## 5 Conclusions  
Overall, this study highlights the need for a better of understanding of linkages between soil C cycling processes and microbial enzyme activity in wetlands in order to further our understanding of the mechanisms driving wetland C biogeochemistry and storage. In organic horizons, specific enzyme activity (SOC and MBC) (AG, BG, XYL, POX, PER) was higher in the natural compared to drained wetland, but lower (AG, CBH, XYL, POX, PER, NAG) in the AB or B mineral soil horizons. Microtopographical variation at both the natural (hummock-hollow) and drained (bed-interbed) wetlands had little effect on enzyme activity rates. Furthermore, we highlight the need for standardization of enzyme measurements within the field of microbial ecology. Data normalized by soil weight was the least sensitive to management and soil depth, indicating that enzyme rates calculated using soil weight may miss key differences in treatment effects [35]. Data normalized by SOC is an easier metric to measure compared to MBC, with both appearing to be more sensitive to drainage and soil depth effects than normalization by soil weight, providing a more robust and ecologically relevant measurement of soil microbial activity. Results from this study provide useful insights into the biogeochemical functioning of forested wetland soils, particularly looking at broad scale issues of land-use change (managed vs. unmanaged), variation in micro-topography (natural or manipulated), and soil profile characteristics associated with surface and subsurface organic and mineral soil horizons. As coastal wetlands worldwide are under threat from land-use change associated with drainage of wetlands for urban, agricultural, or silvicultural purposes, as well as sea level rise [10; 68; 69], it is essential to understand the long-term effects of these disturbances on soil C storage or loss and soil microbial processes which drive soil C cycling within the soil profile. To address these challenges, expansion of such studies to similar sites across the region will increase confidence in the findings and practical application of this study. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/f13060861/s1](https://www.mdpi.com/article/10.3390/f13060861/s1)]([https://www.mdpi.com/article/10.3390/f13060861/s1](https://www.mdpi.com/article/10.3390/f13060861/s1)), Figure S1: Location of field sites in eastern North Carolina, USA. The natural wetland is located in the Alligator River National Wildlife Refuge, Dare County, NC, while the drained wetland (drained for loblolly pine production silviculture) is located in Washington County, NC. Both sites are equipped with an eddy flux tower, with 13 vegetation plots surrounding the tower. Of those thirteen plots, five were utilized for this study (gray shaded circles) (adapted from [PERSON] et al., 2019); Figure S2: Images depicting (A) the natural wetland at Alligator River National Wildlife Refuge and hummock-hollow microtopography (adapted from [PERSON] et al., 2019); and (B) mature loblolly pine plantation in the drained wetland where trees are planted on bedded rows (high microtopographical location) with inter-tree row space (low microtopographical location) (photo credit: [PERSON]); Figure S3: Soil horizon profile for (A) the natural wetland; and (B) the drained wetland. Letters indicate organic and mineral horizons based on the US soil taxonomical classification system and numbers in parenthesis show the average depth in cm of each horizon. Conceptualization, K.J.M. ; methodology, K.J.M. ; software, K.J.M. and M.A. ; validation, K.J.M. ; formal analysis, K.J.M. and M.A. ; investigation, K.J.M. ; resources, J.S.K. ; data curation, K.J.M. ; writing--original draft preparation, K.J.M., J.S.K., B.M. and P.P. ; writing--review and editing, K.J.M., X.L., M.A., B.M., P.P. and J.S.K. ; visualization, K.J.M. and M.A. ; supervision, J.S.K. ; project administration, J.S.K. ; funding acquisition, J.S.K. All authors have read and agreed to the published version of the manuscript.