Graduation Year


Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts



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© 2022 Addison Gleekel


Intertidal species are especially sensitive to changes in the environment because they live on the fringes between land and sea. The daily cycles of tide and light present many challenges, including access to food and oxygen. The intertidal Acorn Barnacle Balanus glandula is a sessile filter feeder, occurring at mid to high shore heights on the pacific coast of North America. The impacts that tidal cycles have on the activity patterns and behavior of B. glandula is unknown. I investigated the impacts of both tide and light cycles on the activity and behavior patterns of B. glandula subjected to a tidal cycle and B. glandula submerged for 24-hours of their day. B. glandula were either continuously submerged or exposed to an intertidal treatment for 7 days. After the 7th day, B. glandula in either group were filmed for a 24-hour period, and the percent of time spent active and performing certain behaviors were quantified. The primary hypothesis was that B. glandula subjected to a tidal cycle will be more active, overall, than B. glandula that are constantly submerged. Nine barnacle behaviors were observed: normal beat, fast beat, pumping, testing, extension, closed, closed/normal, fast/extension, and other (or sexual behavior). Overall, B. glandula (in either treatment group) spent more than half of their time spent in water closed, or not active. B. glandula in the tidal group showed less overall activity than those in the constant submersion group, whether comparing the full 24 hours or just during times submerged, showing that these barnacles, when submerged, do not compensate in activity for their time spent out of water. This experiment provides empirical data for the impacts of tide and light cycles on the activity and behavior of B. glandula, forming a basis for future studies that want to look further into these effects.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.