Multiple approaches to microbial source tracking in tropical northern Australia.
Bottom Line: 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.Two other treated effluent discharges did not appear to influence sites other than those directly adjacent.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.
Affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia.Show MeSH
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Mentions: To more closely examine connections between sites (Figs. 6 and 7; Table 3), a network was drawn that contained only OTUs shared between outfalls and beaches (Fig. 8). Many of the most abundant shared OTUs are typically associated with sewage, such as Clostridiales, Streptococcus, Peptostreptococcaceae, Aeromonas, Enterobacter, and Haemophilus (Scott et al. 2005; McQuaig et al. 2012; McLellan et al. 2013; Newton et al. 2013; Shanks et al., 2013). Again, the Larrakeyah discharge (site 27) appeared to contribute bacteria to surrounding beaches (sites 28 and 29). Similar to the SourceTracker results, Rapid Creek Beach (site 4) contained potential fecal OTUs, and again several sites near Mindil Beach (sites 16, 20 and 23) were linked to fecal OTUs.
Affiliation: Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, Northern Territory, Australia.