Carbon dioxide and methane fluxes from feeding and no-feeding mariculture ponds

The CO2 and CH4 fluxes at the water-air interface were measured in shrimp (Marsupenaeus japonicus) monoculture ponds (S) with feed supply and shrimp-sea cucumber (Apostichopus japonicus) polyculture ponds (SS) without feed supply. During farming seasons of the whole year, cumulated CO2-C fluxes were −5.69 g m−2 (S) and 11.23 g m−2 (SS), respectively. The cumulated CO2 emissions from S and SS did not differ significantly. The cumulated CH4-C emissions from S (0.57 g m−2) were significantly higher than those from SS (0.068 g m−2). S absorbed C from the atmosphere with a mean absorption rate of −5.12 g m−2, whereas SS emitted C to the atmosphere with a mean emission rate of 11.30 g m−2. Over 20-year horizon, the compressive global warming potentials (cGWPs) were 33.55 (S) and 47.71 (SS), respectively, indicating both feeding and no-feeding mariculture ponds could promote global warming.