Date Thesis Awarded
Honors Thesis -- Open Access
Bachelors of Science (BS)
Mark R. Patterson
The physiological role of the gastrovascular system in scleractinians has been understudied; in particular the implications of perforate vs. imperforate coral colony morphology are largely unknown but may be important to understanding coral response to increasing temperature and acidification in the ocean. This project uses concepts from electronics and fluid dynamics to determine the scale of the time constant of mixing in the gastrovascular system of two imperforate coral species Montastraea cavernosa, and Duncanopsammia axifuga. These time constants will be applied in an electrical network model that will give insight into how perforate vs. imperforate coral species handle environmental stresses. Six different conductivity probe designs were built to measure the time constant of mixing inside of the two coral species. I determined an average time constant of mixing for Duncanopsammia axifuga polyps under a ~0.1 m/s flow condition to be 1.45 ± 0.28 seconds and an average time constant of mixing under no flow to be 6.11 ± 2.82 seconds. There is a significant difference between the mixing times under the two flow conditions (p-value of 0.00026). I developed a differential equation model, closely related to the discharging of a capacitor, to be used in accordance with oxygen profiles during a light/dark shift inside a coral polyp as an alternative method to determine the time constant of mixing. I calculated the time constant of mixing to be c. 2 min 10 sec for a Montastraea cavernosa polyp by using the differential equation model. This project is an essential step in better understanding ventilation of the gastrovascular system in imperforate and perforate corals.
Williams, Sara D., "Using an Electrical Network Model to Simulate Gas Flux in Perforate and Imperforate Corals: Calculating the Time Constant of Mixing in Gastrovascular Fluid Compartments" (2013). Undergraduate Honors Theses. William & Mary. Paper 581.
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