Environmental parameters and microbial community profiles as indication towards microbial activities and diversity in aquaponic system compartments

Zala Schmautz,Carlos A Espinal,Ranka Junge,Theo H M Smits,Fabio Rezzonico,Emmanuel Frossard,Andrea M Bohny

doi:10.1186/s12866-020-02075-0

Zala Schmautz, Carlos A Espinal + Show 5 more

Open Access

https://doi.org/10.1186/s12866-020-02075-0

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Abstract

BackgroundAn aquaponic system couples cultivation of plants and fish in the same aqueous medium. The system consists of interconnected compartments for fish rearing and plant production, as well as for water filtration, with all compartments hosting diverse microbial communities, which interact within the system. Due to the design, function and operation mode of the individual compartments, each of them exhibits unique biotic and abiotic conditions. Elucidating how these conditions shape microbial communities is useful in understanding how these compartments may affect the quality of the water, in which plants and fish are cultured.ResultsWe investigated the possible relationships between microbial communities from biofilms and water quality parameters in different compartments of the aquaponic system. Biofilm samples were analyzed by total community profiling for bacterial and archaeal communities. The results implied that the oxygen levels could largely explain the main differences in abiotic parameters and microbial communities in each compartment of the system. Aerobic system compartments are highly biodiverse and work mostly as a nitrifying biofilter, whereas biofilms in the anaerobic compartments contain a less diverse community. Finally, the part of the system connecting the aerobic and anaerobic processes showed common conditions where both aerobic and anaerobic processes were observed.ConclusionDifferent predicted microbial activities for each compartment were found to be supported by the abiotic parameters, of which the oxygen saturation, total organic carbon and total nitrogen differentiated clearly between samples from the main aerobic loop and the anaerobic compartments. The latter was also confirmed using microbial community profile analysis.

Highlights

An aquaponic system couples cultivation of plants and fish in the same aqueous medium
In an aquaponic system, which is a combination of recirculating aquaculture system and hydroponics, Schmautz et al BMC Microbiology (2021) 21:12 microbial communities and their metabolic products play a vital role in various molecular processes
At the time of both samplings, in September 2018 (Table 2), all three systems showed a steady performance based on the water quality measurements (Table 3)

Summary

Introduction

An aquaponic system couples cultivation of plants and fish in the same aqueous medium. Function and operation mode of the individual compartments, each of them exhibits unique biotic and abiotic conditions Elucidating how these conditions shape microbial communities is useful in understanding how these compartments may affect the quality of the water, in which plants and fish are cultured. In an aquaponic system, which is a combination of recirculating aquaculture system and hydroponics, Schmautz et al BMC Microbiology (2021) 21:12 microbial communities and their metabolic products play a vital role in various molecular processes These processes include the transformation of nitrogenous compounds, the consumption of organic matter, the mineralization of complex organic molecules [4], the consumption of dissolved oxygen, the production of carbon dioxide, the consumption and replenishment of water alkalinity [5]. The ability of the C-pool to bind nutrients can affect primary production in an aquatic environment [20] as specific microbial populations can utilize both organic C and inorganic C through heterotrophic, chemoautotrophic, and photoautotrophic pathways under aerobic, anaerobic, and anoxic conditions [5]

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