6/05/2017  |   14:00 - 14:15   |  305B

IMPACTS OF TRICLOSAN EXPOSURE ON ANTIMICROBIAL RESISTANCE IN STREAM BACTERIAL ISOLATES Antimicrobial resistance (AMR) is a major global health challenge. Multidrug-resistance compromises efficacy of antibiotics and hinders infectious disease treatment. Triclosan brings numerous health risks including multidrug-resistance and is commonly found in human and environmental samples. Acquired resistance to triclosan and associated multidrug-resistance has occurred with clinical isolates. Similar patterns in streams or wastewater treatment plants threaten human health. The study goal is to evaluate stream bacterial responses to environmentally-relevant triclosan exposure. Triclosan exposure was predicted to impact susceptibility to triclosan and other antibiotics. Wastewater-associated and forested-stream periphyton were hypothesized to exhibit different overall levels of susceptibility. Triclosan resistance was hypothesized to associate with triclosan exposure and with resistance to other antibiotics. Periphyton underwent 10 microgram/L triclosan exposures in microcosms. Bacterial isolates from microcosms were assayed for AMR through broth microdilution and identified through 16S rRNA sequencing. Exposed and unexposed wastewater-associated isolates showed similar triclosan susceptibility, while exposed forested-stream isolates showed lower triclosan susceptibility compared to those unexposed. Most isolates exhibiting triclosan resistance also show resistance to carbenicillin, chloramphenicol, erythromycin, and trimethoprim. Results of this study indicate that triclosan in streams may alter AMR, possibly adding to the problem of multidrug-resistance.

Kirsten Trowbridge (Primary Presenter/Author), University of North Carolina at Greensboro, ketrowbr@uncg.edu;


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6/05/2017  |   14:15 - 14:30   |  305B

DOES SURFACE COAL-MINING LEAD TO SELENIUM BIOACCUMULATION IN HEADWATER ECOSYSTEMS? Aquatic ecosystems across the globe can be contaminated with excess selenium (Se), a trace element that bioaccumulates within the aquatic food chain. In central Appalachia, U.S.A., surface coal-mining releases Se, often causing elevated concentrations in the water of headwater streams. Though headwaters dominate stream networks in central Appalachia, processes of Se enrichment and trophic transfer in these systems have not been previously documented. In this study, we evaluated Se dynamics by determining concentrations in streamwater and in benthic macroinvertebrates from 23 headwater streams in summer 2015. Nine of these streams, including reference and mining-influenced sites, were selected for intensive sampling of streamwater, sediment, biofilm, leaf detritus, and benthic macroinvertebrates during two sampling periods - fall 2015 and spring 2016. We found Se dynamics were similar between seasons and between reference and mining-influenced streams, but Se concentrations were elevated in all material sampled in the mining-influenced streams relative to reference streams. Elevated Se concentrations indicate that headwater stream ecosystems are capable of accumulating Se via processes similar to those occurring in low-gradient streams and lentic habitats.

Keridwen Whitmore (Primary Presenter/Author), Virginia Tech, keridwen@vt.edu;


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6/05/2017  |   14:30 - 14:45   |  305B

EXPOSURE TO A COMMON ANTIHISTAMINE DOES NOT STRONGLY INFLUENCE PREDATOR-PREY INTERACTIONS IN LARVAL ODONATES Analyses of surface water have documented the presence of trace amounts of many pharmaceutical and personal care products (PPCPs). While some studies have determined the toxicity of some PPCPs to model organisms in the laboratory, ecotoxicologists are only beginning to consider the effects of these compounds on communities and ecosystems. We examined the effects of an antihistamine (fexofenadine) on predator-prey interactions between nymphs of the dragonfly Anax junius and the damselfly Ischnura verticalis. We expected that exposure to fexofenadine would reduce activity levels of both A. junius and I. verticalis resulting in fewer predator-prey interactions and promoting prey survival. Both were exposed to the presence/absence of fexofenadine for 24 hours in a factorial treatment design. Each predation trial included 1 A. junius and 10 I. verticalis, lasted two hours, and was recorded on video. There were no significant effects of fexofenadine exposure on Ischnura survival or Anax behavior. Studies such as this further our understanding of the effects of pharmaceuticals on aquatic insects. Future studies should how exposure duration influences behavior.

Earyn McGee (Primary Presenter/Author), University of Arizona, earynnmcgee@email.arizona.edu;


Patrick Crumrine ( Co-Presenter/Co-Author), Rowan University, crumrine@rowan.edu;


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6/05/2017  |   14:45 - 15:00   |  305B

SUB-LETHAL METABOLIC RESPONSES TO CONTAMINANT MIXTURE TOXICITY IN DAPHNIA MAGNA Anthropogenic factors are increasing the presence of contaminants in freshwater ecosystems, entering waterways through wastewater effluents and urban and/or agricultural runoff. While the concentration of contaminants in surface waters is very low, their occurrence within a complex mixture can cause profound repercussions on aquatic organisms. Here we examined Daphnia magna metabolic responses after sub-lethal (10% of the LC50) acute exposure to propranolol (PRO), carbamazepine (CBZ), and perfluorooctanesulfonic acid (PFOS), and the binary (PRO-CBZ, PRO-PFOS, CBZ-PFOS) and tertiary mixtures (CBZ-PRO-PFOS). The metabolome was measured using 1H nuclear magnetic resonance and characterized using principal component analysis, regression analysis and changes in metabolite concentrations relative to the unexposed group. The averaged PCA scores plots revealed CBZ-PFOS and CBZ-PRO-PFOS exposures were significantly different from the control. These two mixtures also displayed the most pronounced changes in identified metabolites. Overall, our results indicate the severity of toxicity depends on the composition of the contaminant mixture, with some mixtures displaying heightened toxicity versus others.

Nicole Wagner (Primary Presenter/Author), Oakland University, nicolewagner@oakland.edu;


André Simpson ( Co-Presenter/Co-Author), University of Toronto, andre.simpson@utoronto.ca;


Myrna Simpson ( Co-Presenter/Co-Author), University of Toronto, myrna.simpson@utoronto.ca;


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6/05/2017  |   15:00 - 15:15   |  305B

COAL ASH DERIVED SULFUR IN THE DAN RIVER FOOD WEB In February of 2014, a coal ash spill occurred in the Dan River in Eden, NC. Coal ash is a potential sulfur and heavy metal source and can disrupt aquatic and riparian food webs. Sulfur can stimulate mercury methylation, which bioaccumulates in the food web, threatening human and wildlife health. This study aimed to determine if dominant river and riparian invertebrates assimilated coal ash derived sulfur in relation to distance from the spill using stable isotopes of sulfur and carbon. Sulfur d³⁴S analysis showed that approximately 1.5 years after the spill, riparian spiders downstream from the spill were more enriched in ³⁴S than upstream spiders, consistent with incorporation of coal ash derived sulfur. Spider d³⁴S also increased with distance from the spill site. d³⁴S of the Asian clam, Corbicula fluminea, declined downstream of the spill site, a change that was not consistent with coal ash S, and d¹³C suggested that Corbicula shifted their feeding mode away from sediment organic matter at downstream sites.

Anne Hershey ( Co-Presenter/Co-Author), The University of North Carolina at Greensboro, aehershe@uncg.edu;


M.T.K. Tsui ( Co-Presenter/Co-Author), The University of North Carolina at Greensboro, tmtsui@uncg.edu;


Parke Rublee ( Co-Presenter/Co-Author), University of North Carolina at Greensboro, parublee@uncg.edu;


Kimber Corson (Primary Presenter/Author), University of North Carolina at Greensboro, kbcorson@uncg.edu;


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6/05/2017  |   15:15 - 15:30   |  305B

Influences of hyporheic upwelling on the toxicity of zinc contaminated sediments Despite the importance of groundwater-surface water interactions for aquatic habitat, we have limited understanding of how hyporheic flows may interact with contaminants to affect stream biota. This research investigates the effects of hyporheic upwelling on the amphipod, Hyalella azteca, when exposed to zinc contaminated sediments. Elevated zinc concentrations are often observed in urban stream sediments as a produce of stormwater runoff and legacy metal contamination. In this experiment, we manipulated hyporheic upwelling and zinc contamination in flow-through artificial streams over time. Hyalella azteca survival was lowest in streams with both zinc and hyporheic upwelling, compared to streams with zinc contamination only. The results highlight the importance of hyporheic flows in altering metal bioavailability to benthic macroinvertebrates, and suggest future assessments of hyporheic flows in in situ ecotoxicology research.

Anna Harrison (Primary Presenter/Author), Institute for Great Lakes Research, Central Michigan University, harri25a@cmich.edu;


G. Allen Burton ( Co-Presenter/Co-Author), University of Michigan, burtonal@umich.edu;


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6/05/2017  |   15:30 - 15:45   |  305B

Subsidies, salt, and sex ratios: interactive effects of road salt pollution with variation in leaf litter quality on wetland consumers Human activity has led to chemical contamination of freshwater environments, as well as changes in terrestrial vegetation. We examined how variation of tree litter inputs interacts with inputs of road salt deicers, which are common contaminants in northern latitudes. We hypothesized that elevated chloride levels would reduce copepod densities, increase algal abundance, and benefit salt-tolerant consumers. Additionally, we hypothesized that these effects would be most pronounced with highly soluble leaf litter (e.g., Acer rubrum). In experimental freshwater ponds containing phytoplankton, periphyton, zooplankton, Physa acuta snails, and tadpoles (wood frogs [Lithobates sylvaticus] and American toads [Anaxyrus americanus]), we manipulated leaf litter (none, A. rubrum, or Quercus velutina) and chloride concentration (114, 220, 314, and 867 mg Cl- L-1). The highest chloride concentration reduced copepod densities and increased phytoplankton, but only in the presence of maple litter. We found no effects of salt on the survival or growth of wood frog or toads. However, we did find that oak feminizes wood frog sex ratios, and that the addition of salt with oak litter had a masculinizing effect. In addition, road salt addition enhanced sexual size dimorphisms in maple-reared tadpoles, producing larger females.

Aaron Stoler (Primary Presenter/Author), Stockton University, aaron.stoler@stockton.edu;


Max Lambert ( Co-Presenter/Co-Author), Yale University, max.lambert@yale.edu;


William Hintz ( Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, billhintz@gmail.com;


Devin Jones ( Co-Presenter/Co-Author), US Environmental Protection Agency, jones.devin@epa.gov;


Lovisa Lind ( Co-Presenter/Co-Author), Swedish University of Agricultural Sciences, lovalind@gmail.com;


Brian Mattes ( Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, mattes.brian@gmail.com;


Matt Schuler ( Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, matt.s.schuler@gmail.com;


Meredith Smylie ( Co-Presenter/Co-Author), Yale University, meredithsmylie@gmail.com;


David Skelly ( Co-Presenter/Co-Author), Yale University, david.skelly@yale.edu;


Rick Relyea ( Co-Presenter/Co-Author), Rensselaer Polytechnic Institute, relyer@rpi.edu;


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