Fourteen juvenile scalloped hammerhead sharks ( Sphyrna lewini ; SHS) were captured between November and December 2014 in the Rewa Delta in Fiji, and assessed for intestinal microflora characterisation using 16S rRNA amplicon sequencing by Illumina Miseq. The microbial population revealed a fluctuating dominance between the Enterobacteriaceae and Vibrionaceae families, namely Citrobacter and Photobacterium spp. Other related marine operational taxonomic units were closely related to Afipia felis , Chloroflexus aggregans , Psychrobacter oceani , Pontibacter actiniarum and Shigella sonnei . Two sharks had distinctive profiles that were dominated by known pathogens, namely Aeromonas salmonicida and Klebsiella pneumonia . The presence of a Methanosaeta species, and of Shigella and Psychrobacter , would suggest sewage contamination because of a spill that occurred on the 6 th of December 2014. This study successfully establishes a baseline for future research.

Anaerobic propionic acid degradation relies on interspecies electron transfer (IET) between propionate oxidisers and electron acceptor microorganisms, via either molecular hydrogen, formate or direct transfers. We evaluated the possibility of stimulating direct IET, hence enhancing propionate oxidation, by increasing availability of proton carriers to decrease solution resistance and reduce pH gradients. Phosphate was used as a proton carrying anion, and chloride as control ion together with potassium as counter ion. Propionic acid consumption in anaerobic granules was assessed in a square factorial design with ratios (1:0, 2:1, 1:1, 1:2 and 0:1) of total phosphate (TP) to Cl−, at 1X, 10X, and 30X native conductivity (1.5 mS.cm−1). Maximum specific uptake rate, half saturation, and time delay were estimated using model-based analysis. Community profiles were analysed by fluorescent in situ hybridisation and 16S rRNA gene pyrosequencing. The strongest performance was at balanced (1:1) ratios at 10X conductivity where presumptive propionate oxidisers namely Syntrophobacter and Candidatus Cloacamonas were more abundant. There was a shift from Methanobacteriales at high phosphate, to Methanosaeta at low TP:Cl ratios and low conductivity. A lack of response to TP, and low percentage of presumptive electroactive organisms suggested that DIET was not favoured under the current experimental conditions.

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The Standards for water quality in Fiji defined in the Environment Management Regulations (2007) only relate to effluent discharge into the environment. Urbanisation is contributing to wastewater contamination in receiving estuary and marine recreational waters, thus requiring specific guidelines. To create a baseline for this, a sampling programme with relevant physico-chemical and biological parameters was implemented at 3 sites along the Suva foreshore, for 8 consecutive months, during low and high tides. Analysis was done in triplicates, using standard methods approved for the examination of water and wastewater. In the absence of relevant Fiji guidelines, the results were compared with ANZECC (2000) guidelines for estuary and marine waters. Low DO levels, high COD, TN, NH3, TP, OP and heavy metal concentrations were measured in all 3 sites. For instance, TN and NH3 concentrations as high as 4.44 ±0.99 mg/L and 2.58 ± 0.89 mg/L respectively were recorded in Wailea river (Site 2). The colony counts for the TC, FC and E. coli were in most cases above the limits. These results confirm that wastewater discharges add to the inherent levels of parameters in receiving water bodies and support the need for a specific, robust Fiji standards to better monitor water quality in foreshore areas.