Governments and water management agencies have invested many millions of dollars into the management of Australia’s water resources; diverse activities ranging from water buy-back schemes through to construction of major infrastructure and water delivery systems. While consumptive use dominates water needs, the aim also that water can be released in such a way that riverine ecosystems either are maintained or benefit from the ‘environmental water’. eFlows research is a reasonably new field of study, but a clear need exists for reliable and cost effective approaches to monitor responses of riverine biota. Methods must be useful at river reach scales (kms), but also reflect functions occurring at micro scales.
Despite a body of evidence to the contrary, microbes should represent a major path of the pathway moving carbon into foodwebs. Our team has used a range of approaches that measure microbial function and community structure responses to eflows and floods. Broad-scale physical measures demonstrate floods supply large amounts of available carbon that is rapidly respired by microbes; overall status of rivers shifts from autotrophic to heterotrophic. Using measures of stable isotope natural abundance, we have shown that this carbon is rapidly assimilated by microbial communities and transferred into higher food webs. 454 pyrosequencing approaches showed prokaryote and eukaryote community structure responds to the flood water, but the community structure responses were not always predictable.