Decoupled aquaponics facilitates the maintenance of optimal water quality parameters for both fish and plants through a unidirectional flow system. Periphytic organisms possess the ability to enhance nutrient cycling within the cultivation system and play a significant role in the absorption and transformation of toxic and accumulative compounds. This study aims to evaluate the impact of periphyton on the development and nutrient availability for vegetables cultivated in aquaponic systems by assessing five varieties of lettuce (Lactuca sativa) grown in an aquaponic system utilizing a periphyton-based biofilter.
The study assessed five varieties of lettuce: one curly lettuce (Gabriela), one red leaf lettuce (Pira roxa ), one Iceberg lettuce (Megan), one simple lettuce (Stela), and one frisée lettuce (Angélica), under two treatments with three replications each. The experimental design was completely randomized. In the AQ-M treatment, the nutrient solution was sourced from tilapia culture water in a recirculating aquaculture system (RAS) equipped with a moving bed biofilm reactor (MBBR) media biofilter. In contrast, the AQ-P treatment utilized a nutrient solution derived from tilapia grown in RAS with a periphyton-based biofilter (Figure 1) . The parameters evaluated included leaf length, SPAD index, total weight, shoot weight, shoot dry mass, and number of leaves. The periphyton contributed to fish productivity.
The plants in the AQ-P treatment demonstrated superior development outcomes and enhanced micronutrient absorption due to the presence of periphyton. At the end of the 31-day cultivation period, the periphyton increased micronutrient levels in the plants of the AQ-P treatment. This improvement was attributed to nutrient cycling facilitated by the periphytic organisms within the system. Therefore, it can be concluded that the integration of periphyton in aquaponic systems enhances plant performance and micronutrient content, thereby allowing for the replacement of traditional biological filters with substrates conducive to periphyton growth.
Keywords: nutrient cycling; vegetables; periphytic organisms; sustainability.
Acknowledgements: CNPq Processo 406411/2022-0; FAPESP Processo 2024/00010-0