LATERAL PHYSICAL AND CHEMICAL DYNAMICS OF BOREAL PEATLANDS IN SOUTHERN SWEDEN: A Study of Mycklemossen Mire

Abstract

Peatlands are important ecosystems that play a crucial role in global carbon cycling, water regulation, and biodiversity conservation. Investigating the lateral physical and chemical properties of mires, such as changes in peat depth, bulk density, organic matter content, and pH, can provide valuable insights into how these ecosystems are responding to environmental changes, and how they may contribute to climate change mitigation efforts. This study has investigated the physical and chemical properties of a typical boreal mire in southern Sweden, in order to create an overview of current physical and biochemical state of boreal peatlands. Historical data of the surface area of Mycklemossen mire has been used to assess the change of its lateral extent, which has shown to decrease by 34% between 1963 – 2021 by the means of shrubification. The surface area decrease has shown to be accelerating overtime, as nearly a third of the mire was lost in the recent five years (2016-2021). In order to investigate the physical and chemical properties of the peat, peat sampling was conducted on the mire using hand saw and a stainless-steel Russian corer in the field, followed by further elemental analysis. The peat sampling has enabled the estimation of the following parameters: bulk density, root mass, SOM content and pH values, as well as total C and N stocks, C:N ratio and the δ13C and δ15N values, all of which showed to be significantly affected by the depth of the peat horizon, while root mas showed to also be significantly affected by surface layer vegetation communities. Total C and N values along with ground-penetrating radar data were used for upscaling total C and N to the entirety of the mire, estimating the total C content of Mycklemossen mire to 34.8 kt and total N content to 0.9 kt, as well as showing a decreasing trend with depth for both parameters. The retrieved data was used as a proxy to gain a better understating of the physical and chemical properties of boreal peatlands in a changing climate.