The curious diet of deep sea archaea

Hydrocarbon gas seeps on the ocean floor release several alkane gases, amongst these is ethane. This gas can contribute to the greenhouse effect but only a small proportion released reaches the atmosphere due to consumption by microorganisms. Little is understood about the deep sea microorganisms which catalyse the breakdown and consumption of this gas or how by the process of anaerobic oxidation this reaction occurs.

Chen et al. (2019) conducted a 10-year study to investigate the microorganisms capable of processing and consuming ethane. In doing so, a vast array of molecular analysis was used (including CARD-FISH and nanoSIMS) to determine the species responsible for the process. They discovered and identified a new species of anaerobic methanotrophic archaea which they called Candidatus Argoarchaeum ethanivorans. This archaea species works in a syntrophic relationship with sulphate reducing Deltaproteobacteria to consume the ethane.

In this study, they did not culture the archaea which proved the ability to study in-depth microbes without the need to culture them. Additionally, this study echoes the importance of understanding the processes of the deep ocean as these microbes reduce the potential effect of this greenhouse gas which can become an asset to use in the future.

Chen, S.C., Musat, N., Lechtenfeld, O.J., Paschke, H., Schmidt, M., Said, N., Popp, D., Calabrese, F., Stryhanyuk, H., Jaekel, U. and Zhu, Y.G. (2019). Anaerobic oxidation of ethane by archaea from a marine hydrocarbon seep. Nature, 568(7750), 108.