- Institute for Landscape Ecology
Hydrology Group
Heisenbergstr. 2
48149 Münster
Germany - +49-251-8330207
Klaus-Holger Knorr
University of Münster, Institute of Landscape Ecology, Faculty Member
- Biogeoscience, Biogeochemistry (Ecology), Hydrology and Ecohydrology, Biogeochemistry, Stable Isotope Geochemistry, Peatland Ecology, and 15 moreLimnology, Lake Processes, Wetland Ecology, Groundwater Hydrology, Hydrology, Ombrotrophic Bogs, Nitrogen Cycle, Arsenic, Quantification and speciation of Arsenic, Soil Respiration, Climate Change, Ecology, Conservation, Environmental Sustainability, and Geographyedit
- I am a peatland biogeochemist, focusing on anaerobic carbon mineralization, redox processes, organic matter, and the coupling of biogeochemistry with hydrology.edit
Research Interests:
While Si influences nutrient stoichiometry and decomposition of graminoid litter, it is still unclear how Si influences anoxic litter decomposition and CH4 formation in graminoid dominated fen peatlands. First, Eriophorum vaginatum plants... more
While Si influences nutrient stoichiometry and decomposition of graminoid litter, it is still unclear how Si influences anoxic litter decomposition and CH4 formation in graminoid dominated fen peatlands. First, Eriophorum vaginatum plants were grown under different Si and P availabilities, then shoots and roots were characterized regarding their proportions of C, Si, N and P and regarding C quality. Subsequently the Eriophorum shoots were subjected to anoxic decomposition. We hypothesized; that (I) litter grown under high Si availability would show a higher Si but lower nutrient mass fractions and a lower share of recalcitrant carbon moieties; (II) high-Si litter would show higher CH4 and CO2 production rates during anoxic decomposition; (III) methanogenesis would occur earlier in less recalcitrant high-Si litter, compared to low-Si litter. We found a higher Si mass fraction that coincides with a general decrease in C and N mass fractions and decreased share of recalcitrant organic ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
In this study, periods of prehistoric anthropogenic activity in the Hallstatt salt mining area (Upper Austria) are reconstructed from elemental (XRF-scanning, Q-ICP-MS) and Pb isotopic analyses (206 Pb, 207 Pb, 208 Pb) of a... more
In this study, periods of prehistoric anthropogenic activity in the Hallstatt salt mining area (Upper Austria) are reconstructed from elemental (XRF-scanning, Q-ICP-MS) and Pb isotopic analyses (206 Pb, 207 Pb, 208 Pb) of a radiocarbon-dated, 137-cm-long peat core covering the past ~7,000 years. The peat core was retrieved from a minerotrophic fen in the Hallstatt High Valley. Distinct metal enrichments attributed to low anthropogenic impact in Hallstatt can be traced back to a time around 2350 cal BCE and to another period around 1800 cal BCE. The period from the Late Bronze Age to the Early Iron Age (~1300 cal BCE to ~500 cal BCE) is characterised by increased anthropogenic activity. Relatively high Sn concentrations between ~1210 cal BCE and ~540 cal BCE) point towards intensive bronze casting processes, probably associated with the production of bronze picks that were used for local salt mining during this time. Intense human impact was also determined for the early Roman imperi...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Colloids formed during soil flooding can potentially facilitate the mobilization of metal contaminants. Here, laboratory batch incubations with a contaminated soil were performed to monitor temporal changes in the porewater dynamics of... more
Colloids formed during soil flooding can potentially facilitate the mobilization of metal contaminants. Here, laboratory batch incubations with a contaminated soil were performed to monitor temporal changes in the porewater dynamics of metals, the morphology and composition of colloids, and the speciation of colloids-associated metals during 30 days of flooding. The concentrations of colloidal and dissolved metals increased initially and peaked at a certain time, but then decreased with the on-going sulfate reduction. The combined analysis of spectrometric, spectroscopic, and size-fractionation results revealed that the dynamics of Cu were dominated by microbe-associated colloids and were mediated largely by Cu(0) biomineralization and subsequent sulfidation, while the microbe-associated and freely dispersed colloids were equally relevant for governing the dynamics of Cd and Pb. Mobilization of Zn, on the other hand, was dominated by its dissolved form, probably due to the low therm...
