 My name is Ryan Burroughs, and today I'll be talking to you about how the presence of natural gas macrocebes affects a river system. While much attention is focused on quantifying the fluxes of methane to the atmosphere, there has been much less focus on the direct biological ramifications of elevated methane in aquatic environments. Here we investigate how the presence of three natural gas macrocebes along the Condomine River, which increased methane concentrations by more than 3,000 times, affects the river system. The key question we asked was, how do natural gas macrocebes alter the rates of sediment and watercolour methane oxidation? And how does a microbial community abundance and composition vary in relation to these macrocebes? Our study site, the Condomine River, is located in eastern Australia, and we characterize the total microbial community and methanotrophic community composition of benthic sediment using DNA isolated from sediment cores. We quantified the rates of methane oxidation using a mass balance approach. There was a significant increase in the mean relative abundance of methanotrophes in the total bacterial community at the seep sites compared to upriver reference sites. The methanotrophic communities across all samples were dominated by type 1b and type 2 methanotrophes, particularly sequences of Enclade 501 and Methylocystis. Rates of sediment methane oxidation were on average 29 times greater at the seep sites compared to upriver reference sites, and we saw a similar pattern for rates of methane oxidation in the water column. Methane concentration of the water column dissolved oxygen and discharge were all important factors driving the variation we observed in rates of methane oxidation. In summary, rates of sediment methane oxidation and the methanotrophic abundance were greater at seep sites, and while most methane abates the atmosphere at 1200 liters per minute, only a small proportion of Isabella methane was oxidized by methanotrophs. But methane may still be a prominent energy source in this aquatic ecosystem because the rates of methane oxidation were very high when compared to studies elsewhere. Therefore, research should quantify the contribution of methane derived carbon into the aquatic food web. Thank you very much.