Characteristics and influencing factors of greenhouse gas emissions from tidal flat pond aquaculture

Greenhouse gas (GHG) emissions from aquaculture have garnered global attention. Tidal flat pond aquaculture, as a major utilization of tidal flat resources, remains understudied regarding its characteristics and the factors influencing GHG emissions. Takifugu fasciatus is an important high-value species in Chinese tidal flat aquaculture. During a 180-day study, GHG emissions from the water-gas interface of T. fasciatus aquaculture ponds were measured by static floating chamber-gas chromatography. The average fluxes for CO 2 , CH 4 , and N 2 O were respectively 34.6 ± 31.2 mg/(m 2 ·h), 1.3 ± 1.4 mg/(m 2 ·h), and 0.022 ± 0.039 mg/(m 2 ·h). By monitoring water quality and meteorological factors, we conducted correlation analyses and discovered that Chla and total ammoniacal nitrogen (TAN) were the primary environmental drivers of GHG emissions, with a positive association to CO 2 , CH 4 , and N 2 O emissions. In the correlation analyses, 16S rDNA sequencing of pond sediment microorganisms showed that Proteobacteria and Desulfococcus stand as the primary contributors to CO 2 emissions, while Proteobacteria and Synechococcaceae were found to be the main contributors to CH 4 emissions. Actinobacteria was the main contributor to N 2 O emissions. The comparison results showed that tidal flat pond aquaculture produced less GHG emissions than inland freshwater pond aquaculture. These findings provide statistical support for evaluating the tidal flat aquaculture ecosystems’ greenhouse effect and designing targeted emission reduction strategies.