Nitrous Oxide (N2O) Emission from Aquaculture: A Review

Nitrous oxide (N2O) is an important greenhouse gas (GHG) which has a global warming potential 310 times that of carbon dioxide (CO2) over a hundred year lifespan. N2O is generated during microbial nitrification and denitrification, which are common in aquaculture systems. To date, few studies have been conducted to quantify N2O emission from aquaculture. Additionally, very little is known with respect to the microbial pathways through which N2O is formed in aquaculture systems. This review suggests that aquaculture can be an important anthropogenic source of N2O emission. The global N2O-N emission from aquaculture in 2009 is estimated to be 9.30 X 10(10) g, and will increase to 3.83 x 10(11) g which could account for 5.72% of anthropogenic N2O-N emission by 2030 if the aquaculture industry continues to increase at the present annual growth rate (about 7.10%). The possible mechanisms and various factors affecting N2O production are summarized, and two possible methods to minimize N2O emission, namely aquaponic and biofloc technology aquaculture, are also discussed. The paper concludes with future research directions.