Graduation Year
2026
Document Type
Campus Only Senior Thesis
Degree Name
Bachelor of Arts
Department
Environmental Analysis
Second Department
Biology
Reader 1
Dr. Sarah Gilman
Reader 2
Dr. Wes Dowd
Terms of Use & License Information
This work is licensed under a Creative Commons Attribution 4.0 License.
Rights Information
2025 Ana J Rowley
Abstract
Climate change is driving widespread changes in aquatic ecosystems, potentially affecting multiple levels of biological organization, from primary producers to apex predators. Factors such as rising sea temperatures, ocean acidification, and deoxygenation threaten aquatic organisms, with climate change only amplifying the frequency and severity of extreme events. Despite these widespread effects, much of the existing research into its impacts on organisms focuses on individual species in isolation, overlooking important interspecies interactions that shape community responses to environmental stressors. In marine systems, primary producers, like microalgae, are a key nutritional resource for many invertebrates. Recent studies have suggested that the thermal history of these primary producers can also influence the physiology of their consumers. These effects extend beyond caloric content. They involve specific changes in polyunsaturated fatty acids (PUFAS), which play a critical role in cellular function and thermal stress responses. Maintaining membrane fluidity, also known as homeoviscous adaptation, is a key process involved in thermal adaptation and maintaining homeostasis in ectotherms. This physiological process occurs when individuals adjust their fatty acid composition to modulate the fluidity of the membrane at temperature changes. During chronic warmer temperature exposure, polyunsaturated fatty acid content decreases to increase membrane rigidity and maintain membrane structure. Dietary intake of some lipids from thermally stressed algae may influence this process in consumers, affecting their thermal tolerance. This research extends beyond direct effects of abiotic factors to ask whether the indirect effects of thermal stress on prey items alter copepods’ heat tolerance. Specifically, the study examines how thermal history in the consumed green algae Nannochloropsis affects thermal plasticity and tolerance in the intertidal copepod Tigriopus californicus, a well-established model organism for studying how climate change may affect physiological resilience. To address this, we reared green algae (Nannochloropsis spp.) cultures at different temperatures (17 °C and 27 °C) and fed the cultures to adult male copepods (Tigriopus californicus). Then, we compared copepods’ heat tolerance (LT50 assays) based on feed treatment. We found, contrary to our hypothesis, that copepods that consumed warm-grown algae had a significantly lower thermal tolerance than copepods that consumed algae grown at ambient temperatures and the control feed. Future research is required to understand this surprising finding, specifically investigating the PUFA uptake mechanism and its impact on thermal tolerance. It is essential to investigate this current gap in our knowledge to expand understanding of organismal resilience, its mechanistic basis, and its implications for entire oceanic food chains.
Recommended Citation
Rowley, Ana, "Community physiology in splashpools: Interactions of primary producers and consumer responses to thermal stress" (2026). Scripps Senior Theses. 2830.
https://scholarship.claremont.edu/scripps_theses/2830
This thesis is restricted to the Claremont Colleges current faculty, students, and staff.
