title: Tidal fluctuations influence E. coli concentrations in urban estuaries.
abstract: This study investigated the influence of water level and velocity on Escherichia coli levels over multiple tidal cycles in an urban microtidal estuary in Melbourne, Australia. Over 3,500 E. coli samples and high resolution water level and velocity measurements from two locations within the estuary were used for the analysis. E. coli negatively correlated with water level in the upper estuary which was proposed to be linked to increased resuspension of estuarine sediments during low tide. No relationship was found in the lower estuary, likely due to wet weather inputs dwarfing subtler tidal-related processes. Removal of wet weather data enabled significant relationships to emerge in the lower estuary: 1) positive with water level (when a 9-h shift applied corresponding to the phase shift between water levels and velocities) and; 2) positive with velocity (no shift applied). This supports a link between increased E. coli levels and tidal-related resuspension.
authors.affiliation: Environmental and Public Health Microbiology (EPHM) Laboratory, Monash Infrastructure Institute, Department of Civil Engineering, Monash University, Clayton, Victoria 3800, Australia. Electronic address: dusan.jovanovic@monash.edu.
authors.forename: Dusan
authors.initials: D
authors.lastname: Jovanovic
authors.affiliation: Melbourne Water Corporation, Docklands, Victoria 3008, Australia. Electronic address: rhys.coleman@melbournewater.com.au.
authors.forename: Rhys
authors.initials: R
authors.lastname: Coleman
authors.affiliation: Environmental and Public Health Microbiology (EPHM) Laboratory, Monash Infrastructure Institute, Department of Civil Engineering, Monash University, Clayton, Victoria 3800, Australia. Electronic address: ana.deletic@monash.edu.
authors.forename: Ana
authors.initials: A
authors.lastname: Deletic
authors.affiliation: Environmental and Public Health Microbiology (EPHM) Laboratory, Monash Infrastructure Institute, Department of Civil Engineering, Monash University, Clayton, Victoria 3800, Australia. Electronic address: david.mccarthy@monash.edu.
authors.forename: David T
authors.initials: DT
authors.lastname: McCarthy
mesh_terms: D001315:Australia; D002947:Cities; D004784:Environmental Monitoring; D004926:Escherichia coli; D063366:Estuaries; D014872:Water Movements; D014887:Weather
keywords: Distribution; Flow velocity; Pathogens; Tidal currents; Tidal stage; Water level