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Dissolved phenols in ombrotrophic bogs: occurrence and enzymatic transformations

Applicant Sander Michael
Number 159692
Funding scheme Project funding (Div. I-III)
Research institution Institut für Biogeochemie und Schadstoffdynamik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Other disciplines of Environmental Sciences
Start/End 01.01.2016 - 31.12.2018
Approved amount 455'237.00
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All Disciplines (2)

Discipline
Other disciplines of Environmental Sciences
Geochemistry

Keywords (10)

oxidases; ombrotrophic bogs; high resolution mass spectrometry; carbon cycling; enzymic latch; northern peatlands; electrochemistry; phenols; enzymatic oxidation; electron transfer

Lay Summary (German)

Lead
Vorkommen und enzymatischer Abbau gelöster phenolischer Substanzen in HochmoorenHochmoore sind einzigartige Ökosysteme. Diese Moore speichern eine sehr große Menge an Kohlenstoff in Form von Torf, welcher durch den unvollständigen Abbau pflanzlichen Ausgangsmaterials entsteht. Der unvollständige Abbau ist auf die besonderen Bedingungen in diesen Mooren zurückzuführen: sie sind sehr sauer, nährstoffarm, und sind wassergesättigt, was wiederum zur Sauerstoffarmut führt. Das Porenwasser der Hochmoore enthält zudem gelöste phenolische Substanzen, die aktiv von Torfmoosen - den dominierenden Pflanzen in den Mooren- abgeben werden. Diese Phenole wirken hemmend auf die Aktivität von abbauenden Enzymen und Mikroorganismen und tragen somit maßgeblich zur Bildung der Torfe bei. Trotz der großen Bedeutung der Phenole ist wenig über ihre Konzentrationen, chemische Zusammensetzung und Stabilität bekannt.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Dieses Projekt zielt darauf ab, diese Wissenslücken in drei aufeinanderfolgenden Teilprojekten zu füllen. Im ersten Teilprojekt werden wir mittels moderner Analysemethoden die Konzentrationen und chemischen Strukturen von Phenolen in den Porenwassern ausgewählter Hochmoore bestimmen. Im zweiten Teilprojekt untersuchen wir wie die Phenole durch oxidative Enzyme abgebaut werden. Im dritten und letzten Teilprojekt werden wir die Erkenntnisse aus den ersten beiden Teilprojekten zusammenfügen, um direkt in Mooren gemessene Phenoldynamiken zu erklären.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Die im Rahmen der Teilprojekte gewonnen wissenschaftlichen Erkenntnisse  werden ein detailliertes Bild zur Bedeutung und Rolle der phenolischen Substanzen in der Kohlenstoffdynamik von Hochmooren liefern. Dieses Bild ist wichtig, um die Stabilität des festgelegten Kohlenstoffs in Hochmooren beurteilen zu können und um möglicherweise Maßnahmen zu ergreifen, diese Stabilität langfristig zu sichern.

Direct link to Lay Summary Last update: 11.02.2016

Responsible applicant and co-applicants

Employees

Publications

Publication
Electron accepting capacity of dissolved and particulate organic matter control CO2 and CH4 formation in peat soils
Gao Chuanyu, Sander Michael, Agethen Svenja, Knorr Klaus-Holger (2019), Electron accepting capacity of dissolved and particulate organic matter control CO2 and CH4 formation in peat soils, in Geochimica et Cosmochimica Acta, 245, 266-277.
Two analytical approaches quantifying the electron donating capacities of dissolved organic matter to monitor its oxidation during chlorination and ozonation
Önnby Linda, Walpen Nicolas, Salhi Elisabeth, Sander Michael, von Gunten Urs (2018), Two analytical approaches quantifying the electron donating capacities of dissolved organic matter to monitor its oxidation during chlorination and ozonation, in Water Research, 144, 677-689.
Oxidation of Reduced Peat Particulate Organic Matter by Dissolved Oxygen: Quantification of Apparent Rate Constants in the Field
Walpen Nicolas, Lau Maximilian P., Fiskal Annika, Getzinger Gordon J., Meyer Stefan A., Nelson Taylor F., Lever Mark A., Schroth Martin H., Sander Michael (2018), Oxidation of Reduced Peat Particulate Organic Matter by Dissolved Oxygen: Quantification of Apparent Rate Constants in the Field, in Environmental Science & Technology, 52(19), 11151-11160.
Electron-Donating Phenolic and Electron-Accepting Quinone Moieties in Peat Dissolved Organic Matter: Quantities and Redox Transformations in the Context of Peat Biogeochemistry
Walpen Nicolas, Getzinger Gordon J., Schroth Martin H., Sander Michael (2018), Electron-Donating Phenolic and Electron-Accepting Quinone Moieties in Peat Dissolved Organic Matter: Quantities and Redox Transformations in the Context of Peat Biogeochemistry, in Environmental Science & Technology, 52(9), 5236-5245.
Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection
Walpen Nicolas, Schroth Martin H., Sander Michael (2016), Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection, in Environmental Science & Technology, 50(12), 6423-6432.

