Regarding the closed/open mound category, I am not entirely clear on what the hypotheses are for each type. What is the reasoning for measuring both, and what are the implications for gas fluxes? I could see adding a discussion point focusing on this contrast.

Comments on the article  ‘Assessing CO2 and CH4 fluxes from mounds of African fungus-growing termites’ from Matti Räsänen and co-authors

The article is well written, and contains interesting field data about a topic which is still relatively unknown, and of which relatively little data exists. The amount of mounds on which this story is based is small, but this is understandable considering the field conditions, and the difficulty to find suitable mounds. Also, the experiment is well designed in the sense that many environmental variables were measured. It is nice how some entomology studies are used to interpret the data.

There are a few general comments which should be addressed by the authors, followed by many detailed suggestions.

General comments

Dependency between species, nest type and location

The authors explain the difference between open and closed mounds in the beginning, and introduce the 2 termite species. They briefly indicate that 1 species makes closed mounds, and the other species open mounds. So, these variables (open/closed mound and species 1/species 2) are not independent. Nevertheless, this is not superclear through the paper. Looking at Table 1, termite species and mound type are listed as independent variables (separate columns), but they are not independent. Additionally to this, the authors try to compare the 2 different species in 2 different environments. But, looking at Table 1, the M. michaelseni only appears once in the bushland (out of 6 mounds), and the M. subhyalinus appears only 2 in the grassland (out of 6 mounds). While it is likely out of practical considerations that the authors decide to not look for equal sampling at each side, this should be discussed better.

So, I would advise the authors to better discuss and evaluate the fact that mound type and species are not independent and to better discuss whether observed differences between grassland and bushland are a consequence of the environment, or the fact that they were basically measuring different termite species (with different nest properties).

Discussion of diurnal variation

The part about the diurnal variation is interesting, but it is difficult to judge how valid/representative the measurements are. Please add on how many days the measurements were made, and how representative 4 or 5 time points are to determine a daily variation. Also, the authors mention that the largest CO₂ flux coincides with the highest wind speed. But, to what extent can wind speed be a factor of influence on the CO₂ flux if the mound is sheltered from wind speed during the measurement? Can the authors discuss this?

Discussion of differences between seasons

The differences between dry and wet season are interesting, but please discuss it further. For example, on page 17, line 15, the decrease in CH₄/CO₂ ratio is mentioned, seen from dry to wet season, and possibly linked to the activity of methanotrophic bacteria. So, the authors mention that during the wet season, mounds have higher water content, so these bacteria become more active. But, you also mention (page 19, line 5) that the mounds represent a stable humidity and temperature. Is there any data or literature which actually shows that the mound humidity changes with season? Or is this ‘just’ an hypothesis to fit your observation? Please elaborate.

Also, it is observed by the authors that the soil CH₄ flux is positive in the dry season, and uptake is seen in the wet season (‘The dry season mean soil CH4 flux was positive at the grassland and bushland site, whereas the mean wet season flux was nearly zero with most fluxes being negative (Fig. 7, S5 and S6’)).

This is unexpected, since usually higher soil moisture (wet season) leads to CH₄ emission, while uptake occurs when the soil is drier. Maybe I have overlooked it, but did the authors measure soil moisture during both season, and how was it indeed drier/wetter in the wet/dry season? The graphs in the suppl material, are they for wet or dry season? There the authors seem to find a weak relation between soil moisture and CH₄ flux. So, why do the authors observe more soil CH₄ flux in the dry season? Discuss this.

Sample quantity/representativeness

This overlaps with the previous points, but just a general comment. The authors have only studied 12 mounds, only measured during 2 moments in the year, and only once diurnal variation was studied (during x days). Again, field conditions are hard, and it is understandable that the dataset is not larger. But I would encourage the authors to consider and evaluate this in their interpretation (can a comparison be made between dry and wet season based on just 2 moments? Can a conclusion on daily variation be made based on just a few measurements?).

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One curiosity, are there no local Kenyan researchers involved in (writing up) this research?

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Detailed suggestions

-Page 1, Line 19: is there a white space between ‘CO2’ and ‘and’?