Research Interests:
Research Interests:
Research Interests:
Peatlands and peaty riparian zones are major sources of DOM, but are poorly understood in terms of export dynamics and controls thereof. The quality of DOM affects function and behavior of DOM in aquatic ecosystems, but DOM quality can... more
Peatlands and peaty riparian zones are major sources of DOM, but are poorly understood in terms of export dynamics and controls thereof. The quality of DOM affects function and behavior of DOM in aquatic ecosystems, but DOM quality can also help to track DOM sources and their export dynamics under specific hydrologic preconditions. The objective of this study was to elucidate controls on temporal variability in DOM concentration and quality in discharge from a bog and a forested peaty riparian zone, particularly considering drought and storm flow events. DOM quality was monitored using spectrofluorometric indices for aromaticity (SUVA<sub>254</sub>), apparent molecular size (S<sub>R</sub>) and precursor organic material (FI), as well as PARAFAC modeling of excitation emission matrices (EEMs). <br><br> Indices for DOM quality exhibited major changes due to different hydrologic conditions, but patterns were also dependent on season. The forested sit...
Peatlands play an important role in global carbon cycling, however, the response of peatland carbon fluxes to anthropogenically changed hydrologic conditions and long-term infiltration of nutrients is still understudied. Along a transect... more
Peatlands play an important role in global carbon cycling, however, the response of peatland carbon fluxes to anthropogenically changed hydrologic conditions and long-term infiltration of nutrients is still understudied. Along a transect of 4 study sites, spanning from largely pristine to strongly altered conditions within the Wylde Lake peatland complex in Ontario (Canada), we monitored carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes at the soil/atmosphere interface and DIC and CH<sub>4</sub> concentrations in the peat profiles from April 2014 through September 2015. Moreover, we applied δ<sup>13</sup>C-CH<sub>4</sub> and δ<sup>13</sup>C-CO<sub>2</sub> stable isotope abundance analyses to examine CH<sub>4</sub> and CO<sub>2</sub> production and consumption as well as the dominant…
Increasing concentrations of dissolved iron and DOC are likely linked to decreasing nitrogen depositon.
Research Interests:
Environmental contextThe extent to which organic matter decomposition generates carbon dioxide or methane in anaerobic ecosystems is determined by the presence or absence of particular electron acceptors. Evaluating carbon dioxide and... more
Environmental contextThe extent to which organic matter decomposition generates carbon dioxide or methane in anaerobic ecosystems is determined by the presence or absence of particular electron acceptors. Evaluating carbon dioxide and methane production in anaerobic incubation of peat, we found that organic matter predominated as an electron acceptor over considered inorganic electron acceptors. We also observed changes in organic sulfur speciation suggesting a contribution of organic sulfur species to the electron-accepting capacity of organic matter. An often observed excess of CO2 production over CH4 production in freshwater ecosystems presumably results from a direct or indirect role of organic matter (OM) as electron acceptor, possibly supported by a cycling of oxidised and reduced sulfur species. To confirm the role of OM electron-accepting capacities (EACOM) in anaerobic microbial respiration and to elucidate internal sulfur cycling, peat soil virtually devoid of inorganic el...
Research Interests:
Research Interests:
Observed sulfate reduction rates in freshwater wetlands or sediments were often too high to be sustained considering only inorganic sulfate pools. A sulfur recycling process involving the reaction of hydrogen sulfide (H2S) with organic... more
Observed sulfate reduction rates in freshwater wetlands or sediments were often too high to be sustained considering only inorganic sulfate pools. A sulfur recycling process involving the reaction of hydrogen sulfide (H2S) with organic matter has thus been suggested to replenish the oxidized sulfur pool. Nevertheless, studies on the kinetics and the resulting products of the reaction H2S with organic matter are scarce. To address this research gap, we investigated the chemical oxidation of Na2S with dissolved humic acid (HA), in batch experiments at pH 6 under anoxic conditions. Sulfide reacted rapidly with DOM and thereby regenerated more oxidized forms of sulfur, both inorganic sulfur species (S0 and S2O32-) and organic products. Total recovery in the inorganic fraction accounted for 63~78% of the sulfide consumed, yielding electron transfer capacities (ETC) of 2.82~1.75 µeq mg-1 C. Based on a mass balance, about 22~37% of sulfur had added to the HA as organic sulfur. Sulfur K-edg...
