Broadening the Targets for Microbial Water Quality

Bacterial community composition can change as a result of increased nutrient loads and may be useful for assessing ecosystem health in estuaries. However, the ability to understand how bacterial communities respond to increased nutrient concentrations is limited by the paucity of community level bacterial base data, in particular for tropical estuaries. Our aim was to describe and compare the bacterial community in the water column and sediments across tropical tidal creeks in Darwin Harbour (NT). The authors assessed the relationship between communities and increased nutrient loads, comparing sites with sewage effluent inputs to control sites. In this tropical estuary, bacterial species richness and diversity in water increased with increased nutrient load. This result suggests that there is an untapped resource of bacteria that should be explored as potential water quality indicators for receiving environments. The authors’ work has shown that taxa such as Aeromonas, Azomonas and various cyanobacteria have potential as water quality indicators, not just for public health but also as measures of ecosystem health.