Date of Award


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© 2021 Emily N. Branam. All rights reserved. This work is freely available courtesy of the author. It may only be used for non-commercial, educational, and research purposes. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Biology Department

First Advisor

Kit Yu Karen Chan


Marine plankton possess elongated body structures, such as spines and horns, that increase drag on the body. While these extensions are often considered an anti-predation mechanism, the biomechanical implications of these structures are less studied. Using the barnacle nauplii Octolasmis spp., I explore the role of one such body extension, the dorsal thoracic spine, through amputation. Motion analysis revealed slower swimming and more erratic trajectories in dorsal thoracic spine amputees than those in control. Limb kinematic adjustments such as a larger beat amplitude, increased phase lag, and reduced contralateral symmetry were observed in amputees. While these changes may act to partially compensate for the loss of the spine by increasing propulsion and streamlining flow, they were unable to fully restore swimming proficiency. Further Particle Image Velocimetry (PIV) on live nauplii revealed increased predation risk by rheotactic predators as well as reduced feeding in amputees due to increased relative area of influence and decreased flux. A dynamically scaled model of spine loss supported area of influence results observed in live nauplii. The interaction between body extensions and limb motion shape swimming performance in nauplii, and in turn, shapes the evolution of naupliar form.


Part of the information presented in this thesis is published in the Journal of Integrative and Comparative Biology (Branam et al., 2021).

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Biology Commons