Pore Water Quality in Northern Peatlands: Impacts of Drainage and Rewetting

The primary objectives of peatland restoration are to reduce greenhouse gas emissions and maintain water quality. However, the effects of human activities, such as drainage and rewetting, on pore water quality remain insufficiently understood. In this study, we synthesized pore water quality data from 197 northern peatlands, encompassing natural, drained, and rewetted systems. Our analysis revealed that drainage significantly increases the concentrations of dissolved organic carbon (DOC), ammonium, and phosphate in pore water compared to natural peatlands. While rewetting reduced these concentrations, they remained elevated relative to natural systems. Notably, pore water concentrations in rewetted peatlands were closely linked to water table levels, with peak concentrations observed under inundated conditions, particularly in fen peatlands. Over an approximately 30-year observation period, no consistent temporal trends in pore water quality following rewetting were identified. These findings highlight the complexity of pore water quality responses to rewetting and the importance of long-term monitoring for optimizing peatland restoration practices.