BEACHNET==> New Article: Sunlight, season, snowmelt, storm, and source affect E. coli populations in an artificially ponded stream (Dunes Creek)

[Richard L Whitman <rwhitman@usgs.gov>]

Sunlight, season, snowmelt, storm, and source affect
E. coli populations in an artificially ponded stream

Richard L. Whitman^{, 1, a,} , Katarzyna Przybyla-Kelly^a, Dawn A. Shively^a, Meredith B. Nevers^a and Muruleedhara N. Byappanahalli^a
aUnited States Geological Survey, Great Lakes Science Center, Lake Michigan Ecological Research Station, 1100 North Mineral Springs Road, Porter, Indiana, 46304, USA
Received 28 August 2007;  revised 14 September 2007;  accepted 11 October 2007.  Available online 26 November 2007.

Abstract

Reducing fecal indicator bacteria, such as Escherichia coli (E. coli), in streams is important for many downstream areas. E. coli concentrations within streams may be reduced by intervening ponds or wetlands through a number of physical and biological means. A section of Dunes Creek, a small coastal stream of southern Lake Michigan, was impounded and studied for 30 months from pre-through post-construction of the experimental pond. E. coli reduction became more predictable and effective with pond age. E. coli followed the hydrograph and increased several-fold during both rainfall and snowmelt events. Seasonally, the pond was more effective at reducing E. coli during summer than winter. Late summer, non-solar reduction or inactivation of E. coli in the pond was estimated at 72% and solar inactivation at 26%. E. coli DNA fingerprinting demonstrated that the winter population was genetically more homogeneous than the summer population. Detection of FRNA coliphages suggests that there was fecal contamination during heavy rain events. An understanding of how environmental factors interact with E. coli populations is important for assessing anticipated contaminant loading and the reduction of indicator bacteria in downstream reaches.

Keywords: Indicator bacteria; Sunlight reduction; Rainfall; Snowmelt; Remediation; Wetland

Corresponding author. Tel.:+1 219 926 8336x424; fax: +1 219 929 5792.
¹ R. Whitman and M. Byappanahalli contributed equally to this work.

Science of The Total Environment
Volume 390, Issues 2-3, 15 February 2008, Pages 448-455