Doctor of Philosophy (Ph.D.)
Degree Granting Department
Christopher D. Stallings, Ph.D.
Robert H. Byrne, Ph.D.
Christopher Langdon, Ph.D.
Teresa Greely, Ph.D.
Dana L. Zeidler, Ph.D.
climate change, environmental education, inducible defenses, intertidal mussels, ocean acidification, systems engineering
Climate change is ecologically and socially complex, deemed the most important issue of our generation. Through this dissertation I have approached climate change research through an interdisciplinary perspective, investigating how this phenomenon will affect marine ecological systems, how we can better develop experimental systems to answer ecological questions, and how we can effectively educate about this issue.
In Chapter 2, I provided accessible alternatives for researching the effects of climate change (elevated temperatures and pCO2) on marine ecosystems. I designed, built, and troubleshooted two accurate and inexpensive climate-controlled experimental systems capable of maintaining target conditions: a temperature-controlled system and an ocean acidification system. The temperature-controlled system was designed to manipulate experimental tank temperatures indirectly by controlling the temperature in a surrounding water bath, which buffered fluctuations and resulted in a high level of control. The ocean acidification experimental system was designed to elevate normally fluctuating pCO2 levels by a constant factor, which allowed pCO2 to fluctuate as expected in natural environments and made it more ecologically relevant than active pCO2-controlled systems.
In Chapter 3, I experimentally tested the morphological responses of southern ribbed mussels Geukensia granosissima to two simultaneous stressors (elevated temperatures and the presence of water-borne predation cues from blue crab Callinectes sapidus) and if any effects of these treatments led to differences in handling times by predatory crabs. Bivalves may become more susceptible to predation as increased temperatures decrease the protection afforded by their shells, but few studies have tested the effects of elevated temperatures on inducible defenses in bivalves. Results showed that chronic heat stress can have detrimental morphological effects on intertidal mussels. Mussels reared in elevated temperatures manifested elongated shell shapes, exhibited a disruption of the predator effect on inducible defenses, and experienced decreased predator handling times. The observed responses to elevated temperatures could make southern ribbed mussels more vulnerable to predation.
In Chapter 4, I experimentally tested the morphological responses of southern ribbed mussels to elevated pCO2 levels and the presence of water-borne predation cues from blue crabs, and if these effects led to differences in handling times by predatory crabs. Elevated pCO2 can have negative effects on bivalves’ morphology and physiology, but the consequences of these effects on predator-prey interactions are still unclear. I found that adult southern ribbed mussels’ inducible defenses were not affected by a medium-term exposure to elevated pCO2. Mussels grew more in shell length and width as a response to predation cues, independent of pCO2 conditions. However, and unexpectedly, mussels reared under elevated pCO2 exhibited greater growth in shell width independent of predator treatment, driving mussels reared in the presence of a predator under elevated pCO2 conditions to develop rounder shapes. On average, these effects on mussel morphometrics did not affect crab handling times, but mussels reared in the presence of a predator under elevated pCO2 conditions had highly variable handling times. It is important to consider the complexity of animal physiology, morphology, and interspecies relationships when making deductions on predator-prey relationships in a changing ocean.
In Chapter 5, I analyzed the effectiveness of using an interdisciplinary approach to climate change education. Literature suggests that an interdisciplinary instructional framework in an outdoor setting, using tools from the experiential, active, and inquiry- and place-based learning approaches, as well as the socioscientific issues pedagogical framework, would be an excellent approach for climate change education. I found that students: increased their content knowledge on climate change causes and consequences, exhibited a deeper understanding of climate change through the words they used to describe it, and corrected common climate change misconceptions. This work can serve as an example for the development of effective climate change programs that uses already available instructional materials with intentional interdisciplinary goals.
Our search to understand how marine ecosystems will cope with a changing climate has emphasized emerging issues in the way we gather data, the questions we seek to answer through research, and how we translate science of social importance to the public. Through this dissertation I strove to seek the answers to some of these questions and provide feasible solutions to some of the problems in climate change research and education through an interdisciplinary approach. As science continues to move towards answering questions of concern for both science and society, science research is moving towards more interdisciplinary approaches. This dissertation is an example of how this can be an efficient and comprehensive approach.
Scholar Commons Citation
Freytes-Ortiz, Ileana M., "An Interdisciplinary Approach to Understanding Predator-Prey Relationships in a Changing Ocean: From System Design to Education" (2018). USF Tampa Graduate Theses and Dissertations.