Use of Fatty Acid Signatures to Explore the River Continuum Concept

The objective of this study was to evaluate if fatty acid signatures (FAS) of aquatic organisms could be used to assess the river continuum concept (RCC), which predicts biological community responses to physical changes from headwaters to the mouth of any river. Nine sites were chosen throughout the Genesee River, located in Western New York. Largemouth bass, smallmouth bass, northern hogsucker, red horse sucker (e.g., golden, silver, greater, black), and rock bass were collected using backpack or boat electrofishing at each site during the spring and summer of 2016. Gas chromatography/mass spectrometry was used to assess whole body fatty acid signatures of each species. Water quality (e.g., dissolved oxygen, conductivity, pH, temperature, total nitrogen (TN) and total phosphorus (TP)) was evaluated during both seasons to confirm the RCC. Temperature, TN and TP were higher in the mouth during the spring, which followed the RCC prediction. Dissolved oxygen was higher in the mouth of the river during both seasons, which did not follow the prediction. Conductivity and acidity showed trends to be higher in the mouth during both seasons. We will compare changes in FAS of each species throughout the river and discuss any diet shift linked to the RCC (terrestrial/microbial sources in the headwaters to instream sources in the mouth).