## 3 Results and Discussion
### The Physical and Chemical Parameters of Peat Core
Their change along the depth of the layer (0-50 cm), which includes the acrotelm and the upper part of the catotelm, and, as a consequence, the most exposed to the influence of swamp water level fluctuations and sensitive to drainage, is not monotonous. The most significant increase in the degree of degradation and bulk density is observed in the 0-10 cm layer (deposit layer formed since the beginning of drainage works in 1971-1975) (Table 1) and is apparently caused by the activation of the microbiological decomposition organic matter of the peat in the zone of increased aeration. In general, dewatering is largely accompanied by vertical shrinkage of the major part of the peat deposit; in particular, due to a significant decline in proportion of moisture in the peat core, leading to the compaction of its structure. Therefore, the values of bulk density 0.185 \(\div\) 0.410 g/cm\({}^{3}\) are recorded for the dried area, which significantly exceeds this parameter that we previously recorded for the natural section of this bog (0.075 \(\div\) 0.109 g/cm\({}^{3}\)) [29] and other upland peat lands of the Pribelomorsky type in undisturbed conditions [34,54]. The same patterns are observed for the natural density of the deposit; one of the key parameters used to assess the dynamics is the accumulation of the peat deposit. As noted above, drainage is expected to be accompanied by a decline in the natural moisture proportion. The moisture content of the drained area does not have clearly expressed dynamics on the depth of occurrence and is between 6.3 \(\div\) 9.4 g/g and is significantly lower than the values established earlier for this bog site with a natural hydrological regime (15 \(\div\) 24 g/g) [29]. Such a change in this parameter in combination with the fluctuation of the bog water level leads to large fluctuations in the aeration and redox regime of the deposit. On the one hand, a decrease in the bog water level contributes to oxidative processes, but prolonged drainage may contribute to the compaction of the peat structure, which, apparently, may be the reason for a decrease in the diffusion of atmospheric oxygen into deeper layers of the peat core. The trend of the Eh\({}_{4}\) and rH parameters (Table 1) by the depth of the analysed peat column indicates the existence of an expressed redox regime, in that the moderate-oxidizing conditions are slowly changed by reducing ones when moving from the surface to the depth of the peat core. The average indicators (for the spring-autumn period of 2021) of the redox potential for the 0-50 cm layer, recorded within the site with stable drainage, are within 195 \(\div\) 521 mV, which is slightly higher than we noted earlier (109 \(\div\) 428 mV) [29] for the site with a natural hydrological regime. This is caused by a wider interval of bog water level fluctuations, which was \(-\)42 \(\div\) 0 cm during the sampling period. It is also necessary to note the greater seasonal variability of the Eh\({}_{4}\) parameter for the drained site compared to the natural site, which is associated with greater temporal instability of the swamp water level. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Horizon, cm**} & \multirow{2}{*}{**Level of Peat Degradation**} & \multirow{2}{*}{**Moisture Content, R, \%**} & \multirow{2}{*}{**Bulk Density, g/g**} & \multirow{2}{*}{**Eh\({}_{4}\), mV \({}^{*}\)**} & \multirow{2}{*}{**rH**} \\ \cline{1-1}  & & & & & \\ \hline
0–10 & 10 & 7.39 \(\pm\) 0.37 & 0.320 \(\pm\) 0.006 & 510 \(\pm\) 60 & 25.3 \(\pm\) 2.0 \\ \hline
10–20 & 7 & 6.55 \(\pm\) 0.40 & 0.259 \(\pm\) 0.005 & 521 \(\pm\) 28 & 25.7 \(\pm\) 0.9 \\ \hline
20–30 & 7 & 6.25 \(\pm\) 0.44 & 0.185 \(\pm\) 0.003 & 409 \(\pm\) 29 & 21.8 \(\pm\) 1.0 \\ \hline
30–40 & 7 & 9.39 \(\pm\) 0.03 & 0.229 \(\pm\) 0.005 & 298 \(\pm\) 50 & 18.1 \(\pm\) 1.7 \\ \hline
40–50 & 15 & 7.49 \(\pm\) 0.35 & 0.410 \(\pm\) 0.001 & 195 \(\pm\) 51 & 14.6 \(\pm\) 1.7 \\ \hline \end{tabular}  
* Eh\({}_{4}\) values are average for the 2021 summer low water period.  
\end{table}