Dynamic modeling analysis of oxygen transfer mechanism and water quality dynamics in recirculating aquaculture systems

Dissolved oxygen is an important indicator in intensive shrimp farming systems. This study aims to analyze the dynamics of oxygen transfer and identify water quality parameters that influence oxygen production levels in shrimp farming using the Recirculating Aquaculture System (RAS) with a dynamic system model approach. The study was conducted in six ponds in Pekalongan, Indonesia, during the RAS operational cycle. The water quality parameters observed were pH, temperature, dissolved oxygen (DO), and salinity, while oxygen transfer rates were analyzed using the standard oxygen transfer rate approach. Data analysis was carried out using statistical tests and dynamic system model analysis. The results showed that oxygen production levels in the RAS ponds ranged from 1.684 to 3.652 mg O₂/L/hour, with the highest value being 3.195 ± 0.15 mg O₂/L/hour (pond 2). Salinity had the strongest correlation with oxygen transfer rate (r = 0.857; p < 0.01), indicating its dominant influence on oxygen diffusion control through water viscosity and paddle aerator performance. PCA. Model simulation results indicated synchronization between paddle aerator rotation speed, water circulation hydrodynamics, and water quality, forming a positive feedback loop that increases the rate of oxygen diffusion in the pond. Conversely, reduced aeration leads to oxygen deficits and water quality fluctuations. Ecological engineering design, hydrodynamic optimization, and aeration management are fundamental factors in the operational cycle of RAS ponds.