Porewater samples were collected using dialysis samplers with 14 chambers (Zak et al., 2004) from 64 natural and rewetted peatlands across Germany (47 sites), Poland (5), Estonia (6), Scotland (3), Sweden (2), and Georgia (1) between 1997 and 2017. Depth-integrated mobilization rates of soluble reactive phosphorus (SRP) and ammonium (NH₄⁺-N) were calculated for 48 natural and rewetted study sites based on concentration profiles, using Profile V1 (Berg et al., 1998). The computation applied Fick's first law of diffusion, considering pH, temperature, DM content, and loss on ignition of the peat. Diffusion constants for SRP and NH4+-N under defined conditions (10-20°C; pH 4.1–7.2) were sourced from Yuan-Hui and Gregory (1974) and adjusted using chemical equilibrium calculations that account for pH, temperature, and dynamic viscosity of water. The porosity of peat samples, used to estimate tortuosity, was derived from the water content and the composition of inorganic and organic matter content (Lewandowski et al., 2002). The calculations assumed steady-state conditions. Advective transport of dissolved solutes was excluded, particularly for rewetted peatlands, due to the low hydraulic conductivity of the decomposed peat layer. This study aims to compare the vertical concentration profile for SRP and NH4+-N and its mobilization rates between rewetted and natural peatlands (bogs and fens).

Further projects and funding: Ursachen und zeitlich Entwicklung der Phosphorfreisetzung und des Phosphorrūckhaltes in wiedervernässten Niedermooren (Beispielgebiet Peenetal bei Dargun), Award: Department of Environment of Mecklenburg-Vorpommern and the European Agricultural Guidance and Guarantee Fund (EAGGF) WETSCAPES2.0, Web: https://botanik.uni-greifswald.de/experimentelle-pflanzenoekologie/wetscapes2/, Award: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Transregio Collaborative Research Centre 410