Exploring bacterial communities in diversified aquaponic systems

In 2030, the world’s population should reach 8.3 billion people. It is thus necessary to find intensive yet sustainable food production methods to feed this growing population and aquaponics could contribute to it.. Aquaponics is defined as a combination of hydroponic and aquaculture techniques and seems to be a promising technology to meet this resilience. It functions with plants, fish and microorganisms which play a key role in nitrification and mineralisation of fish wastes into nutrients absorbable by plants. Herein we aim at characterising the bacteria present in diversified systems to better understand the composition and role of their communities in aquaponics. To this end, nine diversified aquaponic systems were sampled. The DNA from each bacteria community was extracted and sequenced with Illumina MiSeq technology by targeting the V1-V3 16S rDNA region. The sequences were then analysed with the QIIME bioinformatic software. Results show that Proteobacteria and Bacteroidetes are the dominant phyla for all the aquaponic systems. Depending on each system, different proportions of other phyla are also present among the bacterial community. The genera which compose all the identified phyla are more diverse and an important proportion of them are usually found in soils and rhizosphere. One of the roles that could be linked to these genera is the breaking down of complex organic compounds which could be related to the mineralisation phenomenon observed in aquaponic systems. Further studies should be undertaken to identify the exact species present in aquaponic systems and to understand their specific functions.