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Distribution of Gull Specific Molecular Marker in Coastal Areas of Lake Ontario
Citation:
RYU, H., J. W. SANTO-DOMINGO, J. LU, M. E. SCHOEN, N. ASHBOLT, T. Edge, AND S. Hill. Distribution of Gull Specific Molecular Marker in Coastal Areas of Lake Ontario. Presented at American Society for Microbiology 110th General Meeting, San Diego, CA, May 23 - 27, 2010.
Impact/Purpose:
To inform the public.
Description:
Gulls have been implicated as primary sources of fecal contamination in the Great Lakes, a fact that may have health implications due to the potential spread of microbial pathogens by waterfowl. To better understand the spatial variability of gull fecal contamination, a gull-specific fecal PCR assay was challenged against approximately 1350 samples collected in 15 coastal locations of Lake Ontario during Spring and Summer of 2007. Quantitative PCR assays were also conducted to determine the relative abundance of gull fecal contamination. Overall, 71% of the samples were positive for the conventional gull PCR assay. Logistic analysis for the water DNA extracts showing positive signals indicated significant associations with general locations (p=0.0002) and with sublocations (p<0.001). Multiple comparisons of PCR signals among locations showed that sites with known history of gull contaminations (i.e., beaches; p=0.03) were significantly different from locations with low gull fecal impacts (river or sewage final effluent). The relative abundance of positive PCR signals showed a significant positive correlation with locations with higher levels of gull fecal impacts (p=0.01). Direct comparison between data subsets indicated that there were significant differences in positive PCR signals between low vs. high (p=0.02) and moderate vs. high (p=0.015) locations, although differences between locations with low and moderate fecal impacts were not statistically significant. Significant temporal association (p<0.001) of the relative abundance of positive PCR signals was also revealed in a few specific locations. Overall, the results from this study further demonstrate that gull fecal pollution is widespread in the areas under study. Additionally, the data suggests that the relative abundance of gull specific molecular markers provides relevant information for identifying areas in which waterfowl are the primary sources of fecal pollution.
