Biochemical transformations of nitrogen compounds in the integrated multi–trophic aquaculture the using media filled beds in plant cultivation

Abstract

Quantitative and qualitative transformations of nitrogen compounds in the Integrated Multi-Trophic Aquaculture (IMTA) system using the Media Filled Beds (MFB) method in plant cultivation was investigated experimentally. Three fish tanks were populated with 200 individuals of common carp (Cyprinus carpio L.) in each. The experiment lasted over three months. The following parameters were determined on the weekly basis: ammonium nitrogen, nitrate (III) nitrogen, nitrate (V) nitrogen, total nitrogen, mineral nitrogen, organic nitrogen and dissolved oxygen, according to commonly adopted methods. Water samples for the analyses were taken directly from the fish tanks and locations directly after each type of filtration (mechanical, biological and hydroponic). The presence of all determined forms of nitrogen was established including the mineral nitrogen which concentration remained at levels sufficient for a normal growth and development of plants. Active nitrification process was detected. Loss of nitrogen from the system was not only due to absorption by plants. Initiation of the anaerobic ammonia oxidation (anammox) and denitrification processes was observed.