Honors Theses (Marine Biology)

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    Examining Variations in Fatty Acid Profiles of The Sea Star Pycnopodia Helianthoides On the Coast of British Columbia
    (University of Oregon, 2022-11) Taradash, Aubrey; ; ;
    Pycnopodia helianthoides is a large, predatory sea star native to the northeast Pacific coast. This important intertidal and subtidal predator was historically abundant along the west coast of North America from Alaska to Baja California until the 2013-2015 sea star wasting epidemic caused drastic population declines throughout its range. The opportunistic diet of Pycnopodia on benthic invertebrates has previously been studied through observation, but there are no published diet analyses using fatty acids (a trophic biomarker). In order to investigate the trophic ecology of wild Pycnopodia, fatty acids were extracted and identified from tissues of 119 individuals, ranging in size from 2.6-46 cm in diameter, collected from different sites and habitats near Calvert Island, BC, Canada. The multivariate fatty acid signatures of the stars were compared between collection sites and substrate types, as well as size classes (5 categories). Fatty acids were significantly different between sites and substrates, but not size classes. These differences suggest that the diets of stars found at different sites and substrates could differ significantly, although very few sites featured more than one substrate type, making it difficult to distinguish the potential effects of each. Size class, however, does not appear to have an effect on the fatty acid compositions of the stars, indicating that Pycnopodia diets may not vary much by size, which was unexpected. Further analysis of both wild and captive stars could continue to provide more insight into the diet of this understudied species.
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    Community composition of mussel associates at deep-sea methane seeps in the Gulf of Mexico and the US Atlantic Margin
    (University of Oregon, 2022) Paden, Gianna
    Efforts to understand and preserve methane seep communities of the Gulf of Mexico and the US western Atlantic margin begin with an understanding of biodiversity and community composition. In this study, 10143 individuals representing 63 different taxa were sampled from mussel-beds surrounding methane seeps at various depths within two different ocean basins. Diversity in mussel beds was highest at Baltimore Canyon, the shallowest site sampled in the Atlantic. Although only four species were sampled at more than one site, species composition was most alike among sites found at similar depths. The two deepest sites sampled, Florida Escarpment and Blake Ridge showed a 9.6% similarity. Baltimore Canyon and Chincoteague are both located in the Atlantic Ocean at different depths but had a 5.3% similarity. The high diversity of individuals sampled among these sites emphasizes the importance of preserving seep communities, which provide essential nursery habitats that further support more trophic levels within the deep-sea ecosystem.
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    The Poison of Misinformation: Analyzing the Use of Science in Science Fiction Novels, Including an Original Short Story
    (University of Oregon, 2015-12) Piazzola, Clara
    The purpose of this thesis was to read a variety of science fiction novels and understand how the science progresses each novel. For the novels Creature by Peter Benchley, The Andromeda Strain by Michael Crichton, Dune by Frank Herbert, and The Windup Girl by Paolo Bacigalupi, I considered the role of science in relation to plot and character development. For Jurassic Park by Michael Crichton, I analyzed the creativity that the author used with science in addition to the role science played in the novel. For Jaws by Peter Benchley, I researched the accuracy of the science used and determined that the majority was accurate. With all of these analyses in mind, I created a template to guide authors in writing science fiction. Finally, I wrote my own science fiction short story, titled "Poison."
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    Morphological Variation of Pisaster Orchraceus in Response to Wave Exposure
    (University of Oregon, 2016-06) Bjorkquist, Alyssa
    Pisaster ochraceus (the Ochre Sea Star) is a keystone predator in the NE Pacific that regulates intertidal diversity through consumption of space-competing organisms. Individuals inhabit a broad range of habitats ranging from sheltered coves to exposed cliffs and experience large temporal and spatial variability in water flow throughout their lifetime. However, it is largely unknown how sea star body shape changes between wave-exposed and wave-sheltered environments throughout an organism's lifetime. Wave exposure was measured at sites near Charleston, OR using dissimilar metal dissolution and intertidal zonation of sessile organisms. At these same sites, I measured shapes and sizes of Pisaster juveniles and adults and analyzed how morphology changed as a function of wave exposure. Average zinc anode mass loss differed significantly between sites during seasonal trials (p < 0.001 ). Mean upper intertidal zone limits were significantly higher at the Middle Cove and 01MB Boathouse sites for Ba/anus g/andula (p < 0.01 ), Mytilus spp. (p < 0.01), Neorlwdomela oregona (p < 0.001), and Sacclwrina sessilis (p < 0.05). Adult sea star populations the Middle Cove site had longer, narrower arms (p < 0.00 l) and smaller central discs (p < 0.001) than individuals from the 01MB Boathouse or Bastendorff Jetty sites for a given weight. Juveniles appeared to exhibit similar morphological trends to respective adult populations but results were inconclusive. The lack of a significant relationship between wave exposure and Pisaster morphology is likely due to errors in measurements of exposure and demonstrates that exposure alone does not determine body shape.
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    Anthopleura xanthogrammica Behavior Studied Utilizing Time-Lapse Photography
    (University of Oregon, 2013-11) Reiser, Shannon
    Animals living in a habitat affected by both tidal shifts and day night cycles display a wide variety of behaviors influenced by environmental factors and internal mechanisms. Sessile intertidal invertebrates exhibit extremely slow or subtle behaviors not noticeable during casual observation. This study aimed to observe, analyze, and describe the behaviors associated with the tidal and circadian rhythms of Anthopleura xanthogrammica, giant green anemones, in a tide pool at South Cove, Cape Arago State Park, Oregon. Time lapse video captured using a GoPro camera at a low- to mid-tidal range were used to test the hypothesis A. xamlzogrammica opens on incoming tides. Percent open data were collected from videos and these data were used to evaluate the percentage of animals open in different light conditions. I also examined the data for individual sea anemones to determine if there were individual tendencies. The data suggest that there is a correlation between height of tide and anemone openness. As the tide rises fewer anemones are closed. Additionally the data suggest that anemones are more likely to be closed in direct sunlight. Furthermore, there is a slight, but insignificant difference in average time spent 100% open for each anemone. The most dramatic shifts in behavior occurred in the presence of direct sunlight.