Ecological determinants and effects of manganese oxidation state and bioavailability
Abstract/Contents
- Abstract
- Soil organic matter (SOM) contains more than three times as much C as the atmosphere does. Even a small tip of the balance between SOM formation and SOM decomposition can have disproportionate effects on CO2 concentrations in the atmosphere, therefore on climate. Manganese (Mn) is a biologically essential redox-active metal that remains a largely unexplored but possibly critical element controlling soil C stocks. As Mn undergoes reduction-oxidation reactions, it assumes a reactive, intermediate oxidation state that can oxidize organic C. The significance of Mn redox cycling to ecosystem C storage remains poorly resolved. I combine field measurements from a rainfall gradient and laboratory experiments to elucidate how rainfall shape Mn redox cycling, how Mn redox cycling interacts with SOM in natural soils, and how foliar Mn versus soil Mn influences grass-litter decomposition. This is the first systematic investigation of rainfall's effect on Mn oxidation state within the rhizosphere and on the role of Mn in grassland C stability. Given the existential threat that climate change poses, we need to understand the soil processes that affect this massive, labile C pool. Rainfall gradients are a powerful tool to evaluate how and where Mn potentiates OM decomposition. In Chapter 2, I determine that rainfall defines patterns in Mn oxidation state and redox cycling along a Hawaiian rainfall gradient. In Chapter 3, I analyze the influence of Mn on soil C stability in situ on a grassland rainfall gradient and in vitro using an incubation experiment; the results show that Mn bioavailability does not destabilize organic C in a grassland soil. In Chapter 4, I examine the roles of soil Mn versus foliar Mn on grass-litter decomposition on a rainfall gradient and in laboratory incubations; both experiments demonstrate that Mn, whether foliar- or soil-derived, does not control litter decomposition in a grassland. This research can inform models to revise projections on the capacity of soils to sequester C in the face of climate change.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2023; ©2023 |
| Publication date | 2023; 2023 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Paulus, Elizabeth Louise |
|---|---|
| Degree supervisor | Vitousek, Peter Morrison |
| Thesis advisor | Vitousek, Peter Morrison |
| Thesis advisor | Casciotti, Karen Lynn, 1974- |
| Thesis advisor | Chadwick, Oliver A |
| Thesis advisor | Fendorf, Scott |
| Thesis advisor | Peay, Kabir |
| Degree committee member | Casciotti, Karen Lynn, 1974- |
| Degree committee member | Chadwick, Oliver A |
| Degree committee member | Fendorf, Scott |
| Degree committee member | Peay, Kabir |
| Associated with | Stanford University, School of Humanities and Sciences |
| Associated with | Stanford University, Department of Biology |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Elizabeth L. Paulus. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis Ph.D. Stanford University 2023. |
| Location | https://purl.stanford.edu/tk349vv7950 |
Access conditions
- Copyright
- © 2023 by Elizabeth Louise Paulus
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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