Past and future changes in river temperatures and nitrogen export
Abstract/Contents
- Abstract
- Climate change poses a growing threat to freshwater ecosystems and water quality. This dissertation examines the relationship between changes in climate and two key water quality parameters: the transport of nitrogen within rivers, referred to as nitrogen loading, and river temperature. Chapter 2 examines how changes in air temperature and precipitation influence historical trends in U.S. nitrogen loading. I find that annual precipitation, extreme springtime precipitation, and springtime temperature are key drivers of trends in historical loading. The Appendix addresses time scales for recovery of Gulf of Mexico nitrogen loading, challenging an assertion made in a previous study that achieving nitrogen reduction goals will inevitably take decades. Chapter 3 quantifies how river temperature extremes and variability have changed in recent decades. I find that the majority of rivers have already experienced warming of hot extremes and a significant change in variability. Chapter 4 explores the sensitivity of river heatwaves— periods of persistent, extreme river temperature—to future climate change using a neural network and global climate models. I find that river heatwaves are projected to increase significantly in frequency, duration, and severity in response to climate change, including a tripling of heatwave days by 2050 under a high carbon emissions scenario. Overall, this dissertation reveals that substantial changes in nitrogen loading and river temperatures are already underway in rivers across the U.S. Increases in river temperature extremes and ensuing ecological and socioeconomic impacts may also become critically severe in the coming decades.
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 | Ballard, Tristan Connors |
|---|---|
| Degree committee member | Boehm, Alexandria |
| Degree committee member | Jackson, Robert W. (Robert Wilson), 1970- |
| Degree committee member | Konings, Alexandra |
| Degree committee member | Michalak, Anna M |
| Thesis advisor | Boehm, Alexandria |
| Thesis advisor | Jackson, Robert W. (Robert Wilson), 1970- |
| Thesis advisor | Konings, Alexandra |
| Thesis advisor | Michalak, Anna M |
| Associated with | Stanford University, Department of Environmental Earth System Science |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Tristan C. Ballard. |
|---|---|
| Note | Submitted to the Department of Environmental Earth System Science. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/cn258ph6525 |
Access conditions
- Copyright
- © 2021 by Tristan Connors Ballard
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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