Methane Emission Heterogeneity and Its Temporal Variability on an Abandoned Milled Peatland in the Baltic Region of Russia

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I attaced a file.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you very much for taking the time to review our manuscript. Please find the detailed responses below in the attachment and the corresponding revisions/corrections highlighted in the re-submitted manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Presented manuscript titled: “Methane emission heterogeneity and its temporal variability on an abandoned milled peatland in the Baltic Region of Russia” presents high scientific value and good interdisciplinary soundness.

Methane mitigation, calculation, emission and forecasting has been studying for many researchers and scholars around the world. There were many attempts to unify the methodology of methane emission forecasting/calculation but every methane environment is different.

In submitted article Authors tried to calculate and determine the methane emission from abandoned milled peatland in the Baltic Region of Russia. As authors mentioned “The findings were derived from the analysis of 13,000 air samples obtained by the opaque emission chamber method at 10 peatland sites with different environmental characteristics during regular measurement campaigns of 2022-2024.” There was a massive and good in quality scientific job done.

Materials and method were good specified and described. Methodology comprises the newest (state of the art) instruments and measurements technique.

In the reviewer opinion the most important fact is as follows: “Temperature is a principal factor responsible for the baseline CH4 emission level in a seasonal scale, while water table depth has a stronger effect as warmer environments become more pronounced in the disturbed peatland. The hydrological factor is thus a determining factor in the general methane emission rate during the warm period of the year, as well as in the annual and inter-annual scales.”

The literature is provided, conclusions are supported by the results and results are clearly presented.

The submitted manuscript can be published in the present form.

Author Response

Dear reviewer,

Thank you very much for taking the time to review our manuscript and for your high evaluation of our work! Your opinion is very important for us and we appreciate your positive assessment. 

In line with the other reviewers’ recommendations, we have revised the text and added an appendix. We hope that you will find the corrections relevant. All edits to the revised version of the manuscript are highlighted in yellow.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors, 

Your paper is interesting, well-organized, and well-written, however, some comments should be considered before publishing, such as: 

Write a reference to CH₄ flux measurements.

Do you mean 2022  in Since April 2023,

Write the details of Atmosphere-Soil Measuring 172 Complexes (APIC) and gas chromatography, such as the model and manufacturing country.

Which version of SAGA GIS and QGIS did you use?

In the abstract and conclusion, you mentioned that temperature and hydrology are principal factors responsible for CH₄ emission in different seasons, but you didn't explain how you conducted this because there is no mention of this in the material and methods section. This will also require adding a section about statistical analysis in the material and methods section. As well, in the result section, you should add a section explaining this point in detail based on the method used.

In the result section, you didn't present any data (figure or table) for the meteorological and environmental parameters that you mentioned. You should show these data even as a descriptive statistical analysis.

There is a mistake in numbering the section where the conclusion came before the last parts of the result 3.5 and 3.6, as well 3.4 is missing, so please consider this.

Author Response

Dear reviewer,

Thank you very much for taking the time to review our manuscript. Please find the detailed responses below in the attachment and the corresponding revisions/corrections highlighted in the re-submitted manuscript.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

In this manuscript, Napreenko and coworkers explored the variation in methane fluxes over various areas of peatland sites. Although the mean flux of methane from peatland, an important methane source, is known, the variability within this source was not well explored, and this is the major contribution of this study. A complete understanding of all different sources is paramount to estimate the global methane budget and to predict the effectiveness of mitigation efforts. A number of regional studies have been conducted in recent years with this objective, and this paper is an important addition to them.  In this paper, the seasonal, annual, and inter-annual variabilities of methane fluxes from peatland sites were investigated, and a large heterogeneity was observed. The authors also categorized different peatland sites based on the level of methane emissions. This is an interesting study that is very much relevant to the field. The manuscript is well written, and I recommend publication after the authors address a few minor points mentioned below.

Some important references are missing in the introduction. For example, the Saunois et al. paper on the global methane budget should be cited, including relevant data from that paper in this manuscript. Some recent papers on methane emission from peatland are also not cited. An example of the lack of citation is at line 35, “a significant number of regional-scale studies have been undertaken globally” – however, no citation was provided. Another example is at line 71: “A comprehensive analysis of numerous methane flux studies has revealed several knowledge gaps, including the paucity of measurements during the winter period, the insufficient attention paid to land cover structure, microtopography, and vegetation characteristics on disturbed peatlands”.

The materials and methods are well described. I suggest some further information on the points mentioned below.

Please provide details of the GC method used in this study.

Did you estimate CH4 blanks for the flux chambers used?

Did you measure the temperature inside the chamber?

Provide more details on Emission mapping.

1. 191 “Certain specific values of flux were excluded from further analysis. For example, negative values of specific methane flux were obtained in inundated localities (ditches).” Please provide detailed justification for the exclusion of these data.

The results and discussions are described in a structured and rational way, and I don’t have any major concerns here. The conclusions are generally well supported by the results presented. The only major note is the observed increase in CH₄ fluxes during 2024, when the annual precipitation was below-average. It was explained by the higher temperature and the extreme precipitation event during July. However, the same trend was observed in Spring. Which factors contributed during the spring?

Also, the CH4 fluxes in Autumn of 2023 were higher. Any explanation for this?

Author Response

Dear reviewer,

Thank you very much for taking the time to review our manuscript. Please find the detailed responses below in the attachment and the corresponding revisions/corrections highlighted in the re-submitted manuscript.

Author Response File: Author Response.docx