Research Interests:
Research Interests:
Deposit-Signet, Archivserver deposit.d-nb.de. Logo DDB. Autor : Knorr, Klaus-Holger. Titel : Dynamics of soil processes under extreme meteorological boundary conditions : response of below-ground carbon, sulfur, and iron cycling in fen... more
Deposit-Signet, Archivserver deposit.d-nb.de. Logo DDB. Autor : Knorr, Klaus-Holger. Titel : Dynamics of soil processes under extreme meteorological boundary conditions : response of below-ground carbon, sulfur, and iron cycling in fen soils. ...
Research Interests:
The group „Young geoscientists” of the Senate Commission for Joint Geoscientific Research (Geokommisson, www. geokommission. de) of the German Research Foundation (DFG), is dedicated towards the development of the working environment,... more
The group „Young geoscientists” of the Senate Commission for Joint Geoscientific Research (Geokommisson, www. geokommission. de) of the German Research Foundation (DFG), is dedicated towards the development of the working environment, workforce and scientific outcome of the next generation of geoscientists in Germany.
Research Interests:
Research Interests:
Dissimilatory sulfate reduction in peatlands is sustained by a cryptic sulfur cycle and effectively competes with methanogenic degradation pathways. In a series of peat soil microcosms incubated over 50 days, we identified bacterial... more
Dissimilatory sulfate reduction in peatlands is sustained by a cryptic sulfur cycle and effectively competes with methanogenic degradation pathways. In a series of peat soil microcosms incubated over 50 days, we identified bacterial consortia that responded to small, periodic additions of individual fermentation products (formate, acetate, propionate, lactate or butyrate) in the presence or absence of sulfate. Under sulfate supplementation, net sulfate turnover (ST) steadily increased to 16-174 nmol cm(-3) per day and almost completely blocked methanogenesis. 16S rRNA gene and cDNA amplicon sequencing identified microorganisms whose increases in ribosome numbers strongly correlated to ST. Natively abundant (⩾0.1% estimated genome abundance) species-level operational taxonomic units (OTUs) showed no significant response to sulfate. In contrast, low-abundance OTUs responded significantly to sulfate in incubations with propionate, lactate and butyrate. These OTUs included members of re...
Research Interests:
Cd hyperaccumulator Solanum nigrum L. was a promising plant used to simultaneously remediate Cd-PAHs combined pollution soil through its extra accumulation capacity and rhizosphere degradation. This article compared the strengthening... more
Cd hyperaccumulator Solanum nigrum L. was a promising plant used to simultaneously remediate Cd-PAHs combined pollution soil through its extra accumulation capacity and rhizosphere degradation. This article compared the strengthening remediation role of cysteine (Cys), glycine (Gly) and glutamic acid (Glu) with EDTA and TW80. The results showed that the addition of 0.03 mmol L(-1) Cys, Gly, and Glu didn&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;t significantly impact (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) shoot biomass of S. nigrum, but obviously increased Cd concentration. Therefore, Cd capacity (µg pot(-1)) in shoots of S. nigrum was significantly increased (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) by 37.7% compared to the control without reagent added. At the meantime, the PAHs degradation ratio in rhizoshpere was increased by 34.5%. Basically, the improving role of Cys, Gly, and Glu was higher than EDTA and TW80. The main reasons of enhanced the accumulation of S. nigrum to Cd might lie in the addition of Cys, Gly, and Glu which reduced pH and increased extractable Cd concentration in rhizosphere and phytochelatines (PCs) concentration in leaves. As for the degradation of PAHs in rhizosphere, increased microorganism number might be play important role.