2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
6/05/2017 | 2:15 PM - 2:30 PM | Carbon Sources in Riverine Food Webs: New Evidence from Amino Acid Isotope Techniques | 302B
Carbon Sources in Riverine Food Webs: New Evidence from Amino Acid Isotope Techniques
A nearly 40 yr debate on the origins of carbon supporting animal production in lotic systems has spawned numerous conceptual theories. Testing theories has been hampered by lack of adequate analytical methods to distinguish in consumer tissue between ultimate autochthonous and allochthonous carbon. The newest technique in amino acid, compound specific, stable isotope analysis (AA-CSIA), however, enables investigators to link consumers to food sources by tracing essential amino acids from producers to consumers. We used AA-CSIA to evaluate nutrient sources for 5 invertivorous and 6 piscivorous species in 2 hydrogeomorphically contrasting large rivers: the anastomosing Upper Mississippi River (UMR) and the mostly constricted lower Ohio River (LOR). Our results demonstrate that on average algae contributed 58.5% (LOR) to 75.6% (UMR) of fish diets. The next highest estimated contributions of food sources were from C3 terrestrial plants (21.1 and 11.5% for the LOR and UMR, respectively). Moreover, results from 11 individually examined species consistently demonstrated the importance of algae for most fish species in these trophic guilds. Differences among rivers in relative food source availability resulting from contrasting hydrogeomorphic complexity may account for relative proportions of amino acids derived from algae.
- C25 Food Webs
- S29 Macrosystem Ecology of Aquatic Systems
- C06 Large River Ecology
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Presenters/Authors
Rachel Bowes
(), University of Kansas, Kansas Biological Survey, rebowes@ku.edu;
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James H. Thorp
(), University of Kansas/Kansas Biological Survey, thorp@ku.edu;
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