Northern peatlands are globally important ecosystems for long-term carbon storage (Blodau et al., 2004;Clymo, 1987), and have exerted a global climate cooling effect over millennia (Frolking et al., 2006). While only covering ∼3% of the global land area, peatlands store approximately one third of the global organic soil carbon pool (Gorham, 1991;Xu et al., 2018;Yu et al., 2010). This long-term accumulation of peat is generally facilitated by a water table (WT) level near the peatland surface, which limits peat decomposition rates (Benscoter et al., 2005;Clymo, 1984) and maintains high photosynthetic capacity for the key peat-forming Sphagnum mosses (