Date of Award
Master of Science
Recent studies have demonstrated that use of stable carbon isotopes and fatty acid biomarkers in combination can be a powerful approach to elucidate trophic relationships in aquatic ecosystems. Stable hydrogen and oxygen isotope ratios of lipids and essential fatty acids in fishes may reflect environmental hydrogen and oxygen isotope signatures, enabling identification of the importance of floodplain lake and riverine energy sources for large river fishes. However, relationships between water and fish lipid or fatty acid hydrogen and oxygen isotopes have not been examined. Therefore, I evaluated whether fatty acid profiles of bluegill differed among rivers and lakes that differed in water hydrogen and oxygen isotope signatures and characterized relationships between water and fish lipid and fatty acid hydrogen and oxygen isotope values. Fatty acid profiles of bluegill were different among sites (lake and riverine sites); bluegills could be identified to their environment of capture with 83% accuracy based on their fatty acid profiles. Hydrogen and oxygen isotope values of bluegill lipids were correlated with water hydrogen and oxygen isotope signatures. Hydrogen isotope values of individual fatty acids were strongly correlated with water hydrogen isotope signatures. Results suggest that fatty acid profiles in conjunction with lipid or fatty acid hydrogen and oxygen isotope values may provide new insights into energy sources and environments (e.g., floodplain lakes vs. rivers) that ultimately support fish production.
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