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Lake Vertical Ecosystem Responses to Climate and Environmental Changes: Integrating Comparative Time Series, Modeling, and High-Frequency Approaches

Pilla, Rachel Marie
http://orcid.org/0000-0001-9156-9486
http://rave.ohiolink.edu/etdc/view?acc_num=miami1620646716185966

Abstract Details

2021, Doctor of Philosophy, Miami University, Ecology, Evolution and Environmental Biology.
CHAPTER 1: Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes. As global climate change influences lake physical structure, this chapter analyzed long-term trends and drivers of five metrics of vertical thermal structure across 102 globally-distributed lakes. While increases in surface water temperatures and strength of stratification were common, trends in deepwater temperatures and thermocline depth were highly variable and poorly explained by geomorphological lake characteristics. CHAPTER 2: Attenuation of photosynthetically active radiation and ultraviolet radiation in response to changing dissolved organic carbon in browning lakes: Modeling and parametrization. Lake ecosystem models have limited capacity to address how changes in dissolved organic carbon (DOC) influence light attenuation and consequent vertical structural responses. We developed an update to the MyLake model to dynamically link light attenuation at multiple wavelengths, including the first parameterization of ultraviolet attenuation, with changing concentrations of DOC at the daily time step. CHAPTER 3: Earlier ice breakup induces changepoint responses in duration and variability of spring mixing and summer stratification duration in dimictic lakes. As ice cover duration has shortened in lakes worldwide, the subsequent periods of spring mixing and summer stratification are likely to change in response. We modeled the relationships between these two phenological periods vs. timing of ice breakup by "moving" a single lake across a latitudinal gradient. A key changepoint in the timing of ice breakup on May 9 determined the relative response of longer spring mixing vs. longer summer stratification duration. CHAPTER 4: High-frequency data reveal lake phenology is more strongly associated with oxygen depletion during winter than in summer. Using year-round high-frequency data from 14 lakes, we assessed the role of lake phenology on deepwater oxygen availability in winter vs. summer. Shorter ice cover duration was strongly linked with greater oxygen availability in winter, but there was no clear pattern between summer stratification duration and oxygen availability in summer. CHAPTER 5: Multidecadal trends in ultraviolet radiation, temperature, and dissolved oxygen have altered vertical habitat availability for Daphnia in temperate Lake Giles. Vertical changes in ultraviolet radiation exposure, thermal structure, and oxygen availability influence the habitat for Daphnia, key zooplankton common in lakes across the world. Suitable habitat increased over time due to relief from ultraviolet radiation exposure, but thermally-optimal habitat decreased over time. Expected continued warming of surface waters and severe deepwater oxygen depletion projects a future "habitat squeeze" for Daphnia.
Craig Williamson (Advisor)
Thomas Fisher (Committee Member)
Tereza Jezkova (Committee Member)
Stuart Jones (Committee Member)
Michael Vanni (Committee Member)
Jing Zhang (Committee Member)
181 p.
Biology; Ecology; Limnology
limnology; lake ecology; vertical structure; climate change; water temperature; water transparency; dissolved oxygen; habitat availability

Recommended Citations

Citations

  • Pilla, R. M. (2021). Lake Vertical Ecosystem Responses to Climate and Environmental Changes: Integrating Comparative Time Series, Modeling, and High-Frequency Approaches [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1620646716185966

    APA Style (7th edition)

  • Pilla, Rachel. Lake Vertical Ecosystem Responses to Climate and Environmental Changes: Integrating Comparative Time Series, Modeling, and High-Frequency Approaches. 2021. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1620646716185966.

    MLA Style (8th edition)

  • Pilla, Rachel. "Lake Vertical Ecosystem Responses to Climate and Environmental Changes: Integrating Comparative Time Series, Modeling, and High-Frequency Approaches." Doctoral dissertation, Miami University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1620646716185966

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Miami University and OhioLINK.
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