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).
Porewater and soil samples were collected 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. A total of 812 anoxic porewater samples were taken from water-saturated soil layers (0–0.6 m depth) using dialysis samplers along 10–20 m transects (Hesslein, 1976). Selected fen sites were monitored for 10–20 years post-rewetting to assess seasonal and long-term nutrient dynamics. The peatlands varied in drainage history and land use intensity, resulting in different degrees of decomposition in the upper peat layers (0–0.4 m depth). The dialysis sampling technique enabled unbiased sampling of oxygen-sensitive dissolved solutes and provided vertical concentration profiles of porewater chemistry (Zak et al., 2004). The data were used to compare porewater composition between rewetted and natural peatlands (bogs and fens), (ii) evaluate the influence of peat characteristics on porewater chemistry in rewetted sites, (iii) examine seasonal variations in nutrient concentrations in rewetted fens, and (iv) assess long-term changes in porewater composition following rewetting.
The study investigates the chemical and physical characteristics of porewater and soil samples from peatlands across 64 sites in Germany, Poland, Estonia, Scotland, Sweden, and Georgia sampled between 1997 and 2017. The sites covers oceanic (Cfb, Cfc) and continental (Dfb, Dfc) climate zones and include both minerotrophic fens and ombrotrophic bogs. Fens were further classified into poor and rich types based on acidity and floristic composition, with rich fens characterized by higher pH and calcium concentrations due to mineral-rich groundwater inputs. The study also distinguishes between natural sites with stable near-surface water tables and rewetted sites previously subjected to drainage and agricultural use.