-Page 4, line 12: to be result from→ to be a result of

-Page 4, line 17: and thus may cause different fluxes-→ which may result in different fluxes

-Page 7: line 10-11: diurnal variation measurements were made: on how many days?

-Fig 2: add on the x-axes which method this number belongs to (Calculated Cone volume/)

-Page 8, line 5: was→ were

-Page 9, sentence on line 8 and 9: sentence is incorrect, check if comma or verb is missing?

- Page 10: line 11-12: why are S1 and MR4 compared? They have a similar volume, but have a different species and environment, so is this comparison useful/valid?

- Figure 6: the legend of the triangles and circles is only given in the first figure (6a). Maybe add a sentence in the caption as well

- Fig 6f: you plot here the standard deviation of the CO2 flux. Please add to your material and methods how you obtain the standard deviation. Is this the standard error of the linear regression slope?

- Table 2: is there a white space missing between CH4 and flux?

- Page 16, line 12: mound outer dimensions correlate positively with the size….. This you take from literature, right? Although clear from the paper (you didn’t count the termites), maybe clarify this to the reader (sentence below just a suggestion, feel free to ignore or improve)

As found by previous studies, the mound outer dimensions of the Macrotermes species (of which both our species belong to) correlate positively…..

- Page 16, line 32: elaborate maybe 1 sentence what you mean with sterile, and why that leads to constant activity over the year

-Page 17, line 5 and 8. CO2 not written in subscript

Räsänen and colleagues investigate CO2 and CH4 fluxes from mounds of fungus-growing termites and adjacent soil at selected sites in Kenya. They chose plots in open grassland and bushland and investigate diurnal courses of fluxes. Results highlight the scaling of mound volume to CO2 flux density and lower CH4 emissions compared to literature values from soil and grass-feeding termites. The authors also stress the importance of active or dead mounds in the landscape for upscaling fluxes.

Overall, the paper is well written, methods are well established, the topic is of relevance for greenhouse gas emission budgets as fluxes from termites are still understudied and flux estimates are associated with high uncertainties. A few plotting issues should be addressed. I particularly enjoyed reading the discussion section.

Beside some general thoughts, here are a few points that should be considered in the revision of the manuscript:

• I noticed that the title had already been modified at an earlier stage, but does “Assessing” really fit? What’s been assessed? I’d just leave the word out.
• No local collaborators as co-authors? In times where “helicopter science” is highly debated, it is hard to understand why not a single person from the region or with local expertise made it to the list of co-authors. I’m not saying that random people from the street should be chosen and I fully agree that a co-author must have made a considerable (scientific) contribution to the study, but weren’t there any African institutions involved where people could have been invited to contribute? Please, at least consider this in the planning phase of any upcoming field studies abroad.
• Abstract, Line 20-21: The fact that there is a 35% decrease of CO2 fluxes in the wet season compared to the dry season is unexpected. Maybe already indicate here the potential reasons.
• Carefully check the reference list. Not all papers cited in the text are listed.
• Figure 1 is overall very nice. What is the source of the above-ground biomass data?
• Sections on gas flux measurements: What is the sensitivity of the gas flux calculation to the mound volume? Have you done some calculations and could this be considered in the uncertainty estimation? Also, how stable, i.e. “how linear” was the concentration increase? Was Equation (2) really the best fit? Could you see any saturation of the concentration increase during chamber closure? And would have probably another method for flux calculation been better?
• Page 7, Line 8: How did you assure gas tightness? Was the collar smoothly inserting into the soil?
• Section 2.3: Very nice setup regarding air mixing!
• Section 2.4: How can nest temperatures from another year be used in this study? How comparable would they be? Isn’t nest temperature correlated with air temperature, soil temperature, wind speed? Or was just the relative diurnal course taken into account?
• Page 9, Line 3: “of” missing between “amount” and “woody”?
• Figure 3 (a): Rainfall should not be plotted as time series, but as a bar graph. Here it is the daily sum.
• Figure 3 (b) and (d): x-axes labels, ticks at 0, 6, 12, 18, 24
• Figure 4: The caption does not really tell what the lower panel shows, although it is quite obvious. Please add. A ratio should not be shown as a bar plot, but rather as points.
• Figure 5, x-axes labels, ticks at 6, 12, 18, 24