Submission Date

4-28-2025

Document Type

Paper- Restricted to Campus Access

Department

Biology

Adviser

Colleen Bove

Committee Member

Stephen C. Kolwicz Jr

Committee Member

Cory Straub

Department Chair

Denise Finney

Project Description

Exaiptasia pallida is a tropical sea anemone that serves as a model organism for many symbiotic cnidarian species because of their shared characteristics, including their symbiotic relationship with algal endosymbionts from the family Symbiodiniaceae. The relationship between the symbiont host is characterized as a close circle mutualistic relationship. The energy exchanged between the host and the symbiont allow cnidarians to grow and reproduce at higher rates. Here, we explore the effects of light availability and heterotrophy on the reproduction, growth, and physiology of Exaiptasia pallida anemones. Our results show that anemone with supplemental heterotrophic feeding exhibited the highest symbiont density across light treatments. Similarly, chlorophyll a concentration was shown to be higher in the fed group compared to the starved group across all light treatments. Together this indicates that the symbionts benefit from the extra energy the host receives through supplemental heterotrophic feeding. Photosynthetic efficiency was lower in high light starved conditions suggesting that high light may reduce photosynthetic efficiency when heterotrophic feeding is available. At the end of our experiment. the average number of anemones increased under low light starved conditions. These findings suggest a complex interaction between light, feeding, and asexual reproduction in cnidarians. Finally, protein concentration was found to be highest under high light and fed conditions. This suggests that in presence of higher light conditions, anemones can still maintain high protein concentration if they have heterotrophic feeding opportunities. In conclusion, these results aid in our understanding of the complex interactions between light and feeding in maintaining a healthy cnidarian host-symbiont relationship.

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