Robinson, Isabella2025-08-082025-08-082025-08https://hdl.handle.net/1773/53817This study utilized micro-CT scanning to compare the morphologies of the subtidal clam Glycymeris septentrionalis and the intertidal clam Leukoma staminea. Three subtidal clams (Glycymeris septentrionalis) were collected from Van Veen grabs on the Kittiwake in the San Juan Channel (48 32.491' N, 122 58.940' W) on July 3rd, 2025. Three intertidal clams (Leukoma staminea) were collected from Argyle Lagoon (48°31'15.2"N, 123°00'48.7"W) on June 26th and July 10th, 2025. Clam species were identified based on their size and location compared to iNaturalist to preserve morphology for micro-CT scanning. All six clams were relaxed in magnesium chloride before being preserved in formalin overnight. The clams were stained in iodine, with small holes drilled in ones that did not relax open under the magnesium chloride. Staining the clams with iodine allowed the soft tissues to be imaged by the scanner. To this end, the clams were soaked in iodine for at least 18 hours. All six clams were scanned using a micro-CT scanner at a resolution of 45 μm under a continuous scan. Based on a previous literature search, this was the first time these two clam species were scanned using a micro-CT scanner. The software 3D slicer was used to examine the six clams. Each clam was segmented into its own file. Threshold values 89.25 and 255.0 were used to only render the clam shells. This study had two aims for the micro-CT scans: a qualitative review of what morphology features were modeled by the scans, and a quantitative study of shell thickness with the hypothesis that subtidal clams would have a thicker shell than intertidal clams, since the intertidal is a harsher environment that could wear down the shells. Radial ribs, hinge ligaments, hinge teeth, lateral teeth, and some of an adductor muscle for an intertidal sample were observable in the micro-CT scans. Shell thickness was measured in 3D Slicer for all six clams. An F-test was conducted to determine if the T-test for mean shell thickness should assume equal or unequal variance. The p-value was 0.17. A T-test of two samples assuming unequal variance was conducted in excel to determine if the difference in average shell thickness for the two species was statistically significant. The p-value was greater than 0.05 (p=0.60), indicating a failure to reject the null hypothesis that the average shell thickness between the two species was different. As such, the hypothesis that the subtidal clams would have thicker shells than the intertidal clams was not supported. Still, this study demonstrates how micro-CT scanning allows for measurements to be conducted without sample destruction.Glycymeris septentrionalisLeukoma stamineamicroCT