An international research team led by the University of Münster has investigated the relationship between water levels, temperature, and carbon dioxide (CO2) emissions in peatlands. As reported by the university on Wednesday, the study, published in the journal “Nature Communications,” revealed that the deeper the water level is within the peatland, the more intensely the CO2 emissions react to rising temperatures. Conversely, higher water levels can lessen this amplifying effect.
To conduct this analysis, the scientists utilized what is currently the largest dataset concerning the annual CO2 budgets of peatlands. This comprehensive dataset includes 276 site-years collected from 114 peatlands located in both temperate and boreal regions, spanning diverse locations such as Germany, Estonia, France, Great Britain, and North America. The study covered a range of environments, including natural low and high moors, as well as agricultural land, grasslands, and areas that were formerly used for peat extraction. Given that the relationships observed were non-linear, the researchers employed machine learning methodologies.
The evaluations showed that CO2 release significantly decreases when the water level is raised from extremely low levels to less than 60 to 75 centimeters below the peat surface. The most pronounced reductions were recorded at water levels maintained at least 20 centimeters below the surface. Importantly, at deep water levels, the CO2 release increases noticeably more sharply when temperatures rise. This finding was further supported by a second dataset featuring daily measurements taken over 113 site-years. Nicolas Behrens, the lead author, explained that the impact of the water level cannot be considered independently of temperature. He emphasized that the re-wetting of drained moors will likely become even more critical as warming advances, serving as a vital measure to curb the increase in CO2 emissions driven by rising temperatures. It should be noted that the study focused exclusively on CO2 data, meaning other greenhouse gases such as methane and nitrous oxide were not included in the findings.
