IMPACT OF ROAD SALT ON THE OXYGEN CONSUMPTION AND SWIMMING ENDURANCE OF THE BLACKNOSE DACE (RHINICHTHYS ATRATULUS) Kateline Robinson Department of Biology, York College of Pennsylvania Introduction The salt applied to roads and sidewalks for de-icing purposes may be leading to an increase in water salinization and adversely affecting freshwater ecosystems. According to the U.S. Environmental Protection Agency (2012) salt is a top cause of stream impairment and is considered as equally important as pesticide input (Canedo- Arguelles et al. 2013). Currently there are no restrictions in the U.S. on the amount of salt that is allowed to be released into streams and rivers. Salt can be stored in soils, sub-soils, and ground water (Canedo-Arguelles et al. 2013). Salt concentrations in surface and groundwater will increase, perhaps for decades, even if we stop using road salt today (Kelly et al. 2010). Chloride concentrations from NaCl can remain elevated in spring, summer, and autumn (Kaushal et al. 2005). An increase in salinity can cause an increase in stress and even mortality in freshwater organisms (Silva and Davies, 1999). When salt concentrations get too high, osmoregulatory mechanisms will be insufficient resulting in cell damage and possibly death (Hart et al. 1991). Tyler Run, part of the Codorus Creek watershed, is an urban tributary located in York County, Pennsylvania. It is severely impaired for much of its length due to storm-water runoff from urbanization (Romig 2010). Blacknose dace (Rhinichthys atratulus) are small minnows found in Tyler Run. To determine the effects of salinity on the these fish, they were subjected to oxygen consumption and swim tunnel tests after each exposure to an increasing salinity concentration. Objective To determine if an increase in salinity has an impact on the oxygen consumption and swimming endurance of the blacknose dace. Hypothesis An Increase in salinity levels above what is typical of freshwater will have adverse effects (either an increase or decrease) on the oxygen consumption of the blacknose dace. An increase in salinity will lower the swimming endurance of the blacknose dace. Methods Water samples were collected during January and February from Tyler Run at the road crossing at York College for 29 days. Salinity was measured by conductivity (µS). Each dace was tested in water that had no salt, 3000 µS (low), and 9000 µS (high) concentrations. Results Figure 4. Mean (SD) for the critical swimming velocity (cm/sec) of the blacknose dace (n=10) in fresh water, low salt (3000 µS), and high salt (9000 µS) concentrations. A repeated measures one-way ANOVA found no significant difference between the critical swimming velocities between these groups (p= ). Figure 3. Mean (SD) of consumed oxygen (mg/L) per hour by the blacknose dace (n=10) in fresh water, low salt (3000 µS) and high salt concentrations (9000 µS). A repeated measures one-way ANOVA found oxygen consumption between the groups to be significant (p=0.0063). However, a Dunn’s multiple comparisons test found no significant difference between the mean oxygen consumption of the control and low salt groups. Acknowledgment I would like to thank Dr. Nolan for being my mentor and for helping me design my experiment. I would also like to thank Dr. Rehnberg for the use of his swim tunnel. Figure 2. Salinity measurements (µS) of Tyler Run in York, PA over 29 days from January 22, 2015 through February 19, Conclusion An increase in salinity reduced oxygen consumption in the blacknose dace. An increase in salinity did not appear to compromise their swimming endurance. Literature Cited Canedo-Arguelles, M., Kefford, B., Schafer, R., & Schulz, C. J Salinization of rivers: An urgent ecological issue. Environmental Pollution [serial online] 173: Hart, B.T., Baily, P., Edwards, R., Hortle, K., James, K., McMahan, A., Meredith, C., Swadling, K A Review of the salt sensitivity of the Australian freshwater biota. Hydrobiologia [serial online] 210: Kaushal, S., Groffman, P., Likens, G., Belt, K., Stack, W., Kelly, V., Band, L., Fisher, G Increased salinization of fresh water in the northeastern United States. Proceedings of the National Academy of Sciences of the United States of America [serial online] 102: Kelly, V., Findlay, S., Schlesinger, W., Menking, K., and Chatrchyan, A Road salt: moving toward the solution. The Cary Institute of Ecosystem Studies, Millbrook, NY. Romig, J Engaging local governments circuit rider pilot project: on-the-ground implementation final report. York County Circuit Rider Alliance for the Chesapeake Bay. Nelson, J., Gotwalt, P., Snodgrass, J Swimming performance of blacknose dace mirrors home stream current velocity. Canadian Journal of Fisheries and Aquatic Sciences [serial online] 60: US Environmental Protection Agency, Watershed Assessment, Tracking & Results. Available from: Accessed 2014 May 1. Dace image: * * Swim Tunnel Test Oxygen Consumption Test Future Studies Determine specifically how an increase in salinity lowers oxygen consumption. Explore the effects different salt cations have on the blacknose dace. Investigate the impact salinity has on the development and feeding ability of the dace. After a 24 hour acclimation period, the fish were placed in 0.5 L containers with sealed lids. Fish remained in the containers for 2 hours. Oxygen was measured before addition of fish and after the fish were removed.