Mapping and Characterizing Peatland Using Ground-Penetrating-radar and Nuclear-Magnetic-resonance

Peatlands are of importance for a number of environmental services and ecological processes. They are a crucial component of the global carbon cycle and, therefore, of special interest in times of climate change. On the one hand, drained peatlands irreversibly degenerate when used for agriculture and lose their physicochemical functionality. On the other hand, activities on renaturation or joint use are in discussion or already in practice. Consequently, there is a demand for knowledge of the state of the peat layers and for the ability to monitor their changes, most preferably in high detail and on a large scale. Airborne geophysics and remote sensing (e.g. optical images, radar or electromagnetics) are approaches to gain large-scale information on the lateral extend of peatlands, however, covering the large scale comes along with limitations and uncertainties on knowledge about thickness, internal structure, or degradation states. We conducted a ground-penetrating-radar (GPR) and nuclear-magnetic-resonance (NMR) survey at a peatland site in northern Germany, which has been in agricultural use for decades. The site is characterized by a peat layer of varying thicknesses between 0--4 m covering mineral sediments. While GPR provides a fast 3D insight into the internal structure, extent, and thickness, NMR enables the characterization of the internal layers detected by GPR in more detail and may provide information on their degradation states. The results are compared to visually inspected vertical soil sampling data. Our study demonstrates that ground-based geophysics can provide the demanded detailed information and may easily be upscaled to effectively cover areas at the kilometre scale.