title: Multiple approaches to microbial source tracking in tropical northern Australia.
abstract: Microbial source tracking is an area of research in which multiple approaches are used to identify the sources of elevated bacterial concentrations in recreational lakes and beaches. At our study location in Darwin, northern Australia, water quality in the harbor is generally good, however dry-season beach closures due to elevated Escherichia coli and enterococci counts are a cause for concern. The sources of these high bacteria counts are currently unknown. To address this, we sampled sewage outfalls, other potential inputs, such as urban rivers and drains, and surrounding beaches, and used genetic fingerprints from E. coli and enterococci communities, fecal markers and 454 pyrosequencing to track contamination sources. A sewage effluent outfall (Larrakeyah discharge) was a source of bacteria, including fecal bacteria that impacted nearby beaches. Two other treated effluent discharges did not appear to influence sites other than those directly adjacent. Several beaches contained fecal indicator bacteria that likely originated from urban rivers and creeks within the catchment. Generally, connectivity between the sites was observed within distinct geographical locations and it appeared that most of the bacterial contamination on Darwin beaches was confined to local sources.
authors.affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Neave
authors.forename: Heidi
authors.initials: H
authors.lastname: Luter
authors.forename: Anna
authors.initials: A
authors.lastname: Padovan
authors.forename: Simon
authors.initials: S
authors.lastname: Townsend
authors.forename: Xavier
authors.initials: X
authors.lastname: Schobben
authors.forename: Karen
authors.initials: K
authors.lastname: Gibb
mesh_terms: D001315:Australia; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D060106:Lakes / Q000382:microbiology*; D008969:Molecular Sequence Data; D045483:Rivers / Q000382:microbiology*; D014329:Tropical Climate
keywords: 454 Pyrosequencing; Australia; DGGE; bacteria; fecal; sewage; tracking; tropical