The microbial ecology and biogeochemistry of alluvial subsurface systems
Abstract/Contents
- Abstract
- At the intersection of terrestrial and aquatic environments, alluvial landscapes link up-land, riverine, and subsurface ecosystems. Floodplains and associated alluvial aquifers are hotspots of the biogeochemical processes influencing surface water and groundwater quality. The microbial communities within these zones are often drivers of these processes, and thus their structure and function may affect water quality. Currently, depth-resolved information about the structure and function of microbial communities within floodplains and their impacts on alluvial aquifers is limited. However, such information is critical for understanding biogeochemical cycles and how elemental stores are altered from perturbations initiated by the water cycle within floodplains. Surveyed from the surface to the sediment-bedrock interface, this dissertation illuminates temporal and depth-specific trends in microbial community dynamics within floodplains of the Western U.S. Here I present results from multiple field projects throughout the Western U.S. sampled under different hydrologic conditions. This work employs complementary molecular approaches in a field-based study, where the microbial ecology and geochemistry of key biogeochemical cycles (N, Fe, S, C) are explored. Through concurrent lines of geochemical and microbial evidence, spatiotemporal in-sights on subsurface microbial dynamics over a record flooding event are presented. Semiarid, intermontane cores (down to 6m depth) sampled under drought conditions in the Western U.S. and over drought-to-flood conditions on the Wind River-Little Wind River floodplain at Riverton, WY. Pairing depth-resolved high-throughput sequencing with detailed geochemical measurements for more than 250 samples from five sites, I identified hydrologic regime transitions drove the development of microbial niches and geochemical redox-stratification patterns within the vertical profiles examined. These findings suggest that transitions from unsaturated to saturated conditions coincided with major changes in microbial diversity and community stability, supporting trends in spatiotemporal succession that hold possible microbial and geochemical implications for subsurface systems and riverine water quality extending beyond this work.
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 | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Cardarelli, Emily Lewis |
|---|---|
| Degree committee member | Bargar, John |
| Degree committee member | Fendorf, Scott |
| Degree committee member | Francis, Christopher |
| Thesis advisor | Bargar, John |
| Thesis advisor | Fendorf, Scott |
| Thesis advisor | Francis, Christopher |
| Associated with | Stanford University, Department of Environmental Earth System Science |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Emily Lewis Cardarelli. |
|---|---|
| Note | Submitted to the Department of Environmental Earth System Science. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/jb649zb4746 |
Access conditions
- Copyright
- © 2021 by Emily Lewis Cardarelli
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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