Dissolved organic matter concentration, molecular composition, and functional groups in contrasting management practices of peatlands

Abstract

About 91300 hectares of peatlands have been rewetted in western Europe since the mid-1990s. Still, it is unknown how long-term rewetting alters the dissolved organic matter (DOM) concentration, molecular composition, and functional groups. We examined these DOM characteristics in three peatland types subjected to 47 to 231 yr drainage and 18 to 24 yr rewetting to address this knowledge gap. Cold water-extractable DOM was characterized by pyrolysis field ionization mass spectrometry (Py-FIMS) and X-ray absorption near-edge This article is protected by copyright. All rights reserved. structure (XANES) spectroscopy. The dissolved organic carbon (DOC) concentration in the rewetted forest peatland was 2.7 times higher than in the drained forest peatland. However, rewetting decreased the DOC concentrations by 1.5 and 4 times in the coastal peatland and percolation mire, respectively, compared to their respective drained peatlands at the topsoil horizons. The Py-FIMS analysis revealed that all the nine DOM compound classes' relative abundances differed between the rewetted and drained forest peatland with the lower relative abundances of the labile DOM compound classes in the rewetted forest peatlands. However, most DOM compound classes' relative abundances were similar between the rewetted and drained coastal peatlands and percolation mires. The XANES also revealed nine C-and seven N functional groups with no apparent differences between the two contrasting management practices. The influence of drainage and rewetting on DOC concentration and molecular composition depends on peatland type, drainage period, rewetting intensity, and peat degradation status that should be considered in future research for understanding DOM transformation and transportation from degraded and restored peatland ecosystems.

Peat Formation in Rewetted Fens as Reflected by Saturated n-Alkyl Acid Concentrations and Patterns

“…The latter appears important because this ratio is the first chemical parameter consistently reflecting rewetting. Other previously published data on the bulk chemical composition of SOM [18] and colloidal organic matter [40], and the speciation of phosphorus [41] and sulfur compounds [42] showed similar trends for the rewetted sites but not throughout all sample pairs. Therefore, the rewetting effect on the chain-length distribution of saturated n-alkyl acids is stronger than other disturbing effects, such as peatland genesis and land cover, management history, or current vegetation.…”

Quality Parameters of Soil Chemical Physics and Water Ecosystem in Indonesia

“…This was because the previous research was conducted on pond ecosystems with closed waters, limiting the water circulation compared to mangrove ecosystems with open waters, allowing continuous water circulation. This results in dynamic environmental parameters, including soil and water quality [20], [21].…”

Back to the Future: Restoring Northern Drained Forested Peatlands for Climate Change Mitigation

“…High nutrient availability due to low plant nutrient demand is expected which, added to rewetting associated disturbances, might promote high nutrients exports often reported after rewetting (Koskinen et al, 2017;Nieminen et al, 2020). Due to enhanced decomposition, this phase might be characterized by high dissolved organic matter concentrations (Negassa et al, 2021). Vegetation during this phase is patchy (Hedberg et al, 2012) and growth of mosses such as Sphagnum is likely limited by high water table variability (Kim et al, 2021).…”