Embedded Electronic System for Monitoring the Dynamic CO₂ Concentration in Excavated Aquaculture Ponds

Brazilian aquaculture, particularly fish farming, has shown remarkable growth over the past decade, becoming one of the fastest-expanding sectors in animal production. This study presents the development and validation of an electronic system and a methodology designed to estimate carbon dioxide (CO₂) concentration in excavated fishponds, aiming to enhance understanding of the carbon footprint in aquaculture. The proposed system, composed of small-scale greenhouses equipped with ESP32 microcontrollers and CO₂ and temperature sensors, was tested in fishponds located in western Paraná, Brazil. Correlations between temperature and CO₂ concentration were analyzed under different weather conditions—clear sky, cloudy, and nighttime periods. Results indicated a significant negative correlation between temperature and CO₂ concentration outside the greenhouses, suggesting that daytime heating reduces ambient CO₂ levels. In contrast, internal concentrations within the greenhouses remained relatively stable, averaging 400 ppm on clear days and 416 ppm on cloudy days. During the nighttime, average CO₂ concentrations reached 588 ppm outside and 416.8 ppm inside the greenhouse. These findings highlight the temporal and climatic variability of CO₂ levels in aquaculture environments and reinforce the importance of accurate monitoring systems for assessing the carbon footprint in excavated pond systems.