Assessing the role of reactive metal species in soil organic matter cycling using chemical imaging Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/8s45qc43n

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  • Intimate associations with reactive metal species permanently protect soil organic matter (SOM) from microbial access and oxidation, contributing to the build-up of organic carbon (C) stocks in soils. It is increasingly recognized, however, that such associations can be reversible and that reactive metal species might even facilitate the oxidation of SOM. Both processes would increase the potential for soil C loss, prompting questions regarding the environmental conditions under which interactions of SOM with reactive mineral phases are protective, reversible or even facilitate oxidation. One of the foremost challenges in characterizing these interactions is the need to describe the dynamics of both SOM and metals at fine spatial scales without disturbing existing chemical or physical associations. This thesis thus addresses the general question whether non-invasive chemical imaging techniques can be used to distinguish protective interactions between SOM and reactive metal species from those that are susceptible to or facilitate C loss. The following research aimed to identify the nature of the interactions between SOM and two abundant redox-active metals (iron and manganese) in three soil microenvironments: fungal mats, the rhizosphere and the litter layer. The first of the three chapters describes the rapid formation of protective associations between fungal-derived SOM and iron (hydr)oxide precipitates in ectomycorrhizal mats. The second chapter demonstrates how root exudates can reverse such protective associations between SOM and reactive Fe phases, promoting microbial access to SOM and causing C loss in the rhizosphere. The third chapter establishes the functional role of reactive manganese species in the microbial oxidation of aromatic compounds in forest litter decomposition. Combined, this work not only demonstrates the ability of imaging and spectroscopy techniques to probe the nature of interactions between SOM and reactive minerals in soils. It also highlights the need to extend current conceptual models to reversible and oxidative interactions between reactive minerals and SOM and their implications for SOM cycling.
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  • description.provenance : Approved for entry into archive by Laura Wilson(laura.wilson@oregonstate.edu) on 2013-11-20T19:23:33Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) KeiluweitMarco2013.pdf: 29800247 bytes, checksum: e84b05d174f901241ab705c2a89fdaa6 (MD5)
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2013-11-18T21:33:42Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) KeiluweitMarco2013.pdf: 29800247 bytes, checksum: e84b05d174f901241ab705c2a89fdaa6 (MD5)
  • description.provenance : Rejected by Julie Kurtz(julie.kurtz@oregonstate.edu), reason: Rejecting for several reasons, which are - 1) Abstract page, remove "Dr" before Markus Kleber 2) Title page, Change the commencement date back to - June 2014 instead of December 2013 3) TABLE OF CONTENTS (Continued) appears on the bottom of the first page of the TOC, move to the top of the next page and remove the subheading Table on the left. 4) Remove the blank page between the Table of Contents and List of figures 5) Page numbers are missing on pages - 34, 73, 74, 128, 129, 134, 135, 136, & 139 6) Page 35 has only "8. Figures" on the page and page 135 has only "1. Tables" on the page. Is there something missing? It's fine if you want to keep the page numbers off the chapter heading pages. Once revised, log back into ScholarsArchive. Go to the upload page and replace the attached file with the revised file and resubmit. Thanks, Julie on 2013-11-15T21:39:31Z (GMT)
  • description.provenance : Submitted by Marco Keiluweit (keiluwem@onid.orst.edu) on 2013-11-18T04:37:57Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) KeiluweitMarco2013.pdf: 29800247 bytes, checksum: e84b05d174f901241ab705c2a89fdaa6 (MD5)
  • description.provenance : Made available in DSpace on 2013-11-20T19:23:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) KeiluweitMarco2013.pdf: 29800247 bytes, checksum: e84b05d174f901241ab705c2a89fdaa6 (MD5) Previous issue date: 2013-10-25
  • description.provenance : Submitted by Marco Keiluweit (keiluwem@onid.orst.edu) on 2013-11-11T20:54:41Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) KeiluweitMarco2013.pdf: 29839140 bytes, checksum: 2f33febbfaa0799736a67a45d1576a53 (MD5)

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