title: Differences in DOM of rewetted and natural peatlands - Results from high-field FT-ICR-MS and bulk optical parameters.
abstract: Peatlands can be a potential source of dissolved organic matter (DOM) in fresh water catchment areas. The quantity and quality of DOM can differ between pristine, degraded and rewetted peatlands. Due to the large scale and continuing losses of peatlands, their conservation and restoration has been increasingly emphasized. Mostly rewetting measures are required to improve the hydrology of damaged peatlands, which is a precondition for the resettlement of peat-forming plant species. Thus, in term of DOM, there is a special need to understand how rewetting measures affect DOM characteristics and concentrations. To estimate the potential leaching of humic substances from rewetted areas two natural sites were compared with four artificially rewetted sites in a peatland area of the Harz Mountains National Park, Germany. This was done with regards to DOM quality by combining the results from Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS, measured at one time in Spring) and excitation-emission-matrix fluorescence spectroscopy (EEMF, measured monthly for the period of one year). The DOM quality was significantly less variable in the pristine peatland soil water compared to the rewetted peatland soil waters, from both a spatial and a seasonal perspective. The soil water from the rewetted peatland sites showed a higher degree of humification compared to pristine peatland. DOC concentration was mostly consistent in the pristine peatland over the year. The rewetted peatlands showed higher DOC levels in Summer months and lower DOC in Winter months compared to the pristine peatland. It can be concluded that the rewetting of peatlands is coupled with high concentrations of DOC in soil water and its quality is highly aromatic (as reflected by the observed values from the humification index) during times with elevated temperature. The results may have a significant input for dynamic catchment area studies with regards to rewetting peatland sites.
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Brückstrasse 3a, 39114 Magdeburg, Germany. Electronic address: peter.herzsprung@ufz.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Herzsprung
authors.affiliation: Martin Luther University Halle-Wittenberg, Institute of Agricultural and Nutritional Sciences, Julius-Kühn Str. 23, 06112 Halle, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Osterloh
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Brückstrasse 3a, 39114 Magdeburg, Germany.
authors.forename: Wolf
authors.initials: W
authors.lastname: von Tümpling
authors.affiliation: Helmholtz Centre Munich, German Research Center for Environmental Health, Research Unit Analytical BioGeoChemistry (BGC), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Mourad
authors.initials: M
authors.lastname: Harir
authors.affiliation: Helmholtz Centre Munich, German Research Center for Environmental Health, Research Unit Analytical BioGeoChemistry (BGC), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Hertkorn
authors.affiliation: Helmholtz Centre Munich, German Research Center for Environmental Health, Research Unit Analytical BioGeoChemistry (BGC), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
authors.forename: Philippe
authors.initials: P
authors.lastname: Schmitt-Kopplin
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Brückstrasse 3a, 39114 Magdeburg, Germany; Martin Luther University Halle-Wittenberg, Institute of Agricultural and Nutritional Sciences, Julius-Kühn Str. 23, 06112 Halle, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Meissner
authors.affiliation: Martin Luther University Halle-Wittenberg, Institute of Agricultural and Nutritional Sciences, Julius-Kühn Str. 23, 06112 Halle, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Bernsdorf
authors.affiliation: Helmholtz Centre for Environmental Research - UFZ, Brückstrasse 3a, 39114 Magdeburg, Germany.
authors.forename: Kurt
authors.initials: K
authors.lastname: Friese
keywords: DOC; Fluorescence indices; Germany; Harz Mountains; Seasonality; Spatial resolution; Van Krevelen diagrams