Collaboration

Group / person Country
Types of collaboration
Prof. Dr. Luca Bragazza Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Dr. Martin Schroth Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. Dr. Mark A. Lever Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Prof. Dr. Klaus-Holger Knorr Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Gordon Research Conference; Environmental Sciences: Water Poster Chemodiversity in phenolic dissolved organic matter from ombrotrophic bog pore waters 24.06.2018 Holderness, New Hamsphire, United States of America Sander Michael; Getzinger Gordon;
Environmental Science and Engineering Seminar at EPFL Individual talk Think big: on the environmental (biogeo)chemistry of natural and engineered macromolecules 21.06.2017 Lausanne, Switzerland Sander Michael;
EGU General Assembly 2017 Talk given at a conference Electron transfer properties of peat organic matter: from
to redox processes in peatlands 23.04.2017 Vienna, Austria Getzinger Gordon; Walpen Nicolas; Sander Michael;
CITE Seminar Series, UFZ Leipzig Individual talk Going large: On the distribution, reactivity and transformation of (bio-)macromolecules in natural and engineered systems 13.09.2016 Leipzig, Germany Sander Michael;
Gordon Research Conference; Environmental Sciences: Water Talk given at a conference Quntification of Phenolic Antioxidants in Dissolved Organic Matter by Automated Flow-Injection Analysis With Electrochemical Detection 26.06.2016 Holderness, NH, United States of America Getzinger Gordon; Sander Michael;
Gordon Research Conference; Environmental Sciences: Water Poster Qantification of phenolic antioxidants in dissolved organic matter by automated flow-injection analysis with electrochemical detection 26.06.2016 Holderness, NH , United States of America Walpen Nicolas; Sander Michael;


Communication with the public

Communication Title Media Place Year
Video/Film Carbon Biogeochemistry of Northern Peatlands International 2017

Awards

Title Year
Best Poster Award to Nicolas Walpen Gordon Research Conference; Environmental Sciences: Water June 2016 The awardee was given the opportunity to present the content of his poster in front of the larger scientific audience in an oral presentation (see: Academic Events) 2016
Environ Sci Technol best paper award Top paper of 2016, Category: Environmental Technology for: Nicolas Walpen, Martin H. Schroth, and Michael Sander. Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection. * Environ. Sci. Technol., 2016, 50 (12), 6423 −6432. dx.doi.org/10.1021/ac- s.est.6b01120 See here: https://pubs.acs.org/doi/pdf/10.1021/acs.est.7b01464 2016

Associated projects

Number Title Start Funding scheme
149283 Characterization of the redox properties of iron minerals by combined electrochemical and spectroscopic analyses 01.01.2015 Project funding (Div. I-III)
135515 Humic substance redox properties and redox reactions with oxygen 01.01.2012 Project funding (Div. I-III)
135515 Humic substance redox properties and redox reactions with oxygen 01.01.2012 Project funding (Div. I-III)
182645 Electron transfer to and from peat particulate organic matter in ombrotrophic bogs: characterization and impact on carbon dioxide and methane concentrations 01.10.2019 Project funding (Div. I-III)
129476 Redox Reactivity of Iron-Bearing Clay Minerals 01.06.2010 Project funding (Div. I-III)

Abstract

Northern peatlands, including ombrotrophic bogs, store significant amounts of carbon in the form of peat organic matter. Sphagnum mosses, which are well adapted to the nutrient poor, acidic and wet conditions common to bogs, dominate these ecosystems and actively secrete allelopathic phenolic compounds into bog porewaters. The dissolved phenols possess antimicrobial and enzyme inhibiting properties, which contribute to slow rates of microbial organic matter decomposition. Long hydraulic retention times and low lateral flow in bogs limit physical dissolution, restricting phenol removal to chemical oxidation by extracellular phenol oxidases and peroxidases. These oxidases require molecular oxygen as a co-substrate and are therefore only active in the uppermost, oxygenated part of the bog, the so-called acrotelm. Phenol dynamics in bogs have received considerable research interest in light of the ‘enzymic latch’ hypothesis, which predicts that oxygenation of peats, e.g., due to climate change, would activate oxidase enzymes and thus lower phenol concentrations, starting a cascade of processes that ultimately releases significant fractions of the stored carbon. The work proposed herein aims to overcome existing knowledge gaps in the dynamics of low molecular weight phenols in surface bog porewaters by quantifying dissolved Sphagnum-derived phenols and by providing the first systematic investigation of enzymatic reaction pathways salient to those phenols. To that end, we first propose development of a suite of novel analytical techniques, based on state-of-the-art mass spectrometric and electrochemical techniques, allowing the sensitive and selective determination of specific dissolved low molecular weight phenolic compounds in dilute bog porewater samples and the structural and functional (i.e., redox state) characterization of enzymatic phenol oxidation products. We then propose application of these validated methodologies to determine phenol dynamics in simulated and field collected bog water samples with discrete phenolic substances and selected oxidases. Finally, we propose a confluence of laboratory-based mechanistic studies and natural bog conditions by field studies measuring oxygen gradients, phenol contents, and oxidase activities along vertical redox and activity gradients from the partially oxic acrotelm to the permanently water-saturated and anoxic catotelm in ombrotrophic bogs in Sweden. Overall, the proposed work will advance current knowledge of the biogeochemical roles of dissolved phenols in northern peatlands and their role in peatland carbon dynamics. The proposed work will be carried out by one PhD student and one postdoctoral research fellow.
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