Importance of Water Level Management for Peatland Outflow Water Quality in the Face of Climate Change and Drought

Abstract The impact of different climate scenarios, drought, and water level management on the outflow water quality of peatlands has been investigated. A mesocosm experiment has been conducted within climate control chambers to simulate current (2016–2019 real-time) and future representative concentration pathway (RCP) climate scenarios (RCP 2.6, 4.5 and 8.5) for the peatland mesocosms. To assess the efficiency of a management strategy for improving peatland water quality, water level adjustment was applied to half of the system at the same time for each climate scenario. Furthermore, the mesocosm experienced the 2018 European drought during the simulation years, and the corresponding impact was analyzed. The results of this study indicated that the effect of water level but not climate change on the water quality of peatland mesocosms was significant. The effect of water level management was the largest for ammonium (NH4-N) and five-day biochemical oxygen demand (BOD5), and the smallest for total phosphorus (TP). Drought had a strong impact on chemical variables, increasing their concentration and deteriorating the water quality of peatland outflow. The results highlight the need for water level management in stabilizing nutrient levels in peatland outflows, especially for the warmer climate scenarios to mitigate the negative consequences of global warming.