The manuscript features the undervalued but fundamental redox potential that serves as indicator of peat mineralization processes. Besides, the redox potential is coupled to measurements of enzyme activity. The authors raise interesting hypotheses and present valuable results (although figures and tables might still be distilled better). The results are well-integrated in literature in the discussion, and conclusions are communicated clearly. Nevertheless, I believe that certain improvements should be made before publication. In particular, I have concerns regarding the methodology used to determine the Fe-reduction isopotential (and the associated hypothesis), as well as the discussion regarding bi-modality in Eh (and the answers provided to this hypothesis). Please find more specific comments in the attached file. 

This work provides monitoring data focused on measurements of pH-normalized oxidation-reduction potential (Eh) at four sites encompassing bogs and fens in southern Finland with different drainage histories (undrained, short-term drainage, long-term drainage). As such, the sites have a range in dominant modes of vegetation and moss types, as well as pH range.  The study also measured seasonal changes in three hydrolytic enzyme activity potentials.  The principal objective was to evaluate changes in water table level as a predictor of Eh. The authors explored “wavelet decomposition” to identify patterns that would inform future modelling efforts, as well as more traditional linear and non-linear models with physical parameters as independent variables (temperature, water table level).  The main take-away from this analysis was that the drivers and predictors of Eh across a bog-fen continuum are complex, and while water table and temperature likely do exert some significant predictive capacity for Eh (Appendix findings, A1-A3), the wavelet analysis did not yield straightforward results.  Another significant finding was that Eh was strongly correlated with some hydrolytic enzyme potentials. I note here that the authors devoted 8 figures to the wavelet analysis, and yet the more straightforward linear and non-linear model analysis was buried in the appendix.  I mention this because this manuscript as written is quite long for a peer-reviewed paper (14 figures).  In full disclosure, the wavelet analysis was largely outside my area of knowledge, so I will have to defer to other referees to evaluate that component. I think that with some “tidying up” this manuscript should be a valuable contribution, and I offer comments by line number in hopes they are helpful in revision. 

Lines 110-115: It was interesting to see a focus on hydrolytic enzymes, given the focus on Eh.  Why were no oxidative enzymes chosen?  It seems this would be more relevant to ‘enzymic latch’ mentioned in discussion? I think it would be appropriate to justify that here. 

Lines ~157-162; Line 185: There should be some more information about the “redox probes”. Were these calibrated in any way (run against a standard, like Zobell’s or Lights Solution).  How were they conditioned? Were the pH electrodes calibrated, and how? 

Table 1, Figure 13 bars: I appreciate the theoretical thermodynamic cutoff ranges for redox pairs for context, but seeing as the authors did not measure redox couples in this study, perhaps this could be removed, or put in appendix?  Just a suggestion. 

Line 170: Again, interesting focus on hydrolytic, given the focus on oxidation reduction potential. 

Line 182: Why was 200mV added to the probe reading?  The authors later state that Eh-pH was normalized using the Nernst equation; what is this “+200mV” doing?

Figure 3: It is surprising that there is not really a vertical temperature gradient. 

Wavelet analysis figures:  I think the captions could make these more accessible.  What does the Y axis represent? I apologize for not having expertise in this area, but I suspect a large amount of the readership of this paper won’t either. 

Enzyme activity tables:  Please provide units and provide context in the text (results and discussion).  As written, we do not know if these values are “reasonable”; are these potential activities in the pocket of prior research?

Correlation Matrix Tables: It would be helpful if the x axis could also contain labels, so the reader doesn’t have to count columns to compare r values. 

Discussion:  I am very interested in the analysis performed that is buried in the Appendix (A1-A3).

Lines ~325-330 : It has also been shown that meteoric inputs from rainfall can have an oxidizing effect on pore water chemistry.  Please see the paper by Mitchell and Branfireun (2005) in the journal, “Ecosystems”, 8:731-747. 

Line ~345: Moreover, temperature plays a critical role in the solubility of Oxygen in water (see your appendix models). It is common to see a gradual reduction in DO with the progression of the growing season in peatlands, as soils warm and respiration increases.  I think a brief nod to this would be good, and this would be a good place to engage your linear and nonlinear modelling exercises. 

Figures A1-A3: I would like to see perhaps XY predicted vs. observed plots; if you squint here, it actually looks like these more traditional approaches are doing fairly well at predicting Eh.