The Impact of Hurricane Sandy on the Abundance of Coliforms in Tyler Run Michelle Greaver Department of Biological Sciences, York College of Pennsylvania Introduction Ecosystems disturbed by hurricanes have been able to recover from their effects; however, human development over the past century may be complicating the impacts of hurricanes on water quality (Mallin et al. 2002). Stormwater is the greatest source of pollution affecting freshwater systems (Mallin et. al, 2009). Nutrient-loading and increased levels of fecal coliforms are two ways that stormwater contributes to diminishing water quality (Mallin et al. 2002). Fecal coliforms are found in the intestines of warm-blooded animals. These organisms are often used as indicators of water quality because they are associated with the same sources as dangerous pathogens such as viruses, bacteria and protozoa. In addition to coliform bacteria, surges of nutrients in receiving waters are associated with increased stormwater runoff and flooding caused by hurricanes. High nutrient levels decrease water quality and can produce negative effects such as eutrophication in aquatic ecosystems (Zhang et al. 2009). Objectives Primary Objectives : Compare the number of coliforms and E. coli present in Tyler Run before and after Hurricane Sandy to determine if the total number of coliforms increased. Compare nitrogen and phosphorus levels in Tyler Run before and after Hurricane Sandy to determine if nutrient loading occurred. Secondary Objective: Determine if the surrounding landscape affected the number of coliforms present at specific locations in Tyler Run. Hypotheses The number of coliforms and E. coli will increase significantly after Hurricane Sandy. Nitrogen and phosphorus levels will increase significantly after Hurricane Sandy. Coliforms will be present in smaller numbers in locations with greater vegetation in comparison to areas surrounded by open fields or pavement. Methods Two samples were collected from six different sites before the occurrence of Hurricane Sandy Samples were evaluated for levels of N and P using an electrophotometer Samples were evaluated for total coliforms as well as E.coli using the membrane filtration technique Samples were evaluated for total coliform presence using the most probable number technique Two samples were collected from each of the same six sites after Hurricane Sandy and evaluated using the above three techniques. Before and after samples were then compared using statistical analysis. Results Figure 1. Mean (and SEM) of coliform numbers present in Tyler Run before and after Hurricane Sandy using the membrane filtration technique. N=6. A p-value of was obtained by performing a paired t-test. This value indicates that the number of coliforms was not significantly different before and after Hurricane Sandy. Figure 2. Mean (and SEM) of coliform numbers present in Tyler Run before and after Hurricane Sandy using the most probable number technique. N=6. A p-value of was obtained by performing a paired t-test. This value indicates that the number of coliforms was significantly greater after Hurricane Sandy. Figure 3. Mean (and SEM) of E. coli numbers present in Tyler Run before and after Hurricane Sandy using the membrane filtration technique. N=6. A p-value of < was obtained by performing a paired t-test. This value indicates that the number of E. coli was significantly greater after Hurricane Sandy. Figure 4. Mean (and SEM) of nitrogen and phosphorus levels present in Tyler Run before and after Hurricane Sandy through the use of an electrophotometer. N=6. A p-value of was obtained when comparing phosphorus levels by performing a paired t-test. This value indicates that the levels of phosphorus were significantly greater after Hurricane Sandy. A p-value of was obtained when comparing nitrogen levels by performing a paired t-test. This value indicates that the levels of nitrogen were not significantly different before and after Hurricane Sandy. Conclusions The difference between the number of coliforms present in Tyler Run before and after Hurricane Sandy was not statistically different according to the membrane filtration technique. Using the most probable number technique it was found that the number of coliforms present after Hurricane Sandy was significantly greater than the number present before. The number of E. coli present after the hurricane was significantly greater than before. Statistical analysis of the nutrient levels before and after the hurricane showed that phosphorus was significantly greater after the hurricane but that there was no statistical difference between the levels of nitrogen. Analysis of variations in the number of coliforms between sites revealed that there was not a significant difference between the various locations. Future Studies In a future study it would be advantageous to collect larger sample sizes from each location. Additionally, this idea could be applied to larger waterways or even entire river systems in order to get a more comprehensive view of how hurricanes and stormwater runoff affect water quality on a larger scale. Acknowledgements I would like to thank Dr. Mathur for helping me come up with the idea for this study and for helping me design the experiment. I would also like to thank Dr. Rehnberg for his guidance and advice and Dr. Hagerty for all of her help with the statistical analyses. Literature Cited Mallin, M.A, Johnson, V.L. and Ensign, S.H Comparative impacts of stormwater runoff on water quality of an urban, a suburban and a rural stream. Environmental Monitoring and Assessment 159: Mallin, M.A., Posey, M.H., McIver, M.R., Parsons, D.C., Ensign, S.H., and Alphin, T.D Impacts and recovery from multiple hurricanes in a piedmont-coastal plain river system. Bioscience 52: Zhang, Q., Brady, D.C., Ball, W.P Long-term seasonal trends of nitrogen, phosphorus, and suspended sediment load from the non-tidal Susquehanna River Basin to Chesapeake Bay. Science of the Total Environment 453: