Publication Abstract

Understanding microbial involvement in greenhouse gas (GHG) emissions in prawn farms is essential for proposing climate-friendly solutions, yet is hitherto unexplored. To demonstrate microbial-GHG association, CO2, CH4, and N2O emissions were examined, microbial assemblages were characterized, and the abundances of functional genes in water and sediment of prawn farms were determined. Our data show that CO2 and CH4 fluxes correlated strongly with salinity levels but only CO2 emissions were significantly influenced by culture systems and patterns. We observed that the microbial richness correlated positively with CO2 and N2O emissions but negatively with CH4 emissions. In sediments, methanogenic archaea were relatively most abundant in high-salinity farms but their general role in CO2 consumption appeared insignificant. Conversely, the observed negligible role of Anaerobic methanotrophs (ANME) in CO2 production and significant association with methane breakdown suggest ANME-conducive methane oxidation as a promising approach to reducing the C-footprint of prawns. Consumption of N2O was linked to the most bacterial and archaeal classes identified but surprisingly, N2O-consuming Chloroflexi correlated strongly with N2O emission. Our findings reveal a strong correlation between the mcrA gene present in water and methane production, suggesting possible aerobic functions of the gene beyond its known role in anaerobic methane production. The abundance of pmoA and amoA genes showed significant positive correlations with methane breakdown while the nosZ gene when present in anaerobic conditions was significantly associated with N2O breakdown. Advancing our understanding, this multidisciplinary effort opens a gateway for further investigations to reduce emissions by modulating microbial communities in prawn farms.

Abul Bashar, Amaru Miranda Djurhuus, Patrick Denis Browne, Raju Podduturi, Md. Zahid Hasan, Abdullah Al Rakib, Chantelle Hooper*, Morena Santi*, H. M. Rakibul Islam, Neaz Al Hasan, Muhammad Tofazzal Hossain, M.M.R. Jahangir, David Bass*, Md Ismail Hossain, Niels O. G. Jørgensen, Lars Hestbjerg Hansen, Mohammad Mahfujul Haque