Solid phase speciation controls copper mobilisation from marine sediments by methanobactin
- Autor(en)
- Danielle D Rushworth, Walter D C Schenkeveld, Naresh Kumar, Vincent Noël, Jannes Dewulf, Niels A G M van Helmond, Caroline P Slomp, Moritz F Lehmann, Stephan M Kraemer
- Abstrakt
Although marine environments represent huge reservoirs of the potent greenhouse gas methane, they currently contribute little to global net methane emissions. Most of the methane is oxidized by methanotrophs, minimizing escape to the atmosphere. Aerobic methanotrophs oxidize methane mostly via the copper (Cu)-bearing enzyme particulate methane monooxygenase (pMMO). Therefore, aerobic methane oxidation depends on sufficient Cu acquisition by methanotrophs. Because they require both oxygen and methane, aerobic methanotrophs reside at oxic-anoxic interfaces, often close to sulphidic zones where Cu bioavailability can be limited by poorly soluble Cu sulphide mineral phases. Under Cu-limiting conditions, certain aerobic methanotrophs exude Cu-binding ligands termed chalkophores, such as methanobactin (mb) exuded by Methylosinus trichosporium OB3b. Our main objective was to establish whether chalkophores can mobilise Cu from Cu sulphide-bearing marine sediments to enhance Cu bioavailability. Through a series of kinetic batch experiments, we investigated Cu mobilisation by mb from a set of well-characterized sulphidic marine sediments differing in sediment properties, including Cu content and phase distribution. Characterization of solid-phase Cu speciation included X-ray absorption spectroscopy and a targeted sequential extraction. Furthermore, in batch experiments, we investigated to what extent adsorption of metal-free mb and Cu-mb complexes to marine sediments constrains Cu mobilisation. Our results are the first to show that both solid phase Cu speciation and chalkophore adsorption can constrain methanotrophic Cu acquisition from marine sediments. Only for certain sediments did mb addition enhance dissolved Cu concentrations. Cu mobilisation by mb was not correlated to the total Cu content of the sediment, but was controlled by solid-phase Cu speciation. Cu was only mobilised from sediments containing a mono-Cu-sulphide (CuSx) phase. We also show that mb adsorption to sediments limits Cu acquisition by mb to less compact (surface) sediments. Therefore, in sulphidic sediments, mb-mediated Cu acquisition is presumably constrained to surface-sediment interfaces containing mono-Cu-sulphide phases.
- Organisation(en)
- Department für Umweltgeowissenschaften
- Externe Organisation(en)
- Utrecht University, Universität Basel, Wageningen University and Research Centre, SLAC Natl Accelerator Lab, Radboud University
- Journal
- Science of the Total Environment
- Band
- 934
- Anzahl der Seiten
- 13
- ISSN
- 0048-9697
- DOI
- https://doi.org/10.1016/j.scitotenv.2024.173046
- Publikationsdatum
- 05-2024
- Peer-reviewed
- Ja
- ÖFOS 2012
- 106026 Ökosystemforschung, 106022 Mikrobiologie, 105906 Umweltgeowissenschaften
- Schlagwörter
- ASJC Scopus Sachgebiete
- Pollution, Waste Management and Disposal, Environmental engineering, Environmental Chemistry
- Sustainable Development Goals
- SDG 14 – Leben unter Wasser
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/296ea33d-e0f8-4ab3-b3bb-2c8b589594f6