Influence of eco-substrate addition on organic carbon, nitrogen and phosphorus budgets of intensive aquaculture ponds of the Pearl River, China

Abstract

Eco-substrates were developed to control pollution created in pond-based intensive aquaculture. In this study, organic carbon, nitrogen, and phosphorus budgets and concentrations were quantified to determine if restoring eco-substrate is an effective method to reverse the effects of pollution. The experiment was performed in 1.0 hm2 ponds with and without the addition of eco-substrate, i.e. treatment and control groups, respectively. Results showed that eco-substrate significantly reduced ammonia nitrogen, nitrate nitrogen, total organic carbon, total nitrogen, and total phosphorus in the water of intensive aquaculture ponds (P < .05). The water accumulation of organic carbon, nitrogen, and phosphorus in the treatment group was significantly lower than that in the control group water (P < .05), as was the sediment accumulation of organic carbon and nitrogen (P < .05); no significant difference was found in the sediment accumulation of phosphorus (P > .05). The utilization efficiency of organic carbon, nitrogen, and phosphorus of the eco-substrate group was significantly higher than that of the control group (P < .05). Therefore, eco-substrate could significantly improve water quality, reduce nutrient accumulation, and improve the utilization efficiency of nutrients. Nonetheless, China's large aquaculture industry emits 4.19 × 105 tons of organic carbon, 2.79 × 105 tons of nitrogen, and 2.89 × 104 tons of phosphorus annually. Thus, additional studies are necessary to improve treatment methods for large-scale aquaculture effluents.