Impervious Surface Category Urbanization Alters Fatty Acid Concentrations of Stream Food Webs Within the Narragansett Bay Watershed Sarah B. Whorley1,4, Nathan J. Smucker2, Anne Kuhn3, & John D. Wehr1 1Louis Calder Center, Fordham University, Armonk, NY 10504; 2Environmental Protection Agency, Water Supply and Water Resources Division, Cincinnati, OH 45220; 3Environmental Protection Agency, Atlantic Ecology Division, Narragansett, RI 02882; 4Natural Sciences Department, Daemen College, Amherst, NY 14226 Introduction Urbanization degrades stream ecosystem quality Algae produce many key essential fatty acid compounds, consumed by invertebrates Organism diversity & health often adversely affected by urbanization How does urbanization affect stream food web quality and relationships? Conclusions Increased nutrients in urban runoff may benefit some invertebrates by increasing periphyton EFAs Invertebrate relationships differed by trophic level Higher trophic levels EFA composition less varied Low invertebrate taxonomic diversity Investigate relationship to Stable Isotopes Compare EFA to Algal & Invertebrate IBIs Impervious Surface Category FFG Order or Family <5% 5-10% 10-15% >15% Collecters Chimara (Philopotamidae) 1 Hydropsychidae   4 Shredders Limnephilidae  2 8 Tipulidae 3 6 Omnivores Amphipods (Gammaridea) Cambaridae Isopods (Asellota) Rhyacophilidae Predators Aeshnidae 11 5 Calopterygidae Corydalidae 12 9 Gomphidae Libellulidae Perloidea Few differences among EFA and % Impervious surface Algal trends driven by ↑ Sw3 Invertebrate FFGs have different trends: Collectors ↑, Shredders ↓, Omnivores & Predators stable All FFG: ALA, EPA, DHA, ARA significantly ↑ w/ %Impervious surface Methods GIS Analysis For 78 stream sites: % Impervious surface, developed, forested, wetland Stream Chemistry SRP, NO3-, NH4+, Cl- DOC, TN, TP Impervious Surface Algal Collection 6 cobbles Invertebrate Collection 10 min kick net, 50 m Common taxa from FFGs -Collector, Shredder, Omnivore, Predator EFA Analysis Chloroform extraction ≥18C: Total, Sw3, Sw6, Sother w3: ALA, EPA, DHA w6: LIN, ARA Acknowledgements We would like to thank Carlos Cruz-Quinones and Jonathan Serbst for assistance with sampling and laboratory processing, Colleen Elonen and Terri Jicha for chemistry analyses, and Mike Charpentier for generating GIS data. Funding was provided by the EPA. PCA: Algal & FFG essential fatty acid profiles are distinct Algae & Shredders most similar at lower % Impervious surface Algae & Collectors most similar at high % Impervious surface Predators & Omnivores have distinct patterns GIS characteristics do not explain EFA concentrations Regressions: % Impervious, developed, forested, wetland – n/s Further Reading Cashman, MJ; et al. 2013. Freshwater Biology 58:1447-1457 Smucker, NJ; Detenbeck, NE. 2014. Restoration Ecology 6:741-784 Smucker, NJ; et al. 2015. Environmental Management 57:683-695 Walsh, CJ; Webb, JA. 2015. Freshwater Science 35:324-339