Investigating Small Copepod Trophic Ecology and Diet via Lipid Analysis
Date
2023-03-16
Authors
Hobson, El
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Abstract
Small copepod trophic ecology is widely understudied due to inadequate mesh size of plankton nets and a focus on sampling larger copepod species. Due to their estimated high abundance as well as their involvement in multiple trophic pathways, small copepods are a crucial link between lower and higher trophic levels in marine food webs. The objectives of this study were to determine (i) the diet and (ii) the degree of dietary overlap in small copepod species to gain insights into intraspecific competition. Copepods were sampled from three locations, the Strait of Georgia, the west coast of Vancouver Island, and the NE Pacific open ocean. Lipids (fatty acids) were used as dietary tracers as prey lipids accumulate in consumer tissues over time. Certain fatty acid signatures are indicative of specific prey items; therefore, we can determine dietary preferences of copepods by examining their fatty acid composition. The results of this study revealed a high degree of small copepod dietary overlap, indicated by a wide variety of fatty acids found within each copepod species. The dietary overlap suggests that small copepod trophic ecology is complex with multiple pathways within the food web and therefore requires more specific dietary analysis techniques such as DNA metabarcoding of gut contents to untangle.
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Keywords
Food Chain, Zooplankton, Diet, Lipids, Trophic Ecology, Copepods