Gair, Hana2026-02-092026-02-092021https://hdl.handle.net/1828/23278Copepods, a major group of crustacean zooplankton, occupy a central role within marine food webs. Connecting primary producers to higher trophic levels and influencing global biogeochemical cycles, variations in community composition can have lasting impacts on the marine environment. Small marine copepods often greatly exceed the abundance of large-bodied copepods, yet historically they have been overlooked. As the ocean warms, conditions may favour an increasing abundance of smaller copepod species. Therefore, understanding the ecology of small-bodied copepods and their effect on the ecosystem is crucial for estimations of how climate change may affect the marine ecosystem. In June, July, August, and October 2020, copepod samples were collected at five on-shelf stations, two off-shelf stations, one oceanic station, and an intertidal beach along the west coast of Vancouver Island. Through lipid extraction and quantification, and visualization with multivariate non-metric multidimensional scaling, I observed differences in lipid classes and fatty acid profiles among large-bodied oceanic, small-bodied oceanic, and small-bodied intertidal copepod species. Small oceanic copepods all had relatively similar total lipid masses but differed based on their storage lipid. While Aetideus divergens, Pseudocalanus minutus, Pseudocalanus mimus, and Clausocalanus lividus stored wax esters similarly to the large-bodied copepod species, Acartia longiremis and Mesocalanus tenuicornis both stored triacylglycerols, which are associated with more active year-round life cycles and higher metabolic rates. Intertidal copepod Tigriopus californicus had the lowest total lipid mass. Three significantly distinct feeding strategies were observed among species, with the large-bodied copepod species grouping together, and the small-bodied copepod species diverging into two groups that corresponded to the storage lipid distinctions. Almost all small copepod species were observed to have higher proportions of bacterial fatty acid markers than did the large-bodied copepods, indicating they are more connected to the microbial loop than the omnivorous-herbivorous large-bodied copepods. My research contributes to our understanding of the ecology and life strategies of these small-bodied copepod species, and also provides some of the first lipid analysis for certain species.enHonours thesisDepartment of Biology