, Martin W.; Skiba, Ute

doi:https://doi.org/10.5194/bg-13-2353-2016

Articles | Volume 13, issue 8

https://doi.org/10.5194/bg-13-2353-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/bg-13-2353-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 13, issue 8

Research article

|

21 Apr 2016

Research article |

| 21 Apr 2016

The import and export of organic nitrogen species at a Scottish ombrotrophic peatland

Rebecca M. McKenzie, Mustafa Z. Özel, J. Neil Cape, Julia Drewer, Kerry J. Dinsmore, Eiko Nemitz, Y. Sim Tang, Netty van Dijk, Margaret Anderson, Jacqueline F. Hamilton, Mark A. Sutton, Martin W. Gallagher, and Ute Skiba

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Final revised paper (published on 21 Apr 2016)
Preprint (discussion started on 09 Jan 2015)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC C8: 'review of McKenzie et al', Anonymous Referee #1, 14 Jan 2015
- AC C2520: 'Authors response to referee #1', Rebecca McKenzie, 31 May 2015
- AC C2531: 'Reference corrected', Rebecca McKenzie, 31 May 2015
RC C113: 'The import and export of organic nitrogen species at a Scottish ombrotrophic peatland', Anonymous Referee #2, 09 Feb 2015
- AC C2526: 'Authors reply', Rebecca McKenzie, 31 May 2015
- AC C2532: 'Reference corrected', Rebecca McKenzie, 31 May 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Rebecca McKenzie on behalf of the Authors (01 Jun 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (02 Jun 2015) by Ivonne Trebs

RR by Anonymous Referee #2 (05 Jun 2015)

Suggestions for revision or reasons for rejection

After reading the revised version of the manuscript, I still feel that it could be shortened and focussed. What is the take home message besides the intuitive and not particularly new finding that dissolved N in waters draining from a peatland are dominated by DON, while precipitation is dominated by DIN? What can be learned from the characterization of DON using the combined SPE GCxGC NCD approach? This information is also lacking in the abstract. The abstract states that pyrrole, benzonitrile, dodecylamine, N-nitrosodiproylamine and decylamine were found, but what is the conclusion from that?

It is a pity that no data of chloride concentrations or electrical conductivities of water samples were available to support the interpretation of concentration changes over time, but I acknowledge that much of the discussion regarding the seasonality of concentration has been removed from the manuscript.

The authors added the reference Maie et al. 2006 to the introduction, but it remains unclear why the GCxGC NCD results are not discussed in the light of previous papers characterizing DON with other techniques such as NMR or XANES...The name of the authors cited in the context is Schulten and Schnitzer and not Schulten and Schnizer...

I regard the determination of the recovery of DON extraction from water samples by the C18 SPE method as essential for the interpretation of the data. The quantification of extraction efficiencies is basic analytical quality control. I am not asking for the recoveries for individual organic compounds, but for the overall recovery for the bulk DON. How much of the total DON contained in a precipitation sample, soil water sample or stream water sample can be extracted using the specified SPE procedure? This information can be easily optained by i) measuring DON concentrations of the original samples (SPEinflow) and the outflows of the SPE cartridges (DON_SPEinflow-DON_SPEoutflow/DON_SPEinflow) plus ii) quantifying the amount of N that can be eluted from the SPE cartridges with DCM in relation to the DON amount in the original sample (DON amount eluted/DON amount in original sample). In my opinion the manuscript should not be published without providing such basic information on analytical quality control. This information would be valuable, because it would indicate whether the limited perfomance of the SPE GCxGC NCD appracoh was due to the poor extraction of DON from the aqueous samples (which could be imroved by using other cartridges) or due to the poor volatilization of most DON compounds in the GC (which could be improved e.g. by derivatization of samples or by replacing the GC-MS with an LC-MS).

The authors state that the information from GCxGC NCD measuremetns should be maximized in the future by including more standards with known chemical structure. Wouldn´t it be also necessary to isolate e.g. the most abundant compounds by preparative GC in order to have enough marterial available for spectroscopic characterization by for example NMR?

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ED: Reconsider after major revisions (09 Jun 2015) by Ivonne Trebs

AR by Rebecca McKenzie on behalf of the Authors (16 Feb 2016) Manuscript

ED: Referee Nomination & Report Request started (24 Feb 2016) by Ivonne Trebs

RR by Anonymous Referee #2 (02 Mar 2016)

ED: Publish subject to minor revisions (Editor review) (02 Mar 2016) by Ivonne Trebs

AR by Rebecca McKenzie on behalf of the Authors (26 Mar 2016) Author's response Manuscript

ED: Publish as is (29 Mar 2016) by Ivonne Trebs

AR by Rebecca McKenzie on behalf of the Authors (06 Apr 2016) Manuscript

Short summary

Dissolved organic nitrogen (DON) contributes significantly to the overall nitrogen budget and can potentially be biologically available as a source of N. Despite this it is not routinely measured. This study found that DON contributed up to 10 % of the total dissolved nitrogen (TDN) found in precipitation and was the most dominant fraction in soil water (99 %) and stream water (75 %).