Greenhouse gas emission flux (CO2, CH4, N2O) from marine shrimp (Litopenaeus vannamei) monoculture cultures in the Brazilian semi-arid region

Abstract

Greenhouse gases (GHG) and their rising atmospheric concentrations have been one of the most important international subjects due to their huge impact on climate change (IPCC, 2022). Aquaculture is of crucial importance to the human food supply and nutrition since it is one of the major sectors providing animal protein, besides reducing the pressure on the fishery stocks from natural resources worldwide (Cai, Zhou, 2019; FAO, 2022). On the other hand, it represents a threat to the environment by generating waste. Thus, this research aims to evaluate the GHG flux dynamics in marine shrimp (Litopenaeus vannamei) monoculture cultures. The study was carried out in two aquaculture farms, both located in the Brazilian semi-arid region. In order to measure the production of greenhouse gases, three cultures of marine shrimp were monitored. The dynamics of the diffusive and ebullitive emission of CO2, CH4, and N2O were monitored in the three units during the daytime (6:00 AM) and nighttime (6:00 PM). The results showed the stocking density as the main regulator for ebullitive CO2 emissions. A decreasing trend in diffusive CO2 emissions was observed. Aeration played a crucial role in controlling the diffusive and ebullitive emissions of CH4 and N2O, effectively reducing their release. The diffusive CH4 emissions exceeded ebullitive emissions and the oxygen content suppressed the anoxic pathway for N2O, and the ponds acted as a sink for this gas. This research aims to evaluate the dynamics of greenhouse gas flow in marine shrimp (Litopenaeus vannamei) monoculture cultures in the Brazilian semi-arid region and to verify whether lower stocking densities emit less greenhouse gases when compared to higher densities.