Shrimp mariculture may increase aquatic CO2, CH4, and N2O emissions in semi-indoor and indoor ponds

Abstract

This study revealed the greenhouse gas (GHG) emission patterns during shrimp mariculture in both semi-indoor and indoor ponds. In the semi-indoor ponds, the average carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) concentrations of pond water varied from 1373.0 f 721.7 mu atm, 4.4 f 1.3 nM, and 14.2 f 3.5 nM, respectively, at the initiation of stocking to 5296.0 f 1474.7 mu atm, 3.8 f 0.3 nM, and 28.1 f 17.9 nM, respectively, in the harvest stage. In the indoor pond, these varied from 562 mu atm, 3.5 f 0.2 nM, and 10.7 f 0.1 nM, respectively, at the initiation of stocking to 4728.0 mu atm, 18.2 f 0.7 nM, and 94.1 f 0.6 nM, respectively, in the harvest stage. An upward trend in COQ and NQO concentrations was observed in the water of both semi-indoor and indoor ponds as the culture period progressed. The discharged waters exhibited the highest GHG concentrations, potentially acting as emission hotspots if left untreated. The total average COQ-equivalent (COQ-eq) fluxes from pond water during the shrimp mariculture period were 49.8 f 40.7 mg COQ-eq m _ 2 h _ 1 in the semi- indoor ponds, with 44 % of these GHG emissions attributable to shrimp mariculture practices. In the indoor pond, the fluxes were 101.5 f 52.6 mg COQ-eq m _ 2 h _ 1 , with 86 % of the GHG emissions attributable to shrimp mariculture practices. According to these results, shading effects may increase the GHG emissions from aqua- culture pond waters.