Honors Theses
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Date of Defense
2026
Document Type
Honors Thesis
Degree Type
Bachelors of Science
Degree Other
Marine Biology
College
Halmos College of Arts and Sciences
Faculty Advisor
Amy C. Hirons, Ph.D., Halmos College of Arts and Sciences
Faculty Advisor
Dimitrios G. Giarikos, Ph.D., Halmos College of Arts and Sciences
Honors Program Director
Aileen Miyuki Farrar, Ph.D., Director, Farquhar Honors Program
Faculty Fellow for Student Research
David Kerstetter, Ph.D., Faculty Fellow for Student Research
HCAS Dean
Robin Cooper, Ph.D., Dean, Halmos College of Arts and Sciences
Home College Dean
Robin Cooper, Ph.D., Dean, Halmos College of Arts and Sciences
Abstract
Since the Last Glacial Maximum (20,000 years ago), the North Pacific has remained geologically dynamic and biologically diverse. Natural fluctuations in island arc volcanism and climate likely continue to influence the inputs of trace elements (TEs) to the Aleutian Island Archipelago. Bioaccumulation of these TEs in the region’s marine food webs provides a proxy for long-term environmental variability. In this study, 95 tephra-preserved pinniped bone samples from temporally identified archeological Aleut midden sites on Unalaska Island (5500-200 BP; BP=years before present, c. 1950), were analyzed for 20 TEs using inductively coupled plasma mass spectrometry (ICP-MS). Elemental concentrations were compared temporally with historical (c. 1870-1919) and modern (c. 1920-1950) Alaskan pinniped bone. Archaeological specimens exhibited the highest concentrations in aluminum (Al; 911 μg/g), calcium (Ca; 1184 μg/g), iron (Fe; 968 μg/g), strontium (Sr; 637 μg/g), manganese (Mn; 281 μg/g), and zinc (Zn; 259 μg/g). Concentrations of 15 elements were significantly elevated in archeological samples (ex. Al: 911 μg/g; Fe: 968 μg/g) relative to historical material (ex. Al: 33.3 μg/g; Fe: 87.3 μg/g) and were markedly higher than values typically reported for modern pinnipeds. These enrichments correspond with the surrounding volcanogenic geology, suggesting substantial diagenetic alteration during burial. Inter-species differences in arsenic (As), Fe, lead (Pb), tin (Sn), and Zn likely reflect dietary variation. In contrast, Pb and Sn concentrations were elevated in contemporary samples, potentially indicating anthropogenic inputs following the Industrial Revolution. Overall, this study establishes a quantitative pre-anthropogenic TE baseline and provides evidence for subsequent industrial enrichment in the North Pacific, as recorded in archeological and historic pinniped bone.
NSUWorks Citation
Aidan M. Pflieger. 2026. Marine Sentinels of the Past: Holocene Trace Element Records from North Pacific Pinnipeds. Capstone. Nova Southeastern University. Retrieved from NSUWorks, Halmos College of Arts and Sciences. (50)
https://nsuworks.nova.edu/honors_theses/50.
Included in
Analytical Chemistry Commons, Biogeochemistry Commons, Environmental Chemistry Commons, Environmental Indicators and Impact Assessment Commons, Inorganic Chemistry Commons, Marine Biology Commons, Oceanography Commons, Paleontology